CHAPTER 7. ENERGY CONSUMPTION OF FURNACES AND BOILERS TABLE OF CONTENTS 7.1 INTRODUCTION ..................................................... 7-1 7.2 VIRTUAL FURNACE MODELS ......................................... 7-2 7.2.1 Actual Basic Furnace Models ...................................... 7-3 7.2.2 Input Capacity and Maximum Airflow ............................... 7-3 7.2.2.1 Non-Weatherized Gas Furnaces .............................. 7-3 7.2.2.2 Other Product Classes ...................................... 7-4 7.2.3 Blower Size .................................................... 7-5 7.2.4 Motor Size ..................................................... 7-6 7.2.5 Supply-Air Outlet Area ........................................... 7-6 7.2.6 Power Consumption of Draft Inducer ................................ 7-9 7.2.7 Delay and Ignitor Times ......................................... 7-10 7.3 HOUSING SAMPLE .................................................. 7-10 7.4 ASSIGNING FURNACES TO SAMPLE HOUSES .......................... 7-12 7.4.1 Furnace Input Capacity .......................................... 7-12 7.4.2 Airflow Capacity ............................................... 7-12 7.4.3 Efficiency ..................................................... 7-13 7.4.4 Electricity Consumption of the Furnace Blower ....................... 7-14 7.5 FURNACE BLOWER ELECTRICITY CONSUMPTION .................... 7-14 7.5.1 System Curves ................................................. 7-15 7.5.2 Furnace Fan Curves ............................................. 7-16 7.5.3 Fan Power .................................................... 7-18 7.5.4 Overall Air-Moving Efficiency .................................... 7-20 7.6 ANNUAL HEATING LOADS IN SAMPLE HOUSING UNITS ............... 7-21 7.7 ENERGY CONSUMPTION ............................................ 7-22 7.7.1 Fuel Consumption .............................................. 7-22 7.7.2 Electricity Consumption ......................................... 7-23 7.8 RESULTS .......................................................... 7-24 LIST OF TABLES Table 7.2.1 Characteristics of Basic Furnace Models .............................. 7-3 Table 7.2.2 Virtual Model Furnaces: Capacity and Airflow ........................ 7-4 Table 7.2.3 Relevant Sizes of Virtual Models for Non-Weatherized and

Weatherized Gas Furnaces ......................................... 7-4 Table 7.2.4 Relevant Sizes of Virtual Models for Mobile Home Furnaces ............. 7-5 Table 7.2.5 Relevant Sizes of Virtual Models for Oil-Fired Furnaces ................. 7-5 Table 7.2.6 Relevant Sizes of Virtual Models for Gas Boilers ...................... 7-5 Table 7.2.7 Relevant Sizes of Virtual Models for Oil Boilers .. 7-5 Table 7.2.8 Assigned Blower Size by Airflow Capacity ........................... 7-6

7-i 

### CHAPTER 7. ENERGY CONSUMPTION OF FURNACES AND BOILERS TABLE OF CONTENTS 7.1 INTRODUCTION

..................................................... 7-1 7.2 VIRTUAL FURNACE MODELS

......................................... 7-2 7.2.1 Actual Basic Furnace Models

...................................... 7-3 7.2.2 Input Capacity and Maximum Airflow

............................... 7-3 7.2.2.1 Non-Weatherized Gas Furnaces

.............................. 7-3 7.2.2.2 Other Product Classes

...................................... 7-4 7.2.3 Blower Size

.................................................... 7-S 

### 7.2.4 Motor Size

..................................................... 7-6 7.2.S 

### Supply-Air Outlet Area

........................................... 7-6 7.2.6 Power Consumption ofDraft Inducer

................................ 7-9 7.2.7 Delay and Ignitor Times

......................................... 7-10 7.3 HOUSING SAMPLE

.................................................. 7-10 7.4 ASSIGNING FURNACES TO SAMPLE HOUSES

.......................... 7-12 7.4.1 Furnace Input Capacity

.......................................... 7-12 7.4.2 Airflow Capacity

............................................... 7-12 7.4.3 Efficiency

..................................................... 7-13 7.4.4 Electricity Consumption ofthe Furnace Blower

....................... 7-14 7.S 

### FURNACE BLOWER ELECTRICITY CONSUMPTION

.................... 7-14 7.S.1 

### System Curves

................................................. 7-1S 7.S.2 

### Furnace Fan Curves

............................................. 7-16 7.S.3 

### Fan Power

.................................................... 7-18 7.S.4 

### Overall Air-Moving Efficiency

.................................... 7-20 7.6 ANNUAL HEATING LOADS IN SAMPLE HOUSING UNITS

............... 7-21 7.7 ENERGY CONSUMPTION

............................................ 7-22 7.7.1 Fuel Consumption

.............................................. 7-22 7.7.2 Electricity Consumption

......................................... 7-23 7.8 RESULTS

.......................................................... 7-24

Table 7.2.1 Table 7.2.2 Table 7.2.3 Table 7.2.4 Table 7.2.S 

### Table 7.2.6 Table 7.2.7 Table 7.2.8 LIST OF TABLES Characteristics ofBasic Furnace Models

.............................. 7-3 Virtual Model Furnaces: Capacity and Airflow

........................ 7-4 Relevant Sizes ofVirtual Models for Non-Weatherized and Weatherized Gas Furnaces

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4 Relevant Sizes ofVirtual Models for Mobile Home Furnaces

............. 7-S 

### Relevant Sizes ofVirtual Models for Oil-Fired Furnaces

................. 7-S 

### Relevant Sizes ofVirtual Models for Gas Boilers

...................... 7-S 

### Relevant Sizes ofVirtual Models for Oil Boilers

.. 7-S 

### Assigned Blower Size by Airflow Capacity

........................... 7-6

7-iTable 7.2.9 Assigned Motor Size by Airflow Capacity ............................ 7-6

Table 7.2.10 Supply-Air Outlet Area (in Square Feet) for Virtual Non-Condensing

Gas Furnace Models ............................................. 7-9 Table 7.2.11 Supply

-Air Outlet Area ( in Square Feet) for Virtual Condensing

Gas Furnace Models ............................................. 7-9 Table 7.2.12 Values for Delay and Ignition Times ................................ 7-10 Table 7.3.1 Criteria for Selection of RECS Records by Product Class ............... 7-11 Table 7.5.1 Coefficients for CFM equation for PSC motors ....................... 7-17 Table 7.5.2 Coefficients for CFM equation for Two-Stage and Continuous

Modulating furnaces with brushless permanent magnet motors ........... 7-18 Table 7.5.3 Coefficients for W/CFM equation for PSC motors

..................... 7-19 Table 7.5.4 Coefficients for W/CFM equation for Two-Stage and Continuous

Modulating furnaces with ECM motors ............................. 7-20 Table 7.8.1 Non

- Weatherized Gas Furnace Energy Use .......................... 7-24 Table 7.8.2 Weatherized Gas Furnace Energy Use (Low Cost Scenario ) ............. 7-26 Table 7.8.3 Mobile Home Furnace Energy Use ................................. 7-28 Table 7.8.4 Oil-Fired Furnace Energy Use

..................................... 7-30 Table 7.8.5 Gas Boiler Energy Use (Low Cost Scenario ) ......................... 7-32 Table 7.8.6 Oil-Fired Boiler Energy Use ...................................... 7-34 LIST OF FIGURES Figure 7.2 .1 Supply-Air Outlet Area for Non-Condensing Natural Gas Furnaces ........ 7-7 Figure 7.2 .2 Supply-Air Outlet Area for Condensing Natural Gas Furnaces ............ 7-8 Figure 7.5

. 1 Sample of System Curves with a Typical Fan Curve ................... 7-16 Figure 7.8

. 1 Range of Annual Gas Use in MMBtu for Non-Weatherized Gas Furnaces . . 7-25 Figure 7.8

. 2 Range of Electricity Use in kWh for Non-Weatherized Gas Furnaces ...... 7-25 Figure 7.8

. 3 Range of Annual Gas Use in MMBtu for Weatherized Gas Furnaces

(Low Cost Scenario ) ............................................ 7-27 Figure 7.8

. 4 Range of Electricity Use in kWh for Weatherized Gas Furnaces

(Low Cost Scenario ) ............................................ 7-27 Figure 7.8.5 Range of Annual Gas Use in MMBtu for Mobile Home Furnaces ......... 7-29 Figure 7.8

. 6 Range of Electricity Use in kWh for Mobile Home Furnaces ............. 7-29 Figure 7.8.7 Range of Annual Gas Use in MMBtu for Oil

- Fired Furnaces ............. 7-31 Figure 7.8

. 8 Range of Electricity Use in kWh for Oil-Fired Furnaces ................ 7-31 Figure 7.8.9 Range of Annual Gas Use in MMBtu for Hot-Water Gas Boilers

(Low Cost Scenario ) ............................................ 7-33 Figure 7.8

. 10 Range of Electricity Use in kWh for Hot-Water Gas Boilers

(Low Cost Scenario ) ............................................ 7-33 Figure 7.8

. 11 Range of Annual Gas Use in MMBtu for Hot-Water Oil-Fired Boilers

..... 7-35 Figure 7.8

. 12 Range of Electricity Use in kWh for Hot-Water Oil-Fired Boilers ......... 7-35

7-ii Table 7.2.9 Table 7.2.10 Table 7.2.11 Table 7.2.12 Table 7.3.1 Table 7.5.1 Table 7.5.2 Table 7.5.3 Table 7.5.4 Table 7.8.1 Table 7.8.2 Table 7.8.3 Table 7.8.4 Table 7.8.5 Table 7.8.6

Figure 7.2.1 Figure 7.2.2 Figure 7.5.1 Figure 7.8.1 Figure 7.8.2 Figure 7.8.3 Figure 7.8.4 Figure 7.8.5 Figure 7.8.6 Figure 7.8.7 Figure 7.8.8 Figure 7.8.9 Figure 7.8.10 Figure 7.8.11 Figure 7.8.12 Assigned Motor Size by Airflow Capacity

............................ 7-6 Supply-Air Outlet Area (in Square Feet) for Virtual Non-Condensing Gas Furnace Models

............................................. 7-9 Supply-Air Outlet Area (in Square Feet) for Virtual Condensing Gas Furnace Models

............................................. 7-9 Values for Delay and Ignition Times

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10 Criteria for Selection ofRECS Records by Product Class

............... 7-11 Coefficients for CFM equation for PSC motors
....................... 7-17 Coefficients for CFM equation for Two-Stage and Continuous Modulating furnaces with brushless permanent magnet motors
........... 7-18 Coefficients for W/CFM equation for PSC motors
... . . . . . . . . . . . . . . . . . . 7-19 Coefficients for W/CFM equation for Two-Stage and Continuous Modulating furnaces with ECM motors
............................. 7-20 Non-Weatherized Gas Furnace Energy Use

.......................... 7-24 Weatherized Gas Furnace Energy Use (Low Cost Scenario)

............. 7-26 Mobile Home Furnace Energy Use

................................. 7-28 Oil-Fired Furnace Energy Use

..................................... 7-30 Gas Boiler Energy Use (Low Cost Scenario)

......................... 7-32 Oil-Fired Boiler Energy Use

...................................... 7-34 

### LIST OF FIGURES Supply-Air Outlet Area for Non-Condensing Natural Gas Furnaces

........ 7-7 Supply-Air Outlet Area for Condensing Natural Gas Furnaces

............ 7-8 Sample of System Curves with a Typical Fan Curve

................... 7-16 Range ofAnnual Gas Use in MMBtu for Non-Weatherized Gas Furnaces

.. 7-25 Range ofElectricity Use in kWh for Non-Weatherized Gas Furnaces

...... 7-25 Range ofAnnual Gas Use in MMBtu for Weatherized Gas Furnaces (Low Cost Scenario)

............................................ 7-27 Range ofElectricity Use in kWh for Weatherized Gas Furnaces (Low Cost Scenario)

............................................ 7-27 Range ofAnnual Gas Use in MMBtu for Mobile Home Furnaces

......... 7-29 Range ofElectricity Use in kWh for Mobile Home Furnaces

............. 7-29 Range ofAnnual Gas Use in MMBtu for Oil-Fired Furnaces

............. 7-31 Range ofElectricity Use in kWh for Oil-Fired Furnaces

................ 7-31 Range ofAnnual Gas Use in MMBtu for Hot-Water Gas Boilers (Low Cost Scenario)

............................................ 7-33 Range ofElectricity Use in kWh for Hot-Water Gas Boilers (Low Cost Scenario)

............................................ 7-33 Range ofAnnual Gas Use in MMBtu for Hot-Water Oil-Fired Boilers

..... 7-35 Range ofElectricity Use in kWh for Hot-Water Oil-Fired Boilers

......... 7-35

7-iiCHAPTER 7. ENERGY CONSUMPTION OF FU RNACES AND BOILERS

7.1 INTRODUCTION The furnace and boiler energy-efficiency standards rulemaking considers the change in life-cycle cost (LCC) due to increased energy efficiency of furnaces and boilers. Energy consumption is the key part of the operating-cost input of the LCC calculation. The energy consumption of a furnace or boiler includes gas or oil and electricity. In the engineering analysis, the Department calculated energy consumption of baseline model-sized furnaces and boilers using the DOE test procedure for these types of equipment. For the LCC analysis, DOE estimated energy consumption of furnaces and boilers in actual housing units. To represent actual housing units likely to purchase and use furnaces and boilers in 2015, DOE used a set of housing units from DOE's Energy Information Administration (EIA)'s Residential Energy Consumption Survey of 2001 (RECS 2001).' For each housing unit, RECS reports space-heating energy consumption, which is based on the existing heating equipment. The Department calculated and adjusted the heating load of some of the RECS sample housing units so that they better represent housing units in 2015. The Department then calculated the energy consumption of alternative (more-efficient) equipment if it were purchased and installed in each housing unit in place of the existing equipment.The Department developed the method of calculation described in this chapter for nonweatherized gas furnaces, the most common in the US residential market among the six product classes in the rulemaking analysis. The Department generalized the energy consumption calculation for this product class to the other furnace product classes. Fuel consumption calculations for boilers are similar to those for the furnace product classes. The electricity calculations for boilers are simpler than for furnaces, because boilers do not provide thermal distribution for space cooling as furnaces often do. To begin the analysis, the Department developed representative conceptual furnace models. These " virtual " models incorporated typical features of currently

-marketed furnaces. The Department based the virtual furnaces on models selected from the March 2005 Gas Appliance Manufacturers Association (GAMA) Directory2 and product literature

. The virtual models capture the range of actual furnace sizes. The analysis assigned an appropriately sized virtual furnace to each sample housing unit. As a way of modeling energy consumption of alternative furnace designs , different design options were then applied to the virtual furnace. Estimating the annual energy consumption of alternative furnaces in each housing unit required DOE to estimate the heating loads of each housing unit. These loads represent the amount of heating required to keep a housing unit comfortable during an entire year. The Department estimated the heating loads from the heating energy consumption and the assumed characteristics of the existing furnace and air conditioner in each sample housing unit. The Department assigned the characteristics of the existing equipment to each sample housing unit, depending on the size and climate zone of each housing unit and the age of the heating 7-1 CHAPTER 7. ENERGY CONSUMPTION OF FURNACES AND BOILERS

7.1 INTRODUCTION The furnace and boiler energy-efficiency standards rulemaking considers the change in life-cycle cost (LCC) due to increased energy efficiency of furnaces and boilers. Energy consumption is the key part ofthe operating-cost input ofthe LCC calculation. The energy consumption of a furnace or boiler includes gas or oil and electricity. In the engineering analysis, the Department calculated energy consumption ofbaseline model-sized furnaces and boilers using the DOE test procedure for these types of equipment. For the LCC analysis, DOE estimated energy consumption offurnaces and boilers in actual housing units. To represent actual housing units likely to purchase and use furnaces and boilers in 2015, DOE used a set ofhousing units from DOE's Energy Information Administration (EIA)'s Residential Energy Consumption Survey of2001 (RECS 2001).1 For each housing unit, RECS reports space-heating energy consumption, which is based on the existing heating equipment. The Department calculated and adjusted the heating load of some ofthe RECS sample housing units so that they better represent housing units in 2015. The Department then calculated the energy consumption of alternative (more-efficient) equipment ifit were purchased and installed in each housing unit in place ofthe existing equipment. The Department developed the method ofcalculation described in this chapter for nonweatherized gas furnaces, the most common in the US residential market among the six product classes in the rulemaking analysis. The Department generalized the energy consumption calculation for this product class to the other furnace product classes. Fuel consumption calculations for boilers are similar to those for the furnace product classes. The electricity calculations for boilers are simpler than for furnaces, because boilers do not provide thermal distribution for space cooling as furnaces often do. To begin the analysis, the Department developed representative conceptual furnace models. These "virtual" models incorporated typical features ofcurrently-marketed furnaces. The Department based the virtual furnaces on models selected from the March 2005 Gas Appliance Manufacturers Association (GAMA) Directory2 and product literature. The virtual models capture the range of actual furnace sizes. The analysis assigned an appropriately sized virtual furnace to each sample housing unit. As a way ofmodeling energy consumption of alternative furnace designs, different design options were then applied to the virtual furnace. Estimating the annual energy consumption of alternative furnaces in each housing unit required DOE to estimate the heating loads ofeach housing unit. These loads represent the amount ofheating required to keep a housing unit comfortable during an entire year. The Department estimated the heating loads from the heating energy consumption and the assumed characteristics ofthe existing furnace and air conditioner in each sample housing unit. The Department assigned the characteristics ofthe existing equipment to each sample housing unit, depending on the size and climate zone ofeach housing unit and the age ofthe heating 7-1equipment

. The estimation of heating loads also required calculation of the electricity

consumption of the furnace blower, since heat from the furnace blower contributes to heating of the housing unit. To complete the analysis , the Department calculated how much energy would be required by furnaces with various design options to meet the heating load of each sample housing unit. 7.2 VIRTUAL FURNACE MODELS To conduct the analysis , the Department developed conceptual furnace models. The Department intended these virtual furnace models to represent typical furnaces with basic features , but not to describe specific, existing furnaces. The Department derived the characteristics of the virtual furnace models from existing " basic" furnace models, after examining the March 2005 GAMA Directory2 and the product literature of existing furnaces. See Appendix F, Reduced Set of Furnace Models Database , for more details. As a starting point for choosing values of input capacity for the virtual furnace models, the Department looked at the number of models listed by input capacity in the March 2005 GAMA Directory ( see Chapter 3, Figure 3

. 2.1). The Department selected models that were nonweatherized gas furnaces , not designed for mobile homes, not single packaged unit (combination of heating and cooling), and not discontinued

. Using these selection criteria , DOE reduced the 6,833 non

-weatherized gas furnace models in the GAMA Directory to 1,277 models. For virtual furnaces, DOE selected twelve input capacities that were the most common and that spanned the range on the market

. The Department made these selections based on the assumption that the sizes that have the most models are the most popular. The Department defined airflow capacity as the nominal maximum airflow at 0.5 inches water gauge (in.w.g. ) external static pressure , as listed in the product literature for each models. Manufacturers usually code this airflow capacity in the model number ( see Appendix G on Decoding of Manufacturer Model Numbers, for more details.) Most of the furnaces fit into four airflow capacity sizes: 800 cubic feet per minute (cfm), 1200 cfm, 1600 cfm, and 2000 cfm. These airflow capacities correspond to nominal air-conditioner sizes of two tons, three tons, four tons, and five tons , respectively

. The Department used the same set of airflow and capacity sizes for both non

- condensing and condensing furnaces.

Furnaces are capable of providing several levels of airflow

. For heating and cooling operation the manufacturer default airflow level is used

. If the furnace provides airflow for an air conditioner during cooling operation , it is typically set to provide a higher level of airflow than when heating operation is used. 7-2 equipment. The estimation ofheating loads also required calculation ofthe electricity consumption ofthe furnace blower, since heat from the furnace blower contributes to heating of the housing unit. To complete the analysis, the Department calculated how much energy would be required by furnaces with various design options to meet the heating load of each sample housing unit. 7.2 VIRTUAL FURNACE MODELS To conduct the analysis, the Department developed conceptual furnace models. The Department intended these virtual furnace models to represent typical furnaces with basic features, but not to describe specific, existing furnaces. The Department derived the characteristics ofthe virtual furnace models from existing "basic" furnace models, after examining the March 2005 GAMA Directory2 and the product literature of existing furnaces. See Appendix F, Reduced Set ofFurnace Models Database, for more details. As a starting point for choosing values ofinput capacity for the virtual furnace models, the Department looked at the number ofmodels listed by input capacity in the March 2005 GAMA Directory (see Chapter 3, Figure 3.2.1). The Department selected models that were nonweatherized gas furnaces, not designed for mobile homes, not single packaged unit (combination ofheating and cooling), and not discontinued. Using these selection criteria, DOE reduced the 6,833 non-weatherized gas furnace models in the GAMA Directory to 1,277 models. For virtual furnaces, DOE selected twelve input capacities that were the most common and that spanned the range on the market. The Department made these selections based on the assumption that the sizes that have the most models are the most popular. The Department defined airflow capacity as the nominal maximum airflow at 0.5 inches water gauge (in.w.g.) external static pressure, as listed in the product literature for each model". Manufacturers usually code this airflow capacity in the model number (see Appendix G on Decoding ofManufacturer Model Numbers, for more details.) Most ofthe furnaces fit into four airflow capacity sizes: 800 cubic feet per minute (cfm), 1200 c:fm, 1600 cfm, and 2000 cfm. These airflow capacities correspond to nominal air-conditioner sizes oftwo tons, three tons, four tons, and five tons, respectively. The Department used the same set of airflow and capacity sizes for both non-condensing and condensing furnaces.

a Furnaces are capable ofproviding several levels ofairflow. For heating and cooling operation the manufacturer default airflow level is used. Ifthe furnace provides airflow for an air conditioner during cooling operation, it is typically set to provide a higher level of airflow than when heating operation is used. 7-27.2.1 Actual Basic Furnace Models The Department selected actual furnace models that represent the fundamental characteristics of non-condensing and condensing non-weatherized gas furnaces with no special features. The Department used the characteristics listed in Table 7.2.1 to select basic furnace models. These characteristics are the most common among models on the market (see Appendix H, Determination of Basic Models). The Department selected several dozen furnace models that have these features. It looked in detail at these basic models to determine specific characteristics to use for creating virtual furnaces. Table 7.2.1 Characteristics of Basic Furnace Models Non-Condensing Gas Furnace Condensing Gas Furnace

single-stage single-stage 80% AFUE 90-92% AFUE permanent split capacitor (PSC) blower motor PSC blower motor forward-curved impeller blades forward-curved impeller blades up-flow or horizontal air-flow down-flow, up-flow, or horizontal air-flow The basic furnace models are listed by brand and series in Appendix H, which contains basic non-condensing and condensing model data. 7.2.2 Input Capacity and Maximum Airflow 7.2.2.1 Non-Weatherized Gas Furnaces For virtual furnace models, DOE selected 25 combinations ("bins") of input capacity and maximum airflow. The marked cells in Table 7.2.2 reflect the input capacity and nominal maximum airflow for the virtual furnace models. The selection reflects the most common input and nominal maximum airflow capacities of models in the March 2005 GAMA Directory,2 in product literature, and listed on furnace manufacturer web sites. Most basic models on the market fit into the 25 bins of input capacity and airflow capacity. Some models do not exactly match the bins, but their values are close enough that DOE included them in one of the 25 bins. For example, 40 kBtu/h and 45 kBtu/h models are grouped together into a single 45 kBtu/h bin. Most bins have at least two actual models. 

### 7.2.1 Actual Basic Furnace Models The Department selected actual furnace models that represent the fundamental characteristics ofnon-condensing and condensing non-weatherized gas furnaces with no special features. The Department used the characteristics listed in Table 7.2.1 to select basic furnace models. These characteristics are the most common among models on the market (see Appendix H, Determination ofBasic Models). The Department selected several dozen furnace models that have these features. It 

### looked in detail at these basic models to determine specific characteristics to use for creating virtual furnaces. Table 7 2 1 

### Characteristics of Basic Furnace Models 

## .. Non-Condensing Gas Furnace Condensing Gas Furnace single-stage single-stage 80%AFUE 90-92% AFUE permanent split capacitor (PSC) blower motor PSC blower motor forward-curved impeller blades forward-curved impeller blades up-flow or horizontal air-flow down-flow, up-flow, or horizontal air-flow The basic furnace models are listed by brand and series in Appendix H, which contains basic non-condensing and condensing model data. 7.2.2 Input Capacity and Maximum Airflow 7.2.2.1 Non-Weatherized Gas Furnaces For virtual furnace models, DOE selected 25 combinations ("bins") ofinput capacity and maximum airflow. The marked cells in Table 7.2.2 reflect the input capacity and nominal maximum airflow for the virtual furnace models. The selection reflects the most common input and nominal maximum airflow capacities ofmodels in the March 2005 GAMA Directory/ in product literature, and listed on furnace manufacturer web sites. Most basic models on the market fit into the 25 bins of input capacity and airflow capacity. Some models do not exactly match the bins, but their values are close enough that DOE included them in one ofthe 25 bins. For example, 40 kBtu/h 

### and 45 kBtu/h 

### models are grouped together into a single 45 kBtu/h 

### bin. Most bins have at least two actual models.

7-3Table 7.2.2 Virtual Model Furnaces : Capacity and Airflow Input Capacity (kBtu/h) 45 50 60 70 75 80 90 100 115 120 125 140 800 cfm x x x (2 tons) 1200 cfin x x x x x x x x (3 tons) 1600 cfm x x x x x x x x (4 tons) 2000 cfm :I x x x x x x (5 tons)

- I The Department created one virtual model to represent all the models assigned to each bin. The Department used specifications from the actual models in each bin to determine the specifications for the corresponding virtual model. These specifications include blower size, motor size, supply-air outlet area, power consumption of the draft inducer and the igniter, and several delay times. The specifications are described in the sections below. 7.2.2.2 Other Product Classes In its analysis of weatherized gas furnaces, DOE used the same virtual models as it used in the analysis of non-weatherized gas furnaces. Because of the limited number of sizes available for mobile home gas furnaces, DOE selected a subset of the 25 input and airflow capacity combinations to represent each product class. The selection of oil-fired furnaces reflects the most common input and nominal maximum airflow capacities of models in the March 2005 GAMA Directory. The selection of oil-fired and gas boilers reflects the most common input capacities of models in the March 2005 GAMA Directory. Tables 7.2.3-7.2.7 listthe relevant sizes for non-weatherized and weatherized gas furnaces, mobile home furnaces, oilfired furnaces, gas boilers, and oil-fired boilers. Table 7.2.3 Relevant Sizes of Virtual Models for Non-Weatherized and Weatherized Gas

Furnaces Input Capacity (kBtu/h) 45 50 60 70 75 80 90 100 115 120 125 140 Max. 2 X X X Airflow 3 X X X X X X X X (tons) 4 X X X X X X X X

5 X X X X X X

7-4 

### Table 7.2.2 Virtual Model Furnaces: Capacity and Airflow Input Capacity (kBtu/h) 45 50 60 70 75 80 90 100 115 120 125 140 800 cfm x (2 tons) 1200 dill x (3 tons) 1600 cfm (4 tons) 2000 cfm

(5 tons) x x



### x x x x

x x x x x

x x x x x x

x x x x x x

The Department created one virtual model to represent all the models assigned to each bin. The Department used specifications from the actual models in each bin to determine the specifications for the corresponding virtual model. These specifications include blower size, motor size, supply-air outlet area, power consumption ofthe draft inducer and the igniter, and several delay times. The specifications are described in the sections below. 

### 7.2.2.2 Other Product Classes In its analysis of weatherized gas furnaces, DOE used the same virtual models as it used in the analysis ofnon-weatherized gas furnaces. Because ofthe limited number of sizes available for mobile home gas furnaces, DOE selected a subset ofthe 25 input and airflow capacity combinations to represent each product class. The selection of oil-fired furnaces reflects the most common input and nominal maximum airflow capacities ofmodels in the March 2005 GAMA Directory. The selection of oil-fired and gas boilers reflects the most common input capacities ofmodels in the March 2005 GAMA Directory. Tables 7.2.3-7.2.7 list the relevant sizes for non-weatherized and weatherized gas furnaces, mobile home furnaces, oilfired furnaces, gas boilers, and oil-fired boilers. 

### Table 7.2.3 Relevant Sizes of Virtual Models for Non-Weatherized and Weatherized Gas Furnaces Input Capacity (kBtu/h) 45 50 60 70 75 80 90 100 115 120 125 140 Max. 2 X X X Airflow 3 X X X X X X X X

(tons) 4 X X X X X X X X 5 X X X X X X

7-4Table 7.2.4 Relevant Sizes of Virtual Models for Mobile Home Furnaces Input Capacity (kBtu/h)

Max. Airflow (tons) 60 70 1 75 1 80 1 90 1 100 1 115 1 120 1 125 1 140

X i I X I I X X X X X X X X X X Table 7.2.5 Relevant Sizes of Virtual Models for Oil-Fired Furnaces Input Capacity (kBtu/h) 70 90 105 120 140 154 175 210 Max. Airflow 2 (tons) 3 X X X

4 X X 5 X X X X X X Table 7.2.6 Relevant Sizes of Virtual Models for Gas Boilers Input Capacity (kBtu/h) 50 75 105 125 150 175 200 Table 7.2.7 Relevant Sizes of Virtual Models for Oil Boilers Input Capacity (kBtu/h) 90 105 7.2.3 Blower Size 120 140 155 175 190 225

210 250

245 300

280

The Department selected a blower size (listed as nominal diameter in inches by nominal width in inches) for each virtual furnace model (Table 7.2.8). The blower size is typical for the basic furnace models in each bin. Blower size increases with airflow capacity, but not with inputcapacity. The Department used four blower sizes-the same ones for condensing and noncondensing virtual furnace models. For the blower sizes of basic furnace models, see Appendix H, Determination of Basic Models. 

### Table 7.2.4 Relevant Sizes of Virtual Models for Mobile Home Furnaces Input Capacity (kBtu/h) 60 70 75 80 90 100 115 120 125 140 Max. 2 X X X Airflow 3 X X X

(tons) 4 X X X 5 X X X 

### Table 7.2.5 Relevant Sizes of Virtual Models for Oil-Fired Furnaces Input Capacity (kBtu/h) 70 90 105 120 140 154 175 210 Max. 2 Airflow

(tons) 3 X X X 4 X X 5 X X X X X X 

### Table 7.2.6 Relevant Sizes of Virtual Models for Gas Boilers Input Capacity (kBtu/h) 50 

# I 75 

# I 105 

# I 125 

# I 150 

# I 175 

# I 200 

# I 225 

# I 250 

# I 300 

### Table 7.2.7 Relevant Sizes of Virtual Models for Oil Boilers Input Capacity (kBtu/h) 90 

# I 105 

# I 120 

# I 140 

# I 155 

# I 175 

# I 190 

# I 210 

# I 245 

# I 280 

### 7.2.3 Blower Size The Department selected a blower size (listed as nominal diameter in inches by nominal width in inches) for each virtual furnace model (Table 7.2.8). The blower size is typical for the basic furnace models in each bin. Blower size increases with airflow capacity, but not with input capacity. The Department used four blower sizes-the same ones for condensing and noncondensing virtual furnace models. For the blower sizes ofbasic furnace models, see Appendix H, Determination ofBasic Models.

7-5Table 7.2.8 Assigned Blower Size b y Airflow Capacity

Airflow Capacity ( cfm) Blower Size (inches) 2-ton models (800 cfm) 9 X 8 3-ton models (1200 cfm) 10 X 8 4-ton models (1600 cfm) 10 X 10 5-ton models (2000 cfm) 11 X 10 7.2.4 Motor Size The motors for the basic furnace models are six-pole permanent split capacitor (PSC) induction motors. The motors in the basic furnaces come with three to five taps that are used to set the motor speed. The Department assumed that, at high speed, the motors operate with a speed of 1075 revolutions per minute (rpm) to provide the nominal maximum airflow at 0.5 in.w.g. The Department assigned motor size to virtual furnace models, as shown in Table 7.2.9,to reflect typical-size motors of the basic furnace models. Motor sizes are the same for noncondensing and condensing furnaces. The larger the nominal maximum airflow, the larger the motor size. For the blower motor size and number of taps on basic model furnaces, see Appendix H, Determination of Basic Models, which lists the blower-motor sizes and number of blower motor taps of basic furnace models. Table 7.2.9 Assigned Motor Size by Airflow Capacity Airflow Capacity (cfm) Motor Size (HP) 2-ton models (800 cfm) 1/5 3-ton models (1200 cfm) 1/3 4-ton models (1600 cfm) 1/2 5-ton models (2000 cfm) 3/4 7.2.5 Supply-Air Outlet Area The supply-air outlet area is the opening from the furnace to the supply duct. The supply-air outlet area for basic furnace models increases with airflow capacity and inputcapacity. To capture this trend, DOE constructed a multiple regression equation of the supplyair outlet area to input capacity and airflow capacity for condensing and non-condensing furnaces (see Appendix H, Determination of Basic Models, for supply-air outlet areas of basic furnace models). The Department used the following equations to determine the supply-air outlet area of the non-condensing and condensing virtual model furnace models:

7-6 T bi 7 2 8 A· d Bl

a e 

# .. sSlgne ower 

### S· b A· fl 

### C lze .y lr ow 

### ·t apaclry Airflow Capacity (cfm) Blower Size (inches) 2-ton models (800 cfm) 9x8 3-ton models (1200 cfm) 10 x 8 4-ton models (1600 cfm) lOx 10 5-ton models (2000 cfm) 11 x 10 7.2.4 Motor Size The motors for the basic furnace models are six-pole permanent split capacitor (PSC) induction motors. The motors in the basic furnaces come with three to five taps that are used to set the motor speed. The Department assumed that, at high speed, the motors operate with a speed of 1075 revolutions per minute (rpm) to provide the nominal maximum airflow at 0.5 m.w.g. The Department assigned motor size to virtual furnace models, as shown in Table 7.2.9, to reflect typical-size motors ofthe basic furnace models. Motor sizes are the same for noncondensing and condensing furnaces. The larger the nominal maximum airflow, the larger the motor size. For the blower motor size and number oftaps on basic model furnaces, see Appendix H, Determination ofBasic Models, which lists the blower-motor sizes and number of blower motor taps ofbasic furnace models. T bi 729 A·

a e 

# .. sSlgne

### d M t 

### S· b A· fl C o or lZe 'y lr ow apacuy Airflow Capacity (cfm) Motor Size (HP) 2-ton models (800 cfm) 1/5 3-ton models (1200 cfm) 1/3 4-ton models (1600 cfm) 1/2 5-ton models (2000 cfm) 3/4 7.2.5 Supply-Air Outlet Area The supply-air outlet area is the opening from the furnace to the supply duct. The supply-air outlet area for basic furnace models increases with airflow capacity and input capacity. To capture this trend, DOE constructed a multiple regression equation ofthe supplyair outlet area to input capacity and airflow capacity for condensing and non-condensing furnaces (see Appendix H, Determination ofBasic Models, for supply-air outlet areas ofbasic furnace models). The Department used the following equations to determine the supply-air outlet area of the non-condensing and condensing virtual model furnace models:
7-6

### SNC = 0.9498 + 0.5505 x (Q / 1000) + 0.0073 x (QIN) Eq.1 Sc = 0.7882 + 0.5006 x (Q / 1000) + 0.0087 x (QIN) Eq. 2 where: = supply-air outlet area (sq. ft.) (non-condensing), and

= supply-air outlet area (sq. ft.) (condensing), = nominal maximum airflow (cfm) at 0.5 in.w.g. static pressure, and = input capacity (kBtu/h). SNC Sc Q QIN Figures 7.2.1 and 7.2.2 show the data points for supply-air outlet area for basic furnace models and the linear plane fit used to fit these points.

b

140 XJBG^ C&.^BOf^r(k?Lj SNC = 0.9498 + 0.5505 * (Q/1000) + 0.0073 * AN) R2 = .677 # -a 9 Data Points

Figure 7.2.1 Supply-Air Outlet Area for Non-Condensing Natural Gas Furnaces

7-7 SNC 

### = 

### 0.9498 

## + 0.5505 x 

## CQ / 1000) 

## + 0.0073 X 

## CQIN) Eq. 1 

### Sc = 

### 0.7882 

## + 0.5006 x 

## CQ / 1000) 

## + 0.0087 X 

## CQIN) Eq.2 where: SNC 

### = supply-air outlet area (sq. ft.) (non-condensing), and Sc = supply-air outlet area (sq. ft.) (condensing), Q 

## = nominal maximum airflow (cfm) at 0.5 in.w.g. static pressure, and 

### QIN = input capacity (kBtu/h)

. Figures 7.2.1 and 7.2.2 show the data points for supply-air outlet area for basic furnace models and the linear plane fit used to fit these points.

60 100**{r.p~tc ~** **~ty(It13I(.J** SNC = 0.9498 + 0.5505 * (Q/1000) + 0.0073 * (QIN) R2 = .677 <;> Data Points



### Figure 7.2.1 Supply-Air Outlet Area for Non-Condensing Natural Gas Furnaces

7-7Figure 7.2.2 Supply-Air Outlet Area for Condensing Natural Gas Furnaces Tables 7.2.10 and 7

. 2.11 show the values DOE used for supply-air outlet areas for noncondensing and condensing virtual gas furnaces

. The supply-air outlet area is larger for condensing models

. The larger opening compensates for the increased pressure drop due to the secondary , condensing heat exchanger

. This larger supply-air outlet area reduces the pressure drop across the furnace , so that the pressure rise for condensing furnaces is the same as noncondensing model furnaces at the same airflow. 3.6 3.4- (I) 3.2 .§ 3·0

### ~ 2·8**~**



## ... 2.6 C

## ~ 2.4**~** 2.2 ii 2.0 !!II

### ~

c!fO 100 iFDl.Jtc 120**~/1);-(IcS7LJ** Sc = 0.7882 + 0.5006 * (Q/1000) + 0

.0087 * (QIN) 

### R2 = .654 :Iii"' u.: .lid.. lit



### . 'E "'l"

9 Data Points



### Figure 7.2.2 Supply-Air Outlet Area for Condensing Natural Gas Furnaces Tables 7.2.10 and 7

.2

. 11 show the values DOE used for supply-air outlet areas for noncondensing and condensing virtual gas furnaces. The supply-air outlet area is larger for condensing models. The larger opening compensates for the increased pressure drop due to the secondary, condensing heat exchanger. This larger supply-air outlet area reduces the pressure drop across the furnace, so that the pressure rise for condensing furnaces is the same as noncondensing model furnaces at the same airflow.

7-8Table 7.2.10 Supply-Air Outlet Area (in Square Feet) for Virtual Non-Condensing Gas Furnace Models

Table 7.2.11 Supply-Air Outlet Area ( in Square Feet) for Virtual Condensing Gas

Furnace Models

45

U O O O 00

0 0
N M

0 0

0 0 o V 50

1.72 1 1.76

1.94 1 1.98 60 1 70

1.83

2.05 1 2.13

2.35 75

2.16

2.39 Input Capacity (kBtu/h)

80

2.20

2.42

7.2.6 Power Consumption of Draft Inducer 90

2.27

2.50

2.06 100 1 115

2.35

2.57 1 2.68

2.79 2.90 120

2.72

2.94 125

2.75

2.97 140

3.08

A common value for the power consumption of the draft inducer, PE, for basic non-condensing model furnaces is 75 watts, and the average value is about 75 W, so DOE selected 75 W for all the non-condensing models. The Department found no correlation between the PE and input capacity or between PE and airflow capacity. For condensing furnaces, the Department used a PE of 90 W, which closely matches the mean for that group. See Appendix H, Determination of Basic Models, for the power consumption of the draft inducer in the basic models.

7-9 

### Table 7.2.10 Supply-Air Outlet Area (in Square Feet) for Virtual Non-Condensing Gas Furnace Models**~ ~** **~** '" 1.62**~ ~---+----+---~~---**  0.. "**.~** i/5 v, o 1;J 1.78 1.82 2.00 2.04

2.20 2.24 Input Capacity (kBtu/h)

2.08 2.17

2.29 2.37 2.46 2.59 2.63

2.57 2.66 2.79 2.83 2.88 3.01


### Table 7.2.11 Supply-Air Outlet Area (in Square Feet) for Virtual Condensing Gas Furnace Models Input Capacity (kBtu/h)**cS~** 1.72 1.76

## ~ " 

### " o£ ON 00**~** " '" 0..**.~** E 1.94 1.98 2.13 2.16 2.20 2.27 CIl V, ° 1;J :;: 2.35 2.39 2.42 2.50 2.57 2.68 2.72 0 'E :.;;: 

### s 

## '" s ';< 2.90 3.08 2.06 2.94 2.97 2.79 OJ ::E 

### 7.2.6 Power Consumption of Draft Inducer A common value for the power consumption ofthe draft inducer, PE, for basic non-condensing model furnaces is 75 watts, and the average value is about 75 W, so DOE selected 75 W for all the non-condensing models. The Department found no correlation between the PE and input capacity or between PE and airflow capacity. For condensing furnaces, the Department used a PE of 90 W, which closely matches the mean for that group. See Appendix H, Determination ofBasic Models, for the power consumption ofthe draft inducer in the basic models.

7-97.2.7 Delay and Ignitor Times Pre-purge and post-purge times are the lengths of time the draft inducer operates before and after a firing cycle. On-delay is the amount of time the blower waits to begin operating after the burner starts firing. Off-delay is the time the blower keeps operating after the burner turns off. Ignition time is the length of time the hot surface ignitor is on before gas is sent to the burner. Pre-purge, post-purge, on-delay, and off-delay times are not related to airflow or input capacity. The Department selected common values for the delay and ignition times of condensing and non-condensing virtual furnace models (Table 7.2.12). For these data on basic furnace models, see Appendix H, Determination of Basic Models. Table 7.2.12 Values for Delay and Ignition Times Pre-Purge Post-Purge On-Delay Off-Delay ignition 15 seconds 5 seconds 30 seconds 120 seconds 37 seconds

7.3 HOUSING SAMPLE The Department used a subset of records from the complete RECS 2001 data set that met all of the following criteria: 1) Used central heating equipment, 2) Used a boiler or furnace as the main source of heat, 3) Used a heating fuel that is natural gas, liquefied petroleum gas (LPG), or fuel oil, 4) Heated only one housing unit, and, 5) Had energy consumption greater than zero. The reason for the fourth criterion is that the Department assumed any furnaces or boilers heating more than one unit would be larger than a residential furnace or boiler. Of the 4822 housing units surveyed in RECS 2001, 2121 housing records (44.6 percent of the total weighted sample) had central, forced-air furnaces and met the above criteria; 474 housing records (8.0 percent of the weighted sample) had boilers and met the above criteria. The residential furnace and boiler subset thus represents 52.6 percent of the total housing units in the United States. Appendix 0 presents a description of the subset. The Department divided the RECS 2001 sample by product classes, using different classification algorithms based on fuel type, home type, (the presence of) central airconditioning, etc. (Table 7.3.1). The Department further divided the housing units with nonweatherized gas furnaces into those located in cold and mild climates. The Department assembled the values for each sample housing unit for a number of 7-10 

### 7.2.7 Delay and Ignitor Times Pre-purge and post-purge times are the lengths oftime the draft inducer operates before and after a firing cycle. On-delay is the amount oftime the blower waits to begin operating after the burner starts firing. Off-delay is the time the blower keeps operating after the burner turns off. Ignition time is the length oftime the hot surface ignitor is on before gas is sent to the burner. Pre-purge, post-purge, on-delay, and off-delay times are not related to airflow or input capacity. The Department selected common values for the delay and ignition times of condensing and non-condensing virtual furnace models (Table 7.2.12). For these data on basic furnace models, see Appendix H, Determination ofBasic Models. T hI 7212 V I £ D I



### a e 

# .. a ues or e ayandI "t" 

### T" 19m 

### IOn lmes Pre-Purge Post-Purge On-Delay Off-Delay Ignition 15 seconds 5 seconds 30 seconds 120 seconds 37 seconds



### 7.3 HOUSING SAMPLE The Department used a subset ofrecords from the complete RECS 2001 data set that met all ofthe following criteria: 1) Used central heating equipment, 2) Used a boiler or furnace as the main source ofheat, 3) Used a heating fuel that is natural gas, liquefied petroleum gas (LPG), or fuel oil, 4) Heated only one housing unit, and, 5) Had energy consumption greater than zero. The reason for the fourth criterion is that the Department assumed any furnaces or boilers heating more than one unit would be larger than a residential furnace or boiler. Ofthe 4822 housing units surveyed in RECS 2001, 2121 housing records (44.6 percent ofthe total weighted sample) had central, forced-air furnaces and met the above criteria; 474 housing records (8.0 percent ofthe weighted sample) had boilers and met the above criteria. The residential furnace and boiler subset thus represents 52.6 percent ofthe total housing units in the United States. Appendix 

### 0 presents a description ofthe subset. The Department divided the RECS 2001 sample by product classes, using different classification algorithms based on fuel type, home type, (the presence of) central air conditioning, etc. (Table 7.3.1). The Department further divided the housing units with nonweatherized gas furnaces into those located in cold and mild climates. The Department assembled the values for each sample housing unit for a number of 7-10variables concerning housing unit characteristics, equipment characteristics, household

characteristics, and energy use. Appendix 0 presents the variables included. Table 7.3.1 Criteria for Selection of RIECS Records b y Product Class Product Class Algorithm # of # of US Households Records Represented (million) Non-Weatherized Gas Central heating equipment = furnace 1880 43.5 Furnace Heating fuel = gas Home type = single or multi-family Number of Housing Units Heated = 1 Weatherized* Gas Central heating equipment = furnace 373 8.4 Furnace Heating fuel = gas Central air conditioning = yes (packaged unit) Home type = single or multi-family Number of Housing Units Heated = 1 Census Division = West or East South Central Large State = California, Florida or Texas Manufactured-Home Central heating equipment = furnace 72 1.5 Gas Furnace Heating fuel = gas Home type = manufactured home Number of Housing Units Heated = 1 House Vintage = after 1979** Oil-Fired Furnace Central heating equipment = furnace 169 2.8 Heating fuel = oil Home type = single or multi-family Number of Housing Units Heated = 1 Fuel Oil Consumption >0 Gas Hot-Water Boilert Central heating equipment = boiler 266 5.3 Heating fuel = gas Home type = single or multi -family Number of Housing Units Heated = 1 Oil-Fired Hot-Water Central heating equipment = boiler 208 3.3 Boiler' Heating fuel = oil Home type = single or multi-family Number of Housing Units Heated = 1 Some of the same housing records are used for analyzing both weatherized and non-weatherized furnace product classes, because equipment type is not given in RECS2001. To define weatherized furnaces, DOE looked at the subset of housing records that had gas furnaces and central air conditioners, and were located in the West South Central, East South Central Census divisions, or in the states of California, Florida, or Texas. ** Federal regulation regarding mobile housing construction changed the quality of the structures manufactured after this year. t Because RECS does not distinguish between steam and hot-water boilers, DOE assumed for the purposes of this analysis that all boilers in RECS where the number of units heated equal one are hot-water boilers. Hot-water boilers comprise 84 percent of gas boiler shipments and 88 percent of oil-fired boiler shipments.'

7-11 

### variables concerning housing unit characteristics, equipment characteristics, household characteristics, and energy use. Appendix 0 presents the variables included. 

### T bi 731

a e o 0 

### C °t 0**~** 

### S I f 

### n ena or e ee IOn 0 

### fRECSReeor

### d b Pdt CI s )y 

### ro lie ass Product Class Algorithm # of # of US Households Records Represented (million) Non-Weatherized Gas Central heating equipment = furnace 1880 43.5 Furnace Heating fuel = gas Home type = single or multi-family Number ofHousing Units Heated = 1 Weatherizel Gas Central heating equipment furnace 373 8.4 Furnace Heating fuel = gas Central air conditioning = yes (packaged unit) Home type = single or multi-family Number of Housing Units Heated = 1 Census Division = West or East South Central Large State California, Florida or Texas Manufactured-Home Central heating equipment = furnace 72 1.5 Gas Furnace Heating fuel gas Home type = manufactured home Number ofHousing Units Heated = 1 House Vintage after 1979** Oil-Fired Furnace Central heating equipment = furnace 169 2.8 Heating filel = oil Home type = single or multi-family Number ofHousing Units Heated = 1 Fuel Oil Consumption >0 Gas Hot-Water Boilert Central heating equipment boiler 266 5.3 Heating fuel = gas Home type single or multi-family Number of Housing Units Heated = 1 Oil-Fired Hot-Water Central heating equipment = boiler 208 3.3 Boiler! Heating fuel = oil Home type = single or multi-family Number ofHousing Units Heated = 1 

### * Some ofthe same housmg records are used for analyzmg both weatherized and non-weathenzed furnace product classes, because equipment type is not given in RECS2001. To define weatherized filrnaces, DOE looked at the subset of housing records that had gas filrnaces and central air conditioners, and were located in the West South Central, East South Central Census divisions, or in the states of California, Florida, or Texas. 

### ** Federal regulation regarding mobile housing construction changed the quality of the structures manufactured after this year. 

### t Because RECS does not distinguish between steam and hot-water boilers, DOE assumed for the purposes of this analysis that all boilers in RECS where the number ofunits heated equal one are hot-water boilers. Hot-water boilers comprise 84 percent of gas boiler shipments and 88 percent of oil-fired boiler shipments. 3

7-117.4 ASSIGNING FURNACES TO SAMPLE HOUSES

To estimate the heating load of each sample housing unit, DOE represented the existing furnace by assigning an input capacity , airflow capacity , and annual fuel utilization efficiency (AFUE) to the furnace in the RECS sample housing units. The Department used the input capacity and nominal maximum airflow capacity assigned to the existing furnace to choose a specific virtual furnace model for the housing unit. 7.4.1 Furnace Input Capacity The Department assigned an input capacity for the existing furnace of each housing unit based on an algorithm that correlates the housing unit size with the distribution of input capacity of new furnaces sold the year the furnace was installed

. The following steps describe the assignment process. (1) The Department ranked all the RECS housing units in ascending order by size (square foot) and calculated the percentile rank of each housing unit using the statistical weight of each of the sample records. (2) The Department constructed percentile tables by input capacity of furnaces sold each year for 2003 and prior years , based on the historical shipment information for each year.' (3) After selecting a housing unit from the RECS database during each Monte Carlo iteration, DOE noted the size of the selected housing unit and determined the percentile rank from Step 1. (4) To avoid a one-to

- one deterministic relation between the housing unit size and input capacity , DOE added a random term to the percentile identified in Step 3 so that the correlation was not perfect

. The Department used a normal distribution to characterize the random term

. The random term has a mean of zero and a standard deviation of 8 percent. (5) Using the percentile from Step 4, DOE looked up the input capacity from the input capacity percentile table in Step 2 for the age of the equipment. 7.4.2 Airflow Capacity The Department classified furnaces by nominal maximum airflow in cfm at 0.5 in.w.g. of external static pressure. The Department assigned the airflow capacity of existing furnaces for housing units that had air conditioners in a similar manner that it assigned furnace input capacity. Larger air conditioners go to larger housing units, according to the distribution of sizes of air conditioners sold the year the air conditioner was installed in that housing unit. The Department used the air conditioner nominal size of two , three, four , or five tons to set the airflow capacity with a ratio of 400 cfm per ton of cooling

. The steps were: (1) Based on historical shipment information of residential central air conditioners by capacity, DOE constructed the airflow capacity percentiles tables for air conditioners sold in 2001 and prior years. The Department restricted the airflow sizes to two , three, four , or five tons

- the equivalent of 800, 1200, 1600, or 2000 cfm at 0.5 in. w.g. static pressure. Most of the annual sales of residential central air conditioners from 1976 to 1994 are in these 7-12 7.4 ASSIGNING FURNACES TO SAMPLE HOUSES To estimate the heating load of each sample housing unit, DOE represented the existing furnace by assigning an input capacity, airflow capacity, and annual fuel utilization efficiency (AFUE) to the furnace in the RECS sample housing units. The Department used the input capacity and nominal maximum airflow capacity assigned to the existing furnace to choose a specific virtual furnace model for the housing unit. 7.4.1 

### Furnace Input Capacity The Department assigned an input capacity for the existing furnace ofeach housing unit based on an algorithm that correlates the housing unit size with the distribution ofinput capacity of new furnaces sold the year the furnace was installed. The following steps describe the assignment process. (1) The Department ranked all the RECS housing units in ascending order by size (square foot) and calculated the percentile rank ofeach housing unit using the statistical weight ofeach of the sample records. (2) The Department constructed percentile tables by input capacity of furnaces sold each year for 2003 and prior years, based on the historical shipment information for each year. 3 (3) After selecting a housing unit from the RECS database during each Monte Carlo iteration, DOE noted the size ofthe selected housing unit and determined the percentile rank from Step 1. (4) To avoid a one-to-one deterministic relation between the housing unit size and input capacity, DOE added a random term to the percentile identified in Step 3 so that the correlation was not perfect. The Department used a normal distribution to characterize the random term. The random term has a mean of zero and a standard deviation of 8 percent. (5) Using the percentile from Step 4, DOE looked up the input capacity from the input capacity percentile table in Step 2 for the age ofthe equipment. 7.4.2 

### Airflow Capacity The Department classified furnaces by nominal maximum airflow in cfm at 0.5 in.w.g. of external static pressure. The Department assigned the airflow capacity of existing furnaces for housing units that had air conditioners in a similar manner that it assigned furnace input capacity. Larger air conditioners go to larger housing units, according to the distribution of sizes of air conditioners sold the year the air conditioner was installed in that housing unit. The Department used the air conditioner nominal size oftwo, three, four, or five tons to set the airflow capacity with a ratio of400 cfm per ton ofcooling. The steps were: (1) Based on historical shipment information ofresidential central air conditioners by capacity, DOE constructed the airflow capacity percentiles tables for air conditioners sold in 2001 and prior years. The Department restricted the airflow sizes to two, three, four, or five tons-the equivalent of 800, 1200, 1600, or 2000 cfm at 0.5 in. w.g. static pressure. Most ofthe annual sales ofresidential central air conditioners from 1976 to 1994 are in these 7-12airflow sizes. The variation of the distribution of the four airflow sizes over the years is

small. (2) Since there are no available shipment data on the airflow capacity of furnaces, the Department used the airflow capacity of residential central air conditioners as a proxy. Using the adjusted percentile of housing unit size from Step (4) in the Input Capacity section, DOE determined the airflow capacity by looking up the percentile in the corresponding distribution of nominal air conditioner size for the age of the cooling equipment. The Department selected a virtual model with the identified airflow capacity. If no virtual model with the identified airflow capacity was available, the Department selected the virtual model with the same input capacity and the closest airflow capacity as a substitute. (3) If the RECS record indicated that the housing unit did not have an air conditioner, DOE still used the procedure from step (2) to determine the airflow capacity. In this case, DOE used the age of the housing unit (or 30 years if the housing unit was older than 30 years) as a substitute for the age of the cooling equipment. 7.4.3 Efficiency GAMA shipments data indicate that housing units in colder regions receive more-efficient furnaces.3 Therefore, DOE correlated the AFUE of existing furnaces with the heating degree days (HDD) to base 65°F associated with each sample housing unit. The following steps describe this process: (1) The Department sorted the RECS housing units in ascending order of HDDs, and calculated the percentile rank of each housing unit by HDD using the statistical weight of each sample housing unit. (2) Based on the historical furnace shipment information sorted by AFUE, DOE constructed percentile tables by AFUE shipments of furnaces for 2001 and prior years. (3) After DOE selected a housing unit from the RECS database during each Monte Carlo iteration, it noted the HDD of the selected housing unit. The Department looked up the percentile rank of that housing unit from the HDD percentile table developed in Step (1). (4) The Department added a random uncertainty term to the HDD percentile found in Step (3) to account for variability within the sample. The Department used a normal distribution to characterize the uncertainty term. The distribution of values of the uncertainty term has a mean of zero and a standard deviation of 8 percent. (5) Using the adjusted HDD percentile from Step (4), DOE determined the AFUE by looking it up from the AFUE percentile table from Step (2) corresponding to the age of the existing equipment in the housing unit.
7.4.4 Electricity Consumption of the Furnace Blower Most furnaces manufactured since about 1980 use forward-curved impellers driven directly by a PSC motor. Some models, which utilize modulating design options, use forward-curvedimpellers driven directly by an ECM motor. Currently, there are no models using backward7-13 airflow sizes. The variation ofthe distribution ofthe four airflow sizes over the years is small. (2) Since there are no available shipment data on the airflow capacity offurnaces, the Department used the airflow capacity ofresidential central air conditioners as a proxy. Using the adjusted percentile ofhousing unit size from Step (4) in the Input Capacity section, DOE determined the airflow capacity by looking up the percentile in the corresponding distribution of nominal air conditioner size for the age ofthe cooling equipment. The Department selected a virtual model with the identified airflow capacity. If no virtual model with the identified airflow capacity was available, the Department selected the virtual model with the same input capacity and the closest airflow capacity as a substitute. (3) Ifthe RECS record indicated that the housing unit did not have an air conditioner, DOE still used the procedure from step (2) to determine the airflow capacity. In this case, DOE used the age ofthe housing unit (or 30 years ifthe housing unit was older than 30 years) as a substitute for the age ofthe cooling equipment. 

### 7.4.3 Efficiency GAMA shipments data indicate that housing units in colder regions receive more-efficient furnaces. 3 Therefore, DOE correlated the AFUE of existing furnaces with the heating degree days (HDD) to base 65°F associated with each sample housing unit. The following steps describe this process: (1) The Department sorted the RECS housing units in ascending order ofHDDs, and calculated the percentile rank of each housing unit by HDD using the statistical weight of each sample housing unit. (2) Based on the historical furnace shipment information sorted by AFUE, DOE constructed percentile tables by AFUE shipments offurnaces for 2001 and prior years. (3) After DOE selected a housing unit from the RECS database during each Monte Carlo iteration, it noted the HDD ofthe selected housing unit. The Department looked up the percentile rank ofthat housing unit from the HDD percentile table developed in Step (1). (4) The Department added a random uncertainty term to the HDD percentile found in Step (3) to account for variability within the sample. The Department used a normal distribution to characterize the uncertainty term. The distribution ofvalues ofthe uncertainty term has a mean ofzero and a standard deviation of 8 percent. (5) Using the adjusted HDD percentile from Step (4), DOE determined the AFUE by looking it up from the AFUE percentile table from Step (2) corresponding to the age ofthe existing equipment in the housing unit.



### 7.4.4 Electricity Consumption of the Furnace Blower Most furnaces manufactured since about 1980 use forward-curved impellers driven directly by a PSC motor. Some models, which utilize modulating design options, use forward-curved impellers driven directly by an ECM motor. Currently, there are no models using backward7-13curved impellers

. Thus, most existing furnaces have a blower and blower motor similar to those

in the virtual furnace modelsb

. Therefore , in assigning the electricity consumption of the existing furnace blower for each housing unit , DOE assumed that the electricity use of the existing furnace was equivalent to the electricity use of the virtual furnace model described in section 7.2. The Department calculated electricity use by the existing furnace from the fan curves, watts/CFM curves , and time delays of the virtual furnace model of the same input capacity and airflow capacity.

7.5 FURNACE BLOWER ELECTRICITY CONSUMPTION The electricity consumption (and overall efficiency ) of a blower motor depends on the speed at which the motor operates , the external static pressure difference across the blower, and the airflow through the blower

. To calculate blower-motor electricity consumption, DOE determined the operating conditions (the pressure and airflow) at which a particular furnace in a particular housing unit will operate

. These operating conditions can be graphically displayed as the intersection of a system curve of the ducts in the housing unit (which plots the airflow across the supply and return air ducts as a function of static pressure) with the fan curve of the furnace (which plots the airflow through the furnace as a function of static pressure). The intersection of these two curves is the airflow and the static pressure at which the furnace will operate in that housing unit. Furnace fan curves, reported as tables of airflow rise versus static pressure through the furnace, are available from manufacturers in the product literature for each furnace

. Some of the manufacturers also supply blower-motor input power as a function of static pressure across the furnace. Air power is calculated from the air speed through the furnace and the pressure rise across the furnace. The overall air-moving efficiency is air power divided by the electric power to the blower motor

. All the electric power of the blower motor eventually is converted to heat that contributes to meeting the building heating load. See Appendix K for more information about air handler efficiency.
7.5.1 System Curves The system curve of the air-distribution system is a graphical representation of the airflow through the supply and return ducts in a house for different static pressure. The airflow and pressure drop at which the furnace will operate can be determined by the intersection of the

b A very small share of existing furnaces use belt-drive blowers with shaded-pole motors. That arrangement was less efficient than direct-driven PSC motors, but the airflow from these old model furnaces was less , so electricity consumption was not significantly reduced when this technology became obsolete." 7-14 curved impellers. Thus, most existing furnaces have a blower and blower motor similar to those in the virtual furnace models b• Therefore, in assigning the electricity consumption ofthe existing furnace blower for each housing unit, DOE assumed that the electricity use ofthe existing furnace was equivalent to the electricity use ofthe virtual furnace model described in section 7.2. The Department calculated electricity use by the existing furnace from the fan curves, watts/CFM curves, and time delays ofthe virtual furnace model ofthe same input capacity and airflow capacity.

7.5 FURNACE BLOWER ELECTRICITY CONSUMPTION The electricity consumption (and overall efficiency) of a blower motor depends on the speed at which the motor operates, the external static pressure difference across the blower, and the airflow through the blower. To calculate blower-motor electricity consumption, DOE determined the operating conditions (the pressure and airflow) at which a particular furnace in a particular housing unit will operate. These operating conditions can be graphically displayed as the intersection of a system curve ofthe ducts in the housing unit (which plots the airflow across the supply and return air ducts as a function of static pressure) with the fan curve ofthe furnace (which plots the airflow through the furnace as a function of static pressure). The intersection of these two curves is the airflow and the static pressure at which the furnace will operate in that housing unit. Furnace fan curves, reported as tables of airflow rise versus static pressure through the furnace, are available from manufacturers in the product literature for each furnace. Some ofthe manufacturers also supply blower-motor input power as a function of static pressure across the furnace. Air power is calculated from the air speed through the furnace and the pressure rise across the furnace. The overall air-moving efficiency is air power divided by the electric power to the blower motor. All the electric power ofthe blower motor eventually is converted to heat that contributes to meeting the building heating load. See Appendix K for more information about air handler efficiency.

7.5.1 System Curves The system curve of the air-distribution system is a graphical representation ofthe airflow through the supply and return ducts in a house for different static pressure. The airflow and pressure drop at which the furnace will operate can be determined by the intersection ofthe

b A very small share of existing furnaces use belt-drive blowers with shaded-pole motors. That arrangement was less efficient than direct-driven PSC motors, but the airflow from these old model furnaces was less, so electricity consumption was not significantly reduced when this technology became obsolete. 4 7-14system curve of the house and the fan curve of the furnace circulating air blower.'

The Department modeled system curves as quadratic curves, which is standard in heating, ventilation, and air conditioning (HVAC) design and fan selection handbooks.' The curves are based on Bernoulli's equations for fluid flow and are expressed as the following equation:

where: Q = airflow (cfm), P = static pressure (in.w.g.), and a = a constant coefficient. The Department selected the coefficient in the system curve equation for each housing unit. It randomly sampled a coefficient from one of four distributions, depending on the nominal maximum airflow of the virtual model furnace selected for that housing unit. The Department designed each distribution so that 10 percent of samples would have static pressures below 0.5 in.w.g., and 1 percent of the samples would have static pressures greater than 1 in.w.g at the nominal maximum airflow. This is in line with several field studies.' To keep the system curves from clumping at the higher pressures, the Department used a log-normal distribution of values of the coefficient. See Figure 7.5.1 for an example of a plot of system curves intersecting a furnace fan curve. system curve ofthe house and the fan curve ofthe furnace circulating air blower. 5 The Department modeled system curves as quadratic curves, which is standard in heating, ventilation, and air conditioning (HVAC) design and fan selection handbooks. 6 The curves are based on Bernoulli's equations for fluid flow and are expressed as the following equation:

where: Q = airflow (cfm), 

### P = static pressure (in.w.g.), and ex = a constant coefficient. The Department selected the coefficient in the system curve equation for each housing unit. It randomly sampled a coefficient from one of four distributions, depending on the nominal maximum airflow ofthe virtual model furnace selected for that housing unit. The Department designed each distribution so that 10 percent of samples would have static pressures below 0.5 in.w.g., and 1 percent ofthe samples would have static pressures greater than 1 in.w.g at the nominal maximum airflow. This is in line with several field studies. 7 To keep the system curves from clumping at the higher pressures, the Department used a log-normal distribution ofvalues ofthe coefficient. See Figure 7.5.1 for an example of a plot of system curves intersecting a furnace fan curve.

7-151600

1200

U0

_ 3 800 0

400

0- 0.00 0.25 1.00 - - 1200 CFM Generic Single-Stage Furnace Model (Heating Tap
0.50 External Static Pressure ( in. w.g.) T 0.75 Figure 7.5.1 Sample of System Curves with a Typical Fan Curve 7.5.2 Furnace Fan Curves Depending on the resistance (measured as static pressure) of the supply and return air ducts, a furnace will move more or less air. When these airflow values are plotted graphically against pressure, they are referred to as fan curves. The Department developed fan curves for the single-stage virtual furnace models by fitting the manufacturer airflow and pressure data points from the basic model furnaces8' 9, 10, 11, 12, 13, 14 to a fourth-order polynomial. The Department did this separately for each of the four nominal air handlers sizes for both non-condensing and condensing furnaces. The CFM for PSC blower motors is given by the following equation:

CFM= m0+ m1 X (P) 

### + m 2 X (P2) + m3 X (P3) + m4 X (P4) where, CFM

m0123 , , and 4 P Eq. 3

airflow in CFM reported by manufacturer, coefficients derived from 4th degree polynomial approximation (see Table 7.5.1 for actual coefficient values), and external static pressure (in. w.g.).

7-16 

### i' u.. !2. 3: 0 'E 

# «**1600,------------,------------,------------r----~D_--_,**

1200



# .... .. 800 

# ..**~~~~--"--~**

# ..-**~~** - 

# ..

400 I II Highest 1**%~~m~__**_____ ' t---tlHIf------+---------+-

___ , -<>--median I 

# l '

-4-Lowest 10% ,

- - 1200 CFM Generic Single-StageJ Furnace Model (Heating**T~** O

__**--------+----------~---~--~==-··-~I ---------~**  0.00 0.25 0.50 0.75 1.00 External Static Pressure (in. w.g.) 

### Figure 7.5.1 Sample of System Curves with a Typical Fan Curve 7.5.2 Furnace Fan Curves Depending on the resistance (measured as static pressure) ofthe supply and return air ducts, a furnace will move more or less air. When these airflow values are plotted graphically against pressure, they are referred to as fan curves. The Department developed fan curves for the single-stage virtual furnace models by fitting the manufacturer airflow and pressure data points from the basic model furnaces 8,9, 10, II, 12, 13, 14 to a fourth-order polynomial. The Department did this separately for each ofthe four nominal air handlers sizes for both non-condensing and condensing furnaces. The CFM for PSC blower motors is given by the following equation:

where, 

### CFM rn O ),2,3, and 4 p 

### Eq.3

airflow in CFM reported by manufacturer, coefficients derived from 4th degree polynomial approximation (see Table 7.5.1 for actual coefficient values), and external static pressure (in. w.g.).

7-16Table 7.5

. 1 Coefficients for CFM equation for PSC motors
2-ton 3-ton 4-ton 5-ton 2-ton 3-ton 4-ton 5-ton m0 M, mz m3 m4

891.0 -590.8 564.6 -552.2 0.0 1280.6 -279.8 194.4 -456.3 0.0 1585.1 32.8 -575.7 -78.4 12.3 1998.1 260.9 -93.2 -359.8 115.9 840.4 70.0 -908.4 294.3 56.4 1169.5 -226.1 -272.6 -95.7 137.0 1541.2 -110.3 -777.3 419.0 0.0 1915.1 -198.0 -594.5 -277.8 8.3 Data on the basic models that were used to develop these fan curves and the resulting fan curves for non-condensing and condensing single-stage furnaces are shown in Appendix I, Furnace Fan Curves. The two-stage and continuous modulating design options in this analysis use brushless permanent magnet motors (or sometimes referred as Electronically Commutated Motors (ECM)). Unlike PSC motors , these motors are electronically commutated and the speed they operate at can be varied across a wide range. These motors are controlled to operate the blower fans at a wide variety of air flows and static pressures

. In the furnaces with these motors currently on the market, the controls are designed to provide a nearly constant air flow across the entire range of pressures at which they operate. Because of the versatility of the motors , manufacturers only offer furnaces with blowers nominally designed for operation with five-ton and three

-ton air conditioners. The manufacturers provide control options to decrease the airflow for installations that use smaller air conditioners. To develop fan curves for furnaces with permanent magnet brushless motors, the Department fit quadratic curves through the air flow and pressure data points reported by manufacturers .' s, 16, 17, 18, 19, 20 , 21 DOE did this separately for high-fire and low

- fire operation for both noncondensing and condensing furnaces. The CFM for ECM blower motors is given by the following equation: 

### CFM = mo+m1 where, 

### (P) + m2 x (P2) Eq. 4

CFM = airflow in CFM reported by manufacturer, mo,I, and2 = coefficients derived from 2n' degree polynomial approximation (see

Table 7.5.2 for actual coefficient values), and P = external static pressure (in. w.g.). 7-17 

### T hI 7 5 1 C ffi' t**~** 

### CFM

a e 

## .. oe IClen s or t"**~** 

### PSC equa IOn or t mo ors mo mj m 2 m J m4 bJ) 2-ton 891.0 -590.8 564.6 -552.2 0.0 .5 

### '" 

## = 3-ton 1280.6 -279.8 194.4 -456.3 0.0 Q) '1:l 

## = c 4-ton 1585.1 32.8 -575.7 -78.4 12.3 U I 

## = 5-ton 1998.1 260.9 -93.2 -359.8 115.9 c Z

bJ) 2-ton 840.4 70.0 -908.4 294.3 56.4 .5 3-ton 1169.5 -226.1 -272.6 -95.7 137.0 

### '" 

## = Q) '1:l 4-ton 1541.2 -llO.3 -777.3 419.0 0.0 

## = c U 5-ton 1915.1 -198.0 -594.5 -277.8 8.3
Data on the basic models that were used to develop these fan curves and the resulting fan curves for non-condensing and condensing single-stage furnaces are shown in Appendix I, Furnace Fan Curves. The two-stage and continuous modulating design options in this analysis use brushless permanent magnet motors (or sometimes referred as Electronically Commutated Motors (ECM)). Unlike PSC motors, these motors are electronically commutated and the speed they operate at can be varied across a wide range. These motors are controlled to operate the blower fans at a wide variety of air flows and static pressures. In the furnaces with these motors currently on the market, the controls are designed to provide a nearly constant air flow across the entire range of pressures at which they operate. Because ofthe versatility ofthe motors, manufacturers only offer furnaces with blowers nominally designed for operation with five-ton and three-ton air conditioners. The manufacturers provide control options to decrease the airflow for installations that use smaller air conditioners. To develop fan curves for furnaces with permanent magnet brushless motors, the Department fit quadratic curves through the air flow and pressure data points reported by manufacturers. 15, 16, 17,18,19,20,21 DOE did this separately for high-fire and low-fire operation for both noncondensing and condensing furnaces. The CFM for ECM blower motors is given by the following equation:

where, 

### CFM mO,I, and 2 p 

### Eq. 4

airflow in CFM reported by manufacturer, coefficients derived from 2nd degree polynomial approximation (see Table 7.5.2 for actual coefficient values), and external static pressure (in. w.g.). 7-17Table 7.5.2 Coefficients for CFM equation for Two-Stage and Continuous Modulating

2-ton 3-ton 4-ton 5-ton 2-ton 3-ton 4-ton 5-ton furnaces with brushless permanent magnet motors

High Fire Low Fire
m a m 2 m, MI m2 857.5 62.0 0.0 634.7 37.5 0.0 1091.1 37.4 0.0 831.7 6.4 0.0 1324.8 12.9 0.0 1028.7 -24.7 0.0 1558.5 -11.7 0.0 1225.7 -55.8 0.0 714.0 -16.4 -13.8 489.4 -50.2 0.0 1003.0 -27.4 0.0 680.2 -31.5 0.0 1291.9 -38.4 13.8 870.9 -12.9 0.0 1580.9 -49.5 27.6 1061.6 5.8 0.0 Data on the basic models that were used to develop these fan curves, the methodology used, and the resulting fan curves for non-condensing and condensing single-stage furnaces are shown in Appendix I, Furnace Fan Curves. 7.5.3 Fan Power For furnaces with air handlers with PSC blower motors, one manufacturer reports watts across a range of pressures." 9, 10, 11, 12, 13, 14 The Department divided watts at these pressures by air flow in CFM at these same pressures. These values of watts/CFM across a range of pressures were fit to a fourth order polynomial for the basic furnace models made by the manufacturer. TheDepartment did this separately for each of the four nominal air handlers sizes for both noncondensing and condensing furnaces. The Watts/CFM for PSC blower motors is given by the following equation:



### Watts CFM= mp+m1x(P)+m2X (P2)+m3X(P3)+m4X (P4) Eq. 5 where, Watts/CFM = blower electricity consumption in watts reported by manufacturer divided by the airflow in CFM at the same static pressure, mo r z 3, a„ d4 = coefficients derived from 4" degree polynomial approximation (see

Table 7.5.3 for actual coefficient values), and P = external static pressure (in. w.g.).

7-18 

### Table 7.5.2 Coefficients for CFM equation for Two-Stage and Continuous Modulating f 'th b hI



### urnaces WI 

### rus ess permanent magnet motors High Fire Low Fire mil m J m2 ma m J m2**~** 2-ton 857.5 62.0 0.0 634.7 37.5 0.0 .S '" 

## = Q.l 3-ton 1091.l 37.4 0.0 831.7 6.4 0.0 "0 

## = 0 4-ton 1324.8 12.9 0.0 lO28.7 -24.7 0.0 U I 

## = 5-ton 1558.5 -11.7 0.0 1225.7 -55.8 0.0 0 Z**~** 2-ton 714.0 -16.4 -13.8 489.4 -50.2 0.0 .5 3-ton 1003.0 -27.4 0.0 680.2 -31.5 0.0 

### '" 

## = Q.l "0 4-ton 1291.9 -38.4 13.8 870.9 -12.9 0.0 

## = 0 U 5-ton 1580.9 -49.5 27.6 106l.6 5.8 0.0
Data on the basic models that were used to develop these fan curves, the methodology used, and the resulting fan curves for non-condensing and condensing single-stage furnaces are shown in Appendix I, Furnace Fan Curves. 

### 7.5.3 Fan Power For furnaces with air handlers with PSC blower motors, one manufacturer reports watts across a range ofpressures. 8,9,10,11,12,13,14 The Department divided watts at these pressures by air flow in CFM at these same pressures. These values ofwatts/CFM across a range ofpressures were fit to a fourth order polynomial for the basic furnace models made by the manufacturer. The Department did this separately for each ofthe four nominal air handlers sizes for both noncondensing and condensing furnaces. The Watts/CFM for PSC blower motors is given by the following equation:

where, 

### Watts/CFM

rn O ,l.2,3, and 4 p blower electricity consumption in watts reported by manufacturer divided by the airflow in CFM at the same static pressure, coefficients derived from 4th degree polynomial approximation (see Table 7.5.3 for actual coefficient values), and external static pressure (in. w.g.).

7-18Table 7.5.3 Coefficients for W/CFM equation for PSC motors
2-ton 3-ton 4-ton 5-ton 2-ton 3-ton 4-ton 5-ton m0 mz mj m4

0.39 -0.01 -0.11 0.22 0.03 0.43 -0.15 0.09 0.02 0.06 0.41 -0.16 0.14 -0.07 0.08 0.44 -0.08 0.01 0.05 0.01 0.40 -0.19 0.41 -0.50 0.31 0.45 -0.24 0.19 0.02 -0.04 0.41 -0.12 -0.10 0.20 -0.02 0.47 -0.19 0.30 -0.32 0.17 Data from the models that were used to develop these fan curves and the fit curves of Watts/CFM for pressures from 0 in.w.g. to 1.0 in.w.g. is shown in Appendix J. For the two-stage and continuous modulating furnaces with ECM motors, the Department calculated watts per CFM equations using data from basic models of several manufacturers.'s, 16, 17, 18, 19, 20, 21 These data are in the reduced set of furnace models database. This was done for basic model furnaces nominally designed for use with 5 ton and 3 ton air conditioners. The watts per CFM data points these basic models were fit to straight lines using Equation 2. This was done separately for high fire and low fire for both non-condensing and condensing models. Table 7.5.4 shows the coefficients for two-stage and continuous modulating furnaces with brushless permanent magnet motors using Eq. 6. Data from the models that were used to develop these fan curves and the fit curves of Watts/CFM for pressures from 0 in.w.g. to 1.0 in.w.g. is shown in Appendix J. 

### Watts CFM = mo + ml x (P) Eq. 6 where, Watts/CFM = blower electricity consumption in watts reported by manufacturer divided by the airflow in CFM at the same static pressure, mo,] = coefficients derived from linear approximation (see Table 7.5.4 for

actual coefficient values), and P = external static pressure (in. w.g.). To be consistent with other analyses, the Department calculated the slope and intercept for the w/CFM curves for furnaces intended to operate with 4 ton and 2 ton air conditioner using the same techniques it used to develop the fan curves of these furnaces.

7-19 

### T bi 753 C ffi· t 

### £ 

### W/CFM

a e oe lelen s or f 

### £ PSC equa IOn or t mo ors mo ml m2 m3 m4 ell 2-ton 0.39 -0.01 -0.11 0.22 0.03 .5 '" 

## = 3-ton 0.43 -0.15 0.09 0.02 0.06 Cl.l "0 

## = 0 4-ton 0.41 -0.16 0.14 -0.07 0.08 U I 

## = 5-ton 0.44 -0.08 0.01 0.05 0.01 0 Z

ell 2-ton 0.40 -0.19 0.41 -0.50 0.31 .5 3-ton 0.45 -0.24 0.19 0.02 -0.04 

### '" 

## = Cl.l "0 4-ton 0.41 -0.12 -0.10 0.20 -0.02 

## = 0 U 5-ton 0.47 -0.19 0.30 -0.32 0.17
Data from the models that were used to develop these fan curves and the fit curves of Watts/CFM for pressures from 0 in.w.g. to 1.0 in.w.g. is shown in Appendix J. For the two-stage and continuous modulating furnaces with ECM motors, the Department calculated watts per CFM equations using data from basic models of several manufacturers. IS, 16, 17,18,19,20,21 These data are in the reduced set offurnace models database. This was done for basic model furnaces nominally designed for use with 5 ton and 3 ton air conditioners. The watts per CFM data points these basic models were fit to straight lines using Equation 2. This was done separately for high fire and low fire for both non-condensing and condensing models. Table 7.5.4 shows the coefficients for two-stage and continuous modulating furnaces with brushless permanent magnet motors using Eq. 6. Data from the models that were used to develop these fan curves and the fit curves ofWatts/CFM for pressures from 0 in.w.g. to 1.0 in.w.g. is shown in Appendix J.

where, 

### Watts/CFM

p 

### Watts CFM = 

### mo + m 1 

### x (P) Eq. 6

blower electricity consumption in watts reported by manufacturer divided by the airflow in CFM at the same static pressure, coefficients derived from linear approximation (see Table 7.5.4 for actual coefficient values), and external static pressure (in. w.g.). To be consistent with other analyses, the Department calculated the slope and intercept for the w/CFM curves for furnaces intended to operate with 4 ton and 2 ton air conditioner using the same techniques it used to develop the fan curves ofthese furnaces.

7-19Table 7.5.4 Coefficients for W/CFM equation for Two-Stage and Continuous Modulating furnaces with ECM motors

2-ton 3-ton 4-ton 5-ton 2-ton 3-ton 4-ton 5-ton High Fire Low Fire

m0, m, m0 m, 0.13 0.24 0.06 0.25 0.14 0.24 0.08 0.25 0.15 0.24 0.09 0.25 0.16 0.24 0.11 0.24 0.12 0.23 0.10 0.24 0.14 0.24 0.10 0.25 0.17 0.25 0.11 0.26 0.20 0.26 0.11 0.27 Once the operating point of air flow and static pressure is determined by finding the intersection of the fan curve and the system curve, the watts per CFM are determined using the equations above. The fan power at this operating condition, BE, is calculated by multiplying the Watts/CFM by the CFM at the operating point: 

### - Watts BE 

### CFM) X Q

where,
BE = circulating air fan electrical energy consumption (watts), Watts/CFM = determined by equation 1 or equation 2 in section 7.5.3, and Q = airflow (cfm). 7.5.4 Overall Air-Moving Efficiency The overall air-moving efficiency is a ratio of the air power divided by the electric power used by the blower motor:
AHP ?,overall = BE
where: rl overall AHP BE overall air-moving efficiency,

air horsepower (watts), and circulating air fan electrical energy consumption (watts).

7-20 

### Table 7.5.4 Coefficients for W/CFM equation for Two-Stage and Continuous M d Iff ·th ECM t 0 

### u a mg urnaces WI 

### mo ors High Fire Low Fire mo mJ mo mJ OJ) 2-ton 0.13 0.24 0.06 0.25 .5 

### '" 

## = ClJ 3-ton 0.14 0.24 0.08 0.25 '0 

## = c 4-ton 0.15 0.24 0.09 0.25 U I 

## = 5-ton 0.16 0.24 0.24 0 0.11 Z

OJ) 2-ton 0.12 0.23 0.10 0.24 .5 3-ton 0.14 0.24 0.10 0.25 

### '" 

## = ClJ '0 4-ton 0.17 0.25 0.11 0.26 

## = 0 U 5-ton 0.20 0.26 0.11 0.27
Once the operating point of air flow and static pressure is determined by finding the intersection ofthe fan curve and the system curve, the watts per CFM are determined using the equations above. The fan power at this operating condition, BE, is calculated by multiplying the Watts/CFM by the CFM at the operating point:

where, 

### BE Watts/CFM Q circulating air fan electrical energy consumption (watts), determined by equation 1 or equation 2 in section 

### 7.5.3, and airflow (cfm). 

### 7.5.4 Overall Air-Moving Efficiency The overall air-moving efficiency is a ratio of the air power divided by the electric power used by the blower motor:

where: 170veraU 

### AHP 

## BE AHP 

## n a;erall 

## = -- '/ BE

overall air-moving efficiency, air horsepower (watts), and circulating air fan electrical energy consumption (watts).

7-20Air power is the power embodied in the air due to its motion and pressure increase. Air

power at any operating condition can be calculated for any furnace from pressure, airflow, and supply air outlet area, as explained in Appendix K. See Appendix K for overall air-moving efficiency derivation and curves.

7.6 ANNUAL HEATING LOADS IN SAMPLE HOUSING UNITS The annual house-heating load (HHL) is the total amount of heat output from the furnace that the house needs during the heating season. This includes heat from the burner and heat from the blower and the blower motor. The Department determined HHL for each sampled housing unit, based on the BOH and the characteristics of the assigned existing furnace, using the following calculations:

HHL = QyR,recs x AFUEeX + 3.412 xBE x where: BOHex + N x HLH x t+ t3600

QPR,recs = annual fuel consumption for heating the housing unit, from RECS

2001 (kBtu/yr), AFUEeX = AFUE of existing furnace (see section 7.4.3 to see how this was assigned for each household), 3.412 = constant to convert kW to kBtu/hr, BEex = power consumption of the blower motor of existing furnace (kW), BOHe, = as defined below (hr/yr), N = number of cycles per hour (set equal to 5 for furnaces and 2 for

boilers), HLH = heating load hours (hr) (see Appendix M for the derivation), t + = offdelay (seconds ) ( see section 7.2.7 for values used), and

on delay (seconds ) ( see section 7.2.7 for values used), Burner operating hours (BOHex), the number of hours the existing furnace burner is on during a year, is a key variable in the calculation of HHL. The Department calculated BOH for the existing furnace as:



### BOH = ex QIN, ex where: BOH,, burner operating hours of existing household (hrs/yr), QYR, recs

7-21 Air power is the power embodied in the air due to its motion and pressure increase. Air power at any operating condition can be calculated for any furnace from pressure, airflow, and supply air outlet area, as explained in Appendix K. See Appendix K for overall air-moving efficiency derivation and curves.


### 7.6 ANNUAL HEATING LOADS IN SAMPLE HOUSING UNITS The annual house-heating load (HHL) is the total amount ofheat output from the furnace that the house needs during the heating season. This includes heat from the burner and heat from the blower and the blower motor. The Department determined HHL for each sampled housing unit, based on the BOH and the characteristics ofthe assigned existing furnace, using the following calculations:

where: 

### HHL 

## = QYR 

### recs x 

### AFUEex 

### + 3.412 

### xBE x 

### [BOHex 

### + N x 

### HLH X 

# (t+

- 

# r)]

, 3600

QYR,recs 

### AFUEex 3.412 

### BEex BOH ex 

### N



## t annual fuel consumption for heating the housing unit, from RECS 2001 (kBtu/yr), AFUE of existing furnace (see section 7.4.3 to see how this was assigned for each household), constant to convert kW to kBtu/hr, power consumption ofthe blower motor of existing furnace (kW), as defined below (hr/yr), number of cycles per hour (set equal to 5 for furnaces and 2 for boilers), heating load hours (hr) (see Appendix M for the derivation), off delay (seconds) (see section 7.2.7 for values used), and
on delay (seconds) (see section 7.2.7 for values used), Burner operating hours (BOH ex), the number ofhours the existing furnace burner is on during a year, is a key variable in the calculation ofHHL. The Department calculated BOH for the existing furnace as:

where: 

## BOH ex QYR, rees QIN,ex

burner operating hours of existing household (hrs/yr), 7-21QYR,recs QIN, ex as defined above (kBtu/yr),

input capacity of the existing furnace (see section 7.4.1 to see how this was assigned for each household) (kBtu/hr). The power consumption of the blower motor depends on the steady-state operating conditions (the pressure and airflow) for the furnace. This calculation is explained in section 7.5, Calculating Furnace Blower Electricity Consumption. The Department made adjustments to reflect the expectation that newly-built housing units in 2015 will have a somewhat different heating load than the housing units in the RECS 2001 new construction sub-sample. The adjustment involves multiplying the calculated HHL for each RECS 2001 housing unit in the new construction sub-sample by two factors. The first factor, building thermal efficiency, accounts for the estimated improvement in home insulation and other thermal efficiency practices between 2001 and 2015. The value used is 0.97, which means that the average new home in 2015 requires less heat energy to maintain indoor comfort. The second factor, house floor area, accounts for the estimated increase in average new house floor area between 2001 and 2015. The value used is 1.053, which means that the average new home in 2015 is projected to be larger than in 2001. DOE derived both of these values from the NEMS simulation done for EIA's Annual Energy Outlook 2005. The net effect is that the estimated HHL for homes built in 2015 is 2.1 percent larger than the HHL of the homes in the RECS 2001 new construction sub-sample.

7.7 ENERGY CONSUMPTION Once the heating load of each sample housing unit is known, it is possible to estimate what the energy consumption would be if more-efficient equipment, rather than the baseline equipment, were used in each housing unit. 7.7.1 Fuel Consumption The Department calculated the fuel consumption (Fuel Use) for each furnace and boiler using the following formulas from the current proposed revision to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) test procedure SPC 103- 1993R22 section C:

Fuel Use = BOHss x QIN ^c,d for single

- stage furnace or boiler, where:

` For natural draft equipment this formula is modified to include the pilot light consumption. See Appendix L. d For modulating equipment this formula includes parameters for the operation at full, modulating, and reduced load. See Appendix L. 7-22 QYR,recs QIN,ex as defined above (kBtu/yr), input capacity ofthe existing furnace (see section 7.4.1 to see how this was assigned for each household) (kBtu/hr). The power consumption ofthe blower motor depends on the steady-state operating conditions (the pressure and airflow) for the furnace. This calculation is explained in section 7.5, Calculating Furnace Blower Electricity Consumption. The Department made adjustments to reflect the expectation that newly-built housing units in 2015 will have a somewhat different heating load than the housing units in the RECS 2001 new construction sub-sample. The adjustment involves multiplying the calculated HHL for each RECS 2001 housing unit in the new construction sub-sample by two factors. The first factor, building thermal efficiency, accounts for the estimated improvement in home insulation and other thermal efficiency practices between 2001 and 2015. The value used is 0.97, which means that the average new home in 2015 requires less heat energy to maintain indoor comfort. The second factor, house floor area, accounts for the estimated increase in average new house floor area between 2001 and 2015. The value used is 1.053, which means that the average new home in 2015 is projected to be larger than in 2001. DOE derived both ofthese values from the NEMS simulation done for EIA's 

### Annual Energy Outlook 2005. The net effect is that the estimated HHL for homes built in 2015 is 2.1 percent larger than the HHL ofthe homes in the RECS 2001 new construction sub-sample.



### 7.7 ENERGY CONSUMPTION Once the heating load of each sample housing unit is known, it is possible to estimate what the energy consumption would be ifmore-efficient equipment, rather than the baseline equipment, were used in each housing unit. 

### 7.7.1 Fuel Consumption The Department calculated the fuel consumption 

### (FueIUse) for each furnace and boiler using the following formulas from the current proposed revision to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) test procedure SPC 103- 1993R 22 section C: 

### FuelUse = 

### BOH ss x QIN ,c,d for single-stage furnace or boiler, where:

C For nahlral draft equipment this fOlIDula is modified to include the pilot light consumption. See Appendix L.

d For modulating equipment this fonnula includes parameters for the operation at full, modulating, and reduced load. See Appendix L. 7-22BOHSS = steady

- state burner operating hours (hr), Qi„ = input capacity of existing furnace (kBtu/hr), The details for calculating energy consumption appear in Appendix L, Determination of Furnace and Boiler Energy Use. 7.7.2 Electricity Consumption The Department calculated furnace electricity consumption for the blower, the draft inducer, and the ignitere

. The blower moves heated air through the house whenever the furnace burner is on (adjusted for delay times between burner and blower operation). It also operates in the cooling season (summer) if the house is air

- conditioned , but the Dept only considered use during the heating season. The Department calculated the electricity consumption as: Elec Use = BOHSS x (y x BE + yp x PE + ytg x PE,g) ,f for single

- stage furnace or boiler,
where: BOHss = as defined above, y = ratio ofblower on-time to burner on-time, BE = power consumption of the blower or circulating pump motor (kW), ,1P = ratio of induced-draft blower on-time to burner on-time, PE = power consumption of the draft- inducer blower-motor (kW), yrc = ratio of ignitor on

-time to burner on-time, and PEIG = power consumption of the ignitor (kW). The ratio of blower on

-time to burner on-time and the ratio of induced draft blower ontime to burner on

-time are from the current proposed revision to the ASHRAE test procedure SPC 103-19938222 using delay times for the virtual model furnaces

. The ratio of ignitor on-time to burner on-time comes from the DOE test procedure23 and the ignition time of the virtual model furnaces.5 The details for calculating electricity consumption appear in Appendix L, Determination of Furnace and Boiler Energy Use.

The DOE and ASHRAE test procedures do not count the electricity used by controls when the furnace is not firing. f For modulating equipment this formula includes parameters for the operation at full, modulating , and reduced load. See Appendix L. 8 The ASHRAE test procedure does not deal with ignitor energy consumption. 7-23 BOH ss 

### Qil1 steady-state burner operating hours (hr), input capacity ofexisting furnace (kBtu/hr), The details for calculating energy consumption appear in Appendix L, Determination of Furnace and Boiler Energy Use. 

### 7.7.2 Electricity Consumption The Department calculated furnace electricity consumption for the blower, the draft inducer, and the ignitere. The blower moves heated air through the house whenever the furnace burner is on (adjusted for delay times between burner and blower operation). It also operates in the cooling season (summer) ifthe house is air-conditioned, but the Dept only considered use during the heating season. The Department calculated the electricity consumption as: ElecUse 

## = BOH ss x (y x BE 

### + yp x PE 

### + yig x PEig) / for single-stage furnace or boiler, where: BOH ss 

### y BE 

# yP PE 

## yIG PEIG as defined above, ratio ofblower on-time to burner on-time, power consumption ofthe blower or circulating pump motor (kW), ratio of induced-draft blower on-time to burner on-time, power consumption ofthe draft-inducer blower-motor (kW), ratio ofignitor on-time to burner on-time, and power consumption ofthe ignitor (kW). The ratio ofblower on-time to burner on-time and the ratio of induced draft blower ontime to burner on-time are from the current proposed revision to the ASHRAE test procedure SPC 103-1993R 22 using delay times for the virtual model furnaces. The ratio ofignitor on-time to burner on-time comes from the DOE test procedure 23 and the ignition time ofthe virtual model fumaces. g The details for calculating electricity consumption appear in Appendix L, Determination ofFumace and Boiler Energy Use.

e The DOE and ASHRAE test procedures do not count the electricity used by controls when the furnace is not firing.

f For modulating equipment this fornmla includes parameters for the operation at full, modulating, and reduced load. See Appendix L.

g The ASHRAE test procedure does not deal with ignitor energy consumption. 7-237.8 RESULTS This section presents annual gas or oil consumption and winter electricity consumption for the considered design options in each product class. The average annual energy use for each design option is shown in Tables 7.8.1 through 7.8.6 for each product class. The range of annual gas or oil use and winter electricity consumption for each design option is shown in Figures 7.8.1 through 7.8.12.

7.8.2. Energy use for non-weatherized gas furnaces shown in Table 7.8.1 and Figures 7.8.1 and
Table 7.8.1 Non-Weatherized Gas Furnace Energy Use

Design O ption by AFUE Average Annual Gas Use (MmBtu) Average Electricity Use (kWh) 78% 56.6 496 80% 55.2 484 80% - Modulation (Two-Stage) 56.0 304 81% 54.6 479 81 % - Modulation (Two-Stage) 55.3 300 90% 49.4 417 92% 48.3 409 92% - Modulation (Two-Stage) 48.9 257 92% - Modulation (Continuous) 48.3 416 96% - Modulation (Continuous) 46.4 400 

### 7.8 RESULTS This section presents annual gas or oil consumption and winter electricity consumption for the considered design options in each product class. The average annual energy use for each design option is shown in Tables 7.8.1 through 7.8.6 for each product class. The range of annual gas or oil use and winter electricity consumption for each design option is shown in Figures 7.8.1 through 7.8.12. Energy use for non-weatherized gas furnaces shown in Table 7.8.1 and Figures 7.8.1 and 7.8.2. 

### T 

### hI 7 8 1 N W th . d G F



### a e 

# .. on- ea enze as urnace E

### nergy U 

### se Design Option Average Annual Gas Use Average Electricity Use by AFUE (MMBtu) (kWh) 78% 56.6 496 80% 55.2 484 80%

- Modulation (Two-Stage) 56.0 304 81% 54.6 479 81 % - Modulation (Two-Stage) 55.3 300 90% 49.4 417 92% 48.3 409 92%

- Modulation (Two-Stage) 48.9 257 92%

- Modulation (Continuous) 48.3 416 96%

- Modulation (Continuous) 46.4 400

7-24Annual Gas Vse ROWS e^ Design Option 140 -- hletl Ian 120 a.g4117_.. ...

.. -r- T

80 r..... ,. .... ^._ Yom' 1...^ ^' i
Q s
a u I € 1 3 ._.._ e 73 41) .. .. .. r F a I 20 L-r I

0 'D co lo m lo

1 1^6 1 1 Cs E 'E

N G C

® p

m 06 m mFigure 7.8.1 Range of Annual Gas Use in MMBtu for NonWeatherized Gas Furnaces

1 200

1000
R00

600
400

200 0 co

00fElectricity use Ranges By' Design Option

Figure 7.8.2 Range of Electricity Use in kWh for Non-Weatherized

Gas Furnaces

7-25 Mnual Gas Use**Ran~es** ey DesIgn option

IF 

### '" ", <U 0 lfI 

### '" 0**~ ~**  I!! c E c:>**~** c:> II) :2 :I 0 ::::i: :::> ::2

.... ...: < C1 < Q c**~** II>**~** 

### ..,**~** CD :::> ::l Gl 

### .,. 

# ...**~** .5 

### '" '" is "E ..: 1;6 ts**~** c:> 0 

### E N u N .., ,{, 2- g S .E "# "# 

# "* # "#**~** 

### .., El I:) 05, N Q 0 co 1ii N a> :E**~** 

### '" a>**~ ~**  N ell 

### '" C>I 

### Figure 7.8.1 Range of Annual Gas Use in MMBtu for NonWeatherized Gas Furnaces**1200.-------~--.---c---~------~--,,--~--_r--~--_o--_,**

l;! <U 0 <I> 0 IF 

### '" ", qr 'i:O' <X> E <> E <> I:) I!! 0 ::2 ::s


### .... "I( :2 "I( :2 

### '"**~** :I a c**~** CD**~** 

### ..,**~** 

### '" ::2 2 CR 

### .,. i'

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### '" 

### '" 

## ...**~** ....: 11! ..:**~** c: 0 I:> 

### £ N u N 

# .s cJ. 8-**~** s 

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# "* #

### ~ "# 

### ,., ,., I:) In N a c I:) co 1ii t:;1**~** E co**~ ~**  n !Q 01 a> 

### Figure 7.8.2 Range ofElectricity Use in kWh for Non-Weatherized Gas Furnaces

7-257.8.4. Energy use for weatherized gas furnaces shown in Table 7.8.2 and Figures 7.8.3 and

Table 7.8.2 Weatherized Gas Furnace Ener gy Use (Low Cost Scenario Design Option by AFUE Average Annual Gas Use (MMBtu) Average Electricity Use (kWh) 78% 33.0 293 80% 32.2 286 81% 31.8 283 82% 31.4 279 83% 31.0 276 

### Energy use for weatherized gas furnaces shown in Table 7.8.2 and Figures 7.8.3 and 7.8.4. Table 7.8.2 Weatherized Gas Furnace Ener2Y Use (Low Cost Scenario) Design Option Average Annual Gas Use Average Electricity Use by AFUE (MMBtu) (kWb) 78% 33.0 293 80% 32.2 286 81% 31.8 283 82% 31.4 279 83% 31.0 276

7-26Figure 7.8.3 Range of Annual Gas Use in MMBtu for Weatherized Gas Furnaces (Low Cost Scenario)

Figure 7.8.4 Range of Electricity Use in kWh for Weatherized Gas

Furnaces (Low Cost Scenario)

7-27 M nu81 G as Use Ranges IJY DesIgn OpUon**80r-----~----~------~----~------~----~----~----~** 

### aD
7fi 

### so

10**-M~dlan** lJ**M~~n**

• • • ;. • • 0· • •**o~----~ ~----~----~------~---~-----~---------~**  II> 

### "' m 

### '"
. ", .5 I!? 2! I!:' I!:' iii**~** ..: ..:: ..:: 

# ..**~ .**  

### f f ... ID**~** 

# .. 

# .. .... 

### .... 

### ... . .... ..,**~** 

### "" ..5 ..5 .5 .5



### .... /Po**~** III**~** c:) 

### ,... ..... M 

### "" a:I II:) II:) 

### Figure 7.8.3 Range of Annual Gas Use in MMBtu for Weatherized Gas Furnaces (Low Cost Scenario)
Eleetrlel1'1 Use Ranges BY DesIgn oPtion 700**r-----_.._---~------.._---_.._--__.------..___----__._---__,** SOD
600
400
300 :JOO
1DO**--Me~lan r**  

# '

- .. _

( _.. - r

. • . • ... . . ri • ..**""9l~**...... .. .. ...**~**. ... .. ........... . .... ... "

.....j

.. ... .. ... .. . .. j

.... . . . ..... .... . . .. . . .. ..... . ; .. .**~ ~**  { 1



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# ....**[J ···+·** **·· r±l** **::: ~**  

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. []**L. :~** 

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# =+=**o~---~------~---~--------------------~----~----~** 

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. ..: q: q:**~1 '** **~ .** **~ ~**  OJ m 

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.... llI. /Po llI. llI. o ·**.** 

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### "" "" "" Figure 7.8.4 Range of Electricity Use in kWh for Weatherized Gas Furnaces (Low Cost Scenario)

7-27Energy use for mobile home furnaces shown in Table 7.8.3 and Figures 7.8.5 and 7.8.6.

Table 7.8.3 Mobile Home Furnace Energy Use Design Option by AFUE Average Annual Gas Use (MMBtu) Average Electricity Use (kWh) 75% 44.3 392 80% 39.0 381 80% - Modulation (Two-Stage) 39.6 253 81% 38.6 376 81 % - Modulation (Two-Stage) 39.1 251 82% 38.1 372 82% - Modulation (Two-Stage) 38.6 248 90% 34.9 332 Energy use for mobile home furnaces shown in Table 7.8.3 and Figures 7.8

.5 and 7.8.6. 

### T bl 7 83M bi! H

a e 

# .. 0 e orne 

### Furnace 

### Enere;y U se Design Option Average Annual Gas Use Average Electricity Use by AFUE (MMBtu) (kWh) 75 % 44.3 392 80% 39.0 381 80%

- Modulation (Two-Stage) 39.6 253 81 % 38.6 376 81 %

- Modulation (Two-Stage) 39.1 251 82% 38

. 1 372 82%

- Modulation (Two-Stage) 38.6 24 8 90% 34.9 332

7-28Figure 7.8.5 Range of Annual Gas Use in MMBtu for Mobile Home Furnaces

1 

### 0 0
MI sou 700

.11 son 400 300
200 1011 0 EI trlef+Use Range s Btq Design Onion

Figure 7.8.6 Range of Electricity Use in kWh for Mobile Home

Furnaces

7-29 70 60 50 40 30 20 10 Annual GIiIS use: RlilngeS BY Design oPtion**o~--~----~----------------~----~--~----~--~--~** 

## "" ." '0 ." 

### .., ." -g 

### '" ,§**~** 0:.**~** - a 2! I: 81 0( :::Ii 0( ::II "( ::II "w

. I:**~** (I)**~** 41**~** 4f II> <II 

### ..,. 

# ... ... ., 1%1 

### "" CII CII 

## E q;**~** 0;;
- <:i 0;; I:

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### tt til If.**~** !:II !fl 

# *' c c .- 

### .... N n <=> tI> Q) a> 

### ""

- 

### "" 1%1 

### "" Figure 7.8.5 Range of Annual Gas Use in MMBtu for Mobile Home Furnaces
EIMtrlCItp' USB Ranlles**~** 08sliln OP1on**1000r-------~--~--------~--,_--_,--------~--~--~**
eOD 700 600 SOD 0400 30n 200 100 -""sellan
- il fljeari _0..;..:.

- • •**~** _ w " •• , • •**~i'** 

### ,

D**~**__**~**____**~**__**~**____**~**__**~**____**~**__**~**____ L-

__**~**____**~**__ -J II) 111' -c: 1'$ -c: n: -c: D

_ 5**~** I)**~** I)**~** I) c: Ii ..;C :E ..;C :E ..;C :E - m



### ... :¥ ID**~** ID I» co 

### :¥ II) n: D D III '1lI > al III .... no

.... 35 

### ... 35 .... 35 c: 

### *- .., .., ..., I)



### ..... .5 N .5 N .5 N 00

..... 

### *- # 

# .,.**~** #! #**~** 

## = 00 «i 0:; <"V N 0 co co 00 co CI) 

### Figure 7.8.6 Range of Electricity Use in kWh for Mobile Home Furnaces

7-29Energy use for oil-fired furnaces shown in Table 7.8.4 and Figures 7.8.7 and 7.8.8.

Table 7.8.4 Oil-Fired Furnace Ener gy Use

Design Option by AFUE Average Annual Oil Use (MMBtu) Average Electricity Use (kWh) 78% 73.2 789 80% 71.4 770 81% 70.6 761 81% - Interrupted Ignition 71.3 58981% - Atomized Burner w/ TwoStage 72.2 388
82% 69.8 752 82% - Interrupted Ignition 70.5 58282% - Atomized Burner w/ TwoStage 71.3 383
83% 69.0 743 83% - Interrupted Ignition 69.7 575 83% - Atomized Burner w/ TwoStage 70.5 379
84% 68.2 735 84% - Interrupted Ignition 68.9 56984% - Atomized Burner w/ TwoStage 69.6 375
85% 67.4 727 85% - Interrupted Ignition 68.1 56285% - Atomized Burner w/ TwoStage 68.8 371 Energy use for oil-fired furnaces shown in Table 7.8.4 and Figures 7.8.7 and 7

. 8.8. 

### T bI 7 8 4 01 F" d F

a e 

# . . I - Ire urnace Ener2Y U se Design Option Average Annual Oil Use Average Electricity Use by AFUE (MMBtu) (kWh) 78% 73.2 789 80% 71.4 770 81% 70.6 761 81 %

- Interrupted Ignition 71.3 589 81 %

- Atomized Burner wi Two- 72.2 388 Stage 82% 69.8 752 82%

- Interrupted Ignition 70.5 582 82%

- Atomized Burner wi Two- 71.3 383 Stage 83% 69.0 743 83%

- Interrupted Ignition 69.7 575 83%

- Atomized Burner wi Two- 70.5 379 Stage 84% 68.2 735 84%

- Interrupted Ignition 68.9 569 84%

- Atomized Burner wi Two- 69

.6 375 Stage 85% 67.4 727 85%

- Interrupted Ignition 68

. 1 562 85%

- Atomized Burner wi Two- 68.8 371 Stage

7-30713% Baseline 1 80% Inc r HK Area 81 %1nc r HX Area 8196 Interrupted Ignition 81 %AtomBurner2-rude Mod

82% Incr HE Area 62% Interrupted I gnI[Ion 82%AtomBumer2- loge Mod

83% Incr HJ{ Area 8395 Interrupted Ignition 83%AtomAurner1 geMod

84% IncI HX Area 849fi Interrupted Ignition 84%AM mBurner2- 92 de Mod

85% Incr HX Area 85% Interrupted ignition 81 %At rnBumer2• atage Mod 4 4 Q CM G 0 o a o 0 0 O m Q r C Q O O O O O 4 O

70% Baseline _..... 80% IncrHX Area T ® r , 81 % Incr HE Area 01% Interrupted Ignition 81 %AtamBurner2- E ge Mod. ._.--.l----

82% Incr HE Area 1.__.... _ . -..._................ ..^ 82% Interrupted IUnition IT.-

82% Atom Burner 2- dage Mod r.. 33

83% Incr HE Area a 83% Interrupted Ignition I r ._ 83°.6At3mBurner2- dageMud 4--^ 1 u J I

84% IncrHXArea 84% Interrupted ignition 84% Atom Burner 2- stage Mud

85% Incr Hai Area .... :.,.T ... .. • . , ..^_ 85% Interrupted Ignition -- ^ ® lr--- 81-'AtomBurner 7 -eta eMad ^AnnuslQasUse:RangeSDeSignoptionQ.)'"..0::::.."<IIc:.."..0::::.."'I>0::::.."'I>0::::.."scOJgDOJDOJ.2DQ.)gDgQ<-<2':E<50:E<§:E."<:E§:EX;:t;II>;:t;II>;:t;II>XII>XOJ<Xl""""""""tilED:I: :I:i:r:i:I:i::Li:I:.gj'--::;y'"ysysuCDu<D:ss;Q.......s"'-.....s;"'-.....scQ......sc<>........#-';f.::3';f.::..';f.::l..#-::lD#-2.:..:iimII>II>m mGI0a:;ENEE....EIt)<::CDE'"CD:e'"s''"EllE'"<D$:;tr:m.".m.".m.".m.".mENEME....E'"E<D«>(IQQOQOISISiI.....nM......«>QO«>QOCDFigure7.8.7RangeofAnnualGasUseinMMBtuforOil-FiredFurnacesEIectrlclb'Uis!!RangesBYoesign0pUCnII>..(10<::p..0::::-g'I>C.."(10<::g!0::::"CJ,5CD02!.2DQQ.Di<<:'2:..:'2:E<:E...::.J2<-:ExxE-'";:t;II>XE'GIX."'"XII>,.""....ZII""....m:I::I:]jtil:I:i::L"IS:I:-util:I:i.,.;:;yE;:;ID·;:;AIUQQSC.s:<L.-:...s;........SC11-......s:Q......:s...n......#-2'-'#:::>..#-2..::I....'#2..iiiCD53II>iiiGIj.CDliSga;ENCfT)E...E'"£;::>CD:s:;CD:E'"CDE::>CDE'"lfImtr:mIf!mmtr:m...E"....EME...EIt)ECD<D!XIal<DIf<,...n....."'"OQeo00CDQOFigure7.8.8RangeofElectricityUseinkWhforOil-FiredFurnaces7-31Energy use for gas boilers shown in Table 7.8.5 and Figures 7.8.9 and 7.8.10.

Table 7.8.5 Gas Boiler Ener Use (Low Cost Scenario

Design Option by AFUE Average Annual Gas Use (MMBtu) Average Electricity Use (kWh) 80% 79.4 135 81% 75.7 149 81% - Modulation (Two-Stage) 75.5 189 82% 74.8 147 82% - Modulation (Two-Stage) 74.6 187 83% 73.9 145 83% - Modulation (Two-Stage) 73.7 185 84% 73.0 143 84% - Modulation (Two-Stage) 72.9 183 85% 72.2 142 85% - Modulation (Two-Stage) 72.0 181 86% 71.3 140 91% 67.5 132 99% 62.0 122 Energy use for gas boilers shown in Table 7.8.5 and Figures 7.8.9 and 7.8.10. 

### Table 7.8.5 Gas Boiler**Energ~** 

### Use (Low Cost Scenario) Design Option Average Annual Gas Use Average Electricity Use by AFUE (MMBtu) (kWb) 80% 79.4 135 81% 75.7 149 81%

- Modulation (Two-Stage) 75.5 189 82% 74.8 147 82%

- Modulation (Two-Stage) 74.6 187 83% 73.9 145 83%

- Modulation (Two-Stage) 73.7 185 84% 73.0 143 84%

- Modulation (Two-Stage) 72.9 183 85% 72.2 142 85%

- Modulation (Two-Stage) 72.0 181 86% 71.3 140 91% 67.5 132 99% 62.0 122

7-321 BO 160 140 120 100 BO ii0 40 20 0 du

a,

Ql

ca m a' m

Figure 7.8.9 Range of Annual Gas Use in MMBtu for Hot-Water

Gas Boilers (Low Cost Scenario)

Figure 7.8.10 Range of Electricity Use in kWh for Hot-Water Gas

Boilers (Low Cost Scenario)

7-33 Mnuel Gas Use Ar mges**~** DeSign QPtion

OJ**~** 0:::**~** 0::**~** C**~** 

## 1!**~** 0::**~ ~** **~** r:: E l! 2! !!**~** 

### .... '" <"'> 

### .... ..., '" 

### .... IT.I CD 0 00 Cl 00 a a;. 0 00 Cl <XI 

### "" '" '" 

## ... ... 

# .. "" 

# .. 

# .. "C "C T.l tJ "C CD .5 .5 .5 .5 .5**~** 

# .. t- t- 

# .. t- oO 

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### "" C1 0\ QI C1

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### "" .,:; .,;,**~** III III**~ ~**  

## ... n !:"1 1J!; 

### '" CD

. 00 <XI 00 

### Figure 7.8.9 Range of Annual Gas Use in MMBtu for Hot-Water Gas Boilers (Low Cost Scenario)

OJ**~** .0:::**~** 0:: III 0::**~ ~** **~** 0::**~** Ifl**~** .!: 

# ... E 

### '" !! M 2!
....**~** 

### '" I! <D 

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## "" '" '" 

## ... u OJ 

## ... ...**~** '0 "C T.l 

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# .. .. t- 

## .. t-

-:::I 

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### ..., 

## ... -g CD 0 Q a 0 ::s; E !E E**~** II) III OJ !II II> 

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## ". ('of M N .,;,**~** III**~ ~**  III


## ... n <"'> .... 

### "" CD 00 <XI 00 00 

### Figure 7.8.10 Range of Electricity Use in kWh for Hot-Water Gas Boilers (Low Cost Scenario)

7-33Energy use for oil-fired boilers shown in Table 7.8.6 and Figures 7.8.11 and 7.8.12.

Table 7.8.6 Oil- Fired Boiler Energy Use

Design Option by AFUE Average Annual Oil Use (MMBtu) Average Electricity Use (kWh) 80% 82.7 297 81% 81.7 294 81 % - Interrupted Ignition 82.0 235 82% 80.7 290 82% - Interrupted Ignition 81.0 23282% - Atomized Burner w/ TwoStage 80.7 311
83% 79.8 287 83% - Interrupted Ignition 80.0 230 83% - Atomized Burner w/ TwoStage 79.7 307
84% 78.9 284 84% - Interrupted Ignition 79.1 22784% - Atomized Burner w/ TwoStage 78.8 304
85% 77.9 280 85% - Interrupted Ignition 78.2 22485% - Atomized Burner w/ TwoStage 77.9 301
86% 77.0 277 86% - Interrupted Ignition 77.3 22286% - Atomized Burner w/ TwoStage 77.0 297
90% 73.9 212 95% 70.0 201 Energy use for oil-fired boilers shown in Table 7.8.6 and Figures 7.8.11 and 7.8.12. T bl 7 8 6 0"1 F O d B 

### 01 E U



### a e o 0 I - Ire 01 er nergy se Design Option Average Annual Oil Use Average Electricity Use by AFUE (MMBtu) (kWh) 80% 82.7 297 81% 81.7 294 81 %

- Interrupted Ignition 82

.0 235 82% 80.7 290 82%

- Interrupted Ignition 81.0 232 82%

- Atomized Burner wi Two- 80.7 311 Stage 83% 79.8 287 83%

- Interrupted Ignition 80.0 230 83%

- Atomized Burner wi Two- 79.7 307 Stage 84% 78.9 284 84%

- Interrupted Ignition 79.1 227 84%

- Atomized Burner wi Two- 78.8 304 Stage 85% 77.9 280 85%

- Interrupted Ignition 78.2 224 85%

- Atomized Burner wi Two- 77.9 301 Stage 86% 77.0 277 86%

- Interrupted Ignition 77.3 222 86%

- Atomized Burner wi Two- 77.0 297 Stage 90% 73

.9 212 95% 70.0 201

7-34150 140
120
100

BO
50
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### Figure 7.8.12 Range of Electricity Use in kWh for Hot-Water OilFired Boilers 7-35REFERENCES

1. U.S. Department of Energy - Energy Information Administration, Residential Energy Consumption Survey: Household Energy Consumption and Expenditures 2001, 2001. (Lastaccessed May 18, 2005.) <http://www.eia.doe.gov/emeu/recs/recs200l/publicuse2OOl.html> 2. Gas Appliance Manufacturers Association (GAMA), GAMA Directory March 2005, 2005. (Lastaccessed March, 2005.) <http://www. gamanet. org/gama/inforesources.nsf/vAllDocs/Product+Directories?OpenDo cument> 3. Gas Appliance Manufacturers Association (GAMA), Updated Shipment Data for Residential Furnaces and Boilers , personal communication

. April 25, 2005. 4. Phillips, E ., Blower Efficiency in Domestic Heating Systems, June, 1995. UNIES Ltd. Winnipeg, Manitoba

. Report No . CEA 9202 U 921. 5. Lindeburg, M. R., Fans and Ductwork, Chapter 20. In Mechanical Engineering Reference Manual for the PE Exam, Michael R. Lindeburg PE, Editor. Tenth ed. 1997. Professional Publications, Inc.: Belmont, CA. p. 20-23 6. American Society of Heating Refrigeration and Air-Conditioning Engineers, ASHRAE 1997 Handbook - Fundamentals. 1997.: Atlanta, GA.p. 3.12. 7. Proctor, J. and D

. Parker, Hidden Power Drains: Residential Heating and Cooling Fan Power Demand . In ACEEE 2000 Summer Study on Energy Efficiency in Buildings. 2000. Asilomar , CA, August 20-25

. American Council for an Energy

- Efficient Economy. 1: pp. 225-234. 8. Lennox Industries Inc., Lennox Engineering Data: G40DF ( Merit Series Upflow/ Horizontal Gas Furnace), 2003

. Lennox Industries , Inc. 2003.) <http ://pirl.lennox

. com/C03e7ol4l/76EOZC21u/ehb_g40df 0307.pdf> 9. Lennox Industries Inc., Lennox Engineering Data : G40UH ( Merit Series Upflow/ Horizontal Gas Furnace ), 2004

. Lennox Industries, Inc. <http ://pirl.lennox

. com/C03e7ol4l/76EOZC21u/ehb_g4Ouh

0407.pdf> 10. Lennox Industries Inc., Lennox Engineering Data: G41 UF ( Merit Series Downflow Gas Furnace ), 2004

. Lennox Industries, Inc. <http ://pirl.lennox

. com/C03e7ol41/76EOZC21u/ehb_g4luf 0402.pdf>

7-36 

### REFERENCES 1. U.S. Department ofEnergy

- Energy Information Administration, Residential Energy Consumption Survey: Household Energy Consumption andExpenditures 2001,2001. 

### (Lastaccessed May 18,2005.) <http://www.eia.doe.gov /emeulrecs/recs200 I/publicuse200 l.html> 2. Gas Appliance Manufacturers Association (GAMA), GAMA Directory March 2005, 2005. 

### (Lastaccessed March, 2005.) <http://www.gamanet.org/gama/inforesources.nsf/v AllDocs/Product+ Directories?OpenDo cument> 3. Gas Appliance Manufacturers Association (GAMA), Updated Shipment Data for Residential Furnaces and Boilers,personal communication. 

### Apri125, 2005. 4. Phillips , E., Blower Efficiency in Domestic Heating Systems, 

### June, 1995

. UNIES Ltd. Winnipeg, Manitoba. Report No. CEA 9202 U 921. 5. Lindeburg , M. R., Fans andDuctwork , Chapter 20. 

### In Mechanical Engineering Reference Manualfor the PE Exam, 

### Michael R. Lindeburg PE , Editor. Tenth ed. 1997. Professional Publications, Inc.: Belmont, CA. p. 20-23 6. American Society ofHeating Refrigeration and Air-Conditioning Engineers, ASHRAE 1997 Handbook

- Fundamentals. 

### 1997

. : Atlanta, GA.p. 3.12. 7. Proctor, J. 

### and D. Parker, Hidden Power Drains: Residential Heating and Cooling Fan Power Demand. InACEEE 2000 Summer Study on Energy Efficiency in Buildings. 2000. 

### Asilomar, CA, August 20-25. American Council for an Energy-Efficient Economy.l: pp. 225-234. 8. Lennox Industries Inc., Lennox Engineering Data: G40DF (Merit Series UpjlowlHorizontal Gas Furnace), 

### 2003. Lennox Industries, Inc

. 2003.) <http://pirl.lennox.com/C03e7014lI76EOZC21u1ehb_g40dC0307.pdf> 9. Lennox Industries Inc., Lennox Engineering Data: G40UH (Merit Series UpjlowlHorizontal Gas Furnace), 

### 2004

. Lennox Industries, Inc. <http://pirl.lennox.com/C03e70 14l176EOZC21 ulehb_g40uh

_0407.pdf> 10. Lennox Industries Inc., Lennox Engineering Data: G41 UF (Merit Series Downjlow Gas Furnace), 

### 2004. Lennox Industries , Inc. <http://pirl.lennox.com/C03e7014lI76EOZC21u1ehb_g41uC0402.pdf>

7-3611. Lennox Industries Inc., Lennox Engineering Data: G43 UF (Merit Series Upflow Gas Furnace), 2004. Lennox Industries, Inc. <http://pirl.lennox.com/C03e7ol41/76EOZC21u/ehb_g43uf 0412.pdf> 12. Lennox Industries Inc., Lennox Engineering Data: G50DF (Elite Series Downflow Gas Furnace), 2003. Lennox Industries, Inc. <http://pirl.lennox.com/C03e7ol4l/76EOZC21u/ehb_g5Odf 0307.pdf> 13. Lennox Industries Inc., Lennox Engineering Data. G50UH ( Elite Series Upflow/ Horizontal Gas Furnace ), 2003

. Lennox Industries, Inc. <http://pirl.lennox

. com/C03e7ol4l/76EOZC2 lu/ehb_g50uh

_03 07.pdf> 14. Lennox Industries Inc., Lennox Engineering Data. G51MP (Elite Series Multi-Position Gas Furnace), 2004. Lennox Industries, Inc. <http://pirl.lennox.com/C03e7ol4l/76EOZC2 lu/ehb_g51 mp_0412.pdf> 15. Carrier Corporation , Carrier Product Data : 58CVA/CVX(Infinity 80 Series MultiPoise Furnace ), 2004

. Carrier Co. <http ://www.xpedio

. carrier

. com/idc/groups/public/documents/techlit/5 8cv

- 3pd.pdf> 16. Carrier Co., Carrier Product Data: 58MVP (Infinity 96 Deluxe 4-Way Multipoise Furnace), 2004. Carrier Co. <http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/58mvp-11 pd.pdf> 17. Lennox Industries Inc., Lennox Engineering Data: G61MPV (Multi-Position - Variable Speed Blower - Two-Stage Heat - Direct Vent/Non-Direct Vent). 2004, Lennox Industries, Inc. 18. Lennox Industries Inc., Lennox Engineering Data. G60UHV (Up-Flow /Horizontal - Two Stage Heat - Variable SpeedBlower). 2003 , Lennox Industries, Inc. 19. Lennox Industries Inc., Lennox Engineering Data: G60DFV (Down flow - Variable Speed Blower - Two-Stage Heat). 2004, Lennox Industries, Inc. 20. Trane Co., Trane Product Data : XV 80, 2004. Trane Co. 21. Trane Co., Trane Product Data: XV 90, 2004. Trane Co. 22. American Society of Heating Refrigerating and Air

- Conditioning Engineers Inc., Method of Testing for Annual Fuel Utilization Efficiency of Residential Central Furnaces and Boilers, October , 2003

. Atlanta , GA. Report No. BSR/ASHRAE Standard 103-1993R. First Public Review. 23. Title 10, Code of Federal Regulations , Part 430- Energy Conservation Program for Consumer Products, Appendix N to Subpart B of Part 430-Uniform Test Method for 7-37 

### 11. Lennox Industries Inc

., Lennox Engineering Data: G43 UF (Merit Series Upjlow Gas Furnace), 2004. Lennox Industries, Inc. <http://pirl.1ennox.com/C03e70141/76EOZC21u/ehb_g43uC0412.pdf> 12. Lennox Industries Inc., Lennox Engineering Data: G50DF (Elite Series Downjlow Gas Furnace), 2003. Lennox Industries, Inc. <http://pirl.1ennox.com/C03e70141/76EOZC21u1ehb_gSOdC0307.pdf> 13. Lennox Industries Inc., Lennox Engineering Data: G50UH (Elite Series Upjlow / Horizontal Gas Furnace), 2003. Lennox Industries, Inc. <http://pirl.1ennox.com/C03e70141/76EOZC21u1ehb_gSOuh_0307.pdf> 14. Lennox Industries Inc., Lennox Engineering Data: G

### 51MP (Elite Series Multi-Position Gas Furnace), 2004. Lennox Industries, Inc. <http://pirl.1ennox.com/C03e70141/76EOZC21u1ehb_gSlmp_0412.pdf> IS. Carrier Corporation, Carrier Product Data: 58CVA/CVX(Infinity 80 Series MultiPoise Furnace}, 2004. Carrier Co. <http://www.xpedio.carrier.com/idc/groups/public/documents/techlitlS8cv-3pd.pdf> 16. Carrier Co., Carrier Product Data: 58MVP (Infinity 96 Deluxe 4-Way Multipoise Furnace), 2004. Carrier Co. <http://www.xpedio.carrier.com/idc/groups/public/documents/techlitlS8mvp-llpd.pdf> 17. Lennox Industries Inc., Lennox Engineering Data: G61MPV (Multi-Position

- Variable Speed Blower

- Two-Stage Heat

- Direct Vent/Non-Direct Vent). 2004, Lennox Industries, Inc. 18. Lennox Industries Inc., Lennox Engineering Data: G60UHV (Up-Flow/Horizontal

- Two Stage Heat

- Variable SpeedBlower). 2003, Lennox Industries, Inc. 19. Lennox Industries Inc., Lennox Engineering Data: G60DFV (Down-jlow

- Variable Speed Blower

- Two-Stage Heat). 2004, Lennox Industries, Inc. 20. Trane Co., Trane Product Data: XV 80, 2004. Trane Co. 21. Trane Co., Trane Product Data: XV 90, 2004. Trane Co

.

. 22. American Society ofHeating Refrigerating and Air-Conditioning Engineers Inc., Method o/Testing/orAnnual Fuel Utilization Efficiency o/Residential Central Furnaces and Boilers, October, 2003. Atlanta, GA. Report No. BSRlASHRAE Standard 103-1993R. First Public Review. 23. Title 10, Code o/FederalRegulations, Part 430- Energy Conservation Program/or Consumer Products, Appendix N to Subpart B 

## 0/ Part 430-Uniform Test Method/or 7-37Measuring the Energy Consumption of Furnaces and Boilers, January 1, 1999. Chapter II. 

### Measuring the Energy Consumption a/Furnaces and Boilers, January 1,1999. Chapter II.

7-38