November 2013

Evaluation of Early Performance 

Results for Massachusetts 

Homes in the National Grid Pilot 

Deep Energy Retrofit Program

C. Gates and K. Neuhauser 

Building Science Corporation
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iii

Evaluation of Early Performance Results for Massachusetts Homes in 

the National Grid Pilot Deep Energy Retrofit Program

Prepared for:

The National Renewable Energy Laboratory

On behalf of the U.S. Department of Energy’s Building America Program 

Office of Energy Efficiency and Renewable Energy

15013 Denver West Parkway 

Golden, CO 80401 

NREL Contract No. DE-AC36-08GO28308 

Prepared by: 

C. Gates and K. Neuhauser 

Building Science Corporation 

30 Forest Street 

Somerville, MA 02143 

NREL Technical Monitor: Cheryn Metzger

Prepared under Subcontract No. KNDJ-0-40337-02 

November 2013 
iv

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v 

Contents

List of Figures ............................................................................................................................................ vi

List of Tables ............................................................................................................................................. vii

Definitions ................................................................................................................................................. viii

Executive Summary................................................................................................................................... ix

1 Introduction ........................................................................................................................................... 1

2 Background ........................................................................................................................................... 3

3 The National Grid Deep Energy Retrofit Pilot.................................................................................... 5

3.1 Measures and Targets ...................................................................................................................... 5

3.2 The Community of Retrofits............................................................................................................ 7

4 Analysis ............................................................................................................................................... 11

4.1 Airtightness Results and Analysis ................................................................................................. 11

4.1.1 Airtightness Test Results.................................................................................................. 13

4.1.2 Normalization of Airtightness Test Results...................................................................... 15

4.1.3 Analysis of Airtightness Results....................................................................................... 19

4.1.4 Other Airtightness Analysis.............................................................................................. 27

4.1.5 Conclusions of Airtightness Analysis............................................................................... 27

4.2 Energy Use Results and Analysis.................................................................................................. 27

4.2.1 Energy Use Data ............................................................................................................... 28

4.2.2 Normalization and Benchmarking of Energy Use Data.................................................... 35

4.2.3 Analysis of Energy Use Data............................................................................................ 40

4.2.4 Analysis of Energy Use “Outliers” ................................................................................... 52

4.2.5 Conclusions of Energy Use Analysis................................................................................ 54

4.3 Construction Cost Analysis............................................................................................................ 55

4.3.1 Deep Energy Retrofit Measure Costs Data....................................................................... 55

4.3.2 DER Cost Conclusions ..................................................................................................... 73

4.3.3 Cost and Effect.................................................................................................................. 73

4.3.4 Cost and Effect Analysis................................................................................................... 73

4.3.5 Cost and Effect Conclusions............................................................................................. 81

4.3.6 Measure Costs and Benefits Relative to Homeowner Objectives..................................... 81

4.3.7 Analysis of Project Objectives Relative to Energy-Related Measure Costs..................... 82

4.3.8 Energy-Related Measures Costs and Objectives Conclusions.......................................... 91

5 Conclusions ........................................................................................................................................ 92

5.1 Summary of Results and Conclusions ........................................................................................... 92

5.2 Progress on Research Questions.................................................................................................... 92

5.3 Recommendations for Future Work............................................................................................... 94

5.3.1 Analyze Measured Performance and Costs of Expanded Deep Energy Retrofit Project 

Population ......................................................................................................................... 94

5.3.2 Builder Costs..................................................................................................................... 94

5.3.3 Deep Energy Retrofit Measure Guidance ......................................................................... 95

5.3.4 Case Studies Focused on Comprehensive Performance ................................................... 95

5.3.5 Collaboration With Historic Preservation Stakeholders................................................... 95

References................................................................................................................................................. 96

Appendix A:............................................................................................................................................... 98

Appendix B:............................................................................................................................................. 137

Appendix C:............................................................................................................................................. 143
vi 

List of Figures

Figure 1. Chainsaw retrofit with fully adhered roofing membrane and house wrap as the air 

control layers ...................................................................................................................................... 13

Figure 2. Spray foam insulation used for air control in rafter cavities (with cross strapping) ......... 13

Figure 3. Pre and post-retrofit CFM50 for all projects........................................................................... 14

Figure 4. Post-retrofit CFM50 versus pre-retrofit CFM50...................................................................... 15

Figure 5. Post-retrofit CFM50/ft2 enclosure area results....................................................................... 17

Figure 6. Post-retrofit ACH50 results...................................................................................................... 17

Figure 7. Correlation between ACH50 and CFM50/ft2 enclosure area results .................................... 18

Figure 8. ACH50 results grouped by location of air control layer ....................................................... 21

Figure 9. ACH50 results grouped by location of air control layer and air control layer materials... 22

Figure 10. ACH50 results grouped by location of spray foam insulation, if any................................ 23

Figure 11. ACH50 results grouped by use of spray foam insulation for air control .......................... 24

Figure 12. ACH50 results for unvented versus vented attic................................................................. 25

Figure 13. ACH50 results versus year house was built ........................................................................ 26

Figure 14. ACH50 results versus pre-retrofit total CFM50.................................................................... 26

Figure 15. Source-site energy ratios from EnergyStar.gov.................................................................. 32

Figure 16. Pre- and post-retrofit source energy use for all retrofits.................................................... 33

Figure 17. Percent reduction from pre-retrofit to post-retrofit source energy use............................ 34

Figure 18. Weather-normalized post-retrofit source MMBtu/yr per household.................................. 37

Figure 19. Weather-normalized post-retrofit source kBtu/ft2-yr........................................................... 39

Figure 20. Weather-normalized post-retrofit site kBtu/ft2-yr ................................................................ 40

Figure 21. Post-retrofit 12- or 6-month site and source energy use in kBtu/ft2.................................. 41

Figure 22. Correlation between post-retrofit 6-month source to site ratio and 6-month source 

kBtu/ft2 ................................................................................................................................................. 42

Figure 23. Post-retrofit February 12–July 12 site and source energy use with credit for on-site 

generated electricity........................................................................................................................... 43

Figure 24. Post-retrofit 12- or 6-month total site and source MMBtu for heating and cooling per 

household ............................................................................................................................................ 44

Figure 25. Post-retrofit 6- and 12-month source kBtu/ft2 for heating and cooling............................. 45

Figure 26. Heating and cooling source energy as percent of total source energy use..................... 46

Figure 27. Electric versus nonelectric 6-month site and source heating and cooling kBtu/ft2 for 

February 12–July 12 ........................................................................................................................... 47

Figure 28. Chainsaw versus non-chainsaw 6- and 12-month heating and cooling source kBtu/ft2 . 48

Figure 29. 6- and 12-month heating and cooling source kBtu/ft2 grouped by basement treatment 49

Figure 30. 6- and 12-month heating and cooling source kBtu/ft2 grouped by roof and attic 

treatment ............................................................................................................................................. 50

Figure 31. Relationship between 6-month heating and cooling source kBtu/ft2 and ACH50............ 51

Figure 32. Relationship between 12-month heating and cooling source kBtu/ft2 and ACH50.......... 51

Figure 33. Total, allowable, and energy-related DER measure costs normalized to post-retrofit 

conditioned floor area........................................................................................................................ 58

Figure 34. Total, allowable, and energy-related DER measure costs normalized to treated 

enclosure area .................................................................................................................................... 58

Figure 35. Unit costs for attic and roof measures ................................................................................. 60

Figure 36. Costs for energy-related attic and roof measures per square foot of building footprint 

covered................................................................................................................................................ 61

Figure 37. Unit costs for wall measures ................................................................................................. 62

Figure 38. Unit costs for foundation wall measures ............................................................................. 63

Figure 39. Unit costs for conditioned basement floor and slab measures......................................... 64

Figure 40. Unit costs for window measures........................................................................................... 65

Figure 41. Unit costs relative to enclosure area for air sealing measures ......................................... 66

Figure 42. Unit costs relative to enclosure area for all enclosure measures ..................................... 67

Figure 43. Energy-related enclosure measure costs compared to pre-retrofit air leakage 

measurement ...................................................................................................................................... 68
vii 

Figure 44. Unit (per system) costs for mechanical ventilation............................................................. 69

Figure 45. Unit (per system) costs for heating system measures ....................................................... 70

Figure 46. Unit (per system) costs for HVAC measures ....................................................................... 71

Figure 47. Post-retrofit CFM50/ft2 enclosure area versus energy-related enclosure measure 

costs/ft2 enclosure area ..................................................................................................................... 74

Figure 48. Reduction in post-retrofit CFM50/ft2 enclosure area versus energy-related enclosure 

measure costs/ft2 enclosure area ..................................................................................................... 75

Figure 49. Heating and cooling site EUI versus energy-related enclosure measure costs/ft2

conditioned floor area........................................................................................................................ 76

Figure 50. Heating and cooling site EUI versus energy-related HVAC measure costs/ft2

conditioned floor area........................................................................................................................ 76

Figure 51. Heating and cooling site EUI versus combined energy-related DER measure costs/ft2 

conditioned floor area........................................................................................................................ 77

Figure 52. Site EUI versus combined energy-related DER measure costs/ft2 conditioned floor area77

Figure 53. Source EUI versus combined energy-related DER measure costs/ft2 conditioned floor 

area ...................................................................................................................................................... 78

Figure 54. Site energy use reduction versus combined energy-related DER measure costs .......... 79

Figure 55. Source energy use reduction versus combined energy-related DER measure costs..... 79

Figure 56. Energy-related measure costs relative to energy use reduction....................................... 80

Figure 57. Optional homeowner objectives checklist from DER program application...................... 83

Figure 58. Numerical aggregation of objective priority score.............................................................. 85

Figure 59. Project objectives ranked by aggregate priority score....................................................... 86

Figure 60. Cost of energy-related DER measures relative to project objectives ............................... 89

Figure 61. Numerical aggregation of energy-related objective scores ............................................... 91

Unless otherwise noted, all figures were created by BSC.

List of Tables

Table 1. Overall Measures and Targets or Requirements for National Grid DER Pilot Retrofit.......... 5

Table 2. Enclosure Insulation Measures and Targets for National Grid DER Pilot Retrofit................ 6

Table 3. HVAC Measures and Targets for National Grid DER Pilot Retrofit ......................................... 6

Table 4. Community of DERs..................................................................................................................... 8

Table 5. Blower Door Test Results and Related Characteristics of Retrofits..................................... 12

Table 6. Summary of Pre-Retrofit Energy Use—12 Months .................................................................. 29

Table 7. Summary of Post-Retrofit Energy Use: February 12–July 12 (6 months) and August 11–

July 12 (12 Months) ............................................................................................................................ 30

Table 8. Monthly Comparison of Actual and TMY3 CDD/HDD for Boston Logan Weather Station for 

August 2011–July 2012 ...................................................................................................................... 35

Table 9. National Grid DER Project Costs, Allowable Project Costs and Energy-Related DER 

Measures Costs as Derived From Program Application Forms.................................................... 57

Table 10. HVAC Measures and Composite System Cost...................................................................... 72

Table 11. Allocation of Energy-Related DER Measure Costs According to Project Objectives....... 90

Unless otherwise noted, all tables were created by BSC.
viii

Definitions

AC Air conditioner

ACH Air changes per hour 

ACH50 Air changes per hour at 50 Pascal test pressure

AHU Air handling unit

ASHP Air source heat pump

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning 

Engineers

BA Building America Program. 

BSC Building Science Corporation

Btu British thermal unit

CARB Consortium for Advanced Residential Buildings

CDD Cooling degree day

CFM Cubic feet per minute

CFM50 Cubic feet per minute at 50 Pascal test pressure

DER Deep energy retrofit

EIA Energy Information Administration

ERV Energy recovery ventilator

ft2 Square foot, square feet

HDD Heating degree day

HRV Heat recovery ventilator

HVAC Heating, ventilation, and air conditioning

OSB Oriented strand board

PARR Partnership for Advanced Residential Retrofits

PV Photovoltaic

RECS Residential Energy Consumption Survey

RESNET Residential Energy Services Network

SEER Seasonal energy efficiency ratio

SPF Spray polyurethane foam insulation

TMY3 Typical Meteorological Year 3
ix

Executive Summary

With the increasing demand for energy-efficient solutions for the existing housing stock, it is 

important to have demonstrated evidence that measures being implemented will in fact benefit 

the homeowner through a combination of energy savings, improved durability, and occupant 

comfort. Many of the deep energy retrofit (DER) performance data currently available are in 

terms of individual cases, often of nontypical homes or circumstances, and for many of these 

there has been insufficient post-retrofit time to adequately assess the actual performance results. 

The purpose of this research project is to use actual performance results for a diverse community 

of cold-climate retrofits to assess the effectiveness of a specific package of DER measures. 

Through the performance analysis of a group of post-retrofit homes, all of which have 

implemented the same DER measures and all of which have provided post-retrofit performance 

data for the same time period, a realistic range of post-retrofit performance results is 

demonstrated. By analyzing the post-retrofit data at the community level, the emphasis is shifted 

from the post-retrofit performance for the individual case to the post-retrofit performance 

achievable by using the DER measures package. Trends also begin to emerge about strategies 

that result in the best performance and how to make reasonable cost projections for a DER.

In 2009, National Grid started a DER pilot program that offered technical support and financial 

incentives to qualified Massachusetts homeowners who planned and successfully completed a 

retrofit that incorporated the performance requirements and goals of the National Grid DER 

measures package. This DER measures package, developed through collaboration with Building 

Science Corporation (BSC), includes specific thermal and airtightness goals for the enclosure 

components as well as health, safety, durability, and indoor air quality requirements. By 

providing measures that can be included with common renovation activities such as roof 

replacement, window replacement, re-siding, basement remediation, and remodeling, this DER 

measures package is expected to have widespread application for existing homes in the New 

England area. The post-retrofit performance and cost ranges provided by this research project 

can provide concrete input for homeowners who are considering a DER. 

In this project, the post-retrofit results for 13 existing homes from the DER Pilot program were 

analyzed. Ten of these homes are single-family homes; two are two-family homes, and one is a 

three-family home. The information available for each home that was used in this analysis 

included pre- and post-retrofit blower door test results, a project description, reason for doing the 

project, and project cost information; and actual post-retrofit energy use information provided by 

the utility companies. The post-retrofit energy use for this project was for the 12-month period 

from August 2011 through July 2012 and for the 6-month period from January 2012 through 

July 2012. 

The pre-retrofit energy use information available for the homes differed because in some cases, 

the home had been recently purchased but in other cases, the homeowner had been living in the 

home for many years. Where actual pre-retrofit energy use was not available, energy modeling 

using BEopt v1.3 was used to estimate the pre-retrofit energy use. The reduction of source 

energy use from the pre-retrofit homes to the post-retrofit ranged from 27%–75%. Wellmaintained homes with the same owner for the pre- and post-retrofit and for which the DER was 

not combined with other major renovations ranged from 30%–45%. 
x 

Total post-retrofit source energy use for the retrofits for the 12-month period ranged from 52–

217 MMBtu/yr and from 27–69 kBtu/ft2

-yr. When normalized to account for weather conditions 

and divided by the number of households, all of these were below the Energy Information 

Administration Northeast average total source energy use per household of 174 MMBtu/yr of 

source energy and more than half were below 70% of that average total. Similarly, all but one 

retrofit were below the Northeast average of 67.5 total source kBtu/ft2

-yr per home and many 

were below 50% of that average. Heating is the largest energy load in a cold climate and is most 

impacted by these DER measures. For the post-retrofit 12-month period, the actual source energy 

use for heating and cooling ranged from 8.5–27 kBtu/ft2-yr. 

The airtightness component in the DER package emphasized the need to identify the air control 

layer for each component of the enclosure and to plan continuous transitions between 

components. Using this approach nearly all of the homes were able to reach a post-retrofit 

airtightness result of 1.5 ACH50. The worst airtightness results occurred for the one home that 

did not include the basement in the conditioned space. 

As a group, the homes that used the “chainsaw” retrofit technique along with the air control 

layer, roof insulation, and wall insulation applied to the exterior had the best airtightness results 

and the lowest heating and cooling source energy use results. “Chainsaw” refers to a retrofit 

technique used at the intersection of the roof and wall whereby the existing rafter tails and rake 

overhangs are cut off and new overhangs are attached over the insulation at completion. 

Projects included in this study implemented enclosure retrofit packages at an average cost of 

$18.62/ft2

 of building enclosure. The unit cost for enclosure packages range from $9.99–

$26.87/ft2 of building enclosure. For energy-related enclosure measures, the average unit cost is 

$13.13ft2

 and the range is from $8.62–$22.20/ft2. 

Total HVAC system costs ranged from slightly more than $10,000 to just less than $19,000 for 

projects that met the pilot program target by installing high efficiency heating and cooling 

equipment and distributed ventilation with heat or energy recovery. Some projects replaced only 

certain components of the heating, ventilation, and air conditioning (HVAC) systems as part of 

the DER project. For other projects, HVAC measures were limited to adding mechanical 

ventilation. The projects that installed new high efficiency heating equipment, cooling 

equipment, and distributed ventilation with heat or energy recovery report costs for combined 

HVAC measures ranging from just more than $10,000 to approximately $39,500.

Analysis of energy-related measure costs and project objectives resulted in a categorization of 

measures as follows: (1) measures pursued primarily for energy-related objectives; (2) measures 

pursued for a combination of energy-related and nonenergy-related objectives; and (3) measures 

pursued primarily in response to nonenergy-related objectives. On average for the projects in this 

study about half of the energy-related measure costs are assigned solely to energy-related 

objectives, and 20% of energy-related measure costs are assigned primarily to nonenergy-related 

objectives.
1 

1 Introduction

Home retrofits have been targeted as an area of great potential for significant energy savings, 

employment opportunities, and market growth. However, the barriers to widespread adoption of 

comprehensive retrofit strategies remain high. Two such barriers are the lack of clear evidence 

that there is a substantial benefit to the average homeowner and perceptions relative to the high 

cost of a comprehensive energy retrofit. What is missing is evidence from a substantial sample of 

typical houses and homeowners demonstrating the benefits and indicating costs. 

In this project, reported cost and measured performance data have been evaluated to assess the 

retrofit cost and the post-retrofit airtightness and energy use for a group of houses in 

Massachusetts which participated in a deep energy retrofit (DER) pilot program sponsored and 

administered by National Grid (National Grid 2011). By providing financial incentives and 

technical support to the participating projects, the National Grid DER Pilot program created an 

opportunity for a broad range of homeowners to undertake a DER project. 

As participants in the DER pilot program, these retrofit projects all used the same set of retrofit 

targets, taken here as a “package of measures” for the measures to be implemented. This report 

assesses the effectiveness of the overall package of measures as well as the relationship between 

different implementation strategies used and measures of performance. This is accomplished by 

analyzing the full set of performance data for the group rather than looking at individual case 

studies, as has been done in past studies. This approach results in post-retrofit energy use and 

cost ranges based on the total community data that can be reasonably expected from use of the 

DER package. This is concrete evidence that can be used by homeowners to assess the potential 

benefit and cost of a DER. 

The post-retrofit analysis of a community of retrofits in this research project is unique in that it 

incorporates all of the following: the community consists of a diverse group of New England 

home types as well as differing homeowner lifestyles and values, the DER package is 

comprehensive and advanced, the analysis is based on actual rather than modeled post-retrofit 

data and all energy use data are for the same time period, and the analysis is applied to the full 

community rather than to the individual cases. 

The current research project shows that source energy savings from pre-retrofit to post-retrofit 

conditions ranging from 27%–75% can be achieved. But perhaps more importantly, it 

demonstrates that the DER retrofits can meet energy performance goals and benchmarks that 

apply to new home construction. 

Using this community of retrofits, the following research questions are addressed: 

• Does the DER measures package result in at least 30% actual source energy use reduction 

from the pre-retrofit conditions? A 30% reduction is the Building America (BA) program 

2012 goal for existing homes in cold climates. 

• Are there discernible differences in energy use between the variations allowed within the 

DER measures package?

• What post-retrofit airtightness has been achieved by the DER measures package? 
2 

• Are there discernible differences in air leakage results between the variations allowed 

within the DER measures package?

• What are the costs of the DER measures package?

• Can the net cost of energy performance improvement be separated from the full DER 

measures package cost?
3 

2 Background 

DERs are beginning to be less unusual. It used to be that each time a DER was done, it would 

show up in a magazine article (for example, Pettit 2008; Joyce 2009). Unfortunately, it is still the 

case that much of this work is looked upon as experimental. Because of this, it has not been easy 

to measure the benefits except on a case-by-case basis, or to make the case that the measures 

needed for an effective retrofit are readily accessible to the average homeowner, since most 

homeowners are not comfortable experimenting on their houses. 

The BA program has been working to overcome these two obstacles. There are several other BA

groups doing research to evaluate the performance effectiveness of cold climate home retrofit 

approaches at the community scale. Among these are the Consortium for Advanced Residential 

Buildings’ (CARB) role in the Retrofit NYC Block by Block project (Eisenberg et al. 2012) and 

in the recently completed retrofit of the Chamberlain Heights duplex and quad affordable 

housing complex (Donnelly and Mahle 2012) as well as the Partnership for Advanced 

Residential Retrofits (PARR) team’s work in the Chicagoland project development of energy 

efficiency retrofit packages for typical houses in the Chicago area (Spanier et al. 2012). 

These research projects have the potential to provide a significant set of post-retrofit 

performance data using utility bills and other testing to evaluate the energy use level achieved 

and achievable by fairly comprehensive retrofit measures packages. However, the current reports 

have only limited results available, if any, and thus results are presented in terms of prediction 

models rather than actual performance data. In this current research project, BSC is making use 

of a year of post-retrofit utility bills and performance data for retrofit projects and uses this actual 

performance information to evaluate achievable performance levels for the DER retrofit measure 

package. The projects evaluated in this current report represent fewer than one third of the total 

number of National Grid DER Pilot projects for which similar post-retrofit data will soon be 

available. However, this evaluation of the early projects is deemed important to both establish 

methodologies of evaluation and to begin to meet the need for measured performance data. In 

subsequent a research effort already underway, the performance results for the full set of 

National Grid DER Pilot projects will be evaluated.

The CARB and PARR research projects adopt the approach that the retrofit measures packages 

be tailored for particular house types—e.g., ranch house, NYC row house, triple-decker. BSC 

has found that each retrofit project has its own set of unique constraints that are based not so 

much on house type and age as its history and existing conditions. Therefore, tailoring retrofit 

measure packages to specific house types may not be necessary. In the results described in the 

current report, a single DER retrofit measures package has been applied to a variety of housing 

types, as well as significantly different ages and existing conditions. The evaluation of postretrofit performance suggests that the post-retrofit performance is impacted more by the specific 

implementation methods selected for measures package than by the house characteristics.

Other previous work related to high performance retrofit has focused on individual components 

or measures. For example, in one recent BA project, BSC worked with a weatherization program 

to evaluate and develop plans for inclusion of roof or attic insulation in the weatherization 

program (Neuhauser 2012). The current study evaluates the impact of a comprehensive measures 

package. 
4 

BSC has also worked on several projects using individual retrofits from the National Grid DER 

pilot program. In one project, BSC performed a case by case evaluation of the implementation of 

the DER measures for five of the DER pilot program participants (Neuhauser 2011). In a second 

project, BSC looked at the pre- and post-retrofit performance data for seven DER projects, four 

of which were early participants in the DER pilot program (Osser et al. 2012). 

All of these earlier research projects dealt with the individual projects—either in terms of how 

the DER measures were implemented or the post-retrofit performance that they achieved 

individually. None of them compared and analyzed the performance data as a group. Now that 

additional projects have been completed in the National Grid DER pilot program, there are 

enough data available to warrant the analysis of all of these projects as a community of retrofits 

rather than as individual cases. The number of completed projects is large enough that the impact 

of the retrofit measures as a package can be analyzed and trends from the available data about 

these projects begin to emerge. Using this approach, the emphasis is shifted from the post-retrofit 

performance for the individual case to the post-retrofit performance achievable by using the DER 

package. On the other hand, the number of houses involved is not so large that the results of the 

analysis are limited to statistical assessments. So when a particular project falls out of the 

performance range for the majority of the community, the details for that project can be further 

analyzed to explain the discrepancy.
5 

3 The National Grid Deep Energy Retrofit Pilot

3.1 Measures and Targets

The National Grid DER pilot program was established in 2009. The DER homes included in this 

report are all of those that successfully completed the National Grid DER pilot program and were 

occupied by January 2012. Participants in the DER pilot program are required to meet health, 

safety, and indoor air quality guidelines; specific thermal targets for each enclosure component 

(e.g., roof, above-grade walls); an overall airtightness target; minimum efficiency of mechanical 

equipment; water management; and durability requirements. While there are not specific 

instructions for how these targets are to be met, all implementation plans are reviewed for sound 

building science before the project is accepted into the pilot program and field verification of 

each completed measure is required in order to receive the financial incentives. In addition, all 

project teams are to include a qualified contractor or design consultant with previous DER 

experience and approval by National Grid. 

Implementation of a DER will change the overall dynamics of the existing building systems. The 

overall measures, shown in Table 1, include some essential prerequisites put in place to address 

possible ramifications of those changes.

Table 1. Overall Measures and Targets or Requirements for National Grid DER Pilot Retrofit 

Measure Target or Requirement for 

Measure Comments

Combustion 

Safety

Requirement: No atmospherically 

vented combustion appliances or 

fireplaces

Use direct vent, closed combustion, 

or power-vented mechanical 

equipment

Indoor Air 

Quality

Requirement: Meet ASHRAE 62.2 

ventilation requirements 

Provide background ventilation 

system with easily accessible controls 

that allow residents to operate the 

system at a lower rate as well as to 

temporarily boost to a higher rate.

Durability

Requirement: Vapor and water 

management control of the 

enclosure 

Use appropriate flashings including 

step and kickout flashings and 

integrate flashings effectively into the 

water control layer

Ensure that vapor control methods do 

not trap moisture within building 

components

Air Infiltration Target: CFM50 ≤ 0.10 * total 

6-side enclosure surface area

Identify the air control layer for each 

enclosure component and how the 

layer is transitioned between 

components

Appliances and 

Lighting

Target: ENERGY STAR®

appliances; 90% of lighting to be 

compact fluorescent or better
6 

The enclosure targets, shown in Table 2, are given for each enclosure component and are in 

terms of the installed R-value. 

Table 2. Enclosure Insulation Measures and Targets for National Grid DER Pilot Retrofit 

Measure Target for Measure Comments

Roof R-60+ This is for an unvented attic

Attic R-60+ This is for a vented attic

Above-Grade Exterior Walls R-40+

Insulated Foundation Walls R-20+

Insulated Basement Floor R-10+

Basement Ceiling R-30+ This applies only if the basement 

is not insulated

Floor Over Unheated Garage 

or Overhang R-40+ 

Windows and Doors R-5+

This set of enclosure measures allows the project to choose between a vented or unvented attic 

and between insulated basement walls or an insulated basement ceiling. In addition, some 

projects were unable to provide insulation to the basement floor because of head height or 

structural constraints. This type of flexibility in the measures is necessary when working with 

retrofits because the existing conditions may preclude certain approaches. 

 The heating, ventilation, and air conditioning (HVAC) measures are shown in Table 3. 

Table 3. HVAC Measures and Targets for National Grid DER Pilot Retrofit 

Measure Target for Measure Comments

Mechanical 

Ventilation

Heat recovery, 

balanced, distributed

HRVa, ERVb, exhaust only, or supply only are 

acceptable provided ASHRAE 62.2 is met and 

there is a means of distribution; mechanicals and 

ductwork to be within the thermal enclosure.

Heating 

Equipment

High efficiency 

heating 

Furnace, condensing boiler, GSHPsc or ASHPsd; 

AFUEe 95+%, heating season performance factor

8.2+ equipment rating with configuration or 

operating sequences to allow efficient operation; 

mechanicals and ductwork to be within the 

thermal enclosure.

Cooling 

Equipment

16 SEERf,13 EERg

cooling 

Cooling is not required; mechanicals and 

ductwork, if any, to be within the thermal 

enclosure. a Heat recovery ventilator

b Energy recovery ventilator

c Ground source heat pump

d Air source heat pump

e Annual fuel utilization efficiency

f Seasonal energy efficiency ratio

g Energy efficiency ratio in Btu of cooling per Watt of electricity
7 

3.2 The Community of Retrofits

This report examines the airtightness, energy use, and construction costs of 13 of the homes, all 

of which were participants in the National Grid DER pilot program. Therefore, all of the retrofits 

used the same DER measures package and targets in their planning; had plans reviewed for 

sound building science and for durability, combustion safety, and air quality; and received site 

verification of the implementation of the DER measures package. 

Table 4 provides some basic information about each retrofit, including the three enclosure 

components for which different implementation approaches were taken—roof and attic, abovegrade walls, and basement. Before and after photographs and specific information about each 

project are provided in the appendices. There is also additional information provided in Section 

4.1, Section 4.2, and Section 4.3. 

In the “Roof/Attic Measure” column of Table 4, some DER projects are identified as using the 

“chainsaw” technique. This refers to a retrofit technique used at the intersection of the roof and 

exterior wall whereby the existing rafter tails and rake overhangs are cut off during the retrofit 

and new overhangs are built and attached at completion. This approach is often used in a DER 

when exterior insulation is to be applied to both the roof and the wall, since it allows a 

continuous layer of insulation to be applied across the intersection, thus reducing thermal 

bridging. It also simplifies the air control connection between the roof and the wall when the air 

control layers for both the roof and the wall are on the outside of the existing sheathing, since the 

intersection becomes a simple edge condition (see Figure 1).

In the “Above-Grade Walls Measure” column of Table 4, there is a note “porch/deck not 

detached” for some of the projects. When exterior insulating sheathing is used on the abovegrade walls for a DER, it is recommended that any porches or decks that are attached to the 

above-grade wall be temporarily detached during the retrofit so that the air control layer and the 

insulation can be extended continuously between the porch or deck and the wall. This note 

indicates that the project did not use this approach. 
8 

Table 4. Community of DERs 

House Location; 

Year Built

Post-Retrofit 

Square Feet of 

Conditioned Space

Roof/Attic Measure 

(Installed 

R-Value)

Above-Grade Walls 

Measure (Installed 

R-Value)

Basement 

Measure HVAC Measures

Belchertown; 

Built in 1760

1,907 Insulated below roof 

deck only (R-56) 

Double wall with 

interior insulation 

(R-32)

Foundation 

walls and floor 

slab insulated

HRV; propane 

furnace; no air 

cooling

Belmont 

(2 Units); 

Built in 1925 

4,768 

Exterior and below 

roof deck insulation 

(R-63), chainsaw 

Exterior and cavity 

insulation (R-40) 

Foundation 

walls insulated

HRV for each unit; 

gas furnace; ACa coil 

and outdoor 

condenser for each 

unit

Millbury; 

Built in 1953 1,868 

Exterior and below 

roof deck insulation 

(R-51), chainsaw 

Exterior and cavity 

insulation (R-37) 

Foundation 

walls and floor 

slab insulated

ASHP with two 

AHUsb and outdoor 

supply air; direct 

vented wood pellet 

stove as heating 

backup

Milton; 

built in 1960 2,368 Insulated below roof 

deck only (R-56) 

Exterior and cavity 

insulation (R-38) 

Foundation 

walls and floor 

slab insulated

HRV; hydro air with 

gas boiler; central air 

cooling

Quincy; 

Built in 1905 4,576 

Exterior and below 

roof deck insulation 

(R-62), chainsaw

Exterior and cavity 

insulation (R-38) 

Foundation 

walls and floor 

slab insulated

HRV; hydro air with 

gas boiler; ASHP for 

cooling

Arlington 

(2 Units); 

Built in 1910 

3,627 Insulated below roof 

deck only (R-58) 

Exterior and cavity 

insulation (R-38); 

porch/deck not 

detached

Basement 

ceiling 

insulated

HRV for each unit; 

condensing gas 

furnace for each unit; 

AC coil for upper unit

Newton; 

Built in 1930 2,199 

Exterior and Below 

roof deck insulation 

(R-56), chainsaw 

Exterior and cavity 

insulation (R-39); 

porch/deck not 

detached

Foundation 

walls and floor 

slab insulated

ERV; condensing gas 

boiler; ASHP for 

cooling 
9 

House Location; 

Year Built

Post-Retrofit 

Square Feet of 

Conditioned Space

Roof/Attic Measure 

(Installed 

R-Value)

Above-Grade Walls 

Measure (Installed 

R-Value)

Basement 

Measure HVAC Measures

Jamaica Plain 

(3 Units); 

Built in 1907 

3,885 

Vented attic with 

attic floor insulation 

(R-60) 

Exterior and cavity 

insulation (R-40); 3rd

floor dormer walls 

not treated

Foundation 

walls and floor 

slab insulated

HRV for each unit; 

condensing gas 

boiler; removable 

window air 

conditioners

Northampton; 

Built in 1859 2,747 

Exterior and below 

roof deck insulation 

(R-60), chainsaw

Exterior and cavity 

insulation (R-39) 

Foundation 

walls and floor 

slab insulated

ERV; GSHP, ASHP 

for upper floor office. 

Lancaster; 

Built in 1900

1,440 Vented attic with 

attic floor insulation 

(R-65)

Exterior and cavity 

insulation (R-44) 

Foundation 

walls and floor 

slab insulated

ERV; two ASHPs

Brookline; 

Built in 1899 3,174 

Insulated below roof 

deck only as part of 

an earlier project 

(R-48)

Exterior and cavity 

insulation (R-40) 

Foundation 

walls insulated 

as part of an 

earlier project

HRV; condensing gas 

boiler; no air cooling 

Westford; 

Built in 1993 3,955 Insulated below roof 

deck only (R-62) 

Exterior and cavity 

insulation (R-39) 

Foundation 

walls insulated

ERV; gas furnace; 

AC coil and outdoor 

condenser

Gloucester; 

Built in 1920 2,424 

Exterior and below 

roof deck insulation 

(R-67), chainsaw

Exterior and cavity 

insulation (R-38) 

Foundation 

walls and floor 

slab insulated

HRV; two ASHPs 

with backup electric 

resistance heat a Air conditioner

b Air handling unit
10 

Some of the variations in the implementation of the measures that are apparent from information 

in the table above are as follows:

• Variation in above-grade wall treatment:

o One project used interior insulation only (a new stud wall was built around the 

interior perimeter to create a deeper cavity for insulation).

o Twelve projects applied insulation to the exterior of the existing walls. 

• Variation in roof and attic treatment: 

o Two projects used a vented attic with insulation on the attic floor. 

o Five projects created an unvented attic with all of the required insulation below 

the existing roof sheathing. 

o Six projects created an unvented attic using insulation applied over the existing 

roof sheathing—all of these projects used the chainsaw technique.

• Variation in basement treatment: 

o One project insulated the basement ceiling rather than the basement walls.

o Three projects insulated the basement walls but did not insulate the basement 

floor. 

o Nine projects insulated the basement walls and the basement floor.

As participants in the DER pilot program, all of these DER projects provided data in the 

application forms, had pre- and post-retrofit blower door testing performed, and are providing 

energy use information for at least the first two years following completion of the DER. Data 

from the application form include facts about the house, information about the existing 

conditions, past energy use, performance concerns, existing R-values, as well as description of 

plans for implementing the measures and projected costs. This, together with on-site verification 

of the DER project measures, provided a consistent set of data about each retrofit used for 

analysis in this research project. 
11 

4 Analysis

This analysis section contains five major subsections of analysis: airtightness, energy use, DER 

costs, relationship between cost and performance, and project objectives relative to energyrelated costs. 

4.1 Airtightness Results and Analysis 

One requirement for the participants in the National Grid DER pilot program was to provide a 

plan for airtightness with a target of achieving 0.10 CFM/ft2 of the building enclosure surface 

area (all six sides) at a 50 Pa air pressure differential. Toward meeting this goal, each participant 

was asked to identify the air control system for the house and a means for ensuring that it was 

continuous. 

The air control system is a system of materials designed and constructed to control airflow 

between conditioned space and unconditioned space. It is the primary boundary that separates 

indoor (conditioned) air and outdoor (unconditioned) air. The air control system can be located 

anywhere in the building enclosure—at the exterior surface, the interior surface, or anywhere in 

between—but must be continuous over the entire enclosure, air impermeable, durable, and able 

to withstand forces acting on the building, both during and after construction (Lstiburek 2006). 

The primary purpose of the air control system is to prevent energy loss through direct air 

exchange between the interior and exterior. Since this air exchange also includes air transported 

moisture, the air control system is also part of the vapor control system for the building. A 

typical solution for preventing this air exchange is to “air seal” by locating cracks or leaks and 

caulking or sealing them. For a DER, this approach is not sufficient. Instead, an air control layer 

needs to be established for each building component—e.g., house wrap, with seams taped and 

edges sealed, applied over the exterior wall sheathing can be the air control layer for the exterior 

walls. In addition, the means of transitioning this to the air control layer of adjacent components 

needs to be provided. For example, if the wall air control layer is the taped and sealed house 

wrap and the roof air control layer is fully-adhered roofing membrane over the roof sheathing, a 

continuous connection between these two materials needs to be established. This can be 

challenging, especially for a retrofit, and requires preplanning. 

Table 5 summarizes information about the retrofit projects used in the analysis of airtightness. 

The last two columns of Table 5—“Chainsaw?” and “Use of SPF Insulation”—are specific 

implementation approaches that may impact airtightness. As described in Section 3.2, a chainsaw 

retrofit can simplify the transition of the roof air control layer to the wall air control layer (see 

Figure 1). The use of spray polyurethane foam insulation (SPF) is relevant for airtightness 

because it is an air barrier material and it creates an air seal with the adjacent material provided 

all of the installation conditions are met (see Figure 2). Either of these characteristics could be 

expected to improve the robustness of the air control system. 
12 

Table 5. Blower Door Test Results and Related Characteristics of Retrofits

House Location 

Pre-Retrofit 

CFM50

Post-Retrofit 

CFM50

Post-Retrofit 6-

Sided Surface 

Enclosure Area 

(Square Feet)

Post-Retrofit 

CFM50/ft2

Enclosure Area 

(See Section 4.1.2) 

Volume of Cond 

Space (Cubic 

Feet)

Post-Retrofit 

ACH50 (See 

Section 4.1.2) 

Chainsaw?

Use of SPF 

Insulation (in 

Italics If Part 

of 

Air Control 

Layer) 

Belchertown 9,097 468 4,066 0.12 14,972 1.88 No Under roof deck, in wall 

cavities, on foundation wall

Belmont 5,700 590 9,093 0.06 47,706 0.74 Yes On foundation wall

Millbury 2,860 402 4,278 0.09 17,000 1.42 Yes Under roof deck

Milton 1,695 584 3,740 0.16 24,458 1.43 No Under roof deck, on 

foundation wall

Quincy 5,050 762 6,806 0.11 36,346 1.26 Yes Under roof deck, in wall 

cavities, on foundation wall

Arlington 8,730 3,586 5,925 0.61 29,648 7.26 No Under roof deck, in wall 

cavities

Newton 3,199 1,299 4,337 0.30 21904 3.56 Yes Under roof deck, on foundation

wall

Jamaica Plain 7,729 1,802 7,456 0.24 42,586 2.54 No At sloped ceiling, on 

foundation wall

Northampton 6,155 473 7,798 0.06 34,624 0.82 Yes On foundation wall

Lancaster 4,254 293 3,222 0.09 12,336 1.43 No At attic floor, in wall cavities, 

on foundation wall

Brookline 1,640 655 5,924 0.11 26,187 1.50 No Under roof deck, on 

foundation wall

Westford 2,592 930 9,538 0.10 44,475 1.25 No Under roof deck

Gloucester 2,258 235 6,493 0.04 23,285 0.61 Yes –
13 

Figure 1. Chainsaw retrofit with fully adhered roofing membrane and house wrap 

as the air control layers 

(Photo by Tobias Richon with permission)

Figure 2. Spray foam insulation used for air control in rafter cavities (with cross strapping) 

4.1.1 Airtightness Test Results

Blower door testing was performed prior to the beginning of construction and again after 

construction was completed for each of the retrofits described in this report. Table 5 contains the 

pre-retrofit and post-retrofit blower door test results for each of the houses. 

All blower door testing was done with the house open to the air or thermal enclosure boundary. 

This means, for example, that if the attic is within the thermal enclosure, the attic hatch or door 
14 

was left open during blower door testing. This testing setup matches the protocol for blower door 

testing established by the Residential Energy Services Network (RESNET) (RESNET 2009). In 

all cases, multipoint depressurization testing was performed and the results were normalized for 

50 Pa pressure difference as compared with outside conditions. 

While the pre-retrofit blower door test results are interesting, they are totally dependent on the 

state of the house before the retrofit. Many of the houses in this study were purchased at low 

prices because the houses were structurally sound but were not well maintained or were seriously 

out of date with respect to current energy standards and lifestyle requirements. Others were 

updated at this time because it was a convenient time (e.g., new empty nesters), the upgrade was 

included as part of larger project (such as building an addition), or for other personal reasons. 

Therefore, the most important information that analysis of the blower door test results for the full 

retrofit community provides is to demonstrate the range of air leakage results possible or 

probable for retrofits in general, and more specifically, achievable using the retrofit measures of 

the National Grid DER pilot program. 

That said, Figure 3 and Figure 4 compare the pre-retrofit and post-retrofit blower door test

results. 

Figure 3. Pre and post-retrofit CFM50 for all projects

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Pre-retrofit CFM 50 Post-retrofit CFM 50

CFM 50
15 

Figure 3 shows the pre and post-retrofit CFM50 results that were obtained from the blower door 

testing for each house. When this information is plotted on a graph with the post-retrofit values 

on the vertical axis and the pre-retrofit values on the horizontal axis as shown in Figure 4, all 

points that lie below the dashed line have a post-retrofit CFM50 value that is less than half of the 

pre-retrofit CFM50 value. 

Figure 4. Post-retrofit CFM50 versus pre-retrofit CFM50

This shows that all of the retrofits, regardless of their initial condition, achieved at least a 50% 

reduction in total CFM50 air leakage. 

4.1.2 Normalization of Airtightness Test Results

There are several different ways to report the results of the blower door test. The test itself results 

in a CFM50 result—cubic feet per minute of air that is required to be exhausted from (or 

supplied to) the interior of the house in order to maintain a 50 Pa pressure difference between the 

interior and exterior. This result is calculated using the airflow measured across the calibrated 

opening at the indicated pressure difference. 

Since the sizes of the houses in this community vary significantly, a direct comparison of total 

CFM50 results between houses is not very meaningful. In this report, two different normalization 

metrics are used to make the test results more comparable: a metric in terms of surface area air 

leakage (CFM50/ft2

 enclosure area) and a metric in terms of air changes per hour (ACH50). 

While these metrics are assumed to be standard, there are actually three factors that impact these 

metrics—the setup for the blower door test, the calculation of surface area of the building, and 

0

500

1000

1500

2000

2500

3000

3500

4000

0 2000 4000 6000 8000 10000

Post = 0.5 * Pre

Pre CFM 50

Post CFM 50
16 

the calculation of volume for the building. Before comparing results using these metrics, it is 

important to check that these were computed in the same way.

The blower door test setup specifies what parts of the interior space are open during the testing 

procedure. For the testing in this report, all conditioned space (space within the air control 

boundary) was opened, regardless of whether it was considered living space or not. As 

mentioned earlier, this matches the testing protocol for RESNET. 

To calculate surface area leakage at 50 Pa pressure difference, the total leakage airflow in 

CFM50 measured by the testing is divided by the enclosure surface area. In this report, the 

enclosure surface area calculation includes below grade and above grade surface area. The air 

leakage that occurs through below-grade surfaces is primarily in the form of soil gas; this 

leakage can have indoor air quality and health safety impacts so should not be ignored. It should 

be noted that this metric differs from the Minneapolis Leakage Ratio, which is the ratio between 

the total leakage at 50 Pa and the above-grade surface area.

The CFM50/ft2 enclosure area metric is used for the National Grid Pilot DER target. This metric 

is also used in BSC’s Building America airtightness testing requirements for high performance 

homes (BSC 2012). Figure 5 shows the CFM50/ft2 enclosure area performance results for all of 

the retrofits. As shown, six of the 13 retrofits met the airtightness target which is 0.10 CFM50/ft2

enclosure area, while three others came very close to meeting the target. All but two projects met 

BSC’s BA airtightness requirement of 0.25, which is less stringent than the National Grid DER 

target. The CFM50/ft2 enclosure area results range from 0.04 for the Gloucester retrofit to 0.61 

for the Arlington retrofit, with most retrofits falling between 0.06 and 0.16. 

The ACH50 metric is the most commonly used metric for reporting airtightness. The value of 

this metric depends on what is to be included when computing the volume of a building. In this 

report, volume is computed as the volume of the enclosure established by the air control layer. 

This is consistent with RESNET’s use of ACH50. 

Figure 5 and Figure 6 show the post-retrofit CFM50/ft2

 enclosure area and ACH50 results for all 

of the projects. 
17 

Figure 5. Post-retrofit CFM50/ft2 enclosure area results

Figure 6. Post-retrofit ACH50 results

The ACH50 results range from .61 ACH50 for the Gloucester retrofit to 7.26 for the Arlington 

retrofit, with most of the retrofits being below 1.5 ACH50. Since the blower door testing 

followed the RESNET protocol, these ACH50 results can be compared to the ACH50 ENERGY 

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

Target goal for retrofit 

community: 0.10

BSC's Building America 

testing requirement: 0.25

CFM 50 per sf Enclosure Area

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

ENERGY STAR V3 requirement: 4.0

Mean for retrofit community: 1.98

ACH50
18 

STAR V3 requirements. As shown in Figure 6, all but one of the retrofits (Arlington) were well 

below the ENERGY STAR V3 requirement for airtightness. 

Figure 7 shows that there is a strong correlation between the ACH50 and the CFM50/ft2

enclosure area results. The remaining analysis will use the ACH50 metric, since this is the more 

commonly used airtightness metric. 

Figure 7. Correlation between ACH50 and CFM50/ft2 enclosure area results

The airtightness result for the Arlington retrofit deviates significantly from the rest of the 

community. The Arlington retrofit is the only retrofit in this community that did not include the 

basement within the conditioned space. Therefore, the lower bound of the air control system was 

established at the basement ceiling. As has been observed in previous retrofit projects, it is 

difficult to achieve an effective air separation at the basement ceiling because of the framing and 

the many penetrations through the ceiling (Ueno 2010a). In the case of the Arlington project, 

there were also two stairwell connections through the basement ceiling to the first floor, further 

complicating the geometry of the air control system in the basement. Roughly half of the air 

leakage found during post-retrofit testing for this project was through the basement ceiling (Ueno 

and Lstiburek 2012; Neuhauser 2011). 

The Arlington retrofit was one of the two retrofits for which existing porches and decks were not 

temporarily detached from the exterior wall during retrofit, thus making it difficult to provide 

continuous air control at the connection between the porch or deck and the wall. The other 

project that did not detach the porch and deck is the Newton retrofit; notably, this project also 

has one of the highest post-retrofit air leakage results.

R2 = 0.98

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

Arlington

CFM 50 per sf Enclosure Area

ACH50

Newton
19 

4.1.3 Analysis of Airtightness Results

Both the air infiltration measures and the enclosure insulation measures of the DER package 

contribute to the airtightness results for these projects. The target R-values, especially for the 

roof and the walls, require a change to the existing wall and roof assemblies in order to 

accommodate the extra insulation required for the DER. The air control function must be 

established at an accessible location within the new assembly; in some cases it may be provided 

by the insulation itself. 

Each component of the enclosure—roof or attic, above-grade wall, foundation wall, and 

basement slab—has an air control layer. For the projects in this community, the locations of the 

air control layers for the roof and attic and for the above-grade wall are directly related to the 

DER project’s approach to handling the addition insulation. If exterior insulation was used for 

the component, the air control layer was established between the exterior insulation and the 

existing structural sheathing and was typically either house wrap with all seams taped and edges 

sealed or a fully adhered membrane. When the extra insulation was applied only on the interior, 

the air control layer was established on the interior and typically included spray foam insulation. 

For the foundation wall, if it is cast concrete, the wall itself, with cracks patched, serves as the air 

control layer. Only three of the projects have concrete foundation walls. The other projects have 

fieldstone or concrete block foundation walls, which are not air barriers. For these projects, the 

interior insulation layer needs to serve as both the air control and the thermal layers. The only 

exception to this is the Arlington retrofit for which the basement is not insulated, so the basement 

ceiling is the air control layer. 

The air control layer for a component needs to transition continuously to adjacent components in 

order to establish the full air control system. These transitions have the potential to introduce air 

leakage, particularly if the transition requires a connection between an interior air control layer 

and an exterior air control layer. The major transitions for the air control system occur between 

the wall and roof, between the wall and doors and windows, and between the above-grade wall 

and the foundation wall. 

In the following sections, the airtightness results for the retrofit community as a whole are 

analyzed in terms of project characteristics including type and location of thermal and air control 

layers and pre-retrofit condition of the house. The size of the community is too small to provide 

definitive results about ways to ensure the best airtightness. However, the trends that are seen 

can provide guidance for other retrofit projects—both for best approaches and for approaches 

that will require some extra care for success. 

All of the figures in this section are based on the same blower door test results. The results are

sorted based on the characteristic in question to look for trends or to refute the existence of such 

a trend. The Arlington project will be treated as an “outlier” in the airtightness section and will 

not be considered as contributing toward observed trends. 

4.1.3.1 Location of Air Control Layer

There are several factors related to the location of the air control layer (interior or exterior) that 

could be expected to impact airtightness. Interior side air control of the roof or walls is generally 

more difficult to implement than exterior side air control, especially for a retrofit. This is 
20 

primarily because of the restrictions to full access from the interior as well as the presence of 

framing to framing connections and partition wall obstructions that require special sealing. The 

transition of the air control layer between the roof and the wall is another factor to be considered. 

As described in Section 3.2, when both the roof and the wall air control layers are on the 

exterior, a chainsaw implementation provides a straightforward approach to this transition—

overlap the roof air control layer down onto and seal to the wall air control layer. When the 

transition is from exterior to interior or requires working around rafter tails, it becomes more 

difficult to make the connection airtight. 

Another factor that is relevant if the air and thermal control is on the exterior is the attachment of 

the porch or deck. If the porch or deck is not detached from the exterior wall during the retrofit, 

it is difficult to establish sufficient continuity of the air control system to prevent air leakage at 

these attachments. 

All but one of the retrofits in this community have exterior wall insulation and exterior wall air 

control. All of the retrofits with exterior insulation for both the roof and the wall used the 

chainsaw retrofit technique for both the insulation and the air control layers. So for this 

community, grouping the projects for analysis according to the location—interior or exterior—of 

the roof and wall air control layers is equivalent to first grouping the retrofits according to use or 

nonuse of the chainsaw technique and then looking at the other factors mentioned above. 

In Figure 8, those projects for which porches and decks were not detached during the retrofit 

have been distinguished by color from the others. In addition, the Jamaica Plain retrofit is 

distinguished because the walls of the upper floor dormers were not treated during the retrofit 

creating a discontinuity in the wall air control layer. Both of these situations are likely to 

contribute to higher ACH50 results. 
21 

Figure 8. ACH50 results grouped by location of air control layer

As a group, the overall airtightness results are better for the chainsaw retrofits than for the other 

groups. The group of retrofits for which there is an interior to exterior transition at the wall to 

roof/attic intersection has somewhat more air leakage than the chainsaw group, but the mean 

ACH50 value for the group is still quite good. 

For both the chainsaw and non-chainsaw groups, those retrofits for which porches and decks 

were not detached during the retrofit have the worst individual results. With those retrofits 

(Newton and Arlington) excluded, the overall airtightness results for the chainsaw group are 

significantly lower than those for the non-chainsaw group. If the Jamaica Plain retrofit is also 

excluded from the non-chainsaw group, the difference between the two is reduced but is still 

significant.

The material used for the exterior air control layer could be a contributing factor in the 

airtightness results. All of the retrofits in this community used taped and sealed house wrap for 

the exterior wall air control except for Northampton (taped OSB panels), Westford (taped 

plywood), and Arlington (a combination of taped, sealed house wrap and taped OSB panels). In 

addition, the Belmont, Brookline, and Jamaica Plain retrofits created a secondary air control 

layer at the outer layer of insulating sheathing. For those retrofits with an exterior roof air control 

layer (i.e., the chainsaw group), the roof air control layer was either taped and sealed house wrap 

(Quincy and Newton) or fully adhered roofing membrane (Gloucester, Belmont, Northampton, 

and Millbury). Figure 9 adds the material used for primary air control to the previous chart 

(Figure 8). 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Porch/deck not detached Section of wall not treated

Chainsaw 

Mean: 1.40

Median: 1.04

Non-chainsaw 

Mean w/o Arlington: 1.67

Median w/o Arliington: 1.47

ACH50

Exterior air control on walls;

Interior air control on roof/attic

Mean w/o Newton: 0.97

Exterior air control on 

roof and walls

Interior air 

control on 

roof and 

Mean w/o Arlington: 1.63 walls: 1.88

Median w/o Arlington: 1.43

Mean w/o Arlington and 

w/o Jamaica Plain: 1.40
22 

Figure 9. ACH50 results grouped by location of air control layer and air control layer materials

Figure 9 shows that the three retrofits with the best individual results are among the group with 

fully adhered roof membrane used for roof air control. This may be a contributing factor to their 

performance, particularly in establishing the seal where the roof air control layer overlaps onto 

the wall air control layer. Since none of the retrofits in this community used fully adhered 

roofing membrane as the roof air control layer but did not use the chainsaw technique, no 

comparison can be made to consider whether the fully adhered roof membrane alone is more 

significant than the chainsaw technique. However, it does appear that the combination of 

chainsaw and self-adhered membrane is particularly effective within this retrofit community. 

Similarly, since none of the retrofits in this community used exterior roof and wall insulation but 

did not use the chainsaw technique, no comparison can be made to consider whether the exterior 

insulation alone is more significant than the use of the chainsaw approach. However, in an earlier 

report that presented performance results for a group of seven DER projects, six of which used 

exterior insulation, those which used exterior insulation but were not chainsaw had the highest 

ACH50 results of the group (Osser et al. 2012). This suggests that the exterior insulation alone 

does not fully account for the airtightness results of the chainsaw group. 

4.1.3.2 Use of Spray Foam Insulation in Assembly

In this section, the airtightness results are examined based on the use of spray foam insulation 

used in the roof or attic and in the exterior walls.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Housewrap for walls & roof Housewrap for walls; fully adhered membrane for roof

Housewrap/panels for wall; SPF for roof/attic SPF for walls & roof

Chainsaw 

Mean: 1.40

Median: 1.04

Non-chainsaw 

Mean w/o Arlington: 1.67

Median w/o Arliington: 1.47

ACH50

Exterior air control on walls;

Interior air control on roof/attic

Mean for housewrap on 

walls & roof: 2.41

Mean for housewrap on 

walls & fully adhered 

membrane on roof: 0.90

Exterior air control on 

roof and walls

Interior air 

control on 

roof and 

walls 

Mean for housewrap on 

walls & SPF on roof w/o 

Arlington: 1.72 SPF on 

roof& 

walls: 1.88
23 

Spray foam insulation is often used for the air control layer as well as for part of the thermal 

enclosure because it is air impermeable, it creates a seal with the framing elements when applied 

properly, and it is relatively easy to apply as a continuous layer even where there is limited 

access. In this retrofit community, all wall and roof applications of spray foam insulation were 

applied from the inside to the interstitial or cavity space. Where the spray foam insulation does 

not actually embed the framing, the spray foam insulation alone is not a continuous air control 

layer but instead the combination of the spray foam insulation and the framing (studs in walls, 

rafters in roof) form the air control layer. In this case, the seal of the spray foam insulation to the 

framing plays a significant role in creating the air control layer. Also, wherever there is 

insufficient space between framing members to apply spray foam insulation between the 

members (e.g., at a double stud), a sealant must be applied to transition across this break in the 

air control layer. For all of the retrofits that used spray foam insulation in the exterior walls, the 

wall cavity was fully accessible from the interior during construction. 

Most of the retrofits used spray foam insulation in the exterior walls and/or in the roof or attic, 

but this was only relied upon as the air control layer when there was no exterior insulation 

applied as well. The following chart shows post-retrofit ACH50 values grouped by use of spray 

foam insulation though not necessarily for air control (Figure 10). Those retrofits that explicitly 

used spray foam insulation as part of the air control system are distinguished form the others by 

the color legend. 

Figure 10. ACH50 results grouped by location of spray foam insulation, if any 

The combination of roof and wall spray foam insulation has better overall airtightness results 

than spray foam insulation at the roof only, but the retrofits that did not use spray foam insulation 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

SPF not used for air control SPF used for roof air control

No SPF used SPF used for wall & roof air control

SPF used for attic air control

Spray foam insul in 

roof/attic and walls

Mean: 1.52

Median: 1.43

Spray foam insulation in roof/attic only

Meanw/o Arlington: 1.95 

Median w/o Arlington: 1.47

No spray foam insul in 

roof or walls 

Mean: 0.72

Median: 0.74

ACH50
24 

at all had the best airtightness results. This result is somewhat surprising since, even when not 

being considered as the primary air control layer, spray foam insulation provides some additional 

air sealing. The retrofits that did not use spray foam insulation in the roof or walls at all used 

either densepack or netted cellulose in the wall and rafter cavities with the air control layer on 

the exterior side of the sheathing. 

As shown in Figure 11, the distribution is slightly different when the grouping takes into account 

whether the spray foam insulation was intended as a primary component of the air control 

system. In this case, the group that does not use spray foam insulation for air control is precisely 

the same as the chainsaw group that was discussed earlier. Accepting that spray foam cavity 

insulation tends to have some benefit to air control, it would appear that the impact of other 

factors are dominant relative to the use of spray foam insulation. 

Figure 11. ACH50 results grouped by use of spray foam insulation for air control 

4.1.3.3 Unvented Versus Vented Attic

The National Grid DER package specified the target R-value for the roof or attic enclosure but 

required an unvented attic only if there was to be mechanical equipment or ductwork in the attic. 

Only two of the retrofits in this community have vented attics. Figure 12 is grouped by unvented 

versus vented attic.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

SPF not used for air control SPF used for roof air control No SPF used

SPF used for roof and wall air control SPF used for attic air control

Spray foam insulation used for air control layer for 

walls and/or for roof/attic

Mean w/o Arlington: 1.67 

Median w/o Arlington: 1.47

Spray foam insulation, if any. not used as air control 

layer for walls or roof/attic

Mean = 1.40

Median = 1.04

ACH50
25 

Figure 12. ACH50 results for unvented versus vented attic

The vented attic group has higher ACH50 results than the unvented attic group. However, with 

only two retrofits in the vented attic group, no definitive conclusion can be drawn from this. 

Furthermore, neither of the two vented attics in this community is typical for a vented attic DER. 

For the Jamaica Plain retrofit, a portion of the upper story walls did not have an air control layer 

provided; this would contribute to higher air leakage. For the Lancaster retrofit, the roof and attic 

were completely new construction, which allowed a continuous connection to be established 

between the wall and attic air control layers before the roof trusses were installed. 

With the additional breakdown of the unvented attics between those with exterior air control 

versus those with interior air control, the group with the exterior air control layer has the better 

results though the difference is not large. This group is precisely the chainsaw group. 

4.1.3.4 Impact of Pre-Retrofit Conditions

This section considers the impact of the pre-retrofit conditions of the house on the post-retrofit 

airtightness results. In particular, can an old, leaky house really be expected to achieve DER 

level airtightness? 

The graph in Figure 13 plots ACH50 (vertical axis) versus the year that the house was built 

(horizontal axis). There does not appear to be any correlation between age of house and achieved 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

ACH 50 New construction for attic and roof Section of wall not treated

ACH 50

Vented Attic

Mean & 

Median: 1.98

Exterior air control layer

Mean: 1.40

Median: 1.04

Interior air control layer

Mean w/o Arlington: 1.52

Median w/o Arlington: 1.47

Unvented Attic

Meanw/o Arlington: 1.45

Median w/o Arlington: 1.42
26 

airtightness—both the best and the worst results occurred in houses built between 1850 

and 1950. 

Figure 13. ACH50 results versus year house was built

The graph in Figure 14 plots ACH50 (vertical axis) versus the pre-retrofit total CFM50 results 

(horizontal axis). As with the previous graph, no relationship is apparent. These two graphs 

suggest that a very old or very leaky pre-retrofit condition is not necessarily an impediment to 

very good post-retrofit airtightness results.

Figure 14. ACH50 results versus pre-retrofit total CFM50

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

1700 1750 1800 1850 1900 1950 2000 2050

Year house was built

Post-retrofit ACH50

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 2000 4000 6000 8000 10000

Pre-retrofittotal CFM 50

Post-retrofit ACH50
27 

4.1.4 Other Airtightness Analysis

Additional airtightness analysis considered in the project include conditioned versus 

unconditioned basements and insulation of concrete versus stone foundation walls. With only 

one unconditioned basement, there were insufficient data to identify any trends using the project 

data alone. For the insulation of the foundation walls, it was apparent that the above-grade 

characteristics influenced the results far more than the foundation wall treatment.

4.1.5 Conclusions of Airtightness Analysis

Based on this community of retrofits, the following trends relating DER enclosure and air 

infiltration measures and resulting airtightness were observed: 

• A 50% overall improvement in total air leakage (as measured with 50 Pa pressure 

differential) can be expected from implementation of the enclosure and airtightness 

measures of this DER package.

• Post-retrofit ACH50 values of 1.5 and better can be expected from most implementations 

of the enclosure and airtightness measures of this DER package, provided the basement is 

included in the conditioned space and porches and decks are temporarily detached where 

needed to allow continuity of the air control layer. For this retrofit community, nine of 

the 13 projects were able to achieve this level of airtightness.

• When taken as a group, the best airtightness results in this community are achieved when 

the chainsaw technique is used at the roof/wall intersection and when exterior insulation 

is used for both the roof and the above-grade walls. However, it cannot be concluded that 

these implementation characteristics are the only determining factors.

• The use of spray foam insulation in the roof or walls, whether just for insulation or as a 

component of the air control system, is not a contributing factor for the best airtightness 

results.

• Within this retrofit community, the worst results were obtained for the only retrofit that 

did not condition the basement. However, a larger percentage of unconditioned 

basements in the community would be required before a definite trend could be asserted 

for these conditions. 

4.2 Energy Use Results and Analysis

A key goal of the National Grid DER pilot project was to demonstrate that significant energy use 

reduction of 50% or more could be achieved through enclosure upgrades and efficiency upgrades 

to mechanical equipment. To meet that goal, total installed minimum insulation levels of R-10 

(basement slab or ground floor slab), R-20 (foundation walls), R-40 (above-grade exterior walls), 

and R-60 (roof or attic) were specified and windows were to be at least R-5. These R-values, 

together with improved airtightness, were expected to reduce heating and cooling loads 

significantly. In addition, participants were encouraged to replace old equipment—appliances, 

heating, ventilation, and air conditioning (HVAC) equipment, and lighting—with energyefficient equipment. In the case of HVAC equipment, this included right-sizing of the equipment 

to be more in line with the reduced heating and cooling loads. 

The percentage of energy use reduction that can actually be achieved is dependent on the preretrofit state of the building as well as the relationship between the pre- and post-conditioned 
28 

floor area, since a retrofit project is often combined with other home improvements. Therefore, 

this report concentrates primarily on the energy use levels that were achieved rather than on the 

energy reduction achieved. In this section, the post-retrofit energy use of the projects is analyzed 

to assess the effectiveness of the National Grid DER package by comparison to benchmarks, by 

the energy use levels that are achieved, and by energy consumption implications for different 

implementation strategies. 

The analysis is in terms of both source (or primary) energy and site energy use. Looking at site 

energy allows an analysis in terms of where energy consumption is occurring directly within the 

house itself; this is the level at which the homeowner can precisely measure energy consumption 

using meters or monitors. On the other hand, in order to appropriately assess the environmental 

impact and total energy consumption of the home’s energy use (including production and 

transport of the fuel or electricity), it is the source energy used by the house that is important. In 

addition, source energy is typically comparable to the energy cost for the end user (Ueno 2010b). 

Six of the houses in this retrofit community generate some electricity on site. While this 

approach reduces the source energy used by that particular house, the analysis of energy use in 

this report will not take this into consideration. This approach was taken because most 

homeowners are still unable to generate their own electricity due to budget constraints, site 

constraints, building orientation, or building configuration. The energy use data without on-site 

electricity generation better represent what most homeowners will experience with the retrofit 

measures in the National Grid DER package. 

The actual energy use data referenced in this report is for the 6-month period from February 

2012 through July 2012 and for the 12-month period from August 2011 through July 2012. Since 

all of the projects were completed by January 2012, there are full energy use data for all projects 

for the 6-month period, which includes two months of heating and two months of cooling. Four 

of the projects were not completed by August 2011, so these are not included in the 12-month 

period results. 

4.2.1 Energy Use Data

Table 6 and Table 7 summarize the pre- and post-retrofit energy use data for the houses included 

in this report. The pre-retrofit data are from monthly energy use provided by the utility 

companies or the homeowner, when available, with missing information generated by energy 

modeling using BEopt v1.3. The post-retrofit energy use for the projects was compiled using the 

monthly energy use reported by the electricity and gas utility companies, the delivery amounts 

and dates for propane from the supplier, and on site electricity production reports provided by the 

user, usually from a monitoring website. 
29 

Table 6. Summary of Pre-Retrofit Energy Use—12 Months 

House 

Location Time Period Electricity (kWh)

Natural Gas 

(therm) or 

Propane (gal)

Fuel 

Oil 

(gal)

Other Energy Source

Total Site 

Energy 

(MMBtu)

Total Source 

Energy 

(MMBtu)

Belchertown Oct 08–Sep 09 2,139 162 (P) 7 cords of wood 194 211 

Belmont Energy model 8,811 309 (NG) 3,063 – 486 562 

Millbury May 09–Apr 10 7,809 – 375 150 bags of wood pellets 125 188 

Milton Energy model 8,086 903 (NG) – – 118 187 

Quincy

Jan 09–Dec 09; 

energy model for 

oil 

12,557 – 1301 _ 223 325 

Arlington Energy model 8,866 3,599 (NG) – – 390 478 

Newton Oct 09–Sep 10 7,639 1,222 (NG) – – 148 215 

Jamaica Plain Aug 09—Jul 10 7,192 1,781 (NG) _ – 203 268 

Northampton Jan 09–Dec 09 4,443 1,164 (NG) _ – 132 173 

Lancaster Energy model 5,648 – 738 – 122 168 

Brookline Sep 09–Aug 10 3284 773 (NG) – – 89 118 

Westford Jan 10–Dec 10 9,763 1,761 (NG) – – 209 296 

Gloucester Mar 09–Feb 10 6,428 – 911 – 148 201 
30 

Table 7. Summary of Post-Retrofit Energy Use: February 12–July 12 (6 months) and August 11–July 12 (12 Months) 

House Location 

Time 

Period

6 Months

Electricity (kWh)

6 Months Natural 

Gas (therm) 

or 

Propane (gal)

6 Months Total 

Site Energy 

(MMBtu)

6 Months Total 

Source Energy 

(MMBtu)

12 Months

Electricity (kWh)

12 Months

Natural Gas 

(therm) or 

Propane (gal) 

12 Months Total 

Site Energy 

(MMBtu)

12 Months Total 

Source Energy 

(MMBtu)

Belchertown Aug 11–Jul 12 885 132 

(P) 15 22 1,873 335 (P) 37 52 

Belmont Aug 11–Jul 12 

6,017 

(2,306 

excluding 

on site)

84 

(NG) 29 77 

11,415 

(4,809 

excluding 

on site)

204 (NG) 59 151 

Millbury Aug 11–Jul 12 5,211 28 (P) 21 63 10,597 66 (P) 

45 

(includes 

2.79 for 

wood 

pellets)

130 

(includes 

2.79 for 

wood 

pellets)

Milton Aug 11–Jul 12 

2,973 (865 

excluding 

on site) 

159 

(NG) 26 51 

6,648 

(2,714 

excluding 

on site)

309 (NG) 54 108 

Quincy Aug 11– Jul 12 

4,943 (351 

excluding 

on site) 

128 

(NG) 30 70 

9,894 

(1,671 

excluding 

on site)

262 (NG) 60 140 

Arlington Aug 11–Jul 12 5,777 247 

(NG) 44 92 14,196 523 (NG) 101 217 

Newton Aug 11–Jul 12 3,291 171 

(NG) 28 55 7,167 417 (NG) 66 125 

Jamaica Plain Aug 11–Jul 12 2,915 

(1,479 

404 

(NG) 50 76 6,153 (2,993 798 (NG) 101 154 
31 

House Location 

Time 

Period

6 Months

Electricity (kWh)

6 Months Natural 

Gas (therm) 

or 

Propane (gal)

6 Months Total 

Site Energy 

(MMBtu)

6 Months Total 

Source Energy 

(MMBtu)

12 Months

Electricity (kWh)

12 Months

Natural Gas 

(therm) or 

Propane (gal) 

12 Months Total 

Site Energy 

(MMBtu)

12 Months Total 

Source Energy 

(MMBtu)

excluding 

on site)

excluding 

on site)

Northampton Aug 11–Jul 12 

3,627 (429 

excluding 

on site) 

– 12 41 

7,697 

(1,973 

excluding 

on site)

– 26 88 

Lancaster Feb 12–Jul 12

3,415 (596 

excluding 

on site)

106 

(NG) 22 50 – – – – 

Brookline Feb 12–Jul 12 1,798 219 

(NG) 28 43 – – – – 

Westford Feb 12–Jul 12 5,613 375 

(NG) 57 103 – – – – 

Gloucester Feb 12–Jul 12 5,727 – 20 65 – – – –
32 

For several projects—Belmont, Quincy, and Gloucester—domestic hot water is provided by 

solar thermal systems with electric domestic hot water backup systems. Since there was no 

consistent method used to monitor the actual energy use provided by the solar thermal systems, 

the energy provided by the solar thermal system is not included in the energy consumption data 

in Table 7. 

Six of the projects include on-site generation of electricity: five of those installed photovoltaic 

(PV) panels on the roof of the house; one project uses a high efficiency gas boiler system with a 

generator that converts waste heat to electricity. The electricity data given in Table 7 are the total 

electricity use; the value in parentheses excludes the electricity use that was generated on site.

Source energy use is calculated using the source to site energy conversion factors shown in 

Figure 15. The total site and source energy use reported in Table 7 presumes that all electricity 

was from the grid. 

Figure 15. Source-site energy ratios from EnergyStar.gov 

Using the data in Table 6 and Table 7, Figure 16 compares a year of pre-retrofit source energy 

use with the actual post-retrofit source energy use for either one year (August 2011–July 2012) 

or, where a year of data are not yet available, for 6 months (February 2012–July 2012). 
33 

Figure 16. Pre- and post-retrofit source energy use for all retrofits

The total year of source energy for the pre-retrofits ranges from 118–562 MMBtu. For the postretrofits, the total year of source energy ranges from 52–217 MMBtu. For those with only 6 

months of post-retrofit data available, the source energy use for the 6-month period ranges from 

43–103 MMBtu. 

Figure 17 shows percentage of reduction of the pre-retrofit source energy use that was achieved 

for each project for the year. For those projects with only 6 months of actual post-retrofit energy 

use data, the yearly energy use is projected to be two times the 6-month energy use. This 

approach is plausible since the post-retrofit source data for those four retrofits includes 2 months 

of heating, 2 months of cooling, and 2 months of “shoulder” season. All but one of the retrofits—

Brookline—either have achieved, or are projected to achieve, at least a 30% reduction. Four of 

the retrofits—Belchertown, Belmont, Quincy, and Arlington—have achieved greater than 50% 

reduction. These numbers do not include credit for on site electricity generation. With credit for 

on site generated electricity, the Milton, Jamaica Plain, Northampton and Lancaster projects 

would also show greater than 50% achieved or projected reduction from the pre-retrofit 

conditions. 

0

100

200

300

400

500

600

electricity gas/propane oil other

source MMBtu

Actual pre-retrofit source energy use:

Modeled pre-retrofit source energy use:

Post-retrofit source energy use:

Pre-retrofit source energy use is for 12 months:

Post-retrofit source energy use is for 12 months: Aug 11 - Jul 12

Pre-retrofit source energy use is 

for 12 months;

Post-retrofit source energy use 

is for 6 months: Feb 12 - Jul 12
34 

Figure 17. Percent reduction from pre-retrofit to post-retrofit source energy use 

The percentage reduction achievable is somewhat dependent on the pre-retrofit state of the 

house. In the case of the Brookline retrofit, this was the final stage of a two-stage DER project 

with the roof and basement components having been done several years earlier. Thus, the 27% 

reduction does not capture the effect of the first stage of the DER. 

The Brookline retrofit is one example of a retrofit for which the homeowners had been living in 

the house prior to the retrofit, the retrofit did not involve a significant addition, and the house had 

been reasonably well maintained and updated by the homeowners. Other retrofits that fall into 

that category include the Millbury, Newton, and Jamaica Plain retrofits. The post-retrofit energy 

reduction for this group ranges from 27%–43%. The other retrofits for which the homeowners 

did not change between pre-retrofit and post-retroft are Belchertown, Quincy, Northampton, and 

Westford, but for these retrofits, either the project included a significant upgrade (Belchertown) 

or a significant addition as well as an upgrade to the existing house (Quincy, Northampton, and 

Westford). Both the Belchertown and Belmont retrofits, those with the highest reduction in 

source energy, as well as the Arlington retrofit, were largely uninsulated homes prior to the 

retrofit project. 

75% 73%

31%

42%

57% 55%

42% 43%

49%

40%

27% 30% 35%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

post-retrofit source energy use (as % of pre-retrofit source energy use) 

projected post-retrofit source energy use (only 6 mos data available) (as % of pre-retrofit source energy use)

% reduction from actual pre-retrofit source energy use

% reduction from modeled pre-retrofit source energy use
35 

It should be noted that the pre- and post-retrofit reductions compare energy use between different 

years, or in some cases, between actual and modeled energy use, so the reduction results must be 

viewed as approximate. In Figure 16 and Figure 17, the pre-retrofit data that are from an energy 

model rather than from actual data are indicated by the legend. The information available about 

the pre-retrofit houses is generally not complete or detailed enough for weather normalization 

techniques to provide results that could be considered more accurate (Osser et al. 2012).

However, a weather normalization technique is applied to the post-retrofit energy use data when 

used for benchmarking in the following section. 

4.2.2 Normalization and Benchmarking of Energy Use Data

Total energy use for a house is a function of weather conditions during the time period, the size 

of the house, the number of households, the number of residents, and the life style of the 

residents. In order to compare and analyze the energy use among different houses, it is necessary 

to use performance metrics that normalize some of these conditions. 

4.2.2.1 Normalization by Weather Conditions

With all of these houses located in the same region of the country and the actual data taken in the 

same time frame, the prevailing weather conditions for all of these retrofits were similar.

However, when compared to typical weather conditions for the area, the actual heating degree 

days (HDDs) are lower and the actual cooling degree days (CDDs) are higher for the August 

2011 to July 2012 time period. Table 8 shows this comparison for the Boston Logan weather 

station for August 2011 through July 2012 using Typical Meteorological Year 3 (TMY3) 

weather data. In this case, the actual HDDs were 20% lower and the actual CDDs were 35% 

higher than for the typical year. Therefore, while the actual post-retrofit energy use data in this 

report can be used for comparison among the houses of this particular community, they should 

be normalized for weather conditions when comparisons are to be made to a benchmark for a 

different or otherwise unspecified year. 

Table 8. Monthly Comparison of Actual and TMY3 CDD/HDD for

Boston Logan Weather Station for August 2011–July 2012 

Month Actual 

CDDs

Actual 

HDDs

TMY3 

CDDs

TMY3 

HDDs

August 2011 260 2 193 5

September 2011 115 57 53 66

October 2011 29 267 9 348

November 2011 1 449 0 652

December 2011 0 764 0 902

January 2012 0 959 0 1189

February 2012 0 801 0 950

March 2012 18 608 0 813

April 2012 25 398 0 537

May 2012 42 204 11 204

June 2012 142 94 109 87

July 2012 304 2 95 3

Yearly Total 936 4605 694 5756
36 

Where weather normalized data are used in this report, they have been normalized with respect 

to the TMY3 weather data files for the location of the retrofit. TMY3 data files contain weather 

data meant to represent typical conditions at a particular geographic location over a long period 

of time (Wilcox and Marion 2008). For use in this report, monthly HDDs and CDDs for the 

locations were extracted from TMY3 data files using BEopt v1.3. 

The weather normalized data for each project was generated using a linear regression analysis 

method that adjusts the monthly energy use based on the correlation between degree days and 

energy use. Since this community is located in a heating-dominated climate, only HDDs and 

consumption of the type of fuel used for heating were used in the regression analysis. The 

correlation was established using the actual HDDs and then applied using the TMY3 HDDs at 

the same location to determine the “typical” consumption for that type of fuel for the house. 

These weather-normalized monthly data were then combined with the actual monthly use for the 

other fuels to give an estimated total energy use for a typical year for the house. 

Specifically,

1. A scatter graph of the actual monthly site kWh energy use versus actual monthly HDDs 

for August 2011 through July 2012 was generated for each project using Microsoft Excel. 

Only energy use of the fuel type used for heating was included in the scatter graph. For 

the four projects with only 6 months of actual data, only 6 months of actual data were 

plotted. 

2. A linear best fit regression equation was generated by the Excel software for the scatter 

graph of the form 

Site Energy Use in kWh per Month = X1 × Actual HDDs for Month + A 

along with the values of X1, A, and R2 (coefficient of determination) for the regression 

line. The value of X1 represents the slope of the line on an energy use/HDD graph. The 

value of A is the intercept on the energy use axis, roughly representing the base load. 

3. By replacing “Actual HDDs for month” with TMY3 HDDs for each month, the equation 

was used to generate a rough estimate of the typical site energy use for the month for the 

heating fuel type.

4. These monthly estimates were combined with the actual nonheating site energy use, and 

totaled to provide 12-month weather normalized site energy use for the project. The 12-

month weather-normalized source energy use was computed using the conversion factors 

in Figure 15. 

For those projects with only 6 months of actual data, the additional 6 months of heating energy 

use was projected using the regression equation determined in Step 1; the additional 6 months of 

nonheating energy use was projected by multiplying the 6 months actual nonheating energy use 

by 2. 

Due to the low resolution of the energy use data (approximately monthly) and the varying 

correlation accuracy (R2

) with HDD, the weather-normalized data should be viewed as a rough 
37 

approximation. In this report, weather-normalized source or site energy use is used within this 

section only for the purpose of benchmarking the energy use results and is clearly labeled 

“weather normalized.” All other analysis of the results will be performed using the actual postretrofit energy use data. 

4.2.2.2 Normalization by Number of Households

Several of the houses in this community are multifamily, so one performance metric to consider 

for benchmarking the results is the total energy use per household. This metric is computed by 

dividing the total building energy use by the number of households in the building. 

Figure 18 shows weather-normalized post-retrofit source energy use in MMBtu per household 

for 12 months. For those households with only 6 months of data, the projected results are shown. 

The northeast regional household averages for source energy use, derived from data available 

from the Energy Information Administration (EIA), are shown in the figure for comparison. 

Figure 18. Weather-normalized post-retrofit source MMBtu/yr per household 

The U.S. Department of Energy maintains regional energy performance metrics per household 

that are based on information contained in the EIA Residential Energy Consumption Survey 

(RECS). The most recent information available is from 2009 (DOE/EIA 2009). For the Northeast 

region, the EIA average site energy consumption per household is 107.6 MMBtu/yr. The EIA 

performance information does not include average source energy consumption per household. To 

convert EIA site energy consumption to source energy use, the average site energy per household 

was distributed among fuel types according to the distribution of the total fuel consumption for 

the northeast households in the RECS. The ENERGY STAR source-to-site ratios (Figure 15) 

were applied based on this distribution yielding an EIA Northeast regional average household 

0

50

100

150

200

Weather normalized 12 mo source MMBtu/household

Weather normalized projected 12 mo source MMBtu/household

70% of the regional 

household average:

122 MMBtu/yr source 

energy

50% of regional 

household average: 87 

MMBtu/yr source 

energy

EIAnortheast regional 

household average: 

174 MMBtu/yr source 

energy

source MMBtu per household/yr
38 

source energy use of 174 MMBtu/yr. A 30% reduction in average household source energy use is

122 MMBtu/yr and a 50% reduction is 87 MMBtu/yr. 

For the 12-month time period covered in this report, no retrofit exceeded the EIA Northeast 

regional average household use; however, based on the 6 months of use covered, the Westford 

retrofit is likely to exceed it. Eight of the retrofits were (or are projected to be) below 70% of the 

household average and three of those were below 50% of the household average yearly source 

energy use. 

The Quincy and Westford retrofits, which are the two highest “per household” source energy 

users, are both single-family homes and are the largest in terms of conditioned square feet of the 

single-family homes in this community. This highlights one of the disadvantages of the “per 

household” performance metric—while it compensates for duplication of appliance and other 

miscellaneous use, it does not take into account the square footage of the household. 

4.2.2.3 Normalization by Energy Use Intensity

The most common performance metric used for comparing energy consumption is energy use in 

kBtu per square foot of conditioned floor area per year (kBtu/ft2

-yr). This performance metric, 

computed by dividing the total energy use in kBtu for the year by the square footage, is called 

energy use intensity (EUI) and takes the size of the house into consideration. This is the metric 

used for the energy use targets of the 2030 Challenge and the Passive House program. Since the 

EUI can refer to either source or to site energy use, any comparisons using EUI must be made 

between source to source EUI or site to site EUI. Also, the calculation of “square footage of floor 

area” may vary. In this report, the conditioned space is determined by the interior dimensions of 

each floor and includes an insulated basement but does not include insulated, unvented but 

unfinished attic space or crawlspace. 

Figure 19 shows weather-normalized post-retrofit source EUI for each of the retrofits in the 

community. For those retrofits with only 6 months of data available, the projected source EUI is 

shown. Since these have been weather normalized, they can be compared to the northeast 

regional EIA average source EUI for single-family or multifamily homes. These regional 

averages have been computed by Architecture2030 using the regional EIA RECS data 

(Architecture2030 2006). 

For this 12-month period, only two of the retrofits—Millbury and Lancaster—exceeded (or are 

projected to exceed) the average source EUI for a single-family home. Two projects, 

Belchertown and Quincy, used less than 50% of the single-family average and the Belmont 

multifamily used less than 50% of the multifamily average. Although only 6 months of actual 

data are available, Brookline also appears to be on target to be less than 50% of the single-family 

average. The range of weather normalized source EUI for the retrofit projects is 28–75 kBtu/ft2

-

yr, with most projects falling between 30 and 60 source kBtu/ft2-yr. 
39 

Figure 19. Weather-normalized post-retrofit source kBtu/ft2

-yr 

In 2002, Architecture2030 established the 2030 Challenge with the ultimate goal of reducing 

fossil fuel, greenhouse-gas emitting energy consumption to zero by 2030 and with intermediate 

goals provided along the way. These goals are stated in terms of fossil fuel-generated site energy. 

Therefore this energy consumption includes all electricity use from the grid as well as natural gas 

and propane on site, but does not apply to electricity generated by PV. Goals for the consumption 

of source energy are not provided. The 2030 Challenge goal for 2012 is a 60% reduction of the 

average site energy for the particular building type in the region; the goal for 2015 is a 70% 

reduction. 

Figure 20 shows the weather-normalized site energy use in site kBtu/ft2

-yr for the retrofits. The 

northeast multifamily and single-family 2012 and 2015 goals for the 2030 Challenge are also 

shown. Even without taking credit for PV-generated electricity, two of the single-family retrofits, 

Quincy and Northampton, meet the Northeast region 2012 goal for the 2030 Challenge and the 

Northampton project meets the 2015 goal as well. The Belmont retrofit meets the Northeast 

region 2012 goal for two- to four-unit multifamily houses as well as the 2015 goal. Based on 6 

months of data, the Gloucester retrofit also appears to be meeting the 2030 Challenge for 2012. 

0

10

20

30

40

50

60

70

80

Weather normalized source kBtu/sf-year Weather normalized projected source kBtu/sf-year

Northeast regional 

multifamily average:

78.8 source kBtu/sfyear

Northeast 

regional singlefamily average: 

67.5 source 

kBtu/sf-year

50% of regional 

multifamily 

average source 

kBtu/sf-year

50% of regional 

single-family 

average source

kBtu/sf-year

source kBtu/sf-yr
40 

Figure 20. Weather-normalized post-retrofit site kBtu/ft2

-yr 

4.2.3 Analysis of Energy Use Data

In the following sections, the post-retrofit energy use is analyzed for the retrofit community as a 

whole to look for trends of energy use that are associated with the aspects of the National Grid 

DER package. All energy use is in terms of actual post-retrofit energy use. There is no 

adjustment made for the weather conditions and there is no use of modeled energy use in this 

section. 

4.2.3.1 Post-Retrofit Source to Site Energy Use Ratio 

In the EIA RECS report from 2009, the distribution of total household site energy consumption 

in the Northeast region was 25% electricity, 51% natural gas or propane, 22% oil, and 2% others. 

The distribution of site energy use for the nine retrofits with a full year of post-retrofit data is 

47% electricity and 53% natural gas or propane. This relative increase in electricity use results in 

a greater difference between the site energy and source energy use for the projects because the 

source to site ratio for electricity use is more than three times higher than that for the other fuels.

The increase in electricity use may be a reflection of change in lifestyle—e.g., continued increase 

in use of electronics, more home offices—but more likely is the result of adding air conditioning 

or of switching from gas or oil to electric heating. 

Figure 21 shows the actual total source and site energy use in kBtu/ft2

 for August 2011 through 

July 2012 for all of those projects for which there are 12 months of data; for the others, this is 

shown for February 2012 through July 2012. The range for 12 months is 10–30 kBtu/ft2 of site 

energy and 27 kBtu/ft2 –to 69 kBtu/ft2 of source energy. Most of these retrofits are in the range 

0

5

10

15

20

25

30

35

Weather normalized site kBtu/sf-year Weather normalized projected site kBtu/sf-year

site kBtu/sf-year

2030 Challenge for multifamily:

2012 goal: 23.1 site kBtu/sf-year

2015 goal: 17.3 site kBtu/sf-year

2012 goal: 18.3 site kBtu/sf-year

2015 goal: 13.7 site kBtu/sf-year

2030 Challenge for single-family:
41 

of 30–60 total source kBtu/ft2-yr. For the four projects with only 6 months of data, the range is 

8–15 kBtu/ft2

 of site energy and 14–35 kBtu/ft2 of source energy. 

Figure 21. Post-retrofit 12- or 6-month site and source energy use in kBtu/ft2

With only gas (or propane) and electricity being used for these retrofits, source energy use 

becomes two times the site energy use as soon as the electricity energy use reaches about 42% of 

total site energy use using the current source to site conversion factor for electricity (Figure 15). 

Thus, seemingly low site energy use can quickly result in high source energy use. 

Within this community, two of the retrofits—Northampton and Gloucester—converted to all 

electric energy use. Two other retrofits—Millbury and Lancaster—converted from fossil fuel 

heating to all-electric for heating/cooling (ASHPs) but not for hot water. In these four cases, the 

decision to convert to an all-electric house or to electric heating and cooling was done in 

anticipation of adding on-site generation of electricity, either at the time of the retrofit or as a 

future project. However, on-site electricity generation is not an option for most DER projects so 

that continued increase in percentage of electricity use, particularly if used for heating, could 

undermine the anticipated source energy savings. It should be noted, however, that the increased 

0

10

20

30

40

50

60

70

site and source kBtu/sf

site energy use source energy use

electricity gas/propane other

kBtu/sf for 12 months 

(Aug 11 - Jul 12)

kBtu/sf for 6 months 

(Feb 12 - Jul 12)
42 

use of renewables for the generation of grid electricity will lower the source to site ratio in the 

future, thus reducing the relative impact of grid electricity on total source energy use. 

Figure 22 compares the source to site ratio with the actual source energy kBtu/ft2

 for February 

2012 through July 2012 for all of the projects. The Lancaster, Millbury, and Gloucester projects 

account for the highest 6-month source kBtu/ft2 results and are also among the highest source to 

site ratios for the period. Notably, the other three projects with high source to site ratios are 

among the lowest 6-month source kBtu/ft2 results. These retrofits—Quincy, Belmont, and 

Northampton—are all participants in the Thousand Home Challenge program (ACI 2010). This 

is a program that emphasizes behavior, lifestyle, and community solutions for additional 

reduction of energy use so these households carefully monitored their energy use, which could 

explain why their energy use is low. A contributing factor to the high source to site ratio for the 

Quincy and Belmont retrofits, both of which use gas for heating, is the low post-retrofit heating 

load. 

Figure 22. Correlation between post-retrofit 6-month source to site ratio and

6-month source kBtu/ft2

Several of the projects compensated for the shift toward electricity use by providing PV panels 

or other on-site generation techniques to offset the increase in source energy. For the six retrofits 

that use on site generation of electricity, Figure 23 shows a breakdown of the energy use between 

that which was generated by fossil fuels (which includes electricity from the grid) and that which 

was generated on site for the 6-month period from February 2012 through July 2012. 

0

5

10

15

20

25

30

35

40

1.0 1.5 2.0 2.5 3.0 3.5

6 mo source kBtu/sf vs source-site ratio

6 mo source kBtu/sf 

6 month source-site ratio

Belmont Quincy Northampton

Gloucester

Lancaster Millbury

3.3
43 

Figure 23. Post-retrofit February 12–July 12 site and source energy use with

credit for on-site generated electricity

4.2.3.2 Heating and Cooling Energy Use

Most of the measures in the National Grid DER package address reduction of energy use by 

minimizing heat loss (or gain) through the building enclosure. The effectiveness of these 

enclosure measures is best demonstrated by the post-retrofit heating and cooling energy use. 

The energy use information available for these retrofits does not support a clear disaggregation 

of heating and cooling energy use versus other energy uses. However, an approximate 

disaggregation can be made by asserting that the lowest monthly use for each fuel type 

represents the nonheating/cooling load. Subtracting this amount from each month of post-retrofit 

energy use data results in energy use that can be attributed primarily to heating or cooling. 

Figure 24 shows the total site and source estimated heating and cooling energy use per household 

for August 2011 through July 2012 for those retrofits with a year of data and for February 2012 

through July 2012 for those with only 6 months of data. It should be noted that this is a time 

period that included an exceptionally mild winter and an exceptionally hot summer. The range 

for the 12-month period was 7–35 site and 19–51 source heating and cooling MMBtu per 

household; the range for the 6-month period was 2.5–31 site and 8–45 source heating and 

cooling MMBtu per household. 

11

13 15 7

5

7

11

13

15 7

5

7

0

10

20

30

40

50

60

70

Northampton Belmont Quincy Milton Jamaica Plain Lancaster

5 kW PV

4.3 kW PV

6.25 kW PV 2.8 kW PV 3.75 kW PV

MMBtu

site grid electricity

source grid electricity

site natural gas

source natural gas

on-site generated electricity
44 

Figure 24. Post-retrofit 12- or 6-month total site and source MMBtu for 

heating and cooling per household

Figure 25 shows the post-retrofit heating and cooling source energy use in kBtu/ft2 for February 

2012 through July 2012 for all of the projects and for August 2011 through July 2012 for those 

projects with a full year of data. 

0

10

20

30

40

50

60

Total H/C site energy use per household Total H/C source energy use per household

MMBtu for heating and cooling

12 months 

(Aug 11 - Jul 12)

6 months

(Feb 12 - Jul 12)
45 

Figure 25. Post-retrofit 6- and 12-month source kBtu/ft2 for heating and cooling

For the 6-month period, the range of energy use is 3.3–12.5 source kBtu/ft2 for heating and 

cooling; for the 12-month period, the range is 8.5–27 source kBtu/ft2 for heating and cooling. 

Most of the retrofits with 12 months of data are in the range of 10–25 source kBtu/ft2

-yr for 

heating and cooling. 

As can be seen in Figure 25, the post-retrofit 12-month heating and cooling source energy use in 

kBtu/ft2 for the Millbury retrofit is significantly higher than the other 12-month retrofits, and the 

post-retrofit 6 month heating and cooling source energy use for both the Westford and the 

Millbury retrofits is significantly higher than for the other retrofits. These two retrofits were also 

among the highest in overall source energy use in kBtu/ft2 (and the highest in total heating and 

cooling source energy use per household [Figure 24]). Therefore, these two retrofits are further 

analyzed as “outliers” in Section 4.2.3. 

0

5

10

15

20

25

30

post-retrofit 6 month H/C source kBtu/sf

post retrofit 12 month H/C source kBtu/sf 

6 & 12 month source kBtu/sf 

Mean 6 mo H/C source kBtu/sf: 6.9 

Mean 12 mo H/C source kBtu/sf: 16.6 
46 

Figure 26. Heating and cooling source energy as percent of total source energy use 

Figure 26 shows the source energy use for heating and cooling as a percentage of the total source 

energy use. The range is 27%–54% of the total source energy for those projects with a full year 

of data. For those with only 6 months of data, the range is 16%–43%. 

While all of the projects initially used gas, propane, or oil heating, several of the projects 

switched to electric heating as part of the energy retrofit. As noted earlier, electricity usage 

incurs a higher source to site ratio so the increased efficiency of the electric heating solution 

needs to compensate for this to be an effective energy use reduction strategy. “Efficient” in this 

sense includes not only the efficiency of the equipment, but also that of the design and 

installation, the operation of the equipment, and the building enclosure. In Figure 27 the projects 

on the left use natural gas or propane for heating; the projects on the right use ASHPs or GSHPs. 

With the exception of the Millbury retrofit, the source energy used for the electric heating 

solutions for the retrofits are in the same range as that for efficient natural gas or propane boilers 

or furnaces. 

54%

36% 39% 36% 30%

40% 40% 37%

27%

16%

40% 43%

24%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

H/C source energy use non H/C source energy use

12 months 

(Aug 11 - Jul 12)

6 months 

(Feb 12 - Jul 12)
47 

Figure 27. Electric versus nonelectric 6-month site and source heating and 

cooling kBtu/ft2 for February 12–July 12

For the remainder of this section, the heating and cooling energy use is analyzed in terms of 

specific DER enclosure characteristics and variants to see if these demonstrate any differences in 

heating and cooling energy consumption. 

4.2.3.2.1 Chainsaw Versus Non-Chainsaw

The installed R-value for the enclosure components is approximately the same for all of the 

retrofits, since these were specified in the DER package. However, the performance of the 

enclosure depends on other factors, including the approach chosen for implementing the DER 

measures. 

Two enclosure characteristics that impact the performance of the enclosure are the extent of 

thermal bridging and the amount of air leakage through the enclosure. In the analysis of 

airtightness, the projects that used the chainsaw technique were seen to have the best airtightness 

results. The chainsaw technique also reduces thermal bridging through the enclosure, since the 

thermal control layer is wrapped completely around the exterior of the above-grade portion of the 

house. 

Figure 28 shows the energy use in kBtu/ft2 for the 6-month and 12-month time periods grouped 

according to whether the retrofits used the chainsaw technique or not. This shows only a minimal 

difference in overall heating and cooling energy use in the 6-month source kBtu/ft2

 between the 

chainsaw and the non-chainsaw groups, but the difference becomes more pronounced in favor of 

lower energy consumption by the chainsaw group for the 12-month period. 

0

2

4

6

8

10

12

14

6 mo H/C site kBtu/sf 6 mo H/C source kBtu/sf

electric 

heating

natural gas or 

propane heating

site and source kBtu/sf for 6 months
48 

Figure 28. Chainsaw versus non-chainsaw 6- and 12-month heating and cooling source kBtu/ft2

It should be noted that the two retrofits in the chainsaw group with the highest heating and 

cooling source energy use for both the 6- and 12-month periods—Millbury and Newton—were 

also the retrofits with the highest ACH50 measurements among the chainsaw retrofits. Another 

factor that may increase heating and cooling energy use for the Newton retrofit is that the porch 

roof and deck were not detached during the retrofit which allows some thermal bridging through 

the above-grade wall at the attachment. 

None of the retrofits in this community used exterior insulation on both the roof and wall without 

also using the chainsaw technique. Use of exterior insulation without the chainsaw introduces 

some thermal bridging at the roof/wall intersection in spite of the exterior insulation, and as 

noted in Section 4.1.3 has been observed in other projects to result in more air leakage. 

Therefore, it is unlikely that exterior insulation alone accounts for these energy use results 

achieved by the chainsaw group. 

4.2.3.2.2 Uninsulated Versus Insulated Basement

One of the enclosure variants among the retrofits was the treatment of the basement. Three 

different approaches were used:

• Unconditioned basement with insulation in the ceiling 

• Conditioned basement with insulated walls but uninsulated slab 

• Conditioned basement with insulated walls and insulated slab. 

0

5

10

15

20

25

30

6 mo H/C source kBtu/sf 12 mo H/C source kBtu/sf

Chainsaw retrofit 

Mean 6 mo H/C source kBtu/ft: 6.85

Mean 12 mo H/C source kBtu/ft: 15.83

non Chainsaw retrofit

Mean 6 mo H/C source kBtu/ft:7.00

Mean12 mo H/C source kBtu/ft: 17.55

6 & 12 month source kBtu/sf
49 

As noted in Section 4.1.2, the only retrofit that has an unconditioned basement—Arlington—had 

a significantly higher ACH50 measurement than the other retrofits. This would be expected to 

result in higher heating energy use. This expectation is supported in the overall 6-month and 12-

month group results shown in Figure 29, but no definitive conclusion can be drawn with data 

from just one retrofit.

Figure 29. 6- and 12-month heating and cooling source kBtu/ft2 grouped by basement treatment 

There is no significant difference in heating and cooling kBtu/ft2

 between the conditioned 

basement groups with and without insulated basement slab. This is as expected since the 

moderate ground temperature reduces the potential for heat loss through the basement slab. The 

main reason that insulation on the basement slab is included in the DER package is to prevent 

condensation and control moisture transfer through the slab for improved indoor air quality and 

durability. 

4.2.3.2.3 Unvented Versus Vented Attic

Another variant among the retrofit projects was treatment of the attic. The different approaches 

used were as follows: 

• Vented attic with insulation at the attic floor 

• Unvented attic with insulation under the roof deck 

• Unvented attic with exterior insulation over (as well as under) the roof deck. 

0

5

10

15

20

25

30

6 mo H/C source kBtu/sf 12 mo H/C source kBtu/sf

Insulated

Basement

6 & 12 month source kBtu/sf

Uninsulated 

Basement

Uninsulated slab

Mean 6 mo H/C source 

kBtu/sf: 7.58

Mean 12 mo H/C source 

kBtu/sf: 11.36

Insulated slab

Mean 6 mo H/C source kBtu/sf: 6.66

Mean 12 mo H/C source kBtu/sf: 16.27

7.49

24.11
50 

Vented attics and unvented attics with all insulation below the roof tend to have some heat loss at 

the wall/roof intersection due to the thermal bridging through the framing there and the limitation 

on the amount of insulation that can be installed between the top of the wall and the roof 

sheathing. Figure 30 shows the heating and cooling source kBtu/ft2 for the 6- and 12-month 

periods grouped according to the attic and roof treatment.

Figure 30. 6- and 12-month heating and cooling source kBtu/ft2 grouped by

roof and attic treatment

With this grouping, the vented attics have the best heating and cooling kBtu/ft2

as a group. 

However, only two projects in this community have vented attics and neither of these projects is 

typical for a vented attic DER. For the Lancaster project, the roof and attic are new construction; 

for the Jamaica Plain project, some of the walls in the upper floor are not treated. 

For the unvented attic groups, the overall heating and cooling kBtu/ft2 as a group for the exterior 

roof insulation was better than for the group with interior roof insulation. In this community, the 

group with exterior roof insulation corresponds to the chainsaw group. 

4.2.3.2.4 Airtightness Versus Heating and Cooling 

Air leakage is a major source of heat loss for existing homes in the Northeast region. Figure 31 

and Figure 32 check for a correlation between the post-retrofit heating and cooling source 

kBtu/ft2 and the post-retrofit ACH50 for the 6- and 12-month time periods. 

0

4

8

12

16

20

24

28

6 mo H/C source kBtu/sf 12 mo H/C source kBtu/sf

Vented attic

Mean 6 mo H/C 

source kBtu/sf:

6.31 

Mean 12 mo H/C 

w/ interior insulation:

Mean 6 mo H/C source 

kBtu/sf: 7.28 

Mean 12 mo H/C source 

kBtu/sf: 18.53 

w/ exterior insulation:

Mean 6 mo H/C source kBtu/sf: 6.85 

Mean 12 mo H/C source kBtu/sf: 15.83

6 & 12 month source kBtu/sf

Unvented Attic

Mean 6 mo H/C source kBtu/sf: 7.05; Mean12 mo H/C source kBtu/sf: 16.84 
51 

Figure 31. Relationship between 6-month heating and cooling source kBtu/ft2 and ACH50

Figure 32. Relationship between 12-month heating and cooling source kBtu/ft2 and ACH50

There is not a strong correlation shown for either of the time periods. It can be noted, however, 

that the Arlington, Newton, and Jamaica Plain retrofits had the least successful airtightness 

results and these are among the higher heating and cooling energy consumers in kBtu/ft2 for the 

two time periods. Most of the projects with ACH50 of 1.5 or less are in the lower energy use 

range with the notable exceptions of Millbury and Westford. While ACH50 results lower than 

1.5 may improve comfort and indoor air quality, the results from this group of retrofits do not 

show a clear advantage for those with even lower ACH50 results. 

0

2

4

6

8

10

12

14

0.0 1.5 3.0 4.5 6.0 7.5 9.0

6 month H/C source kBtu/sf

ACH 50

Newton Arlington

Millbury

Westford

Jamaica Plain

0

5

10

15

20

25

30

0.0 1.5 3.0 4.5 6.0 7.5 9.0

12 month H/C source kBtu/sf

ACH 50

Arlington Newton

Millbury

Jamaica Plain
52 

4.2.4 Analysis of Energy Use “Outliers”

In the preceding analysis, the Westford and Millbury retrofits are among the highest projects in 

total source energy use and are the two “outliers” in the analysis of heating and cooling energy 

use. Both of these homes have airtightness below 1.5 ACH50 and have efficient heating and 

cooling equipment, so these results are unexpected. As a result, site investigations and a closer 

look at the energy data for these two homes were undertaken during October 2012 to look for 

explanations. 

4.2.4.1 Further Investigation of Westford Retrofit

The Westford retrofit was completed in December 2011, so only 6 months of post-retrofit energy 

use data are available for this report. The Westford house was built in 1993, the most recently 

built of all of retrofits in this retrofit community. The retrofit project included the addition of 

1,049 ft2 of conditioned space, which was a combination of a two-story addition (with basement)

and a new roof structure to support the development of finished space in the attic. Following the 

retrofit, this house has 2,955 ft2 of conditioned space distributed through three stories and the 

basement. 

Since airtightness had already been tested, the purpose of the site investigation in October 2012 

was to check the operation of the HVAC equipment. Heating is provided by a natural gas furnace 

that was reconfigured from one to three zones (main house, master bedroom suite above garage, 

and basement) as part of the retrofit. The AHU fan has an electronically commutated motor but 

is set to deliver a constant airflow regardless of the zone configuration thus failing to take 

advantage of electronically commutated motor capabilities. 

Cooling is provided by a new indoor air coil attached to the AHU with a 16 SEER outdoor unit. 

There is an ERV in the basement with exhaust air taken from a partially above-grade space in the 

basement (which is to be finished by the owner) and outside air delivered to a single floor 

register on the first floor. The ERV is operated on a 10% run time setting. This outside air is 

further distributed through the main part of the house by operating the furnace AHU in fancycling mode. 

Measurements and observations of the operation of these systems did not indicate any 

malfunction or abnormally high wattage draw. However, during the site investigation, it was 

observed that some of the registers were covered or closed, with approximately half of those in 

the master bedroom suite covered in an attempt by the homeowners to cut back on the 

conditioning or airflow, or both, in certain areas. Given the components and configuration of the 

system, this would result in a somewhat higher wattage draw by the AHU fan than would be the 

case if the system were operated with all registers open. 

There is a dehumidifier located in the basement. The homeowners report that this had run 

essentially 100% of the time in the summer. Since there was probably still moisture in the 

basement from the construction (both from the new concrete in the basement and water that 

accumulated on the basement floor during construction), some operation of the dehumidifier 

would have occurred during the first several months as well. However, the continuous operation 

during the summer would contribute to the reported electricity use for the heating and cooling 

loads. During the site visit, the dehumidifier did not appear to be removing moisture effectively. 

This was determined by operating the dehumidifier for a period of time and then measuring the 
53 

level of humidity at the air intake and output of the dehumidifier. Measurements taken on site 

also found the dehumidifier to draw 450–480 W when operating. If the dehumidifier operates a 

significant portion of time, presumably in response to a humidistat, but does not effectively 

remove moisture, it would use significantly more energy than if the dehumidifier were working 

correctly. Given the draw of this equipment, the energy use associated with this dehumidifier 

would also factor significantly in the total energy use for the home. 

While the Westford retrofit met most of the target DER goals for the enclosure, the window 

component for the Westford retrofit deviates slightly from the DER target U-value of 0.20. Due 

to aesthetic and cost considerations, the owners decided to use a high quality double-glazed 

window with U-value of 0.29 rather than use any of the available windows with U-value of 0.20 

or lower. The glazing to above-grade wall ratio for this house is around 10%. This substitution 

increases the total heat loss coefficient by about 10% for the building enclosure. 

The combination of the observations from the site visit and the less efficient windows would 

contribute to a somewhat elevated energy use for heating and cooling. However, these issues 

would not be expected to be as significant as indicated by the analysis in the previous sections.

Since the project was not completed until December 2011, it may be that some of the additional 

energy use experienced during the 6 months is due to initial operation and learning how to 

effectively use the installed systems. The energy use on this project will continue to be 

monitored to see if the trend for exceptionally high energy use for heating and cooling continues. 

4.2.4.2 Further Investigation of Millbury Retrofit

The Millbury retrofit was completed in December of 2010. In an analysis of post-retrofit energy 

use through August 2011 (Osser et al. 2012), it was noted that the energy use was higher than 

expected. Since this continues to be the case, this cannot be attributed to initial operation issues. 

The Millbury retrofit was among the first participants in the National Grid DER pilot project. 

The house is a compact Cape Cod style with a full basement. An existing shed dormer was 

extended across the rear of the second floor as part of the retrofit. Even with added space, this is 

one of the smallest houses in the retrofit community. The homeowners are recent “empty 

nesters” who have lived in the house for more than 25 years. The retrofit was undertaken in 

keeping with their long-standing goal of being energy efficient and reducing their impact on the 

environment. 

In addition to thermal and airtightness enclosure improvements, the retrofit included installation 

of an ASHP system for heating and cooling to replace an oil boiler system supplemented with a 

pellet stove and four window air conditioners. The pellet stove was converted to a closed 

combustion system and retained as a backup heating system, but the homeowners report that it 

was rarely used during the 12-month period that this report covers. Other energy use 

improvements included switching from desktop to laptop computers, replacement of 

incandescent lighting with compact fluorescent lamps and light-emitting diodes, and installation 

of a propane instantaneous hot water system.

The primary purpose of the site investigation in October 2012 was to check the operation of the 

HVAC system, but also to look for an explanation for why the baseline energy use was not 

appreciably lower than it had been before the retrofit. The ASHP system is a ducted mini-split 
54 

with one outdoor unit supplying two indoor compact AHUs. Both AHUs are located within the 

thermal enclosure—one in the basement and one in the attic. The ventilation system is supplyonly with outside air delivered to the return at each of the AHUs and controlled by a motorized 

damper. The homeowners have been very satisfied with the heating and cooling comfort levels 

since the retrofit, though they noted occasional “stuffiness” (Osser et al. 2012) and somewhat 

slow response time from the AHUs. 

During the site visit in October 2012, the following observations were made:

• The ductwork for the AHUs is very restricted with 4-in. ducts, long runs, and multiple 

elbows that would result in more static pressure than the systems were designed to 

handle. 

• The AHUs are operating significantly below the rated airflow capacity.

• There was a draw of 150–180 W on the heat pump circuits when the system was not 

operating—no fans or compressors were operating. 

• The outdoor air supply controller had no connection to the AHU controls; this type of 

supply-only system is expected to be distributed by fan-cycling. 

• There was an error code displayed at the thermostat—the homeowner’s service manual 

indicated that the resolution of this error is to replace the indoor or outdoor control board, 

or both. 

The first two observations would contribute to higher energy consumption for heating and 

cooling than expected. The third adds to the base load even when the heat pump is not in use. 

The fourth means that the background ventilation air is not being distributed through the living 

space unless there is also a call for heating or cooling. The final observation indicates that there 

is malfunction in the system. 

Subsequent to the site visit, the homeowner has contacted a manufacturer-approved contractor 

for assistance. The error code has been resolved—a wire had come loose—but the other 

performance issues have not yet been resolved. 

4.2.5 Conclusions of Energy Use Analysis

The nine retrofits in this retrofit community for which 12 months of post-retrofit data were 

available each achieved the 2012 BA goal of 30% reduction in total source energy use for 12 

months of pre- versus post-retrofit energy use. Of those, four of the retrofits were able to achieve 

the National Grid DER goal of 50% reduction. For the retrofits for which only 6 months of postretrofit energy data were available, most of these appear to be on track for at least a 30% 

reduction in yearly source energy use. For retrofits that were primarily an enclosure upgrade and

involved a reasonably well-maintained and continuously occupied home, the precentage energy 

use reduction was within 30%–45%. 

The following comparisons to benchmarks are based on weather normalized post-retrofit energy 

use for the nine retrofits with a full year of post-retrofit data:
55 

• All of these retrofits are below the EIA Northeast regional household average of total 

source energy use; three of the retrofits are less than 50% of that household average. 

• All but one of the retrofits are below the EIA Northeast regional multifamily and single 

family average for source EUI averages with three retrofits below 50% of those averages. 

• Three of the retrofits meet the 2012 site EUI goal for the 2030 Challenge without taking 

any credit for on-site electricity generation. 

Based on this community, this DER package may be expected to result in yearly source energy 

use of 30–60 source kBtu/ft2-yr during a year with HDDs and CDDs comparable to August 2011 

through July 2012. Similarly heating and cooling source energy use may be expected to be in the 

range of 10–25 kBtu/ft2

-yr. Post-retrofit thermostat setpoints were not tracked for this 

community, so these ranges do not incorporate specific operating condition assumptions. 

The following trends relating enclosure characteristics to heating and cooling source EUI were 

observed within this community: 

• When taken as groups, heating and cooling source EUI is lower for chainsaw retrofits 

than for non-chainsaw retrofits and lower for unvented attics with exterior insulation than 

for unvented attics with interior insulation only; however, with the available data, it 

cannot be concluded that these are the only determining factors for these results.

• In a conditioned basement, insulation of the basement slab does not appear to impact 

heating and cooling energy use.

• While the lower heating and cooling source EUI results were obtained by retrofits with 

ACH50 of 1.5, there is no clear advantage demonstrated for even lower ACH50 results. 

The follow-up analysis of the two outlier cases suggest that the DER process needs to be more 

specific with the HVAC measures to ensure the following:

• The homeowner’s expectations are factored into the design of the HVAC system. 

• The HVAC designer and contractor has knowledge of, and experience with, the systems 

being installed. 

• The HVAC contractor verifies the operation of, and the performance of, the system after 

installation.

• The homeowners receive simple and clear instructions about the operation of the systems 

that include how to operate these for maximum efficiency.

4.3 Construction Cost Analysis

4.3.1 Deep Energy Retrofit Measure Costs Data

Prior to participating in the National Grid DER Pilot, prospective participants completed a series 

of application forms that provided information about the project team, project financing, existing 

building conditions, energy use history for the building, project plans, project costs, and 

homeowner objectives. (See Appendix B for a blank application form.) The application requires 

projected cost information for specific DER measures. These measures correspond to major 

enclosure components, air sealing (if implemented as a separate retrofit measure), as well as 
56 

ventilation, heating, and cooling systems. The contractor for the prospective project team 

provided the measure cost information included in the application. The cost information in the 

application typically reflects the contractual cost for implementation of these measures. 

Therefore, the cost reported is the cost to the homeowner and not the contractor’s cost to 

implement the measure. 

The application also distinguished between total DER project costs and those costs that are 

“allowable” or eligible for incentives. The types of costs that are not allowable or are excluded 

from the allowable costs include costs for related repair or renovation, third-party contributions, 

and certain deductibles. For example, the materials and labor for installation of new roofing or 

siding over exterior insulation would not be an allowable cost, whereas the labor and materials 

needed to install exterior insulation would be an allowable cost. Rebates or incentives from other 

programs are excluded from DER costs eligible for incentives. Also, the value of donated labor 

and materials (applicable to a Habitat for Humanity project included in this study) would be 

excluded from incentive eligible costs. The DER pilot program provides incentives toward the 

full cost of installing qualified windows less a deductible of $15/ft2

 of window area. 

The project application forms also solicit input from project teams as to the details of the 

reported costs. This cost detail information might indicate, for example, the cost for installation 

of exterior insulation as distinct from the cost for cavity insulation for a DER roof measure. The 

level of cost detail is not consistent among the participants in the DER program. However, the 

information does provide some basis for distinguishing, for each measure and for each project, 

the DER measure costs related to energy performance and those not related to energy 

performance. The homeowner and contractor for one of the projects collaborated on a postcompletion analysis of project that included an analysis of the project costs. Through study of the 

cost detail data provided in the application forms or in separate analysis produced by project 

teams, costs related to measures affecting energy savings were identified. These include some 

necessitated by measures affecting energy performance. In most cases there are modest 

differences between allowable DER measure costs and energy-related cost for each project. The 

energy-related costs include the full window replacement measure cost as the window measure 

affects the energy savings for the building. 

Table 9 below shows the total DER project cost and the allowable DER measures costs reported 

on the applications for the 13 projects in this study. It also shows the energy-related DER 

measure cost as determined through this study. 
57 

Table 9. National Grid DER Project Costs, Allowable Project Costs and Energy-Related DER 

Measures Costs as Derived From Program Application Forms 

DER Project

Total 

DER 

Project 

Cost

Allowable 

DER 

Measures 

Cost

EnergyRelated DER 

Measures Cost

EnergyRelated 

Enclosure 

Measures 

Cost

EnergyRelated 

HVAC 

Measures 

Cost*

Belchertown $64,629 $60,129 $51,642 $35,045 $16,597 

Belmont

(Two-Unit Building) $178,938 $146,453 $174,762** $142,094 $32,668 

Millbury $82,719 $66,234 $71,569 $49,894 $18,875 

Milton $77,762 $59,477 $66,236 $51,236 $15,000 

Quincy $125,547 $99,483 $108,515 $68,915 $39,600

Arlington

(Two-Unit Building) $124,853 $88,628 $95,163 $69,537 $26,856 

Newton $148,252 $92,552 $96,039 $65,539 $31,500 

Jamaica Plain 

(Three-Unit 

Building)

$214,650 $170,060 $180,678 $165,528 $15,150 

Northampton $241,991 $125,931 $119,701 $85,061 $34,640 

Lancaster $75,998 $41,402 $57,446 $47,408 $10,038 

Brookline 

(Partial DER: Walls 

and Windows Only)

$134,409 $80,929 $73,055 $58,850 $14,205 

Westford $117,710 $106,123 $107,464 $94,080 $13,384 

Gloucester $142,316 $95,436 $89,165 $70,665 $18,500 

* HVAC measures costs to not include water heating measure costs that are included in the DER measures costs for 

some projects.

** Energy-related DER measure costs for Belmont are taken from a post-project analysis produced by the 

homeowner with input from the contractor. 

There is considerable variation between projects in the DER measure costs. While many factors 

will affect variation in project costs, the size and scope of the project will have a very significant 

impact. Figure 33 and Figure 34 show the DER measure costs relative to post-retrofit 

conditioned floor area and treated enclosure area, respectively.
58 

Figure 33. Total, allowable, and energy-related DER measure costs normalized to

post-retrofit conditioned floor area

Figure 34. Total, allowable, and energy-related DER measure costs normalized to

treated enclosure area
59 

When normalized to conditioned floor area, the allowable DER measure costs range from 

$21.74–$45.84/ft2

 of post-retrofit conditioned floor area. The average for the group of projects is 

$32.40/ft2 of post-retrofit conditioned floor area. Normalized to treated enclosure surface area, 

the allowable DER measure costs range from $12.39–$26.03 and average $17.00/ft2 of treated 

enclosure surface area. While not exhibiting as much of a range as the nonnormalized DER 

project costs, the normalized project costs still vary by a factor of more than 2. 

The variation in normalized project costs exhibited between projects highlights the varying 

circumstances of each project, experience of the implementing contractors, and variations in 

approach. The remainder of this section presents the total measure cost and energy-related 

measure cost for a number of significant DER project components. This allows for an 

exploration of how different approaches to the DER measure package affect the measure costs. 

To facilitate the comparison between projects of varying size and circumstance, the cost data are 

presented as unit cost; i.e., normalized to area (either conditioned floor area, total enclosure area, 

or treated enclosure area) or number of dwelling units served (for HVAC measures).

4.3.1.1 Building Enclosure Measures

Figure 35 shows the reported unit (per square foot) total measure and energy-related measure 

cost for attic and roof retrofit measures implemented by projects in this study. For the projects 

that implemented insulating sheathing and cavity insulation, the major difference between total 

measure cost and energy-related measure cost is the cost of reroofing. One of the projects that 

implemented cavity insulation only also included the cost of reroofing in the total measure cost. 

The high total measure cost indicated for one of the projects implementing a vented attic 

approach represents the cost of framing and installing a new roof. 
60 

Figure 35. Unit costs for attic and roof measures

Among the different attic and roof approaches implemented by projects included in this study, 

the mean energy-related unit costs are lowest for those projects that implemented an unvented 

attic approach using spray foam insulation applied entirely below the existing roof deck. The 

mean energy-related unit cost is somewhat higher for the vented attic approach. Insulating 

sheathing plus cavity insulation is the attic and roof approach that exhibits the highest mean 

energy-related unit cost. The mean energy-related unit cost for this approach is 16% higher than 

the mean energy-related unit cost for the cavity insulation only approach. 

For all the projects in this study, the energy-related unit cost for the attic/roof measure ranges 

from $9.36–$18.05/ft2. The project with highest energy-related unit cost implemented an 

approach of insulating sheathing and roof framing cavity insulation. There was no insulation in 

the roof framing cavities prior to the DER project and the project also used three layers of 

insulating sheathing on the roof. One project (Millbury) that implemented a roof retrofit strategy 

involving insulating sheathing and cavity insulation has a reported energy-related unit cost that is 

lower than the mean for the cavity insulation only approach. For this project, existing insulation 

in the framing cavities was sufficient to allow the project to substantially meet the performance 

targets with two layers of insulating sheathing installed above the roof sheathing. This house is a 

11⁄2-story cape that presents a relatively low height and simple geometry roof that required 

minimal staging. 

The above analysis of unit costs for attic and roof measures compares measure cost to surface 

area of the enclosure. Once could argue that it would be more appropriate to compare the 

measure cost to the area of the building footprint that is covered by the attic and roof assembly, 

as is shown for the energy-related attic and roof measure costs in Figure 36. 
61 

Figure 36. Costs for energy-related attic and roof measures per square foot of building footprint 

covered

It has been asserted by Straube and Grin (2010) that insulation of the attic floor in a vented attic 

is the least costly strategy for achieving a high R-value attic and roof assembly. This is not 

immediately apparent in the data from this group of projects. In fact, excluding one apparent 

unvented attic outlier, it appears that the cost of providing thermal control at the top of the 

building may, in fact, be noticeably less with an unvented attic strategy using cavity insulation 

directly below the roof deck.1 Regardless of whether the unvented attic approaches are somewhat 

more or somewhat less costly than the vented attic strategy, it must be acknowledged that the 

unvented attic approach has the potential to enclose more usable space than a strategy employing 

insulation at the attic floor. Three of the projects in this study involve Cape Cod style homes that 

included living space within the roof enclosure prior to the retrofit. For four of the projects in this 

study, establishing the thermal enclosure at the plane of the roof allowed an increase in 

conditioned floor area. 

Figure 37 shows the reported unit (per square foot) total measure and energy-related measure 

cost for wall retrofit measures implemented by projects in this study. One project, Belchertown, 

implemented a wall retrofit measure involving interior insulation only. The other 12 projects in 

this study implemented a wall retrofit strategy of exterior insulation in addition to existing or 

new wall cavity insulation.

 

1 The increase in area to be insulated as well as the generally more expensive insulation material typically used in 

the unvented attic approach make this seem implausible. Mitigating factors that would add to the cost of the vented 

attic approach include efforts needed to make penetrations through the top floor ceiling airtight and to provide a well 

gasketed and insulated access (where needed).
62 

Figure 37. Unit costs for wall measures

The mean energy-related unit cost for the insulating sheathing and cavity insulation approach is 

clearly higher than the energy-related wall retrofit cost for the one project that implemented a 

cavity insulation only approach. Interestingly, four of the projects that implemented the 

insulating sheathing and cavity insulation approach exhibit a lower energy-related unit cost for 

this measure than the project implementing the cavity insulation only approach. 

Numbers above the bars in this chart designate the contractor implementing the project. It is 

worth noting that the contractor designated by the number “3” was a subcontractor to contractor 

“2” for the exterior wall insulation at the Belmont and Jamaica Plain projects. The data presented 

in this chart suggest that the variability of unit costs between contractors is more significant than 

the variability of cost between the different approaches.

Figure 38 shows the reported unit (per square foot) total measure and energy-related measure 

cost for foundation wall retrofit measures implemented by projects in this study. All of the 

foundation wall retrofit approaches implemented by projects in this study involve foam plastic 

insulation (rigid board or spray-applied) that requires an ignition barrier. This typically takes the 

form of an intumescent coating (for spray foam) or a frame wall with gypsum sheathing (for 

rigid insulation or spray foam). Two projects installed rigid board foam insulation without a 

frame wall. One of these used a proprietary insulation board with a thick aluminum facer, the 

other used OSB and plywood fastened directly over the foam boards. Only one of the projects in 
63 

this study provided a cost break-out with sufficient detail to distinguish energy-related measure 

costs from total foundation wall measure costs. 

Figure 38. Unit costs for foundation wall measures

There appear to be some unit cost anomalies for the two spray foam insulation approaches. 

Excluding these anomalies, the unit costs for foundation retrofit approaches using rigid 

insulation are clearly lower than for either approach involving spray foam insulation. Among the 

spray foam insulation approaches, the approach that uses a frame wall and gypsum board to 

establish the fire protection exhibits a higher mean unit cost. It should be noted that the rigid 

insulation approach is appropriate only for foundation walls with a flat interior surface. Also, the 

frame wall with gypsum board clearly provides a different level of finish to the basement space 

than does the spray foam with an intumescent coating. 

Figure 39 shows the reported unit (per square foot) total measure and energy-related measure 

cost for the floor or slab insulation retrofit measures implemented by projects in this study. For 

the projects that implemented a strategy of insulating over an existing slab, the cost information 

appears quite consistent. Among the projects that installed a new concrete slab over a new 

insulation layer, the variation in unit cost reflects differences in cost reporting. Only one of these 

projects reported costs in a way that allowed for the distinction of energy-related costs. The 

measure cost appeared to include the cost of a concrete slab in some cases. In one case, the 

basement slab measure is associated with comprehensive work to remediate bulk water 

problems. In another case, the slab retrofit measure cost appears to reflect the cost of the 

insulation only. 
64 

Figure 39. Unit costs for conditioned basement floor and slab measures

Because of the inconsistencies in the cost information for the measures involving insulation 

under a new slab, it is not possible to make comparison between the energy-related unit cost for 

different approaches based on the data used in this study. However, one would expect that 

inclusion of a new concrete slab (plus associated excavation if needed) would render the total 

cost much higher for the approach involving casting a new concrete slab. 

Only one project in this study pursued a strategy of insulating the basement ceiling to exclude the 

basement from the thermal enclosure. The total reported cost (all energy-related) for this measure 

is $5,870 with a unit cost of $5.56/ft2 basement ceiling area. This reported measure cost is lower 

than the reported cost for combined foundation wall and slab retrofit measures for the projects 

that included the basement within the thermal enclosure. For projects in this study that insulated 

foundation walls the average reported total measure cost, including reported costs for insulating 

the framing sill area (sometimes reported separately) is $6,793. For projects that insulated over 

an existing slab the average reported total measure cost is $5,005. Therefore, the average cost for 

combined foundation wall plus basement slab measures would be considerably more than the 

reported cost for insulating at the basement ceiling only.

Although we do not have direct cost comparison between an approach of insulating the basement 

ceiling versus an approach of insulating the foundation walls at a particular house, the cost 

information suggests that establishing the thermal boundary at the basement ceiling costs 

significantly less. As with the unvented versus vented attic strategies, the measure cost 

comparison for basement strategies must also consider the value of usable space that could be 

added through some of the strategies.
65 

Figure 40 shows the reported unit (per square foot) total measure cost for window measures 

implemented by projects in this study. There is no distinction between total measure cost and 

energy-related cost for this measure. 

Figure 40. Unit costs for window measures

All but one of the projects included in this study involved installation of new windows. The cost 

for the window measure varies significantly among the projects that installed new windows. Four 

of the projects that installed triple-pane windows reported a lower unit cost for the window 

measure than the project that installed double-pane windows. 

Figure 41 shows the unit (per square foot) total measure cost for air sealing measures as reported 

by projects in this study. There is no distinction between total measure cost and energy-related 

cost for this measure. 
66 

Figure 41. Unit costs relative to enclosure area for air sealing measures

Three of the projects reported no separate costs for air sealing. For the projects that did report a 

separate cost for air sealing measures, the description of air sealing measures varied widely. 

While some applications provided a description of techniques and materials, others appear to 

provide a general allowance under the heading of air sealing measures. It is interesting that three 

of the projects that reported the highest unit costs for air sealing measures also reported among 

the lowest unit costs for wall retrofit measures. Three of the projects reported no separate costs 

for air sealing.

Figure 42 shows the reported unit (per square foot) total measure cost and energy-related 

measure cost for all enclosure measures combined for each of the projects in this study. The 

combined enclosure measure costs are shown relative to the treated enclosure area for each 

project.
67 

Figure 42. Unit costs relative to enclosure area for all enclosure measures

The enclosure measure costs relative to enclosure surface appears more tightly clustered than the 

unit costs for individual components. For the total measure costs, the average enclosure measure 

cost relative to enclosure surface area is $18.62/ft2

 and the range is $9.99–$26.87/ft2. When 

considering only the energy-related enclosure measures, the average unit cost is $13.13/ft2

 and 

the range is $8.62–$22.20/ft2. 

To assess whether data show the relative cost of enclosure measures to be impacted by preretrofit conditions, the enclosure measure costs normalized to enclosure area are compared to the 

pre-retrofit air leakage measurement also normalized to enclosure area. The pre-retrofit air 

leakage measurement is taken as an indicator of the condition of the building enclosure prior to 

retrofit. As seen in Figure 43, there appears to be a slight relationship between relative enclosure 

measure costs and relative pre-retrofit air leakage measurement.
68 

Figure 43. Energy-related enclosure measure costs compared to 

pre-retrofit air leakage measurement

4.3.1.2 Heating, Ventilation, and Air Conditioning Measures

For mechanical system measures, the unit cost reflects the cost per system. This is important 

given that some of the projects in this study involve two- or three-family buildings with separate 

mechanical systems for each dwelling unit. There is no distinction between total measure cost 

and energy-related cost for these measures. 

Figure 44 shows the unit total measure cost for mechanical ventilation measures reported by 

projects in this study. 
69 

* For the Belchertown project, the mechanical system cost is included in the reported cost for the HVAC measures 

reported in aggregate.

Figure 44. Unit (per system) costs for mechanical ventilation

The central fan-integrated supply ventilation system implemented by the Millbury project has the 

lowest reported system cost at $1,500. The average of the reported system costs for HRV/ERV 

systems ducted directly to central heating and cooling system ductwork is approximately twice 

the reported cost for the central fan-integrated supply system. The average of the reported system 

costs for independently ducted HRV/ERV systems is approximately 40% more than the average 

of the reported system costs for HRV/ERV systems ducted directly to central heating and cooling 

system ductwork. Two of the projects implementing an independently ducted HRV/ERV system 

installed equipment that is significantly more expensive than the equipment installed in other 

implementations of the independently ducted HRV/ERV. 

The cost for the HRV/ERV ducted to a central AHU did not include the cost for dampers needed 

to isolate the HRV/ERV from the heating and cooling system ductwork when the ventilation 

system is idle. Therefore, the costs for a properly functioning ventilation system with HRV/ERV 

ducted to the central AHU are expected to be slightly higher than those reported. The central fanintegrated supply ventilation system implemented is not compatible with the heating and cooling 

system installed at this project and does not provide the desired control of ventilation. However, 

there is no reason that the cost of the ventilation system would be different if connected to a 

compatible heating and cooling system. 

Figure 45 shows the unit total measure cost for heating system measures reported by projects in 

this study. There is no distinction between total measure cost and energy-related cost for this 

measure. 
70 

* For the Belchertown project, the heating system cost includes cost for the ventilation and cooling system measures 

implemented at this project.

Figure 45. Unit (per system) costs for heating system measures

Eleven of the projects included in this study implemented new heating systems as part of the 

DER project. As can be seen in Figure 45, there is considerable variation in the heating system 

approach as well as system cost. For all projects implementing a new heating system the average 

reported system cost is $14,282. This average excludes the reported system cost for the 

Belchertown project, as the reported system cost for this project also includes the cost for the 

ventilation system and cooling measures. 

The cost for the multi-head mini-split ASHP systems appear to be significantly impacted by the 

extent to which these are provided with ducted distribution. The reported cost for both the ducted 

and partially ducted mini-split systems are comparable to reported costs for projects that 

implemented ducted furnace-base heating and ducted air conditioning. 

Costs for cooling system measures are difficult to isolate for many of the projects, because the 

cost of the cooling system measure as well as the cooling system function is represented in the 

heating system measure. Therefore, it is more useful to compare composite HVAC measure costs 

for the projects in this study as shown in Figure 46. 
71 

Figure 46. Unit (per system) costs for HVAC measures

In Figure 46 the HVAC costs for the GSHP system as well as for the HVAC systems that 

combine ASHP with fossil fuel combustion heating are noticeably higher than for other HVAC 

systems. Two projects, Westford and Jamaica Plain, retained pre-retrofit heating systems. One 

project (Brookline) replaced a boiler but retained the pre-retrofit hydronic heating distribution.

Table 10 below provides a summary of the HVAC measures implemented by each project with 

the total cost of HVAC measures implemented by each project. Total system costs ranged from 

just more than $10,000 to just more than $39,000 for projects that included installation of new 

high efficiency heating and cooling equipment and distributed ventilation with heat or energy 

recovery. 
72 

Table 10. HVAC Measures and Composite System Cost

Project Heat Source Cooling Source Heating/Cooling 

Distribution Ventilation Composite System Cost

Quincy New heat pump, and 

New boiler/water heater From heat pump 

Heat pump: new duct system,

Boiler/water heater: hydro-air 

and new radiant

HRV/ERV ducted 

to AHU $39,600 

Northampton Ground-source heat 

pump From heat pump New duct system Independently ducted HRV/ERV $32,590 

Newton New heat pump and 

New boiler/water heater From heat pump

Heat pump: modified existing 

duct system

Boiler/water heater: new and 

existing radiant

HRV/ERV ducted 

to AHU $31,500 

Millbury New Heat pump From heat pump Ducted mini-split (2 heads) Central fanintegrated supply $18,875 

Gloucester New Heat pump from heat pump Ducted (2 heads) and ductless 

(2 heads) mini-split

Independently 

ducted HRV/ERV $18,500 

Westford Existing furnace New AC (outdoor 

unit and indoor coil) Modified existing duct system Independently ducted HRV/ERV $16,868 

Belchertown New furnace New Indoor coil 

only New duct system HRV/ERV ducted to AHU $16,597 

Belmont New furnace New AC New duct system Independently 

ducted HRV/ERV $16,334 

Milton New boiler/water heater New AC New duct system (hydro-air 

heating)

HRV/ERV ducted 

to AHU $15,000 

Brookline New boiler/water heater none Existing hydronic Independently 

ducted HRV/ERV $14,205 

Arlington New furnace New indoor coil 

only New duct system HRV/ERV ducted to AHU $13,428 

Lancaster New heat pump From heat pump Ductless mini-split (2 heads) Independently 

ducted HRV/ERV $10,038 

Jamaica 

Plain

Existing boiler/water 

heater Existing hydronic New gasketed panels for existing window A/C

Independently 

ducted HRV/ERV $5,050 
73 

4.3.2 DER Cost Conclusions

Analysis of the cost information provided for the projects included in this study yield the 

following information regarding DER project costs: 

• Total DER project costs for the group of projects included in this analysis averaged 

$133,060 and ranged from $64,629–$241,991. Energy-related measure costs for the 

group of projects included in this analysis averaged $99,418 and ranged from $51,642–

$180,678. 

• For projects that included comprehensive implementation of the DER enclosure package 

including retrofit of the attic and roof, walls, windows, and either basement ceiling or 

foundation walls: 

o Total enclosure measure costs averaged $112,663 and ranged from $48,032–

$203,151. 

o Energy-related enclosure measure costs averaged $77,219 and ranged from 

$35,045–$165,528 

• Relative to the area of building enclosure treated, energy-related enclosure measure costs 

averaged $13.69/ft2

 and ranged from $8.62–$22.20/ft2. 

• The enclosure measure costs relative to enclosure surface appears more tightly clustered 

than the unit costs for individual components. 

• For projects included in this study that met the HVAC performance targets for heating 

and ventilation and installed new equipment including, at least, ventilation equipment and 

heating equipment, the average combined HVAC measure cost was $22,156 and ranged 

from just more than $10,000 to approximately $39,500. 

• The project that implemented a GSHP system as well as the projects that combined heat 

pump heating with fossil fuel heating exhibited significantly higher HVAC measure 

costs. Excluding these projects, the average HVAC measures cost for projects that 

installed, at least, new heating and ventilation equipment was $15,151. 

The variation in total project costs as well as energy-related measure costs results from many 

factors, including the physical size of the project. The unit costs for building enclosure measures 

reflect varying levels of experience among DER contractors, various conditions of existing 

buildings, as well as various approaches to the DER package of measures. In some cases, the 

contractors less experienced with DER techniques appear to have higher units cost, in some 

cases lower. This variability may decrease as the local market for DER services matures.

4.3.3 Cost and Effect

Despite a relatively uniform package of measures implemented by the projects, the reported costs 

for the DER projects vary greatly. This section explores whether the data collected from the early 

projects in the National Grid DER Pilot show relationships between cost and performance. 

4.3.4 Cost and Effect Analysis

4.3.4.1 Enclosure Measure Costs and Post-Retrofit Airtightness

To assess the relationship between enclosure measure costs and airtightness, both enclosure 

measure costs and post-retrofit air leakage measurements are normalized to enclosure area. 
74 

Figure 47 shows post-retrofit CFM50 per square foot of enclosure area plotted against energyrelated enclosure measure costs relative to enclosure area. There does not appear to be a strong 

relationship. The trendline suggests it is possible that the enclosure tends to be slightly leakier 

with increasing relative enclosure measure costs.

Figure 47. Post-retrofit CFM50/ft2 enclosure area versus energy-related

enclosure measure costs/ft2 enclosure area

Data presented in the previous section hinted at a relationship between pre-retrofit air leakage 

and enclosure measure costs. Therefore, the increase in relative enclosure measure costs seen 

with increasing post-retrofit relative air leakage may be a phenomenon of pre-retrofit air leakage 

affecting both relative enclosure measure costs and post-retrofit air leakage. 

Figure 48 presents, for projects that did not significantly alter the exterior enclosure (e.g., 

through an addition), the reduction in relative air leakage compared to energy-related enclosure 

measure cost relative to unit area of the enclosure. 
75 

Figure 48. Reduction in post-retrofit CFM50/ft2 enclosure area versus energy-related enclosure 

measure costs/ft2 enclosure area

There does appear to be a relationship between the reduction in relative enclosure leakage and 

the energy-related enclosure measure cost per square foot of enclosure area. This is unlikely to 

be a causal relationship, since both enclosure measure cost and available air leakage reduction 

are likely to be impacted by pre-retrofit air leakage.

4.3.4.2 Deep Energy Retrofit Measure Costs and Post-Retrofit Energy 

Performance

Among energy uses, heating and cooling energy use are most directly targeted by the package of 

DER measures. Figure 49, Figure 50, and Figure 51 show estimated heating and cooling EUI

compared to energy-related measure costs for enclosure measures, HVAC measures, and 

aggregate DER project measures, respectively. The energy-related measure costs are normalized 

to post-retrofit conditioned floor area in these charts. The heating and cooling EUI is presented 

only for those projects for which 12 months of post-retrofit energy use data were available. The 

heating and cooling EUI is expressed in terms of site energy to avoid impacts of heating fuel 

choices.
76 

Figure 49. Heating and cooling site EUI versus energy-related

enclosure measure costs/ft2 conditioned floor area

Figure 50. Heating and cooling site EUI versus energy-related

HVAC measure costs/ft2 conditioned floor area
77 

Figure 51. Heating and cooling site EUI versus combined energy-related

DER measure costs/ft2 conditioned floor area

There does not appear to be any relationship between variations in area-normalized energyrelated costs and the level of heating and cooling energy performance achieved. It follows that 

total post-retrofit EUI also appears unrelated to area-normalized energy-related measure costs 

(Figure 52 and Figure 53) 

Figure 52. Site EUI versus combined energy-related DER measure costs/ft2 conditioned floor area
78 

Figure 53. Source EUI versus combined energy-related DER measure

costs/ft2 conditioned floor area

Figure 54 and Figure 55 present a comparison of total energy use reduction to energy-related 

DER costs. There does not appear to be a relationship except for the few cases where pre-retrofit 

energy use is derived from an energy model rather than actual energy use data.
79 

Figure 54. Site energy use reduction versus combined energy-related DER measure costs

Figure 55. Source energy use reduction versus combined energy-related DER measure costs
80 

As appeared to be the case with air leakage, the amount of reduction available for energy use is 

likely to be significantly determined by the pre-retrofit conditions and use of the building. The 

pre-retrofit conditions and use are highly variable. It is possible that deriving a projection of preretrofit energy use from a model removes particular idiosyncrasies that tend to render actual 

energy use highly variable. If the model creates a more stable and more general baseline then it 

may be that greater levels of expenditure in DER tend to be generally correlated with greater 

energy use reductions.

Figure 56 presents the total energy-related measure costs per unit of energy use reduction. This 

metric might be referred to as an “energy-use-reduction-cost-effectiveness” measure as the cost

of energy-related measures are expressed relative to the effect of energy use reduction. 

Figure 56. Energy-related measure costs relative to energy use reduction

The significant outlier in this group, Brookline, represents a DER project consisting of the 

continuation and final stage of a comprehensive DER implemented over the course of several 

years and in discrete stages. Prior to the DER project stage evaluated in this study, the owners 

had undertaken significant measures to reduce energy use. It is likely that this earlier work 

resulted in relatively low energy use prior to the project that is evaluated in the current study. An 

already efficient (relatively speaking) home would yield less opportunity for energy use 

reduction. With smaller energy use reduction available, the general costs for the project are borne 

by lesser energy use savings in the energy-use-reduction-cost-effectiveness measure.

The horizontal lines in Figure 56 represent the approximate cost of achieving a 1 MMBtu energy 

use reduction or offset through the installation of a residential-scale, roof-mounted PV system 
81 

with reasonably favorable exposure. Among the five projects with actual pre-retrofit energy use 

data and 12 months of post-retrofit data, three show site energy-use-reduction-cost-effectiveness 

very near that of the hypothetical PV system, one project shows site energy use reduction cost 

that is significantly above that of the PV system, another project shows site energy use reduction 

cost that is significantly below. Obviously there are too few qualifying observations to be able to 

draw hard conclusions relative to site energy-use-reduction-cost-effectiveness. However, the 

preliminary DER pilot results examined in this study hint at the possibility that the DER package 

can achieve site energy use reductions for approximately the same cost as a PV system could 

offset site energy use. 

With respect to source energy use reductions and offsets, the preliminary results appear to 

indicate that source energy use is offset by a reasonably sited residential-scale PV system at a 

cost that is considerably lower than that of source energy use reductions achieved with the DER 

measures package. 

4.3.5 Cost and Effect Conclusions

Analysis of preliminary performance results and cost data for the DER pilot supports the 

following conclusions: 

• Both in terms of post-retrofit airtightness and EUI, there does not appear to be a 

relationship between performance achieved and variations in energy-related measure 

costs.

• The reduction in air leakage measurement does appear to be mildly correlated with 

variations in energy-related enclosure measure costs. A causal relationship between these 

cannot be suggested, as both air leakage reduction and energy-related enclosure measure 

costs are likely to be impacted by pre-retrofit conditions of the building. 

• When energy use reduction is calculated from actual pre- and post-retrofit energy use 

data, there does not appear to be a relationship between energy use reduction and 

variations in energy-related measure costs. 

• It appears at least possible that energy use reductions are correlated with variations in 

energy-related DER measure costs when and if it is possible to remove idiosyncrasies of 

actual pre-retrofit conditions from the pre-retrofit energy use baseline.

• Considering the energy use reduction effect in isolation, it appears possible that the 

package of DER measures can achieve site energy use reductions and offsets for a cost 

per MMBtu comparable to that of a reasonably well-sited residential PV system. 

However, in terms of source energy use, the preliminary results of the pilot suggest that 

reductions and offsets can generally be achieved at lower cost through installation of a 

reasonably well-sited residential PV system. 

4.3.6 Measure Costs and Benefits Relative to Homeowner Objectives

Homeowners perform upgrades and modifications to homes for a variety of different 

motivations. Sometimes, achieving energy savings might be an objective in performing 

upgrades, perhaps even the only objective of a particular expenditure. In other cases, energy 

savings might be a welcome by-product of an upgrade or modification pursued primarily for 
82 

nonenergy motivations. For most measures involving energy savings, objectives relating to 

energy performance share a place among other motivations. 

Window replacement is one common upgrade or modification where achieving energy savings is 

blended with other objectives. The National Grid DER pilot program imposes a $15/ft2 

deductible in determining the portion of window replacement cost that is eligible for incentives. 

The deductible amount is intended to represent the base cost for windows offering performance 

typical of vinyl-framed double-pane windows. But the increment of cost beyond $15/ft2 cannot 

be associated with purely energy-related objectives. Certainly, one would expect high quality 

wood or fiberglass-framed double-pane windows to cost considerably more than $15/ft2. The 

reported window measure costs shown in Section 4.3 demonstrate that one could pay more for a 

double-glazed window than for windows that offer a higher level of energy performance. Thus, 

the window measure provides an example of a measure for which it would be difficult to 

associate energy performance increment with a measure cost increment. 

Mechanical systems are often replaced because the existing equipment has exceeded its useful 

service life (whether or not this is manifest in the equipment). Mechanical systems might also be 

replaced to provide better comfort or to address concerns for combustion safety. 

Many of the projects participating in the DER pilot program implemented a conversion of 

basement or attic space to living space. Other projects involved a significant addition to the 

building. Because of building code requirements, these modifications and additions would 

require the installation of insulation whether or not the homeowner was interested in saving 

energy. 

Where measures are implemented in response to multiple objectives, how might the measure 

costs be associated with and apportioned among the various intended benefits? Where energy 

savings result from a DER measure, a portion of the costs might be associated with the energy 

savings benefits. But what portion of the measure costs might be attributed solely to energy 

benefits? What portion of measure costs might be assigned to other benefits? Answering these 

questions would first require an understanding of the motivations for a particular project. The 

National Grid DER pilot provides a unique opportunity to explore these questions as many 

project provided specific and general information about project objectives. 

4.3.7 Analysis of Project Objectives Relative to Energy-Related Measure Costs

The application for participation in the DER pilot includes a “Homeowner Objectives Check 

List” where the applicant can indicate the relative importance to the project for each of a list 

of objectives.2

 The importance is rated on a scale of 1 to 5 with 5 being the most important. 

Figure 57 shows, for illustration purposes only, an image of a completed checklist for one of the 

projects in this study. This is an optional input on the application. It was provided for nine of the 

projects included in this study. From this checklist is it possible to identify the priority objectives 

for the project. 

 

2 As indicated in Figure 43, this checklist is adapted from the application form for the Thousand Homes Challenge 

initiative of the Affordable Comfort Institute (ACI).
83 

Figure 57. Optional homeowner objectives checklist from DER program application
84 

For another project in the study, a Web-posted report of the project assembled by the homeowner 

indicates objectives pursued in the DER project. 

For the nine projects that provided input on the “Homeowner Objectives Check List” the 

importance rankings for each objective were aggregated across the checklist forms for individual 

projects to obtain a representation of the relative importance of various objectives for the group 

of projects. Figure 58 shows the results of this aggregation with objectives grouped into 

categories similar to how they are presented on the checklist. Figure 59 shows the top 20 

objectives for this group of projects as determined by this aggregation of importance rankings. 

As might be expected for a sample of projects where the homeowners are pursuing DER 

projects, objectives related to energy savings figure prominently for the group. Nonenergyrelated objectives also appear as significant for the group. Top nonenergy objectives for projects 

in this group include: 

• Changing living space (i.e., addition, comfort zone) 

• Increasing physical comfort 

• Upgrading building systems/façade: replace siding

• Investing resources in a long-term solution

• Improving indoor air quality

• Improving property market value and salability

• Addressing problems related to durability. 
85 

Figure 58. Numerical aggregation of objective priority score
86 

Figure 59. Project objectives ranked by aggregate priority score

Other parts of the program application also provide useful information about the project 

objectives. The applicants are asked to indicate other significant work related to the DER that the 

homeowner plans to undertake with or without the DER. For example, the applicants indicate 

whether reroofing, re-siding, basement conversion, major remodeling, or an addition is planned. 
87 

For individual DER projects, information about project objectives, project scope, as well as 

measure cost detail provides a basis for categorizing DER measures or portions of measures 

according to the relation of these measures to energy performance objectives and nonenergy 

objectives. For the 10 projects that provided information about project objectives, the energyrelated measures or portions of measures were evaluated to determine whether a project 

objective other than energy savings is primary, significant, or ancillary. 

Identifying the nonenergy objective as primary for a given measure indicates that this measure is 

likely to have been implemented in the absence of energy savings objectives. For example, 

where a project includes an addition or renovation that exposes wall cavities, building code 

requires that the wall framing cavities be insulated to the depth of the cavity or up to a nominal 

R-value of R-19 (whichever is less). The cavity insulation portion of a wall measure would have 

a nonenergy objective (i.e., code compliance) that is primary. Similarly, where a rough basement 

is converted to finished space and where the homeowner has indicated that addressing moisture 

issues and improving indoor air quality are important objectives of the project, nonenergy 

objectives would be primary for the depth of spray foam foundation insulation needed to control 

moisture, control airflow, and meet code insulation requirements. Also, for a home that had no 

working automatic heating system and where the homeowners wished to be relieved of the need 

to split several cords of wood each year, installation of a furnace is primarily a measure 

providing comfort and facilitating a change in lifestyle. 

The window allowance (or window deductible) relative to a window replacement measure 

represents a portion of the measure cost allocated to primarily nonenergy objectives where the 

project indicated an intention to replace windows with or without the DER project. The cost for 

replacing a door between a basement and bulkhead access would reflect a portion of project costs 

where nonenergy objectives are primary in the case where the existing door had deteriorated and 

proved ineffective at excluding pests. 

For measures where nonenergy objectives are determined to be significant, the measure may not 

have been pursued without the promise of energy savings; however, other indicated objectives 

for the project support implementation of the measure. In a sense, the nonenergy objectives for 

the project “subsidize” the energy savings benefit of the measure. Examples of measures for 

which a nonenergy project objective is significant include:

• Cooling system measures

• Installation of mechanical HRV or ERV systems

• Basement slab insulation where moisture-sensitive materials are to be installed or stored 

on the basement floor 

• New heating systems where the homeowners indicated an intention to discontinue 

heating with oil and eliminate on-site heating oil storage

• Adding blown-in insulation to undisturbed wall cavities where the project application 

indicates improving comfort as an important project objective.3

 

3 One could argue that all wall insulation could be responding to an objective of increasing comfort. In this analysis 

we apply the judgment that proper cavity insulation is sufficient to alleviate that majority of comfort concerns and 
88 

Cooling system measures are significantly associated with comfort and amenity-related 

objectives. Cooling system measures, particularly adding a cooling system to a home that did not 

have mechanical cooling, may not result in energy savings. Similarly, installing a ventilation 

system will not provide energy savings relative to having no mechanical ventilation. Where the 

ventilation system provides some recovery of energy from the ventilation system exhaust, there 

is assumed to be an intention to reduce the energy impact of ventilation; therefore, the nonenergy 

objectives cannot be primary for this measure. However, because of the net negative impact on 

energy savings, nonenergy objectives would need to be regarded as at least significant. 

The nonenergy-related project objectives are determined to be ancillary for a measure or portion 

of a measure if no other significant or primary project objectives can be associated with the 

measure. In this analysis, nonenergy objectives are determined to be ancillary for layers or depth 

of insulation beyond what is required by code. Insulating sheathing added above a roof as well as 

the cavity insulation added between roof framing are both considered to respond primarily to 

energy-related objectives if insulation at the attic floor is serviceable and no change in use is 

planned for the attic space. A layer of roof sheathing installed as a roofing nail base above 

insulating sheathing is considered primarily an energy-related measure because it is made 

necessary by the layers of insulating sheathing added as part of the roof retrofit measure. Utility 

program rebates (excluding the incentives provided through the DER pilot program) for heating, 

cooling or ventilation systems are considered to be portions of the measure cost reflecting 

energy-related objectives. 

The portion of the window measure cost beyond the window allowance or deductible is 

considered in this analysis to reflect energy-related objectives. This may under-represent the 

project cost allocation to nonenergy benefits because, as is seen in the examples presented in this 

study, homeowners do expend beyond the allowance amount for windows for nonenergy 

objectives. 

The contractor for one project in the study provided code-baseline cost alternates for DER 

measures related to expansion and conversion of space. For another project in the study, a postproject analysis produced by the homeowner in collaboration with the contractor indicated codebaseline costs for some of the DER measures implemented. This provided a clear basis for 

distinguishing between portions of measure cost reflecting primarily nonenergy objectives and 

portions of measure costs reflecting energy-related objectives. In many other instances, another 

method was needed to allocate costs for DER measure between code requirements (i.e., 

nonenergy objectives as primary) and energy-related objectives. Where the energy-related 

component of a particular DER measure involves a single insulation type and the reported 

measure cost detail does not otherwise divide the cost of this measure, the analysis allocated the 

cost of the measure component proportionally according to the R-value for the insulation layer 

that would be required by code and the R-value provided beyond code requirements. For 

example, where a foundation wall measure for a converted basement provides nominal thermal 

resistance of approximately R-20, one half of the reported cost for the insulation measure is 

assigned to primarily nonenergy objectives and one half of the reported cost is assigned to 

energy-related objectives. Admittedly, this is a crude division of cost; however, it provides an 

 

that the motivating comfort objective is typically derived from a desire to improve poor comfort conditions rather 

than to further improve already good comfort conditions.
89 

allocation of costs that is more nearly representative than regarding all of measure cost as either 

only related to nonenergy objectives or only related to energy savings goals. 

Through this measure-by-measure analysis and cost allocation, the total energy-related measure 

costs for each project can be represented in three categories:

1. Costs for energy-related measures for which a nonenergy project objective is primary. 

2. Costs for energy-related measures for which a nonenergy project objective is significant. 

3. Costs for energy-related measures pursued for no other apparent significant objective 

than achieving energy savings. 

The chart in Figure 60 shows the result of the measure cost categorization for each of the 10 

projects that provided information regarding project objectives. Table 11 summarizes the results 

for this group of projects. 

Figure 60. Cost of energy-related DER measures relative to project objectives
90 

Table 11. Allocation of Energy-Related DER Measure Costs According to Project Objectives

Average 

of Sample Minimum Maximum

Portion of energy-related measure costs for which 

nonenergy project objective is primary 20% 0% 49%

Portion of energy-related measure costs for which 

nonenergy project objective is significant 27% 6% 56%

Portion of energy-related measure costs for which 

nonenergy project objective is primary or 

significant

47% 27% 64%

Costs of energy-related measures pursued for no 

other apparent significant objective relative to total 

energy-related measure costs

53% 36% 73%

It is important to note that measure costs associated with no apparent significant project objective 

other than energy savings does not provide the basis for a comparison of measure costs to 

benefits defined in terms of energy cost savings. The projects providing information regarding 

project objectives indicated that energy objectives beyond those reflected in energy cost are 

significant for these projects. Figure 58 showed the project objective importance rankings 

aggregated for nine projects. Among the listed objectives presented in the “Homeowner 

Objectives Check List,” seven relate to energy performance. These are:

• Reduce energy use. 

• Reduce household carbon footprint. 

• Reduce energy cost. 

• Reduce use of finite resources. 

• Reduce water/waste water use. 

• Reduce peak electrical use. Increase adaptability - energy price increases. 

• Contribute to community carbon reduction demonstration. 

Some of these objectives—“Reduce energy cost” and “Increase adaptability [with respect to] 

energy price increases—are clearly related to energy cost. Others—“Reduce energy use” and 

“Reduce peak electrical use”—may reflect energy cost objectives but might also reflect 

objectives related to certain externalities associated with energy use. Three of the energy-related 

objectives—“Reduce household carbon footprint,” “Reduce use of finite resources,” and 

“Contribute to community carbon reduction demonstration”—appear to reflect objectives related 

to externalities of energy use. Objectives related to energy costs can be monetized, that is, they 

can be measured in units that are directly comparable to units used to measure implementation 

costs. Objectives reflecting externalities of energy use are not easily monetized.
91 

Figure 61 represents an aggregation across the same nine projects for only those objectives 

related to energy performance. 

Figure 61. Numerical aggregation of energy-related objective scores

The aggregation of objective ranking represented in Figure 61 indicates that among the two most 

important energy-related objectives for the group of projects, one objective relates to energy cost 

and another may relate to energy cost but might also reflect an objective relating to certain 

externalities associated with energy use. The third and fourth most important energy-related 

objectives for this group reflect concerns for externalities of energy use. The fifth most important 

energy-related objective represents an energy cost objective. 

4.3.8 Energy-Related Measures Costs and Objectives Conclusions

The analysis of measure costs relative to project objectives was able to assert allocation of 

energy-related measure costs to energy objectives alone, energy and other project objectives and 

primarily nonenergy project objectives. As can be seen in Figure 60 and Table 11, the analysis 

suggests that nonenergy project objectives that are either of primary importance or significant for 

a sizeable portion of energy-related measure costs. Figure 61 reminds us that important energyrelated objectives are not necessarily related to energy costs. This suggests that a costeffectiveness measure that compares the cost of a measure to an energy cost benefit is a 

significantly inadequate representation of the effectiveness of the measure relative to project 

objectives.
92 

5 Conclusions

5.1 Summary of Results and Conclusions

General conclusions from this research project are as follows:

• For a homeowner who has kept the home reasonably well maintained and up to date, a 

DER can be expected to result in a 30%–45% energy use reduction, assuming that the 

post-retrofit conditions do not include a major addition or major change in lifestyle. 

• The emphasis in this DER package on establishing the air control system can result in an 

ACH50 of 1.5 or lower, provided the basement is included within the thermal enclosure. 

• As a group within this community, the chainsaw retrofits had the lowest heating and 

cooling energy use (in kBtu/ft2) as well as the best airtightness results. However, given 

the data available, it cannot be concluded that use of the chainsaw technique is the only 

determining factor.

• Improvements are needed in the design, installation, and homeowner education of HVAC 

systems for DERs.

• The costs for building enclosure measures reflect varying levels of experience among 

DER contractors, various conditions of existing buildings as well as various approaches 

to the DER package of measures.

• Contractor experience and a number of other factors impact costs to the extent that trends 

are difficult to identify at this stage and with this size sample of DER projects. This could 

be ameliorated by analysis of a larger sample of DER projects after the local market for 

DER services has had additional time to mature and stabilize.

• When comparing costs for HVAC measures between DER projects it is important to 

consider the composite HVAC measure costs. The projects exhibit a great variety of 

approaches relative to separate HVAC function (i.e., heating, cooling, ventilation). 

• Analysis of measure costs relative to project objectives demonstrate that objectives 

beyond energy cost are often the primary motivation for measures related to energy 

savings. Therefore a cost-effectiveness metric that compares the cost of a measure to an 

energy cost benefit alone is a significantly inadequate representation of the effectiveness 

of the measure relative to project objectives.

Additional specific conclusions for the airtightness, energy use, construction cost, and project 

objective relative to cost analyses are provided at the end of each of the analysis sections. 

5.2 Progress on Research Questions

The following summarizes responses to the research questions based on the analysis of the 13 

retrofits in this community. 

• Does the DER measures package result in 30% source energy reduction use?

o The range of post-retrofit source energy reduction when compared to a year of 

pre-retrofit source energy use was 27%–75%. However, this is dependent on the 

pre-retrofit conditions as well as the lifestyle of the occupants. 
93 

• Are there discernible differences in source energy use reduction between the 

variations allowed within the DER measures package?

o The lowest levels of source energy use for heating and cooling in kBtu/ft2-yr were 

achieved by the chainsaw retrofits with the air control layer outside of the existing 

sheathing and with exterior insulating sheathing for the walls and roof. However, 

given the data available, it cannot be concluded that these characteristics are the 

only determining factors. 

o The lowest levels of source energy use for heating and cooling in kBtu/ft2-yr were 

achieved by retrofits for which the airtightness was measured at 1.5 ACH50 or 

less.

o Failure to include the basement in the thermal enclosure appears to result in 

higher heating and cooling EUI. However, with only one example in this 

community, this is only an anecdotal conclusion at this time. 

• What post-retrofit airtightness has been achieved by the DER measures package?

o For this community, the post-retrofit airtightness results ranged from 0.61–7.26 

ACH50 with all but four of the retrofits falling below 1.5 ACH50. 

• Are there discernible differences in air leakage reduction between the variations 

allowed within the DER measures package?

o When taken as a group, the lowest air leakage results in this community were 

achieved by the chainsaw retrofits with the air control layer outside of the existing 

sheathing and with exterior insulating sheathing for the walls and roof. However, 

given the data available, it cannot be concluded that these characteristics are the 

only determining factors. 

o The highest air leakage result, which was significantly higher than all others, 

occurred for the one retrofit that did not include the basement in the conditioned 

space, for which the air control layer transitioned from the inside for the roof to 

the outside for the exterior walls, and for which porches and decks were not 

temporarily detached during the retrofit—all of these conditions can contribute to 

higher air leakage results. 

• What are the costs of the DER measures package? 

o For projects included in this study, the average enclosure measure cost relative to 

enclosure surface area is $18.62/ft2

 and the range is $9.99–$26.87/ft2. When 

considering the costs for energy-related enclosure measures only, the average unit 

cost is $13.13/ft2 and the range is $8.62–$22.20/ft2. 

o Total HVAC system costs ranged from slightly more than $10,000 to just less 

than $19,000 for projects that met the pilot program target by installing high 

efficiency heating and cooling equipment and distributed ventilation with heat or 

energy recovery. 
94 

• Can the net cost of energy performance improvement be separated from full DER 

measures package cost?

o The net cost of energy performance improvement cannot be fully separated from 

measure package costs. However, given sufficient measure cost detail and 

information pertaining to project scope and objectives, it is possible to assert the 

portion of costs representing (1) measures pursued solely for energy-related 

objectives; (2) measures pursued for a combination of energy-related and 

nonenergy-related objectives; and (3) measures pursued primarily in response to 

nonenergy-related objectives.

5.3 Recommendations for Future Work

Satisfying the long-term goal of significantly reducing residential energy use will require that 

existing homes be retrofit to levels of performance commensurate with current high-performance

practice. DER represents a path toward high performance for existing homes. There are 

significant barriers to widespread adoption of DER among these are the following: 

• Savings potential of DER is not adequately understood or accepted 

• Costs for DER are not adequately understood 

• DER methods are not adequately understood 

• Perceptions that DER will compromise the aesthetics of existing homes. 

Below is an outline of research efforts that would address these barriers.

5.3.1 Analyze Measured Performance and Costs of Expanded Deep Energy 

Retrofit Project Population

The current research advances the understanding of DER savings potential and costs. However, 

with the National Grid DER pilot having completed another year of implementation, there will 

soon be an opportunity to expand the analysis both in terms of number of projects examined and 

time period of examination. In 2012, the final year of the National Grid DER pilot, more projects 

completed a DER project through the program than in the previous years of the program 

combined. Expanding the number of projects included in the analysis is important to evaluating 

trends that are merely suggested or not even apparent in the population analyzed for the current 

research. Expanding the time period of examination for projects that have completed in past 

years will provide an opportunity to assess the durability of energy savings and other 

performance measures.

5.3.2 Builder Costs

The current research has analyzed costs of DER measures in terms of costs to the homeowner. 

Wider adoption of DER measures by contractors is likely to require greater understanding of the 

contractor’s cost of implementation. Revealing actual implementation costs may place 

contractors in an awkward position vis-à-vis current and potential clients. A larger population of 

completed DER projects and deeper experience of contractors having completed multiple DER 

projects may create a situation conducive to sharing implementation cost information. 
95 

5.3.3 Deep Energy Retrofit Measure Guidance

With 44 DER projects completed, the National Grid DER program provides an opportunity to 

review challenges encountered and solutions achieved with the goal of disseminating these 

lessons learned. Information resources could be developed to explain common challenges and 

illustrate successful solutions. Such information resources would support contractors interested 

in implementing high performance retrofit of existing homes. 

5.3.4 Case Studies Focused on Comprehensive Performance

The DER projects supported by National Grid and BSC have pursued comprehensive high 

performance. This includes high performance in terms of health and safety, durability, comfort, 

energy use and, quite arguably, aesthetics. Many of the projects encountered have demonstrated 

significant aesthetic improvement relative to the pre-retrofit conditions. Case studies of 

particularly attractive or visually interesting DER projects could highlight the potential aesthetic 

benefits of DER projects. Placing these case studies in publications oriented toward aesthetic 

performance of homes would strengthen the impact relative to addressing perceptions that DER 

might negatively impact the appearance of a home. 

5.3.5 Collaboration With Historic Preservation Stakeholders

Some resistance to DER of buildings is expected from those interested in preserving the 

character of existing buildings. Collaboration with experts in historic preservation might yield 

guidance for specialized high performance retrofit techniques needed in particularly sensitive or 

significant structures.
96 

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National Grid, https://www1.nationalgridus.com/Files/AddedPDF/POA/der_desc.pdf. Accessed 

December 2012. 

Neuhauser, K. (2011). “RR-1111: National Grid Deep Energy Retrofit Pilot.” Somerville, MA: 

Building Science Corporation, http://www.buildingscience.com/documents/reports/rr-1111-

national-grid-der-pilot/view. Accessed August 17, 2012. 

Neuhauser, K. (2012). “RR-1205: Attic or Roof? An Evaluation of Two Advanced 

Weatherization Packages.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/reports/rr-1205-attic-or-roof-evaluation-two-advancedweatherization-packages/view. Accessed October 29, 2012. 

Osser, R.; Neuhauser, K.; Ueno, K. (2012) “RR-1107: Proven Performance of Seven Cold 

Climate Deep Retrofit Homes.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/reports/rr-1107-final-retrofit-pilot-community-evaluationreport/view. Accessed March 4, 2013.
97 

Pettit, B. (2008) “Remodeling for Energy Efficiency.” Fine Homebuilding Magazine

(April/May).

RESNET. (2009) “Chapter Eight RESNET Standards.” Residential Energy Services Network. 

http://resnet.us/standards/DRAFT_Chapter_8_July_22.pdf. Accessed December 2012. 

Spanier, J.; Scheu, R.; Brand, L.; Yang, J. (2012). Chicagoland Single-Family Housing 

Characterization. Golden, CO: National Renewable Energy Laboratory, NREL/SR-5500-55089. 

Straube, J.; Grin, A. (2010). “Building America Special Research Project: High-R Roofs Case 

Study Analysis.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/reports/rr-1006-ba-high-r-roofs-case-studyanalysis/view?topic=resources/high-r-value-roof-assemblies. Accessed March 13, 2013. 

Ueno, K. (2010a). “RR-1012: Residential Exterior Wall Superinsulation Retrofit Details and 

Analysis.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/reports/rr-1012-residential-exterior-wall-superinsulationretrofit/view. Accessed January 7, 2011. 

Ueno, K. (2010b). “Building Science Digest 151: Understanding Primary/Source and Site 

Energy.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/digests/bsd151-understanding-primary-source-siteenergy/files/BSD-151%20Source-Site_Energy.pdf. Accessed December 20, 2012. 

Ueno, K.; Lstiburek, J. (2012). “RR-1108: Hybrid Foundation Insulation Retrofits—Measure 

Guidelines.” Somerville, MA: Building Science Corporation, 

www.buildingscience.com/documents/reports/rr-1108-hybrid-foundations-retrofits-measureguideline/view. Accessed August 17, 2012. 

Wilcox. S.; Marion,W. (2008). Users Manual for TMY3 Data Sets. Golden, CO: National 

Renewable Energy Laboratory, NREL/TP-581-43156. www.nrel.gov/docs/fy08osti/43156.pdf. 

Accessed December 20, 2012. 
98 

Appendix A:

Appendix A.1: Belchertown MA Retrofit

Figure A.1.1. Belchertown Pre-retrofit (left) and Post-retrofit (right, photo by David Connelly Legg)

The long-time residents of this home have an extremely frugal life style. Prior to the retrofit, the 

house was largely uninsulated and was heated using a wood stove. There was often standing 

water in the basement. The DER project was part of a comprehensive renovation project that 

included structural repairs, extensive water management improvements and a full interior 

rehabilitation as well as a full implementation of the DER package except for the windows.

• House Type: Single-family 1.5 story house with full basement 

• Date Built: around 1760 

• DER Completion: January 2010 

• Pre-Retrofit Conditioned Space: 1,435 sf 

• Post-Retrofit Conditioned Space: 1,907 sf 

• Pre-Retrofit Heating Fuel: Wood

• Post-Retrofit Heating Fuel: Propane
99 

Figure A.1.2. Belchertown DER Enclosure Profile 
100 

Figure A.1.3. Belchertown DER Mechanical Design

Figure A.1.4. Belchertown Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

1

2

3

4

5

6

7

8

9

10

source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
101 

Appendix A.2: Belmont MA Retrofit

Figure A.2.1. Belmont Pre-retrofit (left, with permission of National Grid) and Post-retrofit (right)

This two-family house with attic and full basement was largely uninsulated and in need of major 

renovations and updating when purchased by the current owner. The renovations were combined 

with a DER after which the owner and his family moved into the upper unit and his parents 

moved into the first floor unit. The renovations included extensive interior improvements and 

modifications along with a full implementation of the DER package except that the basement 

slab was not insulated. 

• House Type: Two-family colonial with full basement 

• Date Built: 1925

• DER Completion: September 2010 

• Pre-Retrofit Conditioned Space: 3,417 sf 

• Post-Retrofit Conditioned Space: 4,768 sf 

• Pre-Retrofit Heating Fuel: Oil

• Post-Retrofit Heating Fuel: Natural Gas
102 

Figure A.2.2. Belmont DER Enclosure Profile 
103 

Figure A.2.3. Belmont DER Mechanical Design

Figure A.2.4. Belmont Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

2

4

6

8

10

12

14

16

18

20

Source MMBtu Source MMBtu w/ PV credit HDD CDD
104 

Appendix A.3: Millbury MA Retrofit

Figure A.3.1. Millbury Pre-retrofit (left, with permission of National Grid) and Post-retrofit (right)

The owners have lived in this Cape Cod style house for more than 25 years making interior 

improvements and repairs during that time as needed. Upon becoming “empty nesters”, they 

undertook an exterior-only upgrade that included a full implementation of the DER package. As 

part of the project, a partial shed dormer in the rear of the upper floor was extended to the full 

length of the house. 

• House Type: Single-family 1.5 story Cape Cod style house with full basement 

• Date Built: 1953

• DER Completion: December 2010 

• Pre-Retrofit Conditioned Space: 1,868 sf 

• Post-Retrofit Conditioned Space: 1,868 sf 

• Pre-Retrofit Heating Fuel: Oil and wood pellets 

• Post-Retrofit Heating Fuel: Electricity
105 

Figure A.3.2. Millbury DER Enclosure Profile 
106 

Figure A.3.3. Millbury DER Mechanical Design

Figure A.3.4. Millbury Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

5

10

15

20

25

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
107 

Appendix A.4: Milton MA Retrofit

Figure A.4.1. Milton Pre-retrofit (left) and Post-retrofit (right)

The Milton home was unoccupied and bank-owned when purchased by the current owner in 

2010. The existing home had fiberglass cavity insulation in the exterior walls and in the attic 

floor. A comprehensive interior renovation, including reconfiguration of interior spaces, and a 

full implementation of the DER package was completed prior to when the current owner moved 

in. The owner uses the home for his family as well as for a home office.

• House Type: Single-family garrison colonial with full basement 

• Date Built: around 1960 

• DER Completion: February 2011 (Move in August 2011) 

• Pre-Retrofit Conditioned Space: 2,368 sf 

• Post-Retrofit Conditioned Space: 2,368 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
108 

Figure A.4.2. Milton DER Enclosure Profile 
109 

Figure A.4.3. Milton DER Mechanical Design

Figure A.4.4. Milton Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

2

4

6

8

10

12

14

16

Source MMBtu Source MMBtu w/ PV credit HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
110 

Appendix A.5: Quincy MA Retrofit

Figure A.5.1. Quincy Pre-retrofit (left) and Post-retrofit (right)

This 1.5 story bungalow home with full basement was purchased and occupied by the current 

owners in 1985. In 2011, a major expansion of the original house was combined with 

implementation of the full DER package. The newly expanded home also serves as a home 

office.

• House Type: Single-family 2.5 story expanded bungalow with full basement 

• Date Built: around 1905 

• DER Completion: December 2010 

• Pre-Retrofit Conditioned Space: 3,484 sf 

• Post-Retrofit Conditioned Space: 4,576 sf 

• Pre-Retrofit Heating Fuel: Oil

• Post-Retrofit Heating Fuel: Natural Gas
111 

Figure A.5.2. Quincy DER Enclosure Profile 
112 

Figure A.5.3. Quincy DER Mechanical Design

Figure A.5.4. Quincy Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

2

4

6

8

10

12

14

16

18

Source MMBtu Source MMBtu w/ PV credit HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
113 

Appendix A.6: Arlington MA Retrofit

Figure A.6.1. Arlington Pre-retrofit (left) and Post-retrofit (right)

This two-family home was purchased in 2009 with the intent of renovation and then to serve as 

homes for the owners and the parents of one of the owners. The renovation included the addition 

of space on the upper floor and was combined with a full implementation of the DER package. 

The project team decided to leave the basement unconditioned and to insulate and air seal at the 

basement ceiling.

• House Type: Over-under two-family with full basement

• Date Built: around 1910 

• DER Completion: March 2011 

• Pre-Retrofit Conditioned Space: 2,502 sf 

• Post-Retrofit Conditioned Space: 3,627 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
114 

Figure A.6.2. Arlington DER Enclosure Profile
115 

Figure A.6.3. Arlington DER Mechanical Design

Figure A.6.4. Arlington Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

5

10

15

20

25

30

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
116 

Appendix A.7: Newton MA Retrofit

Figure A.7.1. Newton Pre-retrofit (left, with permission of National Grid) and Post-retrofit (right)

This 1.5 story Cape Cod style house was purchased and occupied by the current owner in 2006. 

The retrofit project started in 2010 as a conversion of the basement to conditioned living space 

along with an upgrade of the existing heating and hot water systems but was expanded to include 

a full implementation of the DER package. 

• House Type: Single-family Cape Cod style with full basement

• Date Built: 1930

• DER Completion: June 2011 

• Pre-Retrofit Conditioned Space: 1,815 sf 

• Post-Retrofit Conditioned Space: 2,199 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
117 

Figure A.7.2. Newton DER Enclosure Profile
118 

Figure A.7.3. Newton DER Mechanical Design

Figure A.7.4. Newton Monthly Total Source Energy Use August 2011 – July 2012 

0

200

400

600

800

1000

1200

0

2

4

6

8

10

12

14

16

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
119 

Appendix A.8: Jamaica Plain MA Retrofit

Figure A.8.1. Jamaica Plain Pre-retrofit (left) and Post-retrofit (right)

The current owner of this triple-decker purchased the house in 2006, occupying the 2nd floor unit. 

As a first step towards improved energy efficiency, a high performance gas boiler system with a 

generator was installed in 2008 to provide heating for all units. Two years later, efficiency 

improvements were continued with a full implementation of the DER package. 

• House Type: Triple-decker with full basement 

• Date Built: 1907

• DER Completion: July 2011 

• Pre-Retrofit Conditioned Space: 3,885 sf 

• Post-Retrofit Conditioned Space: 3,885 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
120 

Figure A.8.2. Jamaica Plain DER Enclosure Profile
121 

Figure A.8.3. Jamaica Plain DER Mechanical Design

Figure A.8.4. Jamaica Plain Monthly Total Source Energy Use August 2011 – July 2012

0

200

400

600

800

1000

1200

0

5

10

15

20

25

Source MMBtu Source MMBtu w on-site gen HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
122 

Appendix A.9: Northampton MA Retrofit

Figure A.9.1. Northampton Pre-retrofit (left, with permission of National Grid) and Post-retrofit 

(right) 

The owners of this house have lived there with a low energy life-style since 1988 and have made 

renovations and additions over the years. In anticipation of needing additional first floor space to 

accommodate an older extended family member, they decided to rebuild an earlier addition and 

to add some new space including a home office. This project was combined with a full 

implementation of the DER package. 

• House Type: Single-family Victorian with full basement

• Date Built: 1859

• DER Completion: August 2011 

• Pre-Retrofit Conditioned Space: 2,032 sf 

• Post-Retrofit Conditioned Space: 2,747 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Electricity
123 

Figure A 9.2. Northampton DER Enclosure Profile
124 

Figure A.9.3. Northampton DER Mechanical Design

Figure A.9.4. Northampton Monthly Total Source Energy Use August 2011 – July 2012 

0

200

400

600

800

1000

1200

0

2

4

6

8

10

12

14

Source MMBtu Source MMBtu w PV credit HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
125 

Appendix A.10: Lancaster MA Retrofit

Figure A.10.1. Lancaster Pre-retrofit (left, with permission of National Grid) and Post-retrofit 

(right) 

This building on property donated to Habitat for Humanity was in a significant state of 

deterioration. The basement and first floor framing of the building were retained though repairs 

of the foundation wall were required. In order to provide the living space required by the 

program, the roof was removed and a new second floor and roof were built. A full 

implementation of the DER package was included as part of the project. The new owners moved 

in after completion of the project. 

• House Type: Single-family 2-story colonial with full basement

• Date Built: 1900

• DER Completion: August 2011 (Move in September 2011) 

• Pre-Retrofit Conditioned Space: 980 sf

• Post-Retrofit Conditioned Space: 1,440 sf 

• Pre-Retrofit Heating Fuel: Oil

• Post-Retrofit Heating Fuel: Electricity
126 

Figure A.10.2. Lancaster DER Enclosure Profile
127 

Figure A.10.3. Lancaster DER Mechanical Design

Figure A.10.4. Lancaster Monthly Total Source Energy Use February 2012 – July 2012

0

200

400

600

800

1000

0

2

4

6

8

10

12

Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12

Source MMBtu Source MMBtu w PV credit HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
128 

Appendix A.11: Brookline MA Retrofit

Figure A.11.1. Brookline Pre-retrofit (left) and Post-retrofit (right)

The current owners purchased and moved into this house in 2006. In 2009, some upgrades for 

modernization and for better energy efficiency were made, including installing insulation under 

the roof deck and on the inside of the existing foundation walls. Therefore, the 2011 DER 

retrofit was actually the 2nd stage of a 2 stage DER after which all of the measures of the DER 

package had been carried out with the exception of insulating the basement floor. 

• House Type: Single-family 3-story Victorian with full basement

• Date Built: 1899

• DER Completion: November 2011 

• Pre-Retrofit Conditioned Space: 3,078 sf 

• Post-Retrofit Conditioned Space: 3,174 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
129 

Figure A.11.2. Brookline DER Enclosure Profile
130 

Figure A.11.3. Brookline DER Mechanical Design

Figure A.11.4. Brookline Monthly Total Source Energy Use February 2012 – July 2012 

0

200

400

600

800

1000

0

2

4

6

8

10

12

Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
131 

Appendix A.12: Westford MA Retrofit

Figure A.12.1. Westford Pre-retrofit (left) and Post-retrofit (right)

Having been built in 1993, this is the newest house among this retrofit community. The current 

owners purchased and moved into the house in 2003. After living there for several years, they 

started planning for improvements that would better meet their needs including an addition on 

the back and reframing the roof so that living space could be accommodated in the attic. These 

modifications were combined with implementation of the full DER package with the exception 

of the insulation of the basement floor. For aesthetic reasons, they also chose to install windows 

that were somewhat below the target R-value. 

• House Type: Single-family modern Colonial with full basement 

• Date Built: 1993

• DER Completion: December 2011 

• Pre-Retrofit Conditioned Space: 2,906 sf 

• Post-Retrofit Conditioned Space: 3,955 sf 

• Pre-Retrofit Heating Fuel: Natural Gas

• Post-Retrofit Heating Fuel: Natural Gas
132 

Figure A.12.2. Westford DER Enclosure Profile
133 

Figure A.12.3. Westford DER Mechanical Design

Figure A.12.4. Westford Monthly Total Source Energy Use February 2012 – July 2012 

0

200

400

600

800

1000

0

5

10

15

20

25

Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
134 

Appendix A.13: Gloucester MA Retrofit

Figure A.13.1. Gloucester Pre-retrofit (left) and Post-retrofit (right)

This cottage on a coastal cove had been in a family for many years but had been unoccupied 

since the death of the owner in 2009. Another family member purchased the house in 2010. 

Prior to moving in, the new owners had the interior updated and, since an upgrade of the 

enclosure was needed as well, incorporated a full implementation of the DER package into the 

renovation project. 

• House Type: Single-family coastal cottage with full basement and crawlspace

• Date Built: 1920

• DER Completion: January 2012 

• Pre-Retrofit Conditioned Space: 2,171 sf 

• Post-Retrofit Conditioned Space: 2,424 sf 

• Pre-Retrofit Heating Fuel: Oil

• Post-Retrofit Heating Fuel: Electricity
135 

Figure A.13.2. Gloucester DER Enclosure Profile
136 

Figure A.13.3. Gloucester DER Mechanical Design

Figure A.13.4. Gloucester Monthly Total Source Energy Use February 2012 – July 2012 

0

200

400

600

800

1000

0

2

4

6

8

10

12

14

16

18

Feb-12 Mar-12 Apr-12 May-12 Jun-12 Jul-12

Source MMBtu HDD CDD

Source Energy MMBtu (monthly)

HDD & CDD (65F)
137 

Appendix B:

Appendix B: BEopt V1.3 Generated Pre-retrofit Data for Belmont, Milton, Quincy, 

Arlington, and Lancaster Retrofits

For several of the projects in this community, pre-retrofit energy use data was not provided in the 

National Grid DER Pilot Program application because it was unavailable or it was incomplete. 

For this research project and report, when the pre-retrofit data was not provided, a BEopt V1.3 

model for the pre-retrofit conditions was created and the yearly site energy use generated by 

BEopt was used for the pre-retrofit data in Table XXX. 

In the following subsections, the graphs of yearly site electricity, natural gas, fuel oil, and/or 

propane site energy use that were generated by BEopt are provided. Since the reference building 

is not relevant for this purpose, the “Existing” and the “Pre-Retrofit” buildings are identical.

Belmont Retrofit

The Belmont pre-retrofit energy use includes electricity, natural gas (for domestic hot water and 

for clothes dryer) and fuel oil (for heating).

Figure B.1. Belmont Pre-Retrofit Yearly Site Electricity Use Generated by BEopt V1.3
138 

Figure B.2. Belmont Pre-Retrofit Yearly Site Fuel Oil Use Generated by BEopt V1.3

Figure B.3. Belmont Pre-Retrofit Yearly Site Natural Gas Use Generated by BEopt V1.3

Milton Retrofit

The Milton pre-retrofit energy use includes electricity and natural gas (for domestic hot water 

and for heating). 
139 

Figure B.4. Milton Pre-Retrofit Yearly Site Electricity Use Generated by BEopt V1.3

Figure B.5. Milton Pre-Retrofit Yearly Site Natural Gas Use Generated by BEopt V1.3 

Quincy Retrofit

The Quincy homeowners provided a year of pre-retrofit electricity use but were unable to 

provide a full year of fuel oil use which was used for heating and domestic hot water. Therefore 

the use of fuel oil (in gallons) for the year of pre-retrofit data was provided by the BEopt model. 
140 

Figure B.6. Quincy Pre-Retrofit Yearly Site Fuel Oil Use Generated by BEopt V3

Arlington Retrofit

The Arlington pre-retrofit energy use includes electricity and natural gas (for domestic hot water 

and for heating). 

Figure B.7. Arlington Pre-Retrofit Yearly Site Electricity Use Generated by BEopt V1.3
141 

Figure B.8. Arlington Pre-Retrofit Yearly Site Natural Gas Use Generated by BEopt V1.3

Lancaster Retrofit

The Lancaster pre-retrofit energy use includes electricity and fuel oil (for heating and domestic 

hot water). 

Figure B.9. Lancaster Pre-Retrofit Yearly Site Electricity Use Generated by BEopt V1.3
142 

Figure B.10. Lancaster Pre-Retrofit Yearly Site Fuel Oil Use Generated by BEopt V1.3
Appendix C 

Appendix C: National Grid Deep Energy Retrofit Application Part (B), Excel 

Component 

143 
Contents 

Part A is Word Document which contains general instructions as well as sections noted here 

Part B is this Excel File 

Application Inputs 

Application Sections In Part 

1) Application Documentation and Signatures A 

2) Project Team Information B 

Please Note:File names for submitted documents, 

photos and materials should be provided in Part A 

3) General Project Information B 

Section 1 for all sections except #9. 

4) Building and Energy Use Profile B 

5) Energy and Baseline Data B 

6) Health, Safety and Durability B 

7) Building Enclosure and HVAC Measures and Incentives B 

8) Summary and Finances B 

9) Level 2 Measures (optional) A 

10) Resources Guidance and calculators, no "Inputs" 

Note: Typical Color coding for inputs; 

(light yellow) = First application input cells (also update with second application) 

(deep yellow) = Second application input cells 

(medium blue) = Cell references data from another section or that is shared across multiple sections 

(light blue) = Cell contains calculation on input data in the current section 

IMPORTANT: Due to formatting and password problems, Google Docs are not an acceptable way 

of handling or sharing these files for the program. 

144
 

 

 

2) Project Team First Application Date: Second Application Date Final Revision for Agreement Date How owner heard of pilot? 

A. Contact information – Customer and Tenants C. Further Verification of Project Team Roles and Experience

 (i) Customer contact information and account # (ii) Tenant contact information for 1-4 family projects 

IMPROTANT NOTE:The General Contractor is required to fullfill all obligations 

for that role per DER Guidelines 

Exceptions may be made for cases where another party will take on some aspects of that 

function, but NEVER insurance requirements. 

Tenant Name: 

Apt# or Indicator: 

Home Phone Number: 

Ok as 

alternate 

contact ? 

Customer Name: 

Other Occupant of Primary Unit 

Name: 

(As name appears on electric bill) 

Other Contact 

Relationship: 

The applicants certify this building is occupied and heated 

through the winter: 

NGRID Elect Acct# = 10 Digits Electric Rate: (e.g. R1) 

NGRID Gas Acct# =11 Digits Gas Rate Type Code:(eg R3) 

Home Phone Number: Other Contact Phone: 

Work 1 Phone Number and ext: Other Occ. Work Phone 

Cell Number: Cell Number Other: 

Project Site Street Address: City/Town: 

State: Zip: 

Mail Address if Different 

Customer E-Mail Address: 1 

Other E-Mail 

Address: 

Tenant Name: 

Apt# or Indicator: 

Home Phone Number: 

Ok as 

alternate 

contact ? 

Tenant Name: 

Apt# or Indicator: 

Home Phone Number: 

Ok as 

alternate 

contact ? 

Note: Permission to obtain tenant fuel use required prior to time of agreement 

The HVAC contractor will be under contract to the General 

Contractor 

Project team member with primary responsibility to provide 

application data 

If the party in either row above isn't the general contractor or designer with DER 

prerequisite expereince please describe credentials and expereince of the primary person 

completing the application and the lead for HVAC. 

This could include prior expereince of HVAC contractor on DER projects specifically related 

to the equipment mentioned above. 

B. Contact information and role – Project Team Professionals 

(iii) General Contractor Role: 

(iv) 2nd Team Member Role: (v) HVAC Contractor: 

Name: Name: Name: 

Indicate planned contractual 

role on team 

Indicate planned contractual role 

on team 

Indicate planned contractual role 

on team 

Confirm if under contract to 

customer 

Confirm if on team Confirm if on team 

Title: Title: Title: 

Company Name: Company Name: Company Name: 

HIC License # HIC License # HIC or Other License # 

Const Supervisor Lic: Qty on staff; Const Supervisor Lic: Qty on staff; 

Office Phone Number: Office Phone Number: Office Phone Number: 

Fax Number: Fax Number: Fax Number: 

Principal’s Cell Number: Principal’s Cell Number: Principal’s Cell Number: 

Street Address: Street Address: Street Address: 

City/Town: City/Town: City/Town: 

State: 

Zip:

State: 

Zip:

State and Zip: MA Zip:

E-Mail Address: E-Mail Address: E-Mail Address: 

Website: Website: Website: 

Other Co. Contact Name: Other Co. Contact Name: Other Co. Contact Name: 

Other Contact Title: Other Contact Title: Other Contact Title: 

Other Contact Phone: Other Contact Phone: Other Contact Phone: 

Other E-Mail Address: Other E-Mail Address: Other E-Mail Address: 

Note or Comment: Note or Comment: Note or Comment: 

HVAC plays a critical role in effective DER 

projects. If the General Contractor with 

DER experience is not overseeing the 

HVAC contractor the project team must 

thoroughly document the experience of 

the party doing or overseeing that work 

with respect to i 

Notes regarding team 

! For the second application, we will need the same information reflecting any updates from the first application. At that point all members of your Project Team should be confirmed. 

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

145
 

 

 

3) General Project Information Customer Name: First Application Date: Second Application Date: #REF! 

Provide the information below. Be sure that each section is complete, checked off below and all attachments are included as required for that application version. 

A. Desired Project Level and Desired Timeline 

This application is for: 

Select Level 

Select Group and Year 

B. Facility Size and Desired Incentives 

Total number of eligible dwelling units Avg Sq Ft\Unit 

Incentive per unit 

Proposed Incentive From Table Below 

Maximum Level One Incentives per Facility 

Dwelling 

Units in 

Facility 

Conditioned [1] 

Sq Ft Floor Area 

per Unit 

Maximum 

Project 

Incentive 

Dwelling Units in 

Facility 

Maximum Project 

Incentive 

1 <2000 $35,000 4 $80,000 

1 2000 - 2500 $38,000 5 $85,000 

1 >2500 $42,000 6 $90,000 

2 <1000 $50,000 7 $94,000 

2 1000 to 1500 $55,000 8 $98,000 

2 >1500 $60,000 9 $102,000 

3 n/a $72,000 =>10 $106,000 

C. Incentive Acknowledgement 

[1] Conditioned area sq ft 

incentive ranges apply to 

interior dimensions of 

usable living space per to 

780 Cmr 5303 Light, 

Ventilation And Heating 

And 780 Cmr 5305 Ceiling 

Height 

Proposed Incentive if competitive mode is deployed for facilities 

over 4 Apt units. 

MF project selection may be competitive in terms of alternate incentives depending upon the number of 

applications received that meet desired criteria. 

Total PLANNED Conditioned Usable Floor Space for 

Building 0% 

Total EXISTING Conditioned Usable Floor Space for 

Building 

Group 2 timeframe; seeking to be selected as a project to be at 

least 50% complete the DESIGNATED year and by April 1 of the 

next 

Sq Ft % Change 

Level 1 incentives (75% cost share of eligible measures) 

Level 2 incentives 25% above level 1 to a maximum of $10,000. 

Group 1 timeframe; seeking to be selected as a project to be fully 

completed in DESIGNATED calendar year. 

D. Non- Energy Renovations Planned

(i) What work were you already planning? 

Applicable? Applicable? 

New Roof 

New Windows and or 

Enter "yes", "no", "High Doors 

Priority", or "TBD" = To Be 

Determined. 

Replace 

Siding\Cladding 

Basement Remediation 

Conversion to finished 

space 

other describe in timing Type(s) of Conversion section below. 

Space(s) 

Major remodeling including 

gut remodel 

Remodel bathroom or 

kitchen 

Adding space (New floor space must be 

no more than 50% of final 

Addition square feet 

TOTAL 

total sq.ft. of floor space) 

Addition sq ft that's 

not converted space 

#DIV/0! 

% new space 

relative to final 

(ii) Indicators related to renovation timing 

Briefly describe condition and age of siding, roof, foundation, water heater, central AC, and boiler or furnace 

E. Summary of Deep Energy Retrofit Plans 

Briefly describe the conceptual plan for deep energy retrofit and remodeling\rehab\addition plan in context with each other. Describe specific 

approach planned for insulation of walls, foundation, attic and other aspects such as HVAC. (500 words max) 

I have read the DER Guidelines and understand that incentives are 

subject to funding availability, project requirements, desired criteria and 

the selection process. F. Comprehensive, Partial or Advanced Deep Energy Retrofit Statements If proposing Level 2 Incentives - indicate approach planned 

Indicate If plan is for Full Building Comprehensive DER or if project team is proposing staged or partial DER 

and has rec'd pre-approval for basic concept in terms of mix of measures and requirements for partial DERs. 

(Describe "staged" approach in narrative in 3E.) 

DER app part B 5-10-11 (11V2 7).xls 

146

7/1/11 
 

 

 

0 

0 

4) Building and Energy Use Profile Customer Name: First Application Date: Second Application Date: 

Complete sections A thru D below. Blue cells linked here from other tabs, in sections with deep yellow cells , those inputs are needed for 2nd application only 

A. Building Characteristics 

# units in building: 0 # stories: (excluding 

basement) 

Age - time period: Year built, if known 

Style 1-4 family: 

Style 5+ Units and Other (specify) 

Year previously 

remodeled 

Year building 

purchased 

Pre DER Air Tightness: 

CFM@50pa 

B. Temperature Settings 

Set back \ Source of Temp 

Zone Description Info 

Zone 1 

Zone 2 

Zone 3 

Zone 4 

C. Occupancy 

Owner Resides in Apt:# (not required for 

incentives)
 

Total number occupants in building in 

Winter: 

Finished Area Existing 

(sq.ft.) 

Total PLANNED 0 Conditioned Sq. Ft. 

Basement heated? 

Foundation Type: 

Type 1: 

Type 2: 

Avg Heating F0	 Give best estimate of average temperature and settings at left for 

evaluation process. This need not correspond to single heating zones 

but temperature zones. For multifamily rough best guess is acceptable. 

Required for Second Application only. 

Note or Comment 

Initial six sided surface area: 

Total six sided surface area after 

project completion 

Garage Configuration: 

Foundation 

material 

Roofing 

Material 

Briefly Describe demographics for occupants of multifamily building. 

e.g. elderly, mixed income, section 8 

Master or Separate Metering 

Apt or Unit # Floor # Loc. Occupants: Bedrooms Floor Area Electric Account Gas Account 

Apt 1: 

Apt 2: 

Apt 3: 

Apt 4: 

Apt 5: 

Apt 6: 

Apt 7: 

Apt 8: 

Apt 9: 

Apt 10: 

For Multifamily - enter common area meter account in Section/Tab 2A, and tenant account#s above. 

D. End-use profile for major end uses 

(i) Energy Sources Used 

Electricity and Heating Fuel Data: 

Please provide usage and billing history data in Section/Tab 5A 

Primary Heating System: 

System Age Existing Count: 

Fuel/Energy Type: 

Will energy/fuel type or system 

type for this end use change in 

DER? 

List any planned changes 

for these enduses 

enter # of systems in building 

Heating System Type: 

Secondary Heating System or Other Non-Electric Fuel Used (if any): 

Fuel/Energy Type: 

Heating System Type: 

Tertiary Heating System or Other Non-Electric Fuel Used (if any): 

Fuel/Energy Type: 

Heating System Type: 

If "other" entered above, please explain: 

(ii) Water Heating, Cooking and Laundry 

Domestic Hot Water:
 

Fuel Source:
 

Type:
 

Will energy/fuel type or 

system type for this end use 

change in DER? 

List any planned changes 

for these enduses 

Total Use Total Cost 

(per year) (per year) 

Electricity 

0 kWh $0 

^ provide data on 5A 

Primary Heating 

0 #N/A 

^ provide data on 5A 

Secondary Heating/other fuel 

0 #N/A $0 

Tertiary Heating/other fuel 

0 #N/A $0 

Proposed 

Count: 

$0 

Note: If some aspects of choices for cost conscious HVAC 

to address guidelines are under consideration but 

undecided at the time of first application. Explain what 

options are under consideration in section 6B or a cover 

email. 

(iv) Electric Appliances (indicate number, enter 0 if none) 

If "other" entered above, please explain: 

Cook top - Fuel Source: 

Oven - Fuel Source: (v) Heating or cooling system and/or ducts located in attic 

Dryer - Fuel Source: spaces?

If "other" entered above, please explain: 

Refrigerator 

Well pump 

Central air conditioning 

Freezer 

Dehumidifier 

Room air conditioners 

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

147
Enter 12 month total 

5 A) Energy Use and Billing History Customer Name: Project Address: , 

First Application Date: Second Application Date: 

National Grid typically has access to either gas or electric use. Records for all fuels are needed for evaluation. The project team may find monthly usage data very helpful to assess end-use savings 

opportunities. For Final submittal after Second Application please scan and submit a summary bill with 12 months usage for electric or heating use if not by National Grid. 

Please provide twelve months usage and a few scattered months of cost data for your primary heating fuel, water heating fuel if different and electric consumption using the table below. Do not 

include arrearage or budget amounts in costs 

Electric Primary Heating Fuel Type: 0 

Electric Company #N/A 

Account number Account number 

Account name Account name 

Billing/Delivery Frequency monthly 

Month Reading Date Usage 

Year-to-Date 

Usage Monthly Cost Year-to-Date Cost Month Reading Date Usage 

Year-to-Date 

Usage Monthly Cost Year-to-Date Cost 

(Month 1 intended 

as most recent 

month) kWh $ 

(Month 1 intended 

as most recent 

month) #N/A $ 

1 1 

2 2 

3 3 

4 4 

5 5 

6 6 

7 7 

8 8 

9 9 

10 10 

11 11 

12 12 

13 13 

14 14 

15 15 

16 16 

17 17 

18 18 

12 Month Total 0 0 12 Month Total 0 0 

(default calculation is most recent 12 

months) 

Enter 12 month total (or accept 

default calculation) 

National Grid 

Secondary Heating or Other Fuel Type: 0 

#N/A 

Account number 

Account name 

Billing/Delivery Frequency periodic / other 

Read / Delivery 

Period Reading or Purchase Date 

Usage or 

Purchase Qty 

Year-to-Date 

Usage Cost for Period Year-to-Date Cost 

Tertiary Heating or Other Fuel Type: 0 

#N/A 

Account number 

Account name 

Billing/Delivery Frequency periodic / other 

Read / Delivery 

Period Reading or Purchase Date 

Usage or 

Purchase Qty 

Year-to-Date 

Usage Cost for Period Year-to-Date Cost 

7/1/11 9:18 AM SOMERDATA:Building America:BA Communities:MA National Grid Retrofit:Program forms and tools:DER app part B 5-10-11 (11V2 7).xls 

148
(Period 1 intended 

as most recent) #N/A $ 

(Period 1 intended 

as most recent) #N/A $ 

1 1 

2 2 

3 3 

4 4 

5 5 

6 6 

7 7 

8 8 

9 9 

10 10 

11 11 

12 12 

13 13 

14 14 

15 15 

16 16 

17 17 

18 18 

0 

<Enter 

total 0 <Enter total 

<Enter 

total <Enter total 

1 Year Total 0 0 1 Year Total 0 0 

Enter 1 year total Enter 1 year total 

7/1/11 9:18 AM SOMERDATA:Building America:BA Communities:MA National Grid Retrofit:Program forms and tools:DER app part B 5-10-11 (11V2 7).xls 

149
Utilit

5B) Energy Use and Baseline Data Customer Name: Project Address: , 

First Application Date: Second Application Date: 

Blue cells linked here from other tabs, in sections with deep yellow cells , those inputs are needed for 2nd application only 

In the second application all participants must provide simple input and output from the Thousand Homes Challenge Calculator to bench mark the building. 

B. Summary - Total annual energy used 

(i) Total annual energy used y 

Units Energy Cost MBtu 

Site Energy 

kWh 

Source (Primary) Energy 

MBtu kWh 

Electricity 0 kWh -$ 

Oil / Kerosene 0 Gallons -$ 

Natural Gas 0 Therms -$ 

Propane 0 Gallons -$ 

Wood - cordwood 0 Cords -$ 

Wood - pellet 0 Tons -$ 

other 0 $ -

0.0 0 0 0 

(Indicate other fuel if applicable and apply conversion factors) 

Total $ - 0.0 0 0 

(ii) Annual energy use intensity 

Site Energy Source (Primary) Energy 

Building Area: Energy Cost/ kBtu/ kWh/ kBtu/ kWh/ 

Sq Ft Sq Ft Sq Ft Sq Ft Sq Ft 

Exisitng Building Conditioned Area: 0 

0 

sq ft #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! 

Building Occupancy: Energy Cost/ MBtu/ kWh/ MBtu/ kWh/ 

Occupant Occupant Occupant Occupant Occupant 

Total Occupants in Building: #DIV/0! #DIV/0! #DIV/0! #DIV/0! #DIV/0! 

C. Annual energy use benchmarking 

Baseline data doesn't determine eligibility for incentives except for level 2 projects (see section 9 instructions). However it is required for the Second 

Application for evaluation. It is vital data, especially if occupancy or space size changes. 

For the second application, all participants must provide the simple Threshold Calculator benchmark from Thousand Homes Challenge. The Threshold 

Calculator EXCEL file is available at: 

http://thousandhomechallenge.com/join-us 

The benchmark there is based on the EPA Home Energy Yardstick but provides more detail than the yardstick score. In the THC calculator*, you will need 

to enter: 

Your zip code: < in THC Calculator Tab 1, cell C:7
 

Number of people living in the building:
 

PROPOSED conditioned floor area '< conditioned and useable area of the building post-retrofit
 

Number of households in the building:
 

As well as the enclosure area abutting other conditioned space (e.g. another buildings) as a % of total building enclosure area.
 

0

0

0

0 

Output from THC Calculator 

Enter the resulting baseline value from tab 2 "Threshold Calculator", cell C36 "EPA Home Energy Yardstick, Avg kWh/yr" below
 

Home Energy Yardstick, Avg kWh/yr:
 

This above Home Energy Yardstick, Avg kWh/yr value represents approximate performance of a code built home based on statistical averages. One goal 

of the DER pilot is for projects to achieve performance 50% better than that level. You can check how this compares with how your building performs 

now by comparing the values in section (ii) to the values below. 

Site Energy Site Energy Intensity 

kBtu/ kWh/ 

MBtu kWh Sq Ft Sq Ft 

EPA Home Energy Yardstick, Avg 

50% of EPA Home Energy Yardstick, Avg 

Your Buildng (existing usage reflecting existing conditions) 

0.0 

0.0 

0.0 

#DIV/0! 

#DIV/0! 

#DIV/0! 

0 

0 

0 

#DIV/0! 

#DIV/0! 

#DIV/0! 

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

150

0 
6) Health, Safety, and Durability Issues Project Name: First Application Date: Second Application Date: #REF! 

Complete sections A, B and C below 

Section (6A) Identification of Health, Safety, and Durability Issues 

Category 

DIRECTIONS: In the Stage 1 Application, please complete Column B with "yes","no", "high priority" or "TBD" (to be determined). Applicable

 to 

project? 

Second Application:Brief description of proposed resolution. (More detail will be needed for 

final work plan) 

Combustion Safety Combustion products from vented furnace or water heater spilling due to inadequate draft or house depressurization (NOTE: 

Natural draft gas & oil combustion appliances are not acceptable see DER Guidelines ) 

Combustion Safety Combustion products (NOX / CO / water vapor) from gas range / cook stove in living space 

Combustion Safety Combustion products from fireplace or woodstove due to house depressurization 

Indoor Env Quality Inadequate source control (exhaust) of moisture & odors 

Indoor Env Quality Inadequate indoor-outdoor air exchange, dilution of contaminants 

Indoor Env Quality Inadequate distribution of indoor and fresh air 

Indoor Env Quality VOCs from building materials, interior finishes 

Indoor Env Quality VOCs and/or SVOCs from consumer products 

Indoor Env Quality Unit-to-unit cross contamination of indoor air pollutants (tobacco smoke, cooking odors, etc.) (Attached dwelling) 

Indoor Env Quality Contaminants from attached garage entering living spaces 

Indoor Env Quality Radon and other soil gases entering living spaces 

Indoor Env Quality Lead health risk from paint 

Indoor Env Quality Lead health risk from outdoor contamination (indoor dust) 

Indoor Env Quality Exposure to asbestos (from zonolite loose-fill insulation, HVAC system, popcorn ceilings, etc.) 

Code Issue Hazard due to unsafe or inadequate electrical system 

Code Issue Structural problem due to rot, subsidence, or substandard construction 

Durability Interior moisture from faulty plumbing 

Durability Bulk water entry from inadequate roof and flashing 

Durability Deterioration of insulation & air sealing due to pests 

Durability Wintertime condensation on cold surfaces 

Durability Summertime condensation on cold surfaces 

Durability Condensation that could support mold growth (or growth of other biologicals/allergens) 

Durability Hidden condensation in building cavities that could support mold growth or deterioration 

Durability Trapped water / moisture / loss of durability due to bulk water event (interior such as plumbing leak or spill) 

Durability Trapped water / moisture due to bulk water event (exterior i.e. rain, flood, sprinkler) 

Durability Excessive moisture in basement or crawl space 

Durability Basement or crawl space flooding (from storm or inadequate drainage) 

Thanks to PG&E for permission to adapt this above part of this worksheet from NorCal Thousand Home Challenge Submittal Form 

B. Combustion Safety 

Describe briefly how your project will meet the requirements in section 4D of the DER Guidelines which starts with this sentence: ”With the exception of oven\ranges and condensing dryers all combustion appliances including, 

but not limited to fireplaces, woodstoves, heating and hot water systems must be direct-vent, sealed combustion or power vented.” 

C. Health Safety and Durability 

If some of the aspects identified in the checklist in Section 6A of the application (other than combustion safety) were significant and are a key part of the remediation or renovations planned describe those planned actions in 

either: (1) Section 6A or (2) in a brief narrative below. Note: This relates to sections 4E and 4F of the DER Guidelines. 

151

7/1/11 DER app part B 5-10-11 (11V2 7).xls 
Propose

d 

7a) Building Enclosure, HVAC and Incentives Customer Name: Project Address: , 

For First Application provide estimated costs and proposed incentives, see notes about costs below. For Second Application Update Section (7A) and Complete (7B) You may 

provide (7B) w/1st Application. For FUTURE STAGE enclosure measures, which must be specified for a DER partial, indicate just existing and proposed area\units in (7A), but 

costs and proposed RValues in (7B.) 

a b c d e f 

Component 

Applicable to

Building

Component

treated in DER

Project? 

Enter areas below! 

Existing 

Conditions 

(Units) Proposed 

Performance Specifications Equipment or Material 

Note 

Existing 

Condiitons * Proposed 

DER Pilot 

Targets 

Enclosure Measures 

Area of Enclosure Component 

(Sq Ft) 

Effective R-value 

(R-value = 1 / U-value) 

Indicate thickness and type of insulation added 

Attic or Roof area likely to change if 

thermal boundary moved R 60+ 

Above Grade Walls gross area including 

windows and doors R 40+ 

Insulated Foundation Wall -

Above Grade 

include if 

basement walls 

insulated or 

basement is 

intentionally 

heated, can shift 

from one way 

existing to another 

in DER 

R 40+ 

Insulated Foundation Wall -

Below Grade R 20+ 

Floor of Insulated/Conditioned 

Basement R 10+ 

Basement Ceiling 

do not include if 

basement walls insulated 

or basement is 

intentionally heated 

R 30+ 

Slab on Grade R 10+ under 

and perimeter 

Floor over Unheated Garage or 

Overhang R 40+ 

Windows Yes R 5 (U.2) ** 

Doors Yes R 5 (U.2) 

Tight Storm or Modify Windows and 

Doors 

area of affected windows 

or doors R 5 (U.2)

 Enclosure surface area enter air leakage test measurement in cfm at 

50 Pascal pressure difference indicate basic strategy for airflow control 

Air sealing Yes 0 0 0 

HVAC exists ? # units # units enter appropriate performance specification indicate equipment type, MBTUh, 

manufacturer and model number 

Mechanical Ventilation include (CFM) and, if 

applicable, recovery 

efficiency (%) 

Heat Recovery, 

Balanced, 

Distributed 

Heating equipment Yes enter AFUE of existing and 

proposed 

Cooling equipment SEER and EER proposed 

(existing if applicable) 16 / 13 

Other (w/ prior approval) 

Applicant Notes or Comment: First Application Date: Second Application Date: 

** use UValue calculator in tab 9 to calculate 

average R-value if window R-values will vary. 

Window Notes> number of basement windows: __ 

* See Input and more R-Value Entry Tips 

for Tab 7A in Application Part A Appendix. 

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

152
AC and Incentives

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

7a) Building Enclosure, HV 

Enclosure Measures 

Attic or Roof 

Above Grade Walls 

Insulated Foundation Wall -

Above Grade 

Insulated Foundation Wall -

Below Grade 

Floor of Insulated/Conditioned 

Basement 

Basement Ceiling 

Slab on Grade 

Floor over Unheated Garage or 

Overhang 

Windows 

Doors 

Tight Storm or Modify Windows and 

Doors 

Air sealing 

HVAC 

Mechanical Ventilation 

Heating equipment 

Cooling equipment 

Other (w/ prior approval) 

Applicant Notes or Comment: 

Component 

* See Input and more R-Value Entry Tips 

for Tab 7A in Application Part A Appendix. 

** use UValue calculator in tab 9 to calculate 

average R-value if window R-values will vary. 

Window Notes> 

Customer Name: Project Address: , 

Comprehensive or Staged DER: Comp Incentive Level: 1 

Estimated Measure Costs and Incentives 

g h i j k l m n 

Incentive % 

Renova-tion Third Party Deduct-ible 

(calculates) 

Enclosure Measures 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 75% $0 

$0 $0 100% $0 

Fenstr % $0 75% $0 

#DIV/0! $0 75% $0 

$0 75% $0 

HVAC 

$0 75% $0 

$0 

50% w/ $4k cap, 

2.5K after 1st 

unit 

$0 

$0 50% w/ $1k cap $0 

$0 75% $0 

Total $0 $0 $0 $0 $0 $0 

* Note - Most incentives will not calculate w/o Sq Ft areas Maximum Incentive: 

Non-allowable Costs Applicant explanation of non-allowable 

cost 

Total Measure 

Cost 

Estimated 

Incentive (e x f) Allowable Cost 

153
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Section (7B) Building Enclosure and HVAC Measures Customer Name: Project Address: , 

For First Application basic measure details will link in from Section 7a into darker blue rows here. NOTES here will help inform those entries. For Second Application update to more 

precise costs in Section 7a and finalize detail explaining materials, and non allowable costs in Section 7b. Section 7 B provides space to describe future measures for a staged DER. 

Select "Future" if DER will be partial but describe in this line what would be done for component that’s excluded from current proposal but planned for potential future deployment. For 

FUTURE after DER partial measures indicate proposed area only in tab 7A, costs and proposed RVaules in tab 7B. 

DER Measure Detail 

a b c d e f 

Component 

Applicable to

Building

Addressed in

DER Project (Y, 

N or Future) Note: regarding entries 

for specific enclosure 

and equipment 

measures 

Existing 

Conditions 

Proposed / 

Potential 

Performance Specifications Equipment or Material 

Existing 

Conditions 

Proposed / 

Potential 

DER Pilot 

Targets 

Enclosure Measures 

Area of Enclosure Component 

(Sq Ft) 

Effective R-value of Enclosure Component 

(R-value = 1 / U-value) 

Provide additional detail for measure components. 

Indicate thickness and type of insulation added. 

0 0 

Attic or Roof 0 0 area likely to change if 

thermal boundary moved 

<- Sum from appropriate entries 

below 

R 60+ 0 

Insulated sloped roof (cavity) from attic flat to roof. 

FOR ANY MEASURE: 

Edit detailed component 

label in Column at LEFT 

to Specify Location or 

other measure attribute. 

Insulated sloped roof (exterior) 

Insulated Attic flat (ceiling) 

Roof Other 

Attic Other 

Attic Other 

0 0 

Above Grade Walls 0 0 <- Sum from appropriate entries 

below 

R 40+ 0 

Above grade wall 1 (cavity) enter gross area 

excluding foundation 

including windows and 

doors 

Above grade wall 1 (exterior) 

Above grade wall 2 (cavity) 

Above grade wall 2 (exterior) 

Above grade wall 3 (other) 

Above grade wall 3 (other) 

Insulated Foundation Wall - 0 0 

Above Grade 0 0 <- Sum from appropriate entries 

below 

R 40+ 0 

Rim/Band Joist 

include if basement walls 

insulated or basement is 

intentionally heated 

Above Grade Foundation Wall 

(interior) 

Above Grade Foundation Wall 

(exterior) 

Insulated Foundation Wall - 0 0 

Below Grade 0 0 <- Sum from appropriate entries 

below 

R 20+ 0 

Below grade walls (interior) 

Below grade walls (exterior) 

0 0 Floor of Insulated/Conditioned 

Basement 0 0 Slab Floor of Basement 

pertains to 

Insulated/Conditioned 

<- Sum from appropriate entries 

below 

R 10+ 0 

Floor of conditioned basement basements. 

for Slab on Grade enter R R 10+ under 

Floor of conditioned basement 

0 0 

Slab on Grade 0 0 value of perimeter 

insulation. Indicate depth 

<- Sum from appropriate entries 

below and perimeter 0 

Slab area 1 of perimeter insul and 

insul. under 

do not include if bsmt 

Slab area 2 

0 0 

Basement Ceiling 0 0 walls insulated or if bsmt 

heated. WHEN bsmt is 

<- Sum from appropriate entries 

below 

R 30+ 0 

Basement ceiling (1) semi- conditioned 

effective R value of floor 

ins derated min 50% 

6.0 

Alternate basement ceiling 

Floor over Unheated Garage or 0 0 

Overhang 0 0 Slab Floor of Basement 

pertains to 

<- Sum from appropriate entries 

below 

R 40+ 0 

Floor over unheated garage Insulated/Conditioned 

basements. Overhang 

other floor over uncond. 

DER app part B 5-10-11 (11V2 7).xls 

154

7/1/11 
AC Measures

DER Measure Detail

Provide additional detail for measure components. 

Indicate thickness and type of insulation added.

 

 

 

 

 

 

 

 

Section (7B) Building Enclosure and HV Customer Name: Project Address: , 

Component 

Enclosure Measures 

Attic or Roof 

Insulated sloped roof (cavity) 

Insulated sloped roof (exterior) 

Insulated Attic flat (ceiling) 

Roof Other 

Attic Other 

Attic Other 

Above Grade Walls 

Above grade wall 1 (cavity) 

Above grade wall 1 (exterior) 

Above grade wall 2 (cavity) 

Above grade wall 2 (exterior) 

Above grade wall 3 (other) 

Above grade wall 3 (other) 

Insulated Foundation Wall -

Above Grade 

Rim/Band Joist 

Above Grade Foundation Wall 

(interior) 

Above Grade Foundation Wall 

(exterior) 

Insulated Foundation Wall -

Below Grade 

Below grade walls (interior) 

Below grade walls (exterior) 

Floor of Insulated/Conditioned 

Basement 

Floor of conditioned basement 

Floor of conditioned basement 

Slab on Grade 

Slab area 1 

Slab area 2 

Basement Ceiling 

Basement ceiling (1) 

Alternate basement ceiling 

Floor over Unheated Garage or 

Overhang 

Floor over unheated garage 

Overhang 

other floor over uncond. 

Comprehensive or Staged DER: Comp Incentive Level: 1 

DER Measure Cost and Incentive Detail 

g h i j k l m n o q r s t u 

Unit Cost and Quantity of 

Proposed Measure Non-allowable Costs 

Cost / 

Measure 

Unit e.g. Sq. 

Ft. 

Number or 

Units for 

Measure 

# of Apt 

Units 

Involved 

Total Potential 

Measure Cost 

Total Future 

Measure 

Cost 

Total DER 

Measure 

Cost Total Renova-tion 

Cost 

Explanation Detail non-allowable cost 

Third Party Deduct-ible 

Allowable Cost Incentive % 

(calculates) 

Estimated Incentive 

(e x f) 

Applicant explanation of provisions for 

measure if that component is in the "future" 

category 

Enclosure Measures 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

Sums From Below > 

0 

75% 

0 

0 

0 

0 

Sums From Below > 

0 

0 

0 

Sums From Below > 

Sums From Below > 

Sums From Below > 

Sums From Below > 

Sums From Below > 

Sums From Below > 

75% 

75% 

75% 

75% 

75% 

75% 

75% 

DER app part B 5-10-11 (11V2 7).xls 

155

7/1/11 
 

 

 

 

 

 

 

 

 

Section (7B) Building Enclosure and HVAC Measures Customer Name: Project Address: , 

For First Application basic measure details will link in from Section 7a into darker blue rows here. NOTES here will help inform those entries. For Second Application update to more 

precise costs in Section 7a and finalize detail explaining materials, and non allowable costs in Section 7b. Section 7 B provides space to describe future measures for a staged DER. 

Select "Future" if DER will be partial but describe in this line what would be done for component that’s excluded from current proposal but planned for potential future deployment. For 

FUTURE after DER partial measures indicate proposed area only in tab 7A, costs and proposed RVaules in tab 7B. 

DER Measure Detail 

a b c d e f 

Performance Specifications Equipment or Material 

Existing 

Conditions 

Proposed / 

Potential 

Existing 

Conditions 

Proposed / 

Potential 

DER Pilot 

Addressed in

DER Project (Y, 

N or Future)

Targets 

Note: regarding entries 

for specific enclosure 

and equipment 

Applicable to

Building

measures

Component 

0.00 0 

<- Sum from appropriate entries 

below 

Windows (Replacement) 

Windows (Replacement) 

0.00 0 

<- Sum from appropriate entries 

below 

Door replacement 

Bulkhead door replacement 

0 0 

<- Sum from appropriate entries 

below 

Windows (storms) 

Doors storms 

Windows (block over, basement) Yes R 20 + 

Windows (reduce or eliminate) 

Doors (block or eliminate)

 Enclosure surface area enter air leakage test measurement in cfm at 50 

Pascal pressure difference indicate basic strategy for airflow control 

Air sealing Yes Enter test results w/ and 

w/o basement 0 0 0 0 

HVAC Provide detail as appropriate for components 

indicate equipment type, manufacturer and 

model number 

0 0 0 

0 <- Sum from appropriate entries 

below 

0 0 

0 <- Sum from appropriate entries 

below 

0 0 16 / 13 

<- Sum from appropriate entries 

below 

Other (w/ prior approval) 0 0 0 0 0 

enter SEER and EER of 

existing and proposed 

equipment 

0 0 

Cooling equipment 

Mechanical Ventilation 

Heating equipment 

Enter sq. ft of modified 

doors and windows, note 

number of windows or 

doors in col F, Equipt. 

for doors or windows 

eliminated or blocked 

indicate proposed R Value 

= to wall Yes R 40 

R 5 (U.2) 

R 5 (U.2) 

0 

0 

0 

Doors Yes 

Windows 0 Enter sq. ft for exisiting 

and proposed conditions, 

note number of windows 

in column F 

Yes R 5 (U.2)

Tight Storm or Modify Windows and 

Doors 0 0 

Enter sq. ft for exisiting 

and proposed conditions, 

note number of doors in 

column F 

Heat Recovery, 

Balanced, 

Distributed 

0 

0 0 include 24 hour average 

airflow (CFM) and, if 

applicable, recovery 

efficiency (%) 

Yes Yes 

0 0 

enter AFUE of existing 

and proposed equipment 

Applicant Notes or Comment: 

DER app part B 5-10-11 (11V2 7).xls 

156

7/1/11 
AC Measures

DER Measure Detail

Enclosure Measures

Section (7B) Building Enclosure and HV Customer Name: Project Address: , 

Component 

Windows (Replacement) 

Windows (Replacement) 

Door replacement 

Bulkhead door replacement 

Windows (storms) 

Doors storms 

Windows (block over, basement) 

Windows (reduce or eliminate) 

Doors (block or eliminate) 

Air sealing 

HVAC 

Other (w/ prior approval) 

Cooling equipment 

Mechanical Ventilation 

Heating equipment 

Doors 

Windows 

Tight Storm or Modify Windows and 

Doors 

Comprehensive or Staged DER: Comp Incentive Level: 1 

DER Measure Cost and Incentive Detail 

g h i j k l m n o q r s t u 

Unit Cost and Quantity of 

Proposed Measure Non-allowable Costs 

Cost / 

Measure 

Unit e.g. Sq. 

Ft. 

Number or 

Units for 

Measure 

# of Apt 

Units 

Involved 

Total Potential 

Measure Cost 

Total Future 

Measure 

Cost 

Total DER 

Measure 

Cost Total Renova-tion 

Cost 

Explanation Detail non-allowable cost 

Third Party Deduct-ible 

Allowable Cost Incentive % 

(calculates) 

Estimated Incentive 

(e x f) 

Applicant explanation of provisions for 

measure if that component is in the "future" 

category 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 $0 $0 $0 $0 

Mechanical Systems 

$0 $0 $0 $0 $0 $0 75% $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 50% w/ $4k cap $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 50% w/ $1k cap $0 

$0 $0 $0 $0 $0 $0 $0 $0 

$0 $0 

$0 $0 

$0 $0 

$0 $0 $0 $0 $0 $0 $0 75% $0 

Total From 7a $0 $0 $0 $0 $0 $0 

Total From 7b above $0 $0 $0 $0 $0 $0 $0 $0

Sums From Below > 

0 

0 

0 

0 

0 

0 

Sums From Below > 

Sums From Below > 

Sums From Below > 

Sums From Below > 

75% 

75% 

100% 

75% 

Sums From Below > 

DER app part B 5-10-11 (11V2 7).xls 

157

7/1/11 
National Grid Deep Energy Retrofit Application Part (B), Excel component First Application Date: ## 

8) Summary of Project and Finances Customer Name: - Second Application Date: 

A) Summary of Measures and Incentives Comprehensive DER Incentive Level: 1 

Component Indicator Existing 

Condiitons *

Proposed 

Value Description or Type and Model Units 

Proposed 

Total Measure 

Cost 

Allowable 

Cost Incentive % Estimated Incentive 

Attic or Roof R Value 0 0 0 $0 $0 75% $0 

Above Grade Walls R Value 0 0 0 $0 $0 75% $0 

Foundation A.G. R Value 0 0 0 $0 $0 75% $0 

Foundation B.G. R Value 0 0 0 $0 $0 75% $0 

Slab Floor R Value 0 0 0 $0 $0 75% $0 

Basement Ceiling R Value 0 0 0 $0 $0 75% $0 

Floor over Garage or 

Overhang R Value 0 0 0 $0 $0 75% $0 

Repl Windows\ Doors R Value 0 0 - 0 $0 $0 100% $0 

Other Window & Door R Value 0 0 0 $0 $0 75% $0 

Air sealing CFM50 0 0 0 0 $0 $0 0% $0 

Mechanical Ventilation Eff % 0 0 0 $0 $0 75% $0 

Heating equipment AFUE 0 0 $0 $0 50% w/ $4k cap, 

2.5K after 1st unit $0 

Cooling equipment SEER / EER 0 0 0 $0 $0 50% w/ $1k cap $0 

Other w/ Prior Approval 0 0 0 $0 $0 1 $0 

TOTALS Enclosure and Heating Ventilation and HVAC $0 $0 $0 

Solar hot water system Qty. panel(s) 

Water Heating En.Factor (EF) - case by case for 

Level 2 projects only 

Wind turbine system kW N/A N/A N/A 

Other Incl. Appliances N/A N/A N/A 

Lighting CFL or better, NGrid to provide $200 worth LED or CFLs

Grand Totals Deep Energy Retrofit $0 $0 N/A $0 

Enter 1, 2 or 3 to indicate which measures to be Installed and 

Inspected in each TIME FRAME group for incentive payment 

purposes 

D) Worksheet for Proposed Payment Plan 

Group 

1, 2, or 3 

Total Group 1 Total Group 2 Total Group 3 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

$0 $0 $0 

Group Split $ $0 $0 $0 

Payment # 1 2 3 

Adjusted for Max $0 $0 $0 

$0 

Total of 

Payment 

Groups 

 ^ May become included in 

Exhibit A of Agreement 

Building Heat Fuel: 0 B. Summary of Project Costs C. Financing Confirmation Type: 

Project Category Pre Application 

Estimated Costs 

Current 

Application Costs 

For first application 

Renovation Associated with DER $0 $0 provide ballpark 

estimates of the 

Addition, Remodeling, other 

Renovation\Remediation 

project cost 

components 

Total non-Energy Related $0 $0 described below. Use 

second column for 

DER Enclosure and HVAC w/o Renovation $0 $0 

second application 

providing revised 

more accurate figures. 

DER Retrofit excluding Enclosure and HVAC $0 $0 

Show full costs 

before value of 

incentives, in-kind 

Total Energy Related $0 $0 

services or materials 

are accounted for. 

Total Project Costs $0 $0 

Construction 

Period: Total Incnt$\Encl SF 

$0 $0.0 

(i) Costs, Incentives and Finances 

Planned Conditioned Sq. Ft. Existing Encl $ \ S.Q F.T. 

$0 Level 1 > $0 0 0 $0.0 

$0 Level 2 25% 

additional $0 0 $0.0 

$0 Combined > $0 Occupants: 0 # Apts 0 

$0 

Level 2 Incentive 

set aside > $0 Site Mbtu 

Pre Plan 

Source kBtu/ 

Sq Ft 

$0 0 0 

Conditioned Sq. Ft. 

DER Enclosure $ 

 (b) Total Incentives minus Level 2 set aside

 (a) Total Project Costs 

Balance of Funds or (Shortfall) = D minus C 

Current 

Application Incentive Level Max Incentives for Project 

(d) Total Customer and Other Funding and 

Financing (from Word Part A Sect 1Biia)

 (c) Costs Less Incentives = a minus b 

This Section of the worksheet is intended to verify that all the funding and incentives are sufficient to cover the entire project. 

This is a vital component of project viability. Sufficient Funds is a MUST. 

NOTICE: This application and 

proposed payment plan is not a 

commitment to provide incentives. 

Incentives are NOT part of an 

"official" offer until project agreement 

is signed 

DER Surface Area \ $SF 

7/1/11 DER app part B 5-10-11 (11V2 7).xls 

158
 

DOE/GO-1013-3929 ▪ November 2013

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