Practices and Processes of 

Leading High Performance 

Home Builders in the 

Upper Midwest 

E. VonThoma and C. Ojczyk 

NorthernSTAR Building America Partnership

December 2012
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iii

Practices and Processes of Leading High Performance 

Home Builders in the Upper Midwest

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: 

Ed Von Thoma, Cindy Ojzcyk 

NorthernSTAR Building America Partnership

University of Minnesota 

2400 Folwell Avenue 

St. Paul, MN 55108 

NREL Technical Monitor: Stacey Rothgeb 

Prepared under Subcontract No. KNDJ-0-40338-00 

December 2012 
iv

[This page left blank]
v 

Acknowledgments

This report was prepared for the U.S. Department of Energy Building America Program. 

Funding for this work was provided by the National Renewable Energy Laboratory under 

contract KNDJ-0-40338-02. Additional funds were provided by the University of Minnesota, the 

Initiative for Renewable Energy and the Environment, and Building Knowledge Inc. 

The primary authors were Ed VonThoma, Building Knowledge Inc., and Cindy Ojczyk, Simply 

Green Design.

These authors would like to acknowledge the assistance of Ray Pruban, Amaris Custom Homes; 

Brad Richardson, Christian Builders; and Mark and Melissa Wahl, Cobblestone Homes for 

participating in interviews. In addition, they recognize Pat O’Malley of Building Knowledge 

Inc., for compiling REM/Rate reports; Tom Schirber of the University of Minnesota for 

coordinating and editing reports; and Louise Goldberg, Energy Systems Design Program, and 

Brianna Steigauf, Bioproducts and Biosystems Engineering, University of Minnesota for 

conducting Building Energy Optimization and EnergyPlus building energy simulations. 
vi 

Contents

Acknowledgments ..................................................................................................................................... v

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

List of Tables .............................................................................................................................................. vi

Definitions.................................................................................................................................................. vii

Executive Summary................................................................................................................................. viii

1 Introduction to the Problem ................................................................................................................ 1

1.1 Background ...................................................................................................................................... 1

1.2 Introduction ...................................................................................................................................... 2

2 Approach............................................................................................................................................... 4

2.1 Builder Interviews............................................................................................................................. 4

2.2 Energy Modeling .............................................................................................................................. 4

3 Results................................................................................................................................................... 5

3.1 Builder Interviews............................................................................................................................. 5

3.1.1 Customary Building Systems ...................................................................................5

3.1.2 Builder Characteristics .............................................................................................7

3.1.3 Builder Process Strategies ........................................................................................8

3.1.4 Common Themes Sited by the Three Builders ........................................................9

3.2 Energy Modeling ............................................................................................................................ 10

3.2.1 BEopt and Adjusted BEopt Analysis .....................................................................10

3.2.2 Program Performance Compliance ........................................................................11

4 Conclusions ........................................................................................................................................ 13

References................................................................................................................................................. 15

Appendix A: Amaris Custom Homes REM/Rate .................................................................................... 16

Appendix B: Christian Builders REM/Rate............................................................................................. 34

Appendix C: Cobblestone Homes REM/Rate ......................................................................................... 52

List of Figures

Figure 1. BEopt and EnergyPlus simulation for prototype home........................................................ 11

This figure was created by NorthernSTAR.

List of Tables

Table 1. Customary Building Systems of the Participating Builders .................................................... 6

Table 2. Builder Characteristics and Key Business Practices............................................................... 8

Table 3. Prototype Building Configuration and Location ..................................................................... 10

Table 4. Annual Energy Use Comparison B10 Benchmark to BEopt and Rem/Rate (MBtu/yr)........ 11

Table 5. Performance Standards Comparison....................................................................................... 12

Unless otherwise indicated, all tables were created by NorthernSTAR. 
vii 

Definitions

ACH Air changes per hour

AFUE Annual fuel utilization efficiency

BA Building America

BEopt Building Energy Optimization

Btu British thermal unit

CFL Compact fluorescent lighting

DOE U.S. Department of Energy

ERV Energy recovery ventilator

ft2 Square foot

HERS Home Energy Rating System

HRV Heat recovery ventilator

IECC International Energy Conservation Code

LEED Leadership in Energy and Environmental Design

MBtu Million Btu

o.c. On center

OSB Oriented strand board

RESNET Residential Energy Services Network

ROI Return on investment

SEER Seasonal energy efficiency ratio

SHGC

UA

Solar heat gain coefficient

Sum of U-factor times assembly area

yr Year
viii

Executive Summary

The U.S. Department of Energy Building America Program is a research and development 

program to improve the energy performance of new and existing homes in all U.S. climate zones 

while increasing comfort, safety, and durability. Although Building America offers a 

comprehensive library of information on improving energy efficiency in new and existing 

homes, only a small number of builders promote and build high performance homes (30% better 

than code). There is a gap between the availability of information to create high performance 

homes and the use of that information by the building industry. The reasons for the gap and for 

why builders are not promoting or applying the available information are unknown. The 

NorthernSTAR Building America Partnership team proposed this study to gain insight into the 

business, sales, and construction processes of successful high performance builders. The 

knowledge gained by understanding the high performance strategies used by individual builders, 

as well as the process each followed to move from traditional builder to high performance 

builder, will be beneficial in proposing more in-depth research. That research, in turn, will yield 

specific action items to assist the industry in transforming to high performance new home 

construction. 

This investigation identified the best practices of three successful high performance, custom 

home builders in the upper Midwest: Amaris Custom Homes, Christian Builders, and 

Cobblestone Homes. In-depth field analysis of the performance levels of their homes, their 

business models, and their strategies for market acceptance was conducted. All three builders 

commonly seek ENERGY STAR certification for their homes and implement strategies that 

would allow them to meet the requirements for the Building America Builders Challenge 

certification program. Their desire for continuous improvement, willingness to seek outside 

assistance, and ambition to be leaders in their field are common themes. Overcoming challenges

in building high performance homes was accepted as part of doing business. It was concluded 

that crossing the gap from code-based building to high performance based building was a natural 

business evolution for these leading builders. 

Each of the builders continues to experience market and field staff challenges when promoting 

and building high performance homes. The primary challenge cited was a lack of education 

among trade contractors, particularly HVAC contractors, about energy efficient construction. 

Collectively, the builders believe that imminent energy code changes are necessary for moving 

the industry forward. They feel that the majority of builders and contractors will not implement 

energy efficient measures if they are not required to engage in the process. The builders also 

commented that the variety of high performance building certification programs (i.e., Builders 

Challenge, ENERGY STAR for Homes, Leadership in Energy and Environmental Design for 

Homes, and National Green Building Standard, among others) was adding to confusion in the 

marketplace. All three builders would welcome more competition that would raise consumer 

awareness and demand for high performance building. 
1 

1 Introduction to the Problem

1.1 Background

Years of research on energy efficiency for residential homes has created an abundance of 

technical information to inform professionals in the building industry about how to achieve 

significant energy savings in new construction. The U.S. Department of Energy (DOE) has been 

leading the way in creating usable, measurable energy improvement strategies for all climates. 

The DOE Building America (BA) Program sponsors research and development designed to 

improve the energy performance of new and existing homes. The ultimate goal of the BA

program is to achieve cost-effective, energy efficient solutions for all U.S. climate zones.

One pathway to energy savings and better buildings is through the BA Builders Challenge 

program. Under this program, builders are certified for energy efficiency and high performance 

homes strategies by meeting minimum requirements for energy performance, mechanical 

ventilation, occupant ventilation, combustion safety, and building envelope moisture control. The 

program uses the Builders Challenge Best Practice Guides and Technology Information 

Packages as the basis for certification (as an example, see DOE [2008]). 

Central to the Builders Challenge is third-party verification of the design and installation process 

to reduce construction risk and increase the opportunities for the home to perform as planned. A 

home must reach a Home Energy Rating Score (HERS) of 70 or less and undergo third-party 

field review. The scoring and the field review must be conducted by an independent home 

energy rater qualified through the Residential Energy Services Network (RESNET) or an 

approved third-party verifier. 

Similarly, the EPA has its own off the shelf technology package for whole-house energy 

efficiency through its ENERGY STAR for Homes Program. A professional that builds a home to 

ENERGY STAR version 2 standards will, on average, create a home that is 20% to 30% more 

energy efficient than a code-based home. Again, a HERS rating and a third-party field review are 

required, both conducted by an independent home energy rater qualified through RESNET. 

April of 2012 ushered in a new partnership between BA and ENERGY STAR when BA aligned 

the Builders Challenge with the new ENERGY STAR for Homes version 3. This partnership 

introduced stricter standards for energy and air quality, as well as strategies for reduced water 

use and pollutant source control. The new program—named DOE Challenge House— positions 

the home builder to construct a home with a HERS of 60 or less or a minimum 40% energy 

savings as compared to the 2004 international residential code. 

Builders Challenge and ENERGY STAR have cultivated industry partners from the 

manufacturing sector to develop and deploy products and systems that will help builders meet 

energy efficiency and high performance home goals. Many of the products and service providers 

can be found on the websites of the two programs, assisting builders in moving easily from 

information to action. The partners in DOE Challenge House can be found 

at www4.eere.energy.gov/buildings/challenge/locator/. ENERGY STAR partners are listed

at www.energystar.gov/index.cfm?fuseaction=estar_partner_list.showpartnersearch. 
2 

The challenge with bringing the residential construction industry, as a whole, into high 

performance building begins with a lack of understanding of what motivates industry 

professionals to adopt new building and business strategies. An understanding of the obstacles 

that prevent professionals from adopting strategies that would improve their product and 

customer experience is also needed. 

 

Although the Builders Challenge website lists “unaware of resources” as one of the top reasons 

why builders are not building high performance homes, additional potential challenges to market 

transformation can include the following: 

• Time, money, and expertise to train contractors/staff might be in short supply. 

• The vast amount of information on high performance building can overwhelm a 

builder who lacks the education or time to discern what is relevant.

• Lack of understanding of the benefits of high performance homes might impede the 

ability of a builder or sales staff to sell confidently to homeowners. 

• According to the Myth of the Best Practice (May 2011), best practices can be 

counterproductive when they are adopted without the intent to learn. 

1.2 Introduction

BA Best Practice Guides and Builders Challenge Technology Information Packages describing 

how to achieve 30%+ energy savings at a net neutral cost to the homebuyer are readily available. 

The question remains, then: Why do some builders adopt high performance building strategies 

but the larger market has not engaged in this level of performance? 

The NorthernSTAR Building America Partnership team proposed this comparison study to gain 

insight into the business, sales, and construction processes of several successful high 

performance builders. The knowledge gained by understanding the high performance strategies 

used by individual builders, as well as the process each followed to move from traditional builder 

to high performance builder, will be beneficial in proposing more in-depth research. Additional 

research will supplement the results of this study to yield specific action items to assist the

industry at large in transforming to high performance new home construction and closing the gap 

between available information and action. 

This study focused on three leading high performance custom home builders in the upper 

Midwest: Amaris Custom Homes, Christian Builders, and Cobblestone Homes. In-depth 

interviews were conducted to gain information about each company’s history and philosophy, to 

understand the energy strategies they typically include in their home designs, to outline the key 

components of their business models, and to learn their general marketing strategies as well as 

those specific to the promotion of high performance homes. The interviews pointed to the 

leadership characteristics of each builder as the key influencer that helped move each from codebased construction to high performance builder. A leader’s attitude was also important in 

keeping the company focused on high performance goals even when their trade partners lacked 

the knowledge or interest in energy efficient construction. Reputation in the community was the 

main feature they all shared and cited as their principal method of obtaining new clients. 
3 

Energy modeling was used to assess predicted energy performance of each builder’s energy 

strategies applied to a prototypical home to determine how each builder’s strategies compare to 

the requirements for 2012 International Energy Conservation Code (IECC), ENERGY STAR 

version 3, and the BA Builders Challenge. Even though all the builders would be considered 

high performance by meeting the requirements for ENERGY STAR version 2 and the Builders 

Challenge Program, only one builder includes enough high performance strategies to comply 

with the most advanced high performance programs (ENERGY STAR version 3 and IECC 

2012). The other two builders are very close to this advanced level, needing just a few upgrades 

to bring them into compliance. 
4 

2 Approach

2.1 Builder Interviews

The three high performance builders that participated in this study were chosen based on their 

leadership in the industry, willingness to adopt new techniques in their companies, and 

relationship to NorthernSTAR as industry partners. They typically build market-rate, singlefamily custom homes with attached garages and full basements with lookout windows. 

The NorthernSTAR team conducted extensive interviewing of each builder at their places of 

business. The interviews were designed in a similar format to gather information on customary 

building practices, business philosophies; targeted price ranges; contracting, construction, and 

sales processes; and sales in the past year. Obstacles to and successes with high performance 

building were also queried. 

2.2 Energy Modeling

The Building Energy Optimization (BEopt)/EnergyPlus version 1.1 energy modeling software

developed by the National Renewable Energy Laboratory in support of the BA program was 

used to evaluate the energy performance of customary building practices of each of the three 

builders. A base home representative of their typical home plans was used in the modeling. The 

base home was two stories and 2,400 ft2

, with four bedrooms, full basements with lookout 

windows, and a three-car garage.

An additional modeling program, Building Foundation Energy Transport Simulation (BUFETS) 

rev. B/EnergyPlus 6.0, was used in conjunction with BEopt to produce “adjusted” outputs. 

BUFETS includes three-dimensional foundation heat transfer including phase change effects and 

nonlinear material properties as a function of moisture content and temperature. It also allows 

above-grade foundation walls, lookout and walkout basement configurations, and nonadiabatic 

slabs to be modeled. (In a lookout basement, the basement walls extend sufficiently above 

ground level that some of the basement windows are above ground level.) The combination of 

programs allows for a better understanding of energy performance of homes in areas where 

regional differences are not captured by BEopt alone. In the Midwest, full and lookout basements 

are common housing features with unique thermal characteristics that can be captured best 

through the BUFETS rev.B/EnergyPlus approach. 

The REM/Rate software analysis tool was also used to evaluate energy performance alongside 

BEopt. REM/Rate is the standard program energy raters used in the field. BEopt is used more 

often in research. Determining if the results are similar for predicting energy use will be useful to 

an energy rater seeking research information that discusses energy via the BEopt format.

The modeling will also be used to determine how the customary practices of each builder 

contribute to meeting the performance requirements for Builders Challenge, ENERGY STAR, 

and IECC 2012. 
5 

3 Results 

All three builders typically build market-rate, single-family custom homes with attached garages 

and full basements with lookout windows. The price points for their homes are similar. Their 

primary selling points are their reputations for quality and their standing in the community. They 

all promote energy efficient strategies on their websites. They all sought outside consultants to 

help transform their construction practices. They all aim to remain competitive while 

encouraging more builders to enter the high performance market as a means to help drive 

consumer interest. In contrast to their common interests and success, they have all become 

successful in the high performance market with different business models, staffing, and 

processes.

3.1 Builder Interviews

3.1.1 Customary Building Systems

Table 1 displays the details of the customary building systems and performance attributes for 

each of the participating builders. 
6 

Table 1. Customary Building Systems of the Participating Builders

Building 

System Amaris Custom Homes Christian Builders Cobblestone Homes

Cooling 

Equipment SEER = 14 SEER = 13 SEER = 13

Heating 

Equipment Gas Furnace AFUE = 95 Gas Furnace AFUE = 95 Gas Furnace AFUE = 92 

Duct Leakage Leakage = 0.5 cfm/100 ft2

to unconditioned spaces

Leakage = 0.5 cfm/100 ft2

to unconditioned spaces

Leakage = 0.5 cfm/100 ft2

to unconditioned spaces

Duct 

Insulation R-8 R-8 R-8 

Infiltration 0.8 ACH50 1.2 ACH50 1.5 ACH50

Ceiling 

Insulation R-60 R-44 R-49

Wall 

Insulation R-21 R-21 R-19

Foundation 

Insulation

R-10 exterior continuous 

and R-10 interior rigid foam 

boarda

R-10 exterior continuous R-5 exterior continuous 

rigid foamb

Windows U-Value = 0.24; SHGC =

0.23

U-Value = 0.30; SHGC = 

0.19

U-Value = 0.30; SHGC = 

0.29

Water Heater 40-gal gas, EF = 0.64 40-gal gas, EF = 0.64 50-gal gas, EF = 0.65

Appliances 

and Lighting

ENERGY STAR 

appliances, 80% CFLs

ENERGY STAR

appliances, 60% CFLs

ENERGY STAR

appliances, 40% CFLs

Mechanical 

Ventilation

ERV @ 76.8 cfm per 

ASHRAE 62.2, 72% 

efficient

ERV @ 76.8 cfm per 

ASHRAE 62.2, 72% 

efficient

ERV @ 76.8 cfm per 

ASHRAE 62.2, 72% 

efficient

Exterior

Walls 2 × 6, 24-in. o.c. 2 × 6, 16-in. o.c. 2 × 6, 16-in. o.c.

Sheathing R-5.5 rigid foam structural 

insulated sheathing

R-1.22 1⁄2-in. fiberboard 

sheathing

OSB w/R-3 rigid foam 

insulated sheathingb

Cladding Cementitious siding Vinyl siding Vinyl siding

Gypsum 5/8 in. 5/8 in. 5/8 in.

Interior 

Walls 2 × 4 2 × 4 2 × 4 

Interzonal 

Walls

16-in. o.c., 1⁄2-in. gypsum, 

not insulated

16-in. o.c., 1⁄2-in. gypsum, 

not insulated

16-in. o.c., 1⁄2-in. gypsum, 

not insulated

a

Amaris currently uses a combined interior/exterior foundation insulation system. Before adopting this system, the 

builder experimented with Thermax on the interior, spray foam on the exterior, and rigid foam on the exterior. 

Amaris is currently looking at insulated concrete forms.

b

Before adopting their current wall sheathing system (OSB with R-3 rigid foam insulated sheathing), Cobblestone 

experimented with OSB sheathing, structural insulating sheathing, and Zip System wall sheathing. 

Notes: SEER, seasonal energy efficiency ratio; AFUE, annual fuel utilization efficiency; ACH, air changes per hour; 

SHGC, solar heat gain coefficient; EF, energy factor; CFL, compact fluorescent lighting; ERV, energy recovery 

ventilator; o.c., on center; OSB, oriented strand board.
7 

3.1.2 Builder Characteristics

3.1.2.1 Amaris Custom Homes, White Bear Lake, Minnesota 

www.minnesotagreenhomebuilder.com 

The staff describes the company as a custom green home builder. The typical sales price of their 

homes is between $275,000 and $350,000. They have been in business since 2003 and have a 

staff of four— the owner, a construction manager, an interior designer, and an office manager. 

The owner does sales and performs contracting functions. The company’s primary marketing 

tools are a website and blog. The contract with the clients is on a cost-plus basis with a flat rate 

construction management fee. All projects are competitively bid with three to four contractors 

based on detailed specifications. The owner uses a documented questionnaire with each client to 

address client’s interests during the sales process, which is used to educate the client on the 

process and practices Amaris employs that differ from competitors. The company positions itself 

as offering the highest quality at the best value. Amaris has built certified ENERGY STAR and 

Leadership in Energy and Environmental Design (LEED) homes. 

3.1.2.2 Christian Builders, Rogers, Minnesota 

www.christianbuilders.com 

The staff describes the company as a local and national leader in energy efficient custom home 

building. The typical sales price of their homes is between $275,000 and $350,000. They have 

been in business since 1974 and have a staff of four: two owners, a construction manager, and an 

office manager. One owner engages in sales; the other owner performs the contracting function. 

Christian Builders has been an ENERGY STAR builder since 1998 and was an EnergyValue 

Housing Award Winner in 1999. The company’s primary marketing tools are a website and its 

reputation. The contract with the clients is on a negotiated lump-sum basis. All projects are 

competitively bid with three to four contractors. Work requirements are loosely defined based on 

custom and practice rather than detailed specifications. The sales process does not address 

energy efficient practices unless the client inquires about energy efficiency. The company 

positions itself as a premier energy efficient custom homebuilder.

3.1.2.3 Cobblestone Homes, Saginaw, Michigan

http://cobblestone.me 

The staff describes the company as an innovative, high performance custom home builder. The 

typical sales price of their homes is between $300,000 and $400,000. They have been in business 

since 2002 and have a staff of nine: two owners, four project managers, a warranty manager, a 

draftsperson, and an office manager. One of the owners engages in sales and performs the 

contracting functions. Cobblestone Homes has been an ENERGY STAR builder since 2005 and 

was an EnergyValue Housing Award winner in 2011. The company’s primary marketing tools 

are a website and a Facebook page. Sales contracts with clients are on a negotiated lump-sum 

basis. Projects are single sourced with key contractors per trade. Work requirements are based on 

custom and practice built on long-term relationships over time. The sales process is used to 

develop close relationships with clients and focuses on customer satisfaction that leads to 

referrals. The company positions itself as leading the market with high performance homes.

Table 2 summarizes the builders’ characteristics and key business practices. 
8 

Table 2. Builder Characteristics and Key Business Practices

Amaris Custom Homes Christian Builders Cobblestone Homes

Builder 

Type Custom Homes Custom Homes Custom Homes

Price Point $275–$350K $275–$350K $300–$400K 

2011 Sales 5 15 60 

Purchasing 

Process

Competitive bid, welldefined specification

Competitive bid, loose 

specification based on 

custom and practice 

Single source, no 

specification, custom 

and practice

Construction 

Process Design-build Design-build Design-build

Sales 

Process Direct sales by owner Direct sales by owner Direct sales by owner 

Positioning Highest quality at best 

value 

Premier energy efficient 

custom homebuilder 

Leading the market with 

high performance 

homes

Marketing 

Process Website and blog Website and reputation Website and Facebook 

page

3.1.3 Builder Process Strategies

All three companies are custom builders and have custom approaches to general sales, customer 

education about the design and construction process, and the selling of energy strategies to 

homeowners. The following paragraphs outline each builder’s unique processes. 

3.1.3.1 Amaris Custom Homes

Amaris Custom Homes applies a “sales as education” approach working with interested clients 

in a quality assurance meeting for approximately 2 hours for every project. Eighty percent of the 

meeting time is spent reviewing the Amaris approach to construction specifications. Amaris also 

applies an open book approach to costing with its clients. Trade contractor bids are shared with 

the client, the client is charged a flat construction management fee for the project, and a cost-plus 

percentage is applied on top of hard costs. The owner has also become a dealer of residential 

solar power systems, offering these systems as options to their clients at wholesale pricing as a 

differentiator to competitors. 

3.1.3.2 Christian Builders

Christian Builders was an early pioneer in energy efficiency by building demonstration projects 

with a local municipality. Christian Builders also offers extensive homebuyer education 

opportunities through videos on its website with topics including comfortable living, health and 

safety, durability, energy efficiency, and operations and maintenance. The website also features

video testimonials from clients. Visitors to the website spend approximately 8 minutes on the 

site. Considering that the average duration a visitor spends at a website is 56 seconds (Marketing 

Charts [2012]), Christian Builders has created a way to effectively engage readers. 
9 

3.1.3.3 Cobblestone Homes

Cobblestone Homes began its journey with high performance homes under the mentorship of 

Ideal Homes of Norman, Oklahoma. Ideal Homes has been an industry-leading energy efficient 

builder for the past 20 years. Cobblestone Homes pays only a 2.5% commission to outside 

realtors. With outside realtors accounting for approximately one-half of Cobblestone’s annual 

sales, the effective rate is a 1.25% commission. Competitive builders in this market pay a total of 

5% commission to realtors. Cobblestone applies this difference in commission rates toward 

energy efficiency measures as part of their budgeting process. Cobblestone Homes’ performance 

metrics also include goals for obtaining local press coverage. The company accomplishes this by 

showcasing new technologies and building demonstration homes. 

3.1.4 Common Themes Sited by the Three Builders

Results of the builder interviews found that the builders in this report shared commonalities in 

both philosophy and approach to their businesses. They also experienced similar obstacles when 

trying to implement energy efficient strategies in their processes.

3.1.4.1 Business Practices

The builders all have experience working with outside experts for both technical and business 

(marketing and management) improvement. All three builders consult with Building Knowledge 

Inc. on building science and best building practices as a means to improve their homes. 

Cobblestone also enlisted the expertise of Ideal Homes as a mentor when the company entered 

the home building market. 

The builders are metric driven and participate in a continuous improvement cycle. They all focus 

on home performance (typically HERS), profitability, and internal metrics. (Cobblestone Homes 

lists targeting a specific number of articles in the local newspaper as a yearly strategic goal.) 

All the builders experiment with materials and systems to learn what does and does not work 

with their construction process and metrics. They are all willing to challenge the status quo of the 

industry to drive consumer interest. 

Although all three builders feature energy efficiency prominently in their marketing efforts, they 

all note that it is a small part of their overall distinction as home builders. Their primary selling 

point is a reputation of quality and community standing. 

3.1.4.2 Obstacles to High Performance

The builders cited trade contractor education about energy efficient construction as a primary 

challenge. The HVAC contractor was singled out as the most challenging because they have 

experienced issues related to design calculations, proper sizing, and distribution. 

The three builders cite the variety of high performance building certification programs (i.e., 

Builders Challenge, ENERGY STAR for Homes, LEED for Homes, and the National Green 

Building Standard, among others) as adding confusion to the marketplace and leading to inaction 

by other builders. 
10 

The builders have stated that energy code changes are necessary for moving the industry forward 

and that the majority of builders would not implement energy efficient measures if they were not 

required to do so. 

3.2 Energy Modeling

3.2.1 BEopt and Adjusted BEopt Analysis

A prototype base home configuration was developed to represent a typical move-up custom 

home in the upper Midwest and to reflect the designs offered by the participating builders. Table 

3 outlines this typical plan. 

Table 3. Prototype Building Configuration and Location

Figure 1 represents the BEopt outcomes when the customary building systems of the three 

builders, as displayed in Table 1, are input into the prototype building configuration outlined in 

Table 3. The column labeled BAB represents the B10 Building America Benchmark house built 

to the 2009 IECC, as well as the federal appliance standards that took effect on January 1, 2010, 

and lighting characteristics and miscellaneous electric loads most common in 2010. The B10 

Benchmark is used as the point of reference for tracking progress toward multiyear energy 

savings goals established by Building America. The adjusted BEopt outcomes are also displayed 

to show the energy use when the additional basement characteristics, as noted in Section 2.2, are 

input into the computation using the BUFETS rev.B/EnergyPlus 6.0. 

Building Specifications Details

First-Floor Square Footage 1,320: 30 × 44

Second-Floor Square Footage 1,290: 30 × 43

Basement Square Footage 1,320: 30 × 44

Stories 2

Roof Gable 6/12 slope

Bedrooms 4

Bath 21⁄2

Attic Std. attic, vented

Window to Wall Area Above-Grade Wall .051 (S); .011 (W); .032 (N); .031 (E)

Foundation Lookout Basement

Garage Attached; 750 ft2

: 30 × 25

Above-Grade Exposed

Foundation Wall Height 10 in. 

Climate Minneapolis
11 

Figure 1. BEopt and EnergyPlus simulation for prototype home 

Table 4 summarizes the projected annual energy use of the three builder prototype homes using 

BEopt with a full basement, BEopt and EnergyPlus with a lookout basement, and REM/Rate. It 

also includes the adjusted source energy savings of the selected builders’ current practices. These 

savings range from 31.7% to 38.6% over the B10 Benchmark. 

Table 4. Annual Energy Use Comparison B10 Benchmark to BEopt and Rem/Rate (MBtu/yr)

Builder

B10 

Benchmark 

Source 

Energy Use

(MBtu/yr) 

BEopt 

Raw 

Source 

Energy 

Use

(Mbtu/yr)

BEopt Raw 

Source 

Energy 

Savings 

Relative to 

B10 

(%)

EnergyPlus 

Source 

Energy Use 

With 

Lookout 

Basement 

(MBtu/yr)

EnergyPlus 

Simulation 

Source 

Savings 

Relative to 

B10 (%)

REM/Rate 

Source 

Energy Use

(MBtu/yr) 

Amaris 

Custom 

Homes

301.0 206.3 31.5 184.9 38.6 195.8

Christian 

Builders 301.0 224.1 25.5 200.0 33.6 222.8

Cobblestone 

Homes 301.0 233.0 22.6 205.7 31.7 234.7

3.2.2 Program Performance Compliance

Table 5 summarizes how the builders’ current practices comply with the performance standards 

of the noted programs. Compliance was determined through the REM/Rate home energy 

modeling software program. The compliance paths are noted in the individual reports contained

in Appendices A, B, and C. 
12 

Table 5. Performance Standards Comparison 

Performance Standards

Amaris 

Custom 

Homes

Christian 

Builders

Cobblestone 

Homes

HERS Index 43 49 52

ENERGY STAR v3 Compliance Yes Noa No a

Exceeds IECC 2006 UA Compliance by 30.6% 7.6% 6.5%

Exceeds IECC 2006 Annual Energy Cost 

Compliance by 62.4% 52.4% 49.5% 

Exceeds IECC 2009 UA Compliance by 29.2% 5.7% 4.5%

Exceeds IECC 2009 Annual Energy Cost 

Compliance by 48.3% 34.8% 33.5% 

Exceeds IECC 2012 UA Compliance by 21.8% Nob Noc

Exceeds IECC 2012 Annual Energy Cost 

Compliance by 39.0% 23.5% 21.7% 

Builders Challenge Compliance Yes Yes Yes a Would meet ENERGY STAR v3 with R-5 exterior insulation or advanced framing

b Would meet IECC 2012 UA with R-5 exterior above-grade wall insulation and additional R-5 foundation 

insulation

c Would meet IECC 2012 UA with R-5 exterior above grade wall insulation and additional R-10 foundation 

insulation
13 

4 Conclusions 

All of the participating builders are involved in continuous improvement processes that have led

to their success in the high performance building market. Each seeks information, engages 

metrics, and hires outside consultants as needed. 

Table 5 shows that all three builders engage in building practices that exceed the 2006 and 2009 

IECC UA Compliance as well as the Builders Challenge. Although Amaris is the only company 

currently in a position to meet the IECC 2012 UA compliance and ENERGY STAR v.3, the 

other two builders need to make a only few changes to reach these metrics. This conclusion 

parallels the information from Table 4 where the simulation models show that all of the 

participating builders exceed the BA 30%+ energy savings goals over the BA B10 Benchmark 

with their current standard practices. 

Figure 1 and Table 4 demonstrate that the BEopt with EnergyPlus was a more refined method 

than BEopt for determining source energy savings for homes with lookout basements (a common 

feature in cold-climate homes). BEopt does not allow lookout basements to be modeled at all, 

only full basements with the entire wall height located below grade. The energy savings gained 

from the strategies applied to the lookout wall (entirely above grade in the cases modeled), then, 

are higher than those obtained by modeling the walls as if they were below grade. The energy 

savings gained as a result of the strategies employed by the builders would have been missed 

entirely if not for the BEopt with EnergyPlus with Lookout Basement modeling. Only three 

samples comprised the test population in this study, but a deeper investigation into the 

differences between BEopt and BEopt with EnergyPlus might demonstrate that more homes are 

in line with, or getting closer to, the BA 30%+ energy savings goals, especially in cold-climate 

regions. 

Table 4 also demonstrates that the BEopt and REM/Rate energy analysis programs are fairly 

equal in predicting source energy savings. This information serves as a beginning point toward

understanding how REM/Rate and BEopt language is interchangeable, especially for the builder 

or energy professional in the field seeking advanced research where results are presented in 

BEopt language. Because three samples cannot represent conclusive results, further study on the 

alignment of BEopt and REM/Rate would be useful to advancing an understanding of research 

results within the industry. 

In looking at Table 1, it is interesting to note that each of the builders has been able to employ 

different building techniques to achieve similar energy performance results. The building 

techniques being used to achieve high performance represent the evolution of each builder. The 

reported systems are a combination of strategies each builder has used from the beginning stages 

of their businesses; strategies with which they experimented and found to be beneficial additions; 

and those strategies they have added because of the influence of HERS scores, the ENERGY 

STAR process, and guidance from experts such as building scientists and mentors. Building 

science is part of each company’s equation for high performance, it is not the sole guiding 

principle for decision making. 
14 

No single concern was noted by the builders as a primary barrier to seeking additional industry 

certifications. Instead, a variety of concerns—cost, market demand, retooling, and/or lack of 

building science knowledge—seem to be the underlying reasons they do not pursue additional 

industry recognition. Note, however, that all three builders have similar attitudes in that none 

sees the various programs or code requirements as their end goal. Instead, the builders are more 

driven to risk, experimentation, and metrics rather than alignment with the processes required of 

a particular program. 

The participating builders are all custom builders. They view the design/build process and 

owner-led sales as an opportunity to remain flexible in the delivery of high performance 

strategies while balancing client needs and retaining a competitive price point. Energy efficiency

is a point of marketing distinction and is promoted through their websites, social marketing

efforts, and demonstration homes. They all strongly believe, however, that reputation for quality 

and community standing are the predominant values that separate them from the competition. It 

is also noteworthy that they have achieved parallel success in high performance with vastly 

different business models. Additionally, all three have maintained or grown their businesses 

through the downturn in the economy. 

Through all of their success, they have had to deal with obstacles in becoming high performance 

builders. Trade contractors’ lack of education on energy efficiency strategies requires diligence 

in the field as well as in-depth knowledge in specialty areas. The abundance of building 

certification programs adds to confusion in the marketplace. All three builders are committed to 

improvement, so overcoming obstacles is accepted as part of doing business. They are not 

convinced, though, that other builders will follow suit. It was their collective belief that 

imminent energy code changes are necessary for moving the industry forward, stating that the

majority of builders would not implement energy efficient measures if they were not required to 

engage in the process.

It can be argued that these builders are not leaders in their markets because they are energy 

efficient builders; they incorporate energy efficient measures because they are leaders. In other 

words, these builders see themselves as leaders in quality, innovation, and customer service, and 

employing energy efficient technologies is one of the ways they demonstrate that leadership. 

They all welcome any efforts to increase competition to help drive market interest in high 

performance homes. 

A future study that investigates the business, sales, and construction processes of a greater 

number of high performance builders would be important for determining whether the results of 

this small sample are relevant and able to be duplicated. This study looks only at what three high 

performance builders are doing now. A future study that gives insight into what high 

performance builders are planning to do as codes change or competition increases would be 

helpful in charting a pathway to high performance for code-based builders. A larger study that 

investigates attitudes of code-based builders and perceived obstacles to adopting high 

performance strategies would also lend insight into methods for helping these builders to achieve 

greater energy efficiencies in their homes.
15 

Bibliography

BA (2005). Building America Best Practice Series: Volume 3. NREL/TP-550-38309. Golden, 

CO: National Renewable Energy Laboratory. Accessed February 8, 

2012: http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/38309.pdf. 

DOE (2008). Builders Challenge Technology Information Package Cold Climate: Chicago. CCHI-02. Accessed February 8, 2012: 

http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/btp_c_chicago_dec08

v2_r4.pdf. 

EPA. “ENERGY STAR for Homes Version 3 Guidelines.” Accessed February 8, 2012: 

www.energystar.gov/index.cfm?c=bldrs_lenders_raters.nh_v3_guidelines, 

IECC 2006. “2006 International Energy Conservation Code and Commentary.” 

IECC 2009. “2009 International Energy Conservation Code and Commentary.” 

IECC 2012. “2012 International Energy Conservation Code and Commentary.” 

Marketing Charts (February 22, 2010). “Americans Spend Less Time, Do More Online.” 

Accessed July 21, 2012: www.marketingcharts.com/interactive/americans-spend-less-time-domore-online-12037. 

May, M.E. (2011). “The Myth of the Best Practice.” Accessed February 8, 2012: 

http://matthewemay.com/2011/01/17/the-myth-of-the-best-practice/. 
16 

Appendix A: Amaris Custom Homes REM/Rate 
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Appendix B: Christian Builders REM/Rate 
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Appendix C: Cobblestone Homes REM/Rate 
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DOE/GO-102012-3754 ▪ December 2012

Printed with a renewable-source ink on paper containing at 

least 50% wastepaper, including 10% post-consumer waste.