APPENDIX D. DETERMINATION OF FURNACE AND BOILER ENERGY USE IN

THE ENGINEERING ANALYSIS

TABLE OF CONTENTS

D.l INTRODUCTION .................................................... D-1

D.2 CALCULATIONS .................................................... D-1

D.2.1 Determination of Average Annual Fuel Energy Consumption (EF) ........ D-1

D.2.2 Determination of Average Annual Electrical Energy Consumption (EAE) ... D-2

D.2.3 Determination of National Average Number of Burner Operating Hours

(BOHss) ...................................................... D-3

D.2.5 Determination of Heating Seasonal Efficiency (Effyss) ................. D-5

D.3 PARAMETERS TO DETERMINE THE ENERGY USE OF MODULATING

FURNACES ......................................................... D-6

D.3.1 Parameters to Determine Average Annual Fuel Energy Consumption ...... D-6

D.3.2 Parameters to Determine Annual Fuel Utilization Efficiency ............. D-7

D.3.3 Conclusions ................................................... D-8

D.4 SUMMARY TABLES ................................................. D-8

LIST OF TABLES

Table D.3.1 AFUE for Similar Single-Stage and Two-Stage Furnace Models Series .... D-8

Table D.4.1 Energy Use Results for Non-Weatherized Gas Furnaces

(Single-Stage Controls) .......................................... D-9

Table D.4.2 Energy Use Results for Non-Weatherized Gas Furnaces

(Two-Stage Controls) ........................................... D-9

Table D.4.3 Energy Use Results for Non-Weatherized Gas Furnaces

(Continuous Modulating Controls) ................................. D-9

Table D.4.4 Energy Use Results for Weatherized Gas Furnaces (Single-Stage Controls) . D-9

Table D.4.5 Energy Use Results for Mobile Home Furnaces (Single-Stage Controls) ... D-10

Table D.4.6 Energy Use Results for Mobile Home Furnaces (Two-Stage Controls) .... D-10

Table D.4.7 Energy Use Results for Oil-Fired Furnaces (Single-Stage Controls) ...... D-10

Table D.4.8 Energy Use Results for Hot-Water Oil Furnaces (Two-Stage Controls) .... D-11

Table D.4.9 Energy Use Results for Hot-Water Gas Boilers (Single-Stage Controls) ... D-11

Table D.4.10 Energy Use Results for Hot-Water Gas Boilers (Two-Stage Controls) .... D-11

Table D.4.11 Energy Use Results for Hot-Water Oil Boilers (Single-Stage Controls) .... D-12

Table D.4.12 Energy Use Results for Hot-Water Oil Boilers (Two-Stage Controls) ..... D-12

 EE-RM/STD-01-350 COMMENT 164

APPENDIX D. DETERMINATION OF FURNACE AND BOILER ENERGY USE IN 

THE ENGINEERING ANALYSIS 

TABLE OF CONTENTS 

D.I INTRODUCTION .................................................... D-I 

D.2 CALCULATIONS .................................................... D-I 

D.2.1 Determination of Average Annual Fuel Energy Consumption (EF) •....... D-I 

D.2.2 Determination of Average Annual Electrical Energy Consumption (EAE) .,. D-2 

D.2.3 Determination of National Average Number of Burner Operating Hours 

(BOHss) ...................................................... D-3 

D.2.5 Determination of Heating Seasonal Efficiency (Effyss) ................. D-5 

D.3 PARAMETERS TO DETERMINE THE ENERGY USE OF MODULATING 

FURNACES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. D-6 

D.3.1 Parameters to Determine Average Annual Fuel Energy Consumption ...... D-6 

D.3.2 Parameters to Determine Annual Fuel Utilization Efficiency. . . . . . . . . . . .. D-7 

D.3.3 Conclusions ................................................... D-8 

D.4 SUMMARY TABLES ................................................. D-8 

Table D.3.1 

Table D.4.1 

Table D.4.2 

Table D.4.3 

Table D.4.4 

Table D.4.5 

Table D.4.6 

Table D.4.7 

Table D.4.8 

Table D.4.9 

Table D.4.10 

Table D.4.11 

Table D.4.12 

LIST OF TABLES 

AFUE for Similar Single-Stage and Two-Stage Furnace Models Series D-8 

Energy Use Results for Non-Weatherized Gas Furnaces 

(Single-Stage Controls) .......................................... D-9 

Energy Use Results for Non-Weatherized Gas Furnaces 

(Two-Stage Controls) ........................................... D-9 

Energy Use Results for Non-Weatherized Gas Furnaces 

(Continuous Modulating Controls) ................................. D-9 

Energy Use Results for Weatherized Gas Furnaces (Single-Stage Controls) . D-9 

Energy Use Results for Mobile Home Furnaces (Single-Stage Controls) .. , D-IO 

Energy Use Results for Mobile Home Furnaces (Two-Stage Controls) .... D-IO 

Energy Use Results for Oil-Fired Furnaces (Single-Stage Controls) ...... D-IO 

Energy Use Results for Hot-Water Oil Furnaces (Two-Stage Controls) ... , D-ll 

Energy Use Results for Hot-Water Gas Boilers (Single-Stage Controls) .. , D-II 

Energy Use Results for Hot-Water Gas Boilers (Two-Stage Controls) .... D-II 

Energy Use Results for Hot-Water Oil Boilers (Single-Stage Controls) .... D-12 

Energy Use Results for Hot-Water Oil Boilers (Two-Stage Controls) .... , D-12 

D-i 
APPENDIX D. DETERMINATION OF FURNACE AND BOILER ENERGY USE IN

THE ENGINEERING ANALYSIS

D.1 INTRODUCTION

The DOE test procedure for measuring the energy consumption of furnaces and boilers

provides a calculation approach for determining the energy use of furnaces and boilers under test

conditions.' This approach requires the calculation of the average annual fuel energy

consumption (EF), the average annual electrical energy consumption (EAE), and the national

average number of burner operating hours (BOHSS) of furnaces and boilers.

The following calculations and summary tables describe the determination ofEF, EAE, and

BOHSS for gas- and oil-fired furnaces and boilers.

D.2 CALCULATIONS

D.2.1 Determination of Average Annual Fuel Energy Consumption (EF)

The Department calculated the average annual fuel consumption in sections 10.2.2 and

10.2.2.1 of the DOE test procedure:'

for single-stage furnaces and boilers

EF = BOHss * (QIN - Q') + 8,760 * QP Eq. 1

and for two-stage and continuous modulatinga furnaces and boilers

EF = EM + 4,600 * QP Eq. 2

where:

BOHss = National average number of burner operating hours (see section D.2.4 of this

appendix for derivation),

QJN = Steady-state nameplate input rate in Btu/h for single-stage furnaces and

boilers or steady-state nameplate maximum input rate in Btu/h for two-stage

and continuous modulating furnaces and boilers,

QP = Pilot flame fuel input rate in Btu/h, and

EM = Average annual energy used during the heating season for two-stage and

continuous modulating furnaces and boilers.

a In this Technical Support Documentation, "continuous modulating" term is used instead of "step-modulating". Both

terms are interchangeable used in the literature.

D-1

 EE-RM/STD-01-350 COMMENT 164

APPENDIX D. DETERMINATION OF FURNACE AND BOILER ENERGY USE IN 

THE ENGINEERING ANALYSIS 

D.l INTRODUCTION 

The DOE test procedure for measuring the energy consumption of furnaces and boilers 

provides a calculation approach for determining the energy use of furnaces and boilers under test 

conditions. I This approach requires the calculation of the average annual fuel energy 

consumption (EF), the average annual electrical energy consumption (EAE), and the national 

average number of burner operating hours (BOHss) of furnaces and boilers. 

The following calculations and summary tables describe the determination of EF, EAE, and 

BOHss for gas- and oil-fired furnaces and boilers. 

D.2 CALCULATIONS 

D.2.l Determination of Average Annual Fuel Energy Consumption (EF) 

The Department calculated the average annual fuel consumption in sections 10.2.2 and 

10.2.2.1 of the DOE test procedure: I 

for single-stage furnaces and boilers 

Eq.l 

and for two-stage and continuous modulatinga furnaces and boilers 

where: 

BOHss 

Eq.2 

National average number ofbumer operating hours (see section D.2.4 of this 

appendix for derivation), 

Steady-state nameplate input rate in Btu/h for single-stage furnaces and 

boilers or steady-state nameplate maximum input rate in Btu/h for two-stage 

and continuous modulating furnaces and boilers, 

Pilot flame fuel input rate in Btu/h, and 

Average annual energy used during the heating season for two-stage and 

continuous modulating furnaces and boilers. 

a In this Technical Support Documentation, "continuous modulating" term is used instead of "step-modulating". Both 

terms are interchangeable used in the literature. 

D-l 
QIN is based on the baseline value for each product class. QP is zero for all product

classes, except for the baseline mobile home gas furnace and gas boiler.

D.2.2 Determination of Average Annual Electrical Energy Consumption (EAE)

Using the DOE test procedure,' DOE calculated the average annual electrical energy

consumption in sections 10.2.3, 10.2.3.1, and 10.2.3.2:

for single-stage furnaces and boilers

EAE = BOHss (yP * PE +YIG * PEIG + y * BE) Eq. 3

and for two-stage and continuous modulating furnaces and boilers

EAE = BOHR (yP*PER +YIC*PEIG + y*BER) + BOHH0YM (yP*PEH +YIC*PEIG + y*BEH)Eq. 4

where:

BOHss = See section D.2.3 of this appendix,

BOHH = National average number of burner operating hours at the maximum operating

mode (see section D.2.4 of this appendix),

BOHM = National average number of burner operating hours at the modulating

operating mode (see section D.2.4 ofthis appendix),

BOHR = National average number of burner operating hours at the reduced operating

mode (see section D.2.4 of this appendix),

YP = Ratio ofinduced or forced draft blower on-time to average burner on-time,

PE = Burner electrical power input at full-load steady-state operation in kW,

PER = Burner electrical power input at full-load steady-state operation in kW,

measured at the reduced fuel input rate,

PEH = Burner electrical power input at full-load steady-state operation in kW,

measured at the maximum fuel input rate,

YIG = Ratio of burner interrupted-ignition device on-time to average burner on-time,

PE,G = Electrical input rate to the interrupted ignition device on the burner,

y = Ratio of blower or pump on-time to burner on-time,

BE = Circulating-air fan or water pump electrical energy input rate in kW,

BER = Circulating-air fan or water pump electrical energy input rate in kW,

measured at the reduced fuel input rate, and

BEH = Circulating-air fan or water pump electrical energy input rate in kW,

measured at the maximum fuel input rate.

The Department calculated the value yP using tP (post-purge time in minutes). For

this calculation, the Department took tp to be less than or equal to 30 seconds and therefore set it

equal to 0 seconds, according to sections 8.2 and 8.4 of the DOE test procedure.' The

Department calculated the value yIG using tIG (on-time of the burner interrupted ignition device

D-2

 EE-RM/STD-01-350 COMMENT 164

QIN is based on the baseline value for each product class. Qp is zero for all product 

classes, except for the baseline mobile home gas furnace and gas boiler. 

D.2.2 Determination of Average Annual Electrical Energy Consumption (EAE) 

Using the DOE test procedure,l DOE calculated the average annual electrical energy 

consumption in sections 10.2.3, 10.2.3.1, and 10.2.3.2: 

for single-stage furnaces and boilers 

EAE BOHss (yp * PE + YIG * PEIG + Y * BE) Eq.3 

and for two-stage and continuous modulating furnaces and boilers 

where: 

BOHss 

BOHH 

See section D.2.3 of this appendix, 

National average number of burner operating hours at the maximum operating 

mode (see section D.2.4 of this appendix), 

National average number of burner operating hours at the modulating 

operating mode (see section D.2.4 of this appendix), 

National average number of burner operating hours at the reduced operating 

mode (see section D.2.4 of this appendix), 

Ratio of induced or forced draft blower on-time to average burner on-time, 

Burner electrical power input at full-load steady-state operation in kW, 

Burner electrical power input at full-load steady-state operation in kW, 

measured at the reduced fuel input rate, 

Burner electrical power input at full-load steady-state operation in kW, 

measured at the maximum fuel input rate, 

Ratio of burner interrupted-ignition device on-time to average burner on-time, 

Electrical input rate to the interrupted ignition device on the burner, 

Ratio of blower or pump on-time to burner on-time, 

Circulating-air fan or water pump electrical energy input rate in kW, 

Circulating-air fan or water pump electrical energy input rate in kW, 

measured at the reduced fuel input rate, and 

Circulating-air fan or water pump electrical energy input rate in kW, 

measured at the maximum fuel input rate. 

The Department calculated the value yP using tp (post-purge time in minutes). For 

this calculation, the Department took tp to be less than or equal to 30 seconds and therefore set it 

equal to 0 seconds, according to sections 8.2 and 8.4 of the DOE test procedure.l The 

Department calculated the value YIG using tlG (on-time of the burner interrupted ignition device 

D-2 
in minutes), which is set equal to .62 minutest for gas furnaces and boilers, 26 minutes for oil

equipment without interrupted ignition3 , and 45 seconds for oil equipment with interrupted

ignition3 . The Department calculated the value y using t+ (blower or pump on-delay in minutes)

and f (blower or pump off-delay in minutes). For furnaces, t+ = 2 min and t- = 1.5 min and for

boilers, t+ = 0 and t- = 0, which are default values from the test procedure . PE is equal to 0.076

watts for gas furnaces and boilers4 and equal to 220 watts for oil furances and boiler3. The

Department corrected the PEIG, tIG, and BE values for different design options (see summary

tables in section D.4 for more details). For design options which include modulation, the

Department set PER and PEH to have the same values as PE, since it assumed no inducer

modulation. The Department set BEH equal to BE, and set BER to be 80 percent ofBE for

furnaces.'

D.2.3 Determination of National Average Number of Burner Operating Hours (BOHss)

From the test procedure , DOE calculated the national average number of burner operating

hours in section 10.2.1 ':

BOHSS = 2080 * 0.77 * A * DHR - 2080 * B Eq. 5

where:

A = as defined in sections 10.2.1 and 10.2.1.1,

B = as defined in sections 10.2.1, and

DHR = typical design heating requirements as listed in Table 8,6 using the proper

value of QoUT.

To calculate factors A and B, the Department calculated y1,, PE, yIG, PEIG, y, BE, QIN, and

Q, as described in section D.2.2 of this appendix. To calculate A, the Department assumed the

burner motor efficiency Eff,o,or = 0.5 (as defined in section 10.2.1 '), except for oil furnaces and

boilers with fan-atomized burners-where Effnotor = 0.8. The Department calculated EffyHS,

heating seasonal efficiency, as defined in section 10.2.1 '. For Qp = 0, EffyHS is equal to the

annual fuel utilization efficiency (AFUE). The factor R, used in calculating A, the Department

defined in section 10 .2.1.1 '. For factor B, if Qp = 0, then B = 0, which is true for all cases except

for the baseline mobile home gas furnace and baseline gas boiler . To calculate factor A for

weatherized furnaces, the Department used the equation for induced-draft unit isolated

combustion systems (ICS), because the intention is to account for the heat from the motor,

which always goes into the air distribution system.

The Department used QGUT (heating capacity for single-stage furnaces and boilers, or

maximum heat capacity for two-stage and continuous modulating furnaces and boilers) to

calculate design heating rate (DHR) for the considered efficiency levels and design options.

Furthermore, to calculate QoUT (see eqn. 8 defined in section D.2.5 of this appendix), DOE used

QIN(defined in section D.2.1 of this appendix), Effyss (defined in section D.2.5 of this appendix),

K (factor that adjusts the jacket losses , where K = 1.7 for non-weatherized furnaces, 3.3 for

weatherized furnaces, and 1 for boilers), and Lj (jacket loss, where Lj = 1 is the default value).

D-3

 EE-RM/STD-01-350 COMMENT 164

in minutes), which is set equal to .62 minutes2 for gas furnaces and boilers, 26 minutes for oil 

equipment without interrupted ignition3

, and 45 seconds for oil equipment with interrupted 

ignition3

. The Department calculated the value y using t (blower or pump on-delay in minutes) 

and r (blower or pump off-delay in minutes). For furnaces, t+ = 2 min and r = 1.5 min and for 

boilers, t = 0 and r = 0, which are default values from the test procedure. PE is equal to 0.076 

watts for gas furnaces and boilers4 and equal to 220 watts for oil furances and boiler3

• The 

Department corrected the PEIG, tIG, and BE values for different design options (see summary 

tables in section D.4 for more details). For design options which include modulation, the 

Department set PER and PEH to have the same values as PE, since it assumed no inducer 

modulation. The Department set BEH equal to BE, and set BER to be 80 percent of BE for 

furnaces.s 

D.2.3 Determination of National Average Number of Burner Operating Hours (BOHss) 

From the test procedure, DOE calculated the national average number of burner operating 

hours in section 10.2.1 1: 

where: 

A 

B 

DHR 

BOHss = 2080 * 0.77 * A * DHR - 2080 * B 

as defined in sections 10.2.1 and 10.2.1.1, 

as defined in sections 10.2.1, and 

Eq.5 

typical design heating requirements as listed in Table 8,6 using the proper 

value of QOUT' 

To calculate factors A and B, the Department calculated YP' PE, YIG' PEIG, y, BE, QIN' and 

Qp as described in section D.2.2 of this appendix. To calculate A, the Department assumed the 

burner motor efficiency Effmotor = 0.5 (as defined in section 10.2.1 1), except for oil furnaces and 

boilers with fan-atomized burners-where Effmotor = 0.8. The Department calculated EffyHs, 

heating seasonal efficiency, as defined in section 10.2.1 1. For Qp = 0, EflYHs is equal to the 

annual fuel utilization efficiency (AFUE). The factor R, used in calculating A, the Department 

defined in section 10.2.1.1 1. For factor B, if Qp = 0, then B = 0, which is true for all cases except 

for the baseline mobile home gas furnace and baseline gas boiler. To calculate factor A for 

weatherized furnaces, the Department used the equation for induced-draft unit isolated 

combustion systems (ICS), because the intention is to account for the heat from the motor, 

which always goes into the air distribution system. 

The Department used QOUT (heating capacity for single-stage furnaces and boilers, or 

maximum heat capacity for two-stage and continuous modulating furnaces and boilers) to 

calculate design heating rate (DHR) for the considered efficiency levels and design options. 

Furthermore, to calculate QOUT (see eqn. 8 defined in section D.2.5 of this appendix), DOE used 

QIN(defined in section D.2.1 of this appendix), EflYss (defined in section D.2.5 of this appendix), 

K (factor that adjusts the jacket losses, where K = 1.7 for non-weatherized furnaces, 3.3 for 

weatherized furnaces, and 1 for boilers), and Lj Uacket loss, where Lj = 1 is the default value). 

D-3 
In the current test procedure DHR is a step function of furnace output capacity ranges

(Table 86). DOE observed that small changes in QOUT may assign an efficiency level to a

different DHR range, which could cause significant variations of BOHSS (in some cases up to

20-30 percent). For example, the non-weatherized gas furnace at 81 percent AFUE and at 75

kBtu/h capacity has a QouT which calls for a DHR value of 30, while the same capacity furnace

at 82 percent AFUE require a DHR value of 40. As a result, an AFUE change of 1 percent (from

81 percent to 82 percent AFUE) represents a 24 percent increase in energy consumption for the

82 percent AFUE furnace as compared to the 81 percent AFUE furnace. It results in higher

energy consumption for a more efficient furnace (82 percent AFUE vs 81 percent AFUE) and as

a result the payback for 82 percent AFUE becomes negative. This test procedure feature impacts

several efficiency levels in the engineering analysis for non-weatherized gas furnaces, mobile

home furnaces and gas and oil-fired boilers.

Note: The ASHRAE committee in charge of the furnace/boiler test procedure (SPC 103)

is taking steps to correct this anomaly in the current proposed test procedure: BSR/ASHRAE

SPC 103R "Method of testing for Annual Fuel Efficiency of Residential Furnaces & Boilers".'

The approach by SPC 103R is to eliminate the DHR parameter from the formula for calculating

BOHSS and replace it with a parameter containing QoUT and an oversized factor, which has a

constant value of 0.7. DOE used this new proposed test procedure in the LCC analysis (see

Appendix L).

D.2.4 Determination of National Average Number of Burner Operating Hours for

Two-Stage and Continuous Modulating Furnaces and Boilers

From the test procedure, DOE calcuated the national average number of burner operating

hours in sections 10.2.1.2, 10.2.1.3, and 10.2.1.4':

at the reduced operating mode, and

BOHR = XR*EM l X.INR,

at the maximum operating mode, and

BOHH = XH*EM l QIN'

at the modulating operating mode

BOHMLM = XH*EM l QIN,M

where:

XR

XH

EM

Eq. 6

Eq. 7

Eq. 8

fraction of heating load at the reduced fuel input operating mode, Table 10,6

fraction of heating load at the reduced fuel input operating mode, Table 10,6

average annual energy used during the heating season for two-stage and

continuous modulating furnaces and boilers,

D-4

 EE-RM/STD-01-350 COMMENT 164

In the current test procedure DHR is a step function of furnace output capacity ranges 

(Table 86

). DOE observed that small changes in QOUT may assign an efficiency level to a 

different DHR range, which could cause significant variations of BOHss (in some cases up to 

20-30 percent). For example, the non-weatherized gas furnace at 81 percent AFUE and at 75 

kBtulh capacity has a QOUT which calls for a DHR value of 30, while the same capacity furnace 

at 82 percent AFUE require a DHR value of 40. As a result, an AFUE change of 1 percent (from 

81 percent to 82 percent AFUE) represents a 24 percent increase in energy consumption for the 

82 percent AFUE furnace as compared to the 81 percent AFUE furnace. It results in higher 

energy consumption for a more efficient furnace (82 percent AFUE vs 81 percent AFUE) and as 

a result the payback for 82 percent AFUE becomes negative. This test procedure feature impacts 

several efficiency levels in the engineering analysis for non-weatherized gas furnaces, mobile 

horne furnaces and gas and oil-fired boilers. 

Note: The ASHRAE committee in charge of the furnace/boiler test procedure (Spe 103) 

is taking steps to correct this anomaly in the current proposed test procedure: BSRI ASHRAE 

spe 103R "Method of testing for Annual Fuel Efficiency of Residential Furnaces & Boilers".7 

The approach by spe 1 03R is to eliminate the DHR parameter from the formula for calculating 

BOHss and replace it with a parameter containing QOUT and an oversized factor, which has a 

constant value ofO.7. DOE used this new proposed test procedure in the Lee analysis (see 

Appendix L). 

D.2.4 Determination of National Average Number of Burner Operating Hours for 

Two-Stage and Continuous Modulating Furnaces and Boilers 

From the test procedure, DOE calcuated the national average number of burner operating 

hours in sections 10.2.1.2, 10.2.1.3, and 10.2.1.41

: 

at the reduced operating mode, and 

Eq.6 

at the maximum operating mode, and 

Eq.7 

at the modulating operating mode 

where: 

Eq.8 

fraction of heating load at the reduced fuel input operating mode, Table 10,6 

fraction of heating load at the reduced fuel input operating mode, Table 10,6 

average annual energy used during the heating season for two-stage and 

continuous modulating furnaces and boilers, 

D-4 
QIN

QINR

QIN, M

as defined in section D.2.1 of this appendix,

steady-state reduced-fuel input rate, and

steady-state modulating fuel input rate.

The Department calculated XR and XH using Tc (balance-point temparature), a (the

oversize factor), QOUTR (reduced fuel input rate heating capacity ), EffyssM (steady-state efficiency

at the modulating fuel input rate), Effyss R (steady-state efficiency at the reduced fuel input rate),

TOA,H (average outdoor temperature at the modulating or maximum fuel input operating mode),

and QoUTM (modulating fuel input rate heating capacity), which DOE defined in section 11.4 of

DOE test procedure.' The Department determined QoUT, as defined in section D.2.3 of this

appendix. To calculate EM, the Department used BOHss, QINR and Qp as defined in section D.2.1

of this appendix . The Department set QJNR to be 68 percent of QIN, where this value represents

the average ratio QIN/QINR as derived using manufacturer product literature and Gas Appliance

Manufacturers Association (GAMA) March 2005 Directory data for all listed two-stage furnace

models.' From section 11 . 4.8.6 or 11 . 5.8.6,6 QINM is calculated using QoUT and EffyssM (as

defined in section 11.4.8.8 or 11 . 5.8.8)6.

D.2.5 Determination of Heating Seasonal Efficiency (Effyss)

The Department needed Effyss to calculate QoUT, the heating capacity, and to determine

AFUE, the annual fuel utilization efficiency for heating equipment with pilot lights. DOE chose

the approach which requires determining the average (Effyss - AFUE) difference for each product

class.

From Section 11.2.8.1 of ANSI/ASHRAE 103-19936:

QOUT QIN* [Effyss - (K)(Lj)]/ 100 Eq. 9

The Department calculated (Effyss -AFUE) values by solving Equation 9 for Effyss and

subtracting AFUE from both sides:

Effyss -AFUE = 100*[(QoUT IQIN) + (K)(Lj)] - AFUE Eq. 10

The Department used the available model information (QIN, QoUT, and AFUE) from the

GAMA directory to determine average (Effyss -AFUE) values for each product class.' DOE

listed the average (Effyss -AFUE) values in the look-up table, which is a part of the engineering

spreadsheet (see "SSE Analysis. xls" spreadsheet).

D.3 PARAMETERS TO DETERMINE THE ENERGY USE OF MODULATING

D-5

 EE-RM/STD-01-350 COMMENT 164

as defined in section D.2.1 of this appendix, 

steady-state reduced-fuel input rate, and 

steady-state modulating fuel input rate. 

The Department calculated XR and XH using Tc (balance-point temparature), a (the 

oversize factor), QOUT,R (reduced fuel input rate heating capacity), E.ffj;SS,M (steady-state efficiency 

at the modulating fuel input rate), E.ffj; SS,R (steady-state efficiency at the reduced fuel input rate), 

TOA,H (average outdoor temperature at the modulating or maximum fuel input operating mode), 

and QOUTM (modulating fuel input rate heating capacity), which DOE defined in section 11.4 of 

DOE test procedure.6 The Department determined QOUT' as defined in section D.2.3 of this 

appendix. To calculate EM' the Department used BOHss, QIN' and Qp as defined in section D.2.1 

of this appendix. The Department set QIN.R to be 68 percent of QIN' where this value represents 

the average ratio QlN1QIN,R as derived using manufacturer product literature and Gas Appliance 

Manufacturers Association (GAMA) March 2005 Directory data for all listed two-stage furnace 

models.5 From section 11.4.8.6 or 11.5.8.6,6 QIN,M is calculated using QOUT and E.ffj;SS,M (as 

defined in section 11.4.8.8 or 11.5.8.8l 

D.2.5 Determination of Heating Seasonal Efficiency (Effyss) 

The Department needed E.ffj;ss to calculate QOUT' the heating capacity, and to determine 

AFUE, the annual fuel utilization efficiency for heating equipment with pilot lights. DOE chose 

the approach which requires determining the average (E.ffj;ss - AFUE) difference for each product 

class. 

From Section 11.2.8.1 of ANSIIASHRAE 103-19936: 

QlN*[E.ffj;ss - (K)(Lj)]/I00 Eq.9 

The Department calculated (E.ffj;ss -AFUE) values by solving Equation 9 for Effyss and 

subtracting AFUE from both sides: 

E.ffj;ss -AFUE = 100*[(QouT IQIN) + (K)(Lj)] - AFUE Eq.l0 

The Department used the available model information (QIN' QOUT' and AFUE) from the 

GAMA directory to determine average (E.ffj;ss -AFUE) values for each product class. 5 DOE 

listed the average (E.ffj;ss -AFUE) values in the look-up table, which is a part of the engineering 

spreadsheet (see "SSE Analysis.xls" spreadsheet). 

D.3 PARAMETERS TO DETERMINE THE ENERGY USE OF MODULATING 

D-5 
FURNACES

DOE based the furnace energy use calculations on the current DOE test procedure for

determining the AFUE of residential furnaces and boilers,' which for the most part references the

industry test standard ANSI/ASHRAE 103/1993 of the American Society of Heating,

Refrigerating, and Air Conditioning (ASHRAE).2 In the case of single stage and two-stage

furnaces rated at one and the same AFUE level, the analysis points to a significant difference in

the energy use between both designs. This introduces an inconsistency, because with a ratio of

reduced to maximum input of about 70 percent the test procedure shows that the furnace would

supply almost 95 percent of the annual heating load at the reduced input. Therefore a two-stage

furnace operates almost all of the time as a single-stage furnace at a reduced input rate.

However, as pointed out above, the calculations based on the current test procedure indicate

much more efficient operation.

This section outlines the parameters involved in the calculations and provides an

additional basis upon which the stakeholders can comment on this part of the analysis.

D.3.1 Parameters to Determine Average Annual Fuel Energy Consumption

The average annual fuel energy consumption for both single-stage and two-stage furnaces

(as calculated using CFR Appendix N, Subpart B of Part 430, Uniform Test Method for

Measuring the Energy Consumption of Furnaces and Boilers, sections 10.2.2 and 10.2.2.1 ') is:

EF = BOHss * (QIN - QP) + 8,760 * QP Eq. 11

EF (for single and two-stage furnaces) differs due to the different approach used to

calculate the national average number of burner operating hours - BOHss:

BOHss = 2080 * 0.77 * A * DHR - 2080 * B Eq. 12

where for single-stage furnaces

A = 100,000 / [341,300 * (Y1G* PEIG + y * BE) + (QIN - QP) * Effyff], Eq. 13

and for two-stage and continuous modulating furnaces

A = 100,000 / [341,300 * (yIG * PEIG + y * BE)*R + (QIN - QP) * E.ffyxs]Eq. 14

where the term (y1G * PEIG + y * BE) in the formula for two-stage furnaces is increased by the

factor R=2.3.

Kweller$ described the derivation of R-values for single and two-stage furnaces as

follows: Burner on-time for single-stage furnace is assigned values in the DOE test procedure of

3.8 minutes on and 13.3 minutes off. The corresponding values for two-stage furnaces are 10

minutes and 10 minutes. The ratio of percent time-on for a single-stage furnace is

3.8/(3.8+13.3)=0.22 and for a two-stage furnace is 10/(10+10)=0.50. Using these on-time

fractions, the ratio "R" of on-time for the two-stage furnace vs the single-stage furnace is

D-6

 EE-RM/STD-01-350 COMMENT 164

FURNACES 

DOE based the furnace energy use calculations on the current DOE test procedure for 

determining the AFUE of residential furnaces and boilers,1 which for the most part references the 

industry test standard ANSII ASHRAE 10311993 of the American Society of Heating, 

Refrigerating, and Air Conditioning (ASHRAE).2 In the case of single stage and two-stage 

furnaces rated at one and the same AFUE level, the analysis points to a significant difference in 

the energy use between both designs. This introduces an inconsistency, because with a ratio of 

reduced to maximum input of about 70 percent the test procedure shows that the furnace would 

supply almost 95 percent of the annual heating load at the reduced input. Therefore a two-stage 

furnace operates almost all of the time as a single-stage furnace at a reduced input rate. 

However, as pointed out above, the calculations based on the current test procedure indicate 

much more efficient operation. 

This section outlines the parameters involved in the calculations and provides an 

additional basis upon which the stakeholders can comment on this part of the analysis. 

D.3.1 Parameters to Determine Average Annual Fuel Energy Consumption 

The average annual fuel energy consumption for both single-stage and two-stage furnaces 

(as calculated using CFR Appendix N, Subpart B of Part 430, Uniform Test Method/or 

Measuring the Energy Consumption 0/ Furnaces and Boilers, sections 10.2.2 and 10.2.2.1 1) is: 

EF (for single and two-stage furnaces) differs due to the different approach used to 

calculate the national average number of burner operating hours - BOHss: 

BOHss = 2080 * 0.77 * A * DHR - 2080 * B 

where for single-stage furnaces 

Eq.ll 

Eq.12 

A = 100,000 1 [341,300 * (YIG * PEIG + Y * BE) + (QIN - Qp) * EffyHS]' Eq. 13 

and for two-stage and continuous modulating furnaces 

A = 100,0001 [341,300 * (Y/G * PE1G + Y * BE)*R + (QIN - Qp) * EffyHs]Eq. 14 

where the term (Y/G * PE/G + Y * BE) in the formula for two-stage furnaces is increased by the 

factor R=2.3. 

Kweller8 described the derivation of R-values for single and two-stage furnaces as 

follows: Burner on-time for single-stage furnace is assigned values in the DOE test procedure of 

3.8 minutes on and 13.3 minutes off. The corresponding values for two-stage furnaces are 10 

minutes and 10 minutes. The ratio of percent time-on for a single-stage furnace is 

3.8/(3.8+13.3)=0.22 and for a two-stage furnace is 10/(10+10)=0.50. Using these on-time 

fractions, the ratio "R" of on-time for the two-stage furnace vs the single-stage furnace is 

D-6 
0.50/0.22=2.27. In other words the amount of electrical energy required for the two-stage

furnaces is 227 percent (or R=2.3 ) of the single-stage furnace.

The different value of R is the cause for the reduced energy consumption for modulating

furnaces compared to single-stage at the same efficiency level. In this case, the increased

electrical energy use for two-stage furnaces is credited in reducing the house heating load.

D.3.2 Parameters to Determine Annual Fuel Utilization Efficiency

The AFUE equals the heating seasonal efficiency (EffyHS) when no pilot light is present.

The detailed test procedure approach to determine EffyHs requires specific information on heat-up

and cool down temperatures as measured during an actual test. When test results are not

available, DOE made an assumption for the value of the AFUE.

From Section 11.2.12 and 11.4.12 of ANSI/ASHRAE 103-19936 (DOE furnace/boiler

test procedure refers to this standard):

AFUE = EffyNs (when no pilot light is present) Eq. 15

EffyHs for two-stage furnaces is a function of X. and XR = 1 - XH, ratios representing the

fraction of heating load at maximum and reduced input rate.

XH is a function of the steady-state efficiency at maximum (Effyss) and reduced (EffyssR)

fuel input rate capacities. From several actual modulating furnace tests described in Liu9 DOE

found that the values for Effyss R are sometimes higher and sometimes lower than the Effyss

values. Therefore , based on these tests it is possible to assume that Effyss R = E.ffyss• DOE

confirmed this assumption in the above cited reference,' where the furnace steady-state

efficiency at maximum (Effyss) and reduced (EffyssR) fuel input rate capacities are assumed the

same. Once confirmed, it is straightforward to calculate the reduced fuel input heating capacity

QOUT,R = QOUT * QIN,R / QIN and the balance-point temperature Tc. Knowing Tc allows one to

determine X. and XR from Table 10.6

DOE did not use the above approach to determine Effyffs. The Department examined 8

families of furnace models at 80 percent AFUE from six manufacturers, and compared pairs of

models which are essentially identical with the exception of the modulating component. (See

Table D.3. 1) The comparison showed that the reported AFUE for each pair is identical. This

finding indicates that EffyNs is the same for single-stage and two-stage furnaces, which are

otherwise identical and therefore AFUE value may be used as proxy for EffyHS in the equation 13

and 14.

 EE-RM/STD-01-350 COMMENT 164

0.50/0.22=2.27. In other words the amount of electrical energy required for the two-stage 

furnaces is 227 percent (or R=2.3) of the single-stage furnace. 

The different value of R is the cause for the reduced energy consumption for modulating 

furnaces compared to single-stage at the same efficiency level. In this case, the increased 

electrical energy use for two-stage furnaces is credited in reducing the house heating load. 

D.3.2 Parameters to Determine Annual Fuel Utilization Efficiency 

The AFUE equals the heating seasonal efficiency (EffyHS) when no pilot light is present. 

The detailed test procedure approach to determine EffyHS requires specific information on heat-up 

and cool down temperatures as measured during an actual test. When test results are not 

available, DOE made an assumption for the value of the AFUE. 

From Section 11.2.12 and 11.4.12 of ANSIIASHRAE 103-19936 (DOE furnacelboiler 

test procedure refers to this standard): 

AFUE = EffyHS (when no pilot light is present) Eq.15 

EffyHS for two-stage furnaces is a function of XH and XR = 1 - XH, ratios representing the 

fraction of heating load at maximum and reduced input rate. 

XH is a function of the steady-state efficiency at maximum (Effyss) and reduced (EffySS.R) 

fuel input rate capacities. From several actual modulating furnace tests described in Liu9 DOE 

found that the values for EffySS.R are sometimes higher and sometimes lower than the Effyss 

values. Therefore, based on these tests it is possible to assume that EffySS.R = Effyss. DOE 

confirmed this assumption in the above cited reference, 8 where the furnace steady-state 

efficiency at maximum (Effyss) and reduced (EffySS.R) fuel input rate capacities are assumed the 

same. Once confirmed, it is straightforward to calculate the reduced fuel input heating capacity 

QOUT.R= QOUT * QIN.R / QIN and the balance-point temperature Te. Knowing Te allows one to 

determineXHandXR from Table 10.6 

DOE did not use the above approach to determine EffyHS' The Department examined 8 

families of furnace models at 80 percent AFUE from six manufacturers, and compared pairs of 

models which are essentially identical with the exception of the modulating component. (See 

Table D.3.1) The comparison showed that the reported AFUE for each pair is identical. This 

finding indicates that Effy HS is the same for single-stage and two-stage furnaces, which are 

otherwise identical and therefore AFUE value may be used as proxy for EffyHS in the equation 13 

and 14. 

D-7 
Table D.3.1 AFUE for Similar Single-Stage and Two-Sta ge Furnace Models Series

Manufacturer Single-Stage Series Two-Stage Series AFUE

Amana GUIC GUIS 80%

Carrier 58DLA 58CTA 80%

Lennox G50 (UH/DF) G60 (UH/DF) 80%

Rheema RGLJ/RGPH RGLK/RGPK 80%

Trane TDD-C/TUD-C TDD-R/TUD-R 80%

York PDN/PHU PDD/PDU 80%

D.3.3 Conclusions

DOE determined the fuel consumption difference between single-stage and modulating

furnaces by:

1) the value of the parameter R, and

2) the value ofXR and XH, (ratios representing the fraction of heating load at maximum and

reduced input rate), where they are functions of the steady-state efficiency at maximum and

reduced fuel input rate capacities as determined by test procedure measured quantities.

To bring the energy use of single-stage and two-stage furnaces in line with the actually

observed field performance it may be necessary to correct at least the above parameters. This

may require assuming different values for the furnace time on/off and also changing the

oversizing factor. There may be other factors in the test procedure which should be examined.

D.4 SUMMARY TABLES

Tables D.4.1 through D.4.12 present the calculated energy use values BOHss, BOHR, EAE,

and EE, as well as the data used to determine them. These tables are divided by product class and

by single-stage, two-stage, and continuous modulating design option.

a Some models in this series have AFUE of 80% or 81%.

D-8

 EE-RM/STD-01-350 COMMENT 164

T a e bi D 3 1 .. AFUE ~ or S· Iml ·1 ar S· m~le-I St a~e an dT wo-S ta~e F urnace M o e s dIS enes . 

Manufacturer Single-Stage Series Two-Stage Series AFUE 

Amana GUIC GUIS 80% 

Carrier 58DLA 58CTA 80% 

Lennox G50 (UH/DF) G60 (UH/DF) 80% 

Rheema RGLJ/RGPH RGLKlRGPK 80% 

Trane TDD-C/TUD-C TDD-RlTUD-R 80% 

York PDN/PHU PDD/PDU 80% 

D.3.3 Conclusions 

DOE determined the fuel consumption difference between single-stage and modulating 

furnaces by: 

I) the value of the parameter R, and 

2) the value of XR and X H, (ratios representing the fraction of heating load at maximum and 

reduced input rate), where they are functions of the steady-state efficiency at maximum and 

reduced fuel input rate capacities as determined by test procedure measured quantities. 

To bring the energy use of single-stage and two-stage furnaces in line with the actually 

observed field performance it may be necessary to correct at least the above parameters. This 

may require assuming different values for the furnace time on/off and also changing the 

oversizing factor. There may be other factors in the test procedure which should be examined. 

D.4 SUMMARY TABLES 

Tables D.4.1 through D.4.12 present the calculated energy use values BOHss, BOHR' EAE, 

and EF, as well as the data used to determine them. These tables are divided by product class and 

by single-stage, two-stage, and continuous modulating design option. 

a Some models in this series have AFUE of 80% or 81 %. 

D-8 
Table D.4.1 Energy Use Results for Non-Weatherized Gas Furnaces (Sin le-Stage Controls)

Description QIN QOIJT Q EFF PE BE PE T RDHR BOH EAF EF

78% AFUE - w/time delays, w/o pilot 75,000 57,809 0 78 0.076 0.50 0.4 0.62 30 792 558 59.42

80% AFUE - w/time delays, w/o pilot 75,000 59,309 0 80 0.076 0.50 0.4 0.62 30 773 545 57.99

81 % AFUE - w/time delays, w/o pilot 75,000 60,059 0 81 0.076 0.50 0.4 0.62 40 1019 718 76.39

90% AFUE - w/time delays, w/o pilot 75,000 66,809 0 90 0.076 0.50 0.4 0.62 40 920 648 68.99

92% AFUE - w/tune delays, w/o pilot 1 75,000 68,309 0 92 0.076 0.50 0.4 0.62 40 900 635 67.53

Table D.4.2 Energy Use Results for Non-Weatherized Gas Furnaces (Two-Stage Controls)

Description Q QO,jT Q My., I BE. I BE PE T RDHR BOH BOH E EF

80% AFUE - w/ Two-stage Modulation + ECM 75,000 59,309 0 80 0.398 0.318 0.4 0.62 30 757 1113 484 56.77

81% AFUE - w/ Two-stage Modulation + ECM 75,000 60,059 0 81 0.398 0.318 0.4 0.62 40 997 1467 638 74.81

92% AFUE - w/ Two-stage Modulation + ECM 75,000 68,309 0 92 0.398 0.318 0.4 0.62 40 866 1273 554 64.94

Table D.4.3 Energy Use Results for Non-Weatherized Gas Furnaces (Continuous Modulatin Controls)

Description QN QOjjT Q EFF BE BE PE T RDHR BOH ! I! E E

92% AFUE - w/ Continuous Modulation + ECM 75,000 68,309 0 92 0.398 0.318 0.4 0.62 40 884--j-1-30-0-1 566 66.30

96% AFUE - w/ Continuous Modulation + ECM 75,000 _ 71 ,309 0 96 0.398 0.318 0 .4 0 .62 40 849 1248 543 63.66

Table D.4.4 Energy Use Results for Weatherized Gas Furnaces (Single-Stage Controls)

Description QIN QOUT Qe EFFy1S PE BE PE,, T,, RDHR BOHss EAE EF

78% AFUE - w/time delays, w/o pilot 75,000 56,004 0 78.0 0.076 0.50 0.4 0.62 30 792 558 59.42

80% AFUE - w/time delays, w/o pilot 75,000 57,504 0 80.0 0.076 0.50 0.4 0.62 30 773 545 57.99

80% AFUE - Improved Insulation 75,000 57,616 0 80.2 0.076 0.50 0.4 0.62 30 772 544 57.88

81% AFUE - w/time delays, w/o pilot 75,000 58,254 0 81.0 0.076 0.50 0.4 0.62 30 764 538 57.29

81 % AFUE - Improved Insulation 75,000 58,366 0 81.2 0.076 0.50 0.4 0.62 30 763 537 57.19

82% AFUE - w/time delays, w/o pilot 75,000 59,004 0 82.0 0.076 0.50 0.4 0.62 30 755 532 56.62

82% AFUE - Improved Insulation 75,000 59,116 0 82.2 0.076 0.50 0.4 0.62 30 754 531 56.52

83% AFUE - w/time delays, w/o pilot 75,000 59,379 0 83.0 0.076 0.50 0.4 0.62 30 751 529 56.29

83% AFUE - Improved Insulation 75,000 59,866 0 83.2 0.076 0.50 0.4 0.62 30 745 525 55.86

D-9

 EE-RM/STD-01-350 COMMENT 164

T a bi e D 41 E · . nergy U R se esu It s £ or N W on- ea th enze . d G F as urnaces (S' mgle- I St age C t on ro I) s 

Description QrN QOIJT Qp EFFYHS PE BE PErc; Trc; RDHR BOHss E"c E" 

78% AFUE - w/time delays, wlo pilot 75,000 57,809 0 78 0.076 0.50 0.4 0.62 30 792 558 59.42 

80% AFUE - w/time delays, wlo pilot 75,000 59,309 0 80 0.076 0.50 0.4 0.62 30 773 545 57.99 

81 % AFUE - w/time delays, wlo pilot 75,000 60,059 0 81 0.076 0.50 0.4 0.62 40 1019 718 76.39 

90% AFUE - w/time delays, wlo pilot 75,000 66,809 0 90 0.076 0.50 0.4 0.62 40 920 648 68.99 

92% AFUE - w/time delays, wlo pilot 75000 68,309 0 92 0.076 0.50 0.4 0.62 40 900 635 67.53 

T a e bi D 4 2 E · . nergy U R se esu It s £ or N W on- ea th enze . dG as F urnaces (T wo-St age C t on ro I) s 

Description QrN QOIJT Qp EFFYHS BEH BE" PEw Trc; RDHR BOH,s, BOH" E,,, EF 

80% AFUE - wi Two-stage Modulation + ECM 75,000 59,309 0 80 0.398 0.318 0.4 0.62 30 757 1113 484 56.77 

81 % AFUE - wi Two-stage Modulation + ECM 75,000 60,059 0 81 0.398 0.318 0.4 0.62 40 997 1467 638 74.81 

92% AFUE - wi Two-stage Modulation + ECM 75000 68309 0 92 0.398 0.318 0.4 0.62 40 866 1273 554 64.94 

T a e bi D 4 3 E · . nergy U R se esu It s £ or N W on- ea th enze . d G F as urnaces (C on f muous Mdif 0 u a mg C on t ro I) s 

Description QrN QOIIT Qp EFFYHS BEH BE" PErc; Trc; RDHR BOHss BOHR E • ., EF 

92% AFUE - wi Continuous Modulation + ECM 75,000 68,309 0 92 0.398 0.318 0.4 0.62 40 884 1300 566 66.30 

96% AFUE - wi Continuous Modulation + ECM 75000 71 309 0 96 0.398 0.318 0.4 0.62 40 849 1248 543 63.66 

T a e bi D 4 4 E · . nergy U R se esu It s £ or W ea th enze . d G F as urnaces (S' mgle- I St age C on t ro I) s 

Description QIN QOUT Qp EFFYHS PE BE PE1G TIG RDHR BOHss EAE EF 

78% AFUE - w/time delays, wlo pilot 75,000 56,004 0 78.0 0.076 0.50 0.4 0.62 30 792 558 59.42 

80% AFUE - w/time delays, wlo pilot 75,000 57,504 0 80.0 0.076 0.50 0.4 0.62 30 773 545 57.99 

80% AFUE - Improved Insulation 75,000 57,616 0 80.2 0.076 0.50 0.4 0.62 30 772 544 57.88 

81 % AFUE - w/time delays, wlo pilot 75,000 58,254 0 81.0 0.076 0.50 0.4 0.62 30 764 538 57.29 

81 % AFUE - Improved Insulation 75,000 58,366 0 81.2 0.076 0.50 0.4 0.62 30 763 537 57.19 

82% AFUE - w/time delays, wlo pilot 75,000 59,004 0 82.0 0.076 0.50 0.4 0.62 30 755 532 56.62 

82% AFUE - Improved Insulation 75,000 59,116 0 82.2 0.076 0.50 0.4 0.62 30 754 531 56.52 

83% AFUE - w/time delays, wlo pilot 75,000 59,379 0 83.0 0.076 0.50 0.4 0.62 30 751 529 56.29 

83% AFUE - Improved Insulation 75,000 59,866 0 83.2 0.076 0.50 0.4 0.62 30 745 525 55.86 

D-9 
Table D.4.5 Energy Use Results for Mobile Home Furnaces (Sin le-Sta a Controls)

Description QIN QOUT Q, EFFyHS PE BE PEIG TIG RDHR BOHSS EAE EF

75% AFUE - w/time delays, w/ pilot 75,000 55,992 500 77 0.076 0.50 0 0.00 30 781 500 62.57

80% AFUE - w/time delays, w/o pilot 75,000 59,742 0 80 0.076 0.50 0.4 0.62 30 773 545 57.99

81 % AFUE - w/time delays, w/o pilot 75,000 60,492 0 81 0.076 0.50 0.4 0.62 40 1019 718 76.39

82% AFUE - w/time dela s, w/o pilot 75,000 61,242 0 82 0.076 0.50 0.4 0.62 40 1007 709 75.49

90% AFUE - w/time delay s w/o pilot 1 75,000 67,242 0 90 0.076 0.50 0.4 0.62 40 920 648 68.99

Table D.4.6 Energy Use Results for Mobile Home Furnaces (Two-Stage Controls)

Description Q . Q Q EFF BE BE, I PE T RDHR BOH BOHR E E

80%AFUE - w/ Two-stage Modulation + ECM 75,000 59,742 0 80 0.398 0.318 0.4 0.62 30 757 1113 484 56.77

81%AFUE - w/Two-stage Modulation + ECM 75,000 60,492 0 81 0.398 0.318 0.4 0.62 40 997 1467 638 74.81

82% AFUE - w/ Two-stage Modulation + ECM 75,000 61,242 0 82 0.398 0.318 0.4 0.62 40 986 1450 631 73.95

Table D.4.7 Energy Use Results for Oil-Fired Furnaces (Sin le-Stage Controls)

Description QIN QOUT Qp EFFyHS PE BE PE,, T,G RDHR BOHss EAE EF

78% AFUE - w/time delays, w/o pilot 105,000 80,689 0 78 0.22 0.50 0.045 26.00 50 944 1026 99.09

80% AFUE - w/time delays, w/o pilot 105,000 82,789 0 80 0.22 0.50 0.045 26.00 50 921 1001 96.69

81% AFUE - w/tune delays, w/o pilot 105,000 83,839 0 81 0.22 0.50 0.045 26.00 50 910 989 95.54

81%AFUE - Interrupted Ignition 105,000 83,839 0 81 0.22 0.50 0.025 0.75 50 921 727 96.66

82% AFUE - w/time delays, w/o pilot 105,000 84,889 0 82 0.22 0.50 0.045 26.00 50 899 977 94.41

82% AFUE - Interrupted Ignition 105,000 84,889 0 82 0.22 0.50 0.025 0.75 50 910 718 95.50

83% AFUE - w/time delays, w/o pilot 105,000 85,939 0 83 0.22 0.50 0.045 26.00 50 889 966 93.31

83% AFUE - Interrupted Ignition 105,000 85,939 0 83 0.22 0.50 0.025 0.75 50 899 710 94.38

84% AFUE - w/time delays, w/o pilot 105,000 86,989 0 84 0.22 0.50 0.045 26.00 50 878 955 92.24

84% AFUE - Interrupted Ignition 105,000 86,989 0 84 0.22 0.50 0.025 0.75 50 888 701 93.28

85% AFUE - w/tune delays, w/o pilot 105,000 88,039 0 85 0.22 0.50 0.045 26.00 50 868 944 91.19

85% AFUE - Interrupted Ignition 105 ,000 88,039 0 85 0.22 0.50 0.025 0.75 50 878 693 92.20

 EE-RM/STD-01-350 COMMENT 164

T a bi e D 45 E " " nergy URI se esu ts £ or M Ole b"I H orne F urnaces (S" mgJe- I SCI) tage ontro s 

Description QIN QOUT Qp EFFYHS PE BE PEIG TIG RDHR BOHss EAE EF 

75% AFUE - w/time delays, wi pilot 75,000 55,992 500 77 0.076 0.50 0 0.00 30 781 500 62.57 

80% AFUE - w/time delays, wlo pilot 75,000 59,742 0 80 0.076 0.50 0.4 0.62 30 773 545 57.99 

81 % AFUE - w/time delays, wlo pilot 75,000 60,492 0 81 0.076 0.50 0.4 0.62 40 1019 718 76.39 

82% AFUE - w/time delays, wlo pilot 75,000 61,242 0 82 0.076 0.50 0.4 0.62 40 1007 709 75.49 

90% AFUE - w/time delays wlo pilot 75000 67242 0 90 0.076 0.50 0.4 0.62 40 920 648 68.99 

T a e bi D 4 6 E .. nergy URI se esu ts £ or M ole b"I H orne F urnaces (T wo-St age C on t ro I) s 

Description Q'N QOIlT Qp EFFYHS BEH BER PE'G TIG RDHR BOHss BOHR Ell, E" 

80% AFUE - wi Two-stage Modulation + ECM 75,000 59,742 0 80 0.398 0.318 0.4 0.62 30 757 1113 484 56.77 

81 % AFUE - wi Two-stage Modulation + ECM 75,000 60,492 0 81 0.398 0.318 0.4 0.62 40 997 1467 638 74.81 

82% AFUE - wi Two-stage Modulation + ECM 75,000 61,242 0 82 0.398 0.318 0.4 0.62 40 986 1450 631 73.95 

T a e bi D 47 E " . nergy U R se esu It s £ or 0"1 l-F" Ire d F urn aces (S" m gJe- I St age C on t ro I) s 

Description QrN QOUT Qp EFFYHS PE BE PEIG TIG RDHR BOHss EAE EF 

78% AFUE - w/time delays, wlo pilot 105,000 80,689 0 78 0.22 0.50 0.045 26.00 50 944 1026 99.09 

80% AFUE - w/time delays, wlo pilot 105,000 82,789 0 80 0.22 0.50 0.045 26.00 50 921 1001 96.69 

81 % AFUE - w/time delays, wlo pilot 105,000 83,839 0 81 0.22 0.50 0.045 26.00 50 910 989 95.54 

81 %AFUE - Interrupted Ignition 105,000 83,839 0 81 0.22 0.50 0.025 0.75 50 921 727 96.66 

82% AFUE - w/time delays, wlo pilot 105,000 84,889 0 82 0.22 0.50 0.045 26.00 50 899 977 94.41 

82% AFUE - Interrupted Ignition 105,000 84,889 0 82 0.22 0.50 0.025 0.75 50 910 718 95.50 

83% AFUE - w/time delays, wlo pilot 105,000 85,939 0 83 0.22 0.50 0.045 26.00 50 889 966 93.31 

83% AFUE - Interrupted Ignition 105,000 85,939 0 83 0.22 0.50 0.025 0.75 50 899 710 94.38 

84% AFUE - w/time delays, wlo pilot 105,000 86,989 0 84 0.22 0.50 0.045 26.00 50 878 955 92.24 

84% AFUE - Interrupted Ignition 105,000 86,989 0 84 0.22 0.50 0.025 0.75 50 888 701 93.28 

85% AFUE - w/time delays, wlo pilot 105,000 88,039 0 85 0.22 0.50 0.045 26.00 50 868 944 9l.l9 

85% AFUE - Interrupted Ignition 105000 88039 0 85 0.22 0.50 0.025 0.75 50 878 693 92.20 

D-10 
Table D.4.8 Energy Use Results for Hot-Water Oil Furnaces (Two-Sta ge Controls)

Description QIN Qoj,T Q EFFy,s BE BE PE T RDHR BOH BOH EAT' E

81%AFUE - Fan Atomized Burner w/ Two- 105,000 83,839 0 81 0.398 0,318 0.045 26.00 50 897 1319 886 94.12

stage Modulation

82%AFUE - Fan Atomized Burner w/ Two- 105,000 84,889 0 82 0.398 0.318 0.045 26.00 50 887 1304 876 93.12

stage Modulation

83%AFUE - Fan Atomized Burner w/ Two- 105,000 85,939 0 83 0.398 0.318 0.045 26.00 50 877 1289 866 92.05

stage Modulation

84%AFUE - Fan Atomized Burner w/ Two- 105,000 86,989 0 84 0.398 0.318 0.045 26.00 50 867 1275 856 91.00

stage Modulation

85%AFUE - Fan Atomized Burner w/ Two- 105,000 88,039 0 85 0.398 0.318 0.045 26.00 50 857 1260 846 89.98

stage Modulation

Table D.4.9 Energy Use Results for Hot-Water Gas Boilers (Single-Stage Controls)

Description Q , QOIJT Q EFF PE BE PE T RDHR BOH E E,

80% AFUE - w/time delays, w/ pilot 105,000 84,754 500 81 0.076 0.07 0 0.00 50 916 134 100.06

81% AFUE - w/time delays, w/o pilot 105,000 85,804 0 81 0.076 0.07 0.4 0.62 50 937 161 98.34

82% AFUE - w/time delays, w/o pilot 105,000 86,854 0 82 0.076 0.07 0.4 0.62 50 925 159 97.14

83% AFUE - w/time delays, w/o pilot 105,000 87,904 0 83 0.076 0.07 0.4 0.62 50 914 157 95.98

84% AFUE - w/time delays, w/o pilot 105,000 88,954 0 84 0.076 0.07 0.4 0.62 50 903 155 94.84

85% AFUE - w/time delays, w/o pilot 105,000 90,004 0 86 0.076 0.07 0.4 0.62 50 893 153 93.73

86% AFUE - w/time delays, w/o pilot 105,000 93,154 0 88 0.076 0 .07 0.4 0.62 50 882 151 92.65

91 % AFUE - w/time delays, w/o pilot 105,000 96,304 0 91 0.076 0.07 0.4 0.62 60 1001 172 105.10

99% AFUE - w/tune delays, w/o pilot 105 ,000 104 704 0 99 0.076 0.07 0.4 0.62 60 920 158 96.64

Table D.4.10 Energy Use Results for Hot-Water Gas Boilers (Two-Stage Controls)

Description QIN QoTjT Q EFF BE. I BE PE, T RDHR BOH BOH E EF

Gas Boiler, 81% w/ Two-stage Modulation 105,000 85,804 0 81 0.070 0.030 0.076 0.62 50 931 1369 168 97.74

Gas Boiler, 82% w/ Two-stage Modulation 105,000 86,854 0 82 0.070 0.030 0.076 0.62 50 920 1352 166 96.56

Gas Boiler, 83% w/ Two-stage Modulation 105,000 87,904 0 83 0.070 0.030 0.076 0.62 50 909 1336 164 95.41

Gas Boiler, 84% w/ Two-stage Modulation 105 ,000 88,954 0 84 0.070 0.030 0.076 0.62 50 898 1321 162 94.29

Gas Boiler, 85% w/ Two-stage Modulation 1 105 ,000 90,004 0 85 0.070 0.030 0.076 0.62 50 888 1305 160 93.19

D-11

 EE-RM/STD-01-350 COMMENT 164

T a e bl D 4 8 E .. ner~y U R se esu It s fi or H o -t W a t er 0·1 I F urnaces (T wo-St a~e C on t ro I) s 

Description QrN QOIlT Qp EFFYH~ BEH BEn PErro Trr. RDHR BOHss BOHR EAE EF 

81 %AFUE - Fan Atomized Burner wi Two- 105,000 83,839 0 81 0.398 0.318 0.045 26.00 50 897 1319 886 94.12 

stage Modulation 

82%AFUE - Fan Atomized Burner wi Two- 105,000 84,889 0 82 0.398 0.318 0.045 26.00 50 887 1304 876 93.12 

stage Modulation 

83%AFUE - Fan Atomized Burner wi Two- 105,000 85,939 0 83 0.398 0.318 0.045 26.00 50 877 1289 866 92.05 

stage Modulation 

84%AFUE - Fan Atomized Burner wi Two- 105,000 86,989 0 84 0.398 0.318 0.045 26.00 50 867 1275 856 91.00 

stage Modulation 

85%AFUE - Fan Atomized Burner wi Two- 105,000 88,039 0 85 0.398 0.318 0.045 26.00 50 857 1260 846 89.98 

stage Modulation 

Table D.4.9 Energy Use Results for Hot-Water Gas Boilers (Single-Stage Controls) 

Description QrN QOIIT Qp EFFYH~ PE BE PErro Trr. RDHR BOHss EAR EF 

80% AFUE - w/time delays, wi pilot 105,000 84,754 500 81 0.076 0.07 0 0.00 50 916 134 100.06 

81 % AFUE - w/time delays, wlo pilot 105,000 85,804 0 81 0.076 0.07 0.4 0.62 50 937 161 98.34 

82% AFUE - w/time delays, wlo pilot 105,000 86,854 0 82 0.076 0.07 0.4 0.62 50 925 159 97.14 

83% AFUE - w/time delays, wlo pilot 105,000 87,904 0 83 0.076 0.07 0.4 0.62 50 914 157 95.98 

84% AFUE - w/time delays, wlo pilot 105,000 88,954 0 84 0.076 0.07 0.4 0.62 50 903 155 94.84 

85% AFUE - w/time delays, wlo pilot 105,000 90,004 0 86 0.076 0.07 0.4 0.62 50 893 153 93.73 

86% AFUE - w/time delays, wlo pilot 105,000 93,154 0 88 0.076 0.07 0.4 0.62 50 882 151 92.65 

91 % AFUE - w/time delays, wlo pilot 105,000 96,304 0 91 0.076 0.07 0.4 0.62 60 1001 172 105.10 

99% AFUE - w/time delays wlo pilot 105000 104704 0 99 0.076 0.07 0.4 0.62 60 920 158 96.64 

T a e bl D .. 410 E nergy U R se esu lt s fi or H t W t G 0- a er as B·I 01 ers (T wo-St age C on t ro I) s 

Description QrN QOIlT Qp EFFYH~ BEH BEn PErro Trr. RDHR BOHss BOHR E\R EF 

Gas Boiler, 81 % wi Two-stage Modulation 105,000 85,804 0 81 0.070 0.030 0.076 0.62 50 931 1369 168 97.74 

Gas Boiler, 82% wi Two-stage Modulation 105,000 86,854 0 82 0.070 0.030 0.076 0.62 50 920 1352 166 96.56 

Gas Boiler, 83% wi Two-stage Modulation 105,000 87,904 0 83 0.070 0.030 0.076 0.62 50 909 1336 164 95.41 

Gas Boiler 84% wi Two-stage Modulation 105000 88954 0 84 0.070 0.030 0.076 0.62 50 898 1321 162 94.29 

Gas Boiler 85% wi Two-stage Modulation 105000 90004 0 85 0.070 0.030 0.076 0.62 50 888 1305 160 93.19 

D-ll 
Table D.4.11 Ener gy Use Results for Hot-Water Oil Boilers (Single-Stage Controls)

Description QIN Q0jjT Q ElTyu, PE BE PE T RDHR BOH E E

80% AFUE - w/time delays 140,000 113,413 0 80 0.22 0.07 0.045 26.00 70 992 408 138.87

81% AFUE - w/time delays 140,000 114,813 0 81 0.22 0.07 0.045 26.00 70 980 403 137.17

81% AFUE - Interrupted Ignition 140,000 114,813 0 81 0.22 0.07 0.025 0.75 70 983 287 137.66

82% AFUE - w/time delays 140,000 116,213 0 82 0.22 0.07 0.045 26.00 70 968 398 135.51

82%AFUE Interrupted Ignition 140,000 116,213 0 82 0.22 0.07 0.025 0.75 70 971 284 135.99

83% AFUE - w/time delays 140,000 117,613 0 83 0.22 0.07 0.045 26.00 70 956 393 133.89

83%AFUE - Interrupted Ignition 140,000 117,613 0 83 0.22 0.07 0.025 0.75 70 960 280 134.36

84% AFUE - w/time delays 140,000 119,013 0 84 0.22 0.07 0.045 26.00 70 945 388 132.31

84%AFUE - Interrupted Ignition 140,000 119,013 0 84 0.22 0.07 0.025 0.75 70 948 277 132.77

85% AFUE - w/time delays 140,000 120,413 0 85 0.22 0.07 0.045 26.00 70 934 384 130.77

85%AFUE - Interrupted Ignition 140,000 120,413 0 85 0.22 0.07 0.025 0.75 70 937 274 131.21

86%AFUE - w/time delays 140,000 121,813 0 86 0.22 0.07 0.045 26.00 70 923 379 129.26

86%AFUE - Interrupted Ignition 140,000 121,813 0 86 0.22 0.07 0.025 0.75 70 926 270 129.69

90% AFUE - w/time delays 140,000 127,413 0 90 0.22 0.07 0.045 26.00 70 883 363 123.56

95% AFUE - w/time delays 140,000 134,413 0 95 0.22 0.07 0.045 26.00 80 956 393 133.84

Table D.4.12 Energy Use Results for Hot-Water Oil Boilers (Two-Stage Controls)

Description QIN QouT Q EFFyHs BE BE PE T RDHR BOH BOH E EF

Oil Boiler, 82% Fan Atomized Burner w/ Two- 140,000 116,213 0 82 0.070 0.030 0.045 26.00 70 964 1417 465 134.91

stage Modulation

Oil Boiler, 83% Fan Atomized Burner w/ Two- 140,000 117,613 0 83 0.070 0.030 0.045 26.00 70 952 1400 459 133.31

stage Modulation

Oil Boiler, 84% Fan Atomized Burner w/ Two- 140,000 119,013 0 84 0.070 0.030 0.045 26.00 70 941 1384 454 131.74

stage Modulation

Oil Boiler, 85% Fan Atomized Burner w/ Two- 140,000 120,413 0 85 0.070 0.030 0.045 26.00 70 930 1368 449 130.21

stage Modulation

Oil Boiler, 86% Fan Atomized Burner w/ Two- 140,000 121,813 0 86 0.070 0.030 0.045 26.00 70 919 1352 443 128.71

stage Modulation

 EE-RM/STD-01-350 COMMENT 164

T a e bi D .. 411 E nergy U R se esu It s ~ or H t W t o - a er 0·1 I B·I 01 ers (S· III I e-St age C on t ro I) s 

Description QJN QorrT Qp EFFYHS PE BE PErc: Trc: RDHR BOHss E\E EF 

80% AFUE - w/time delays 140,000 113,413 0 80 0.22 0.07 0.045 26.00 70 992 408 l38.87 

81 % AFUE - w/time delays 140,000 114,813 0 81 0.22 0.07 0.045 26.00 70 980 403 137.17 

81 % AFUE - Interrupted Ignition 140,000 114,813 0 81 0.22 0.07 0.025 0.75 70 983 287 137.66 

82% AFUE - w/time delays 140,000 116,213 0 82 0.22 0.07 0.045 26.00 70 968 398 135.51 

82%AFUE Intemlpted Ignition 140,000 116,213 0 82 0.22 0.07 0.025 0.75 70 971 284 135.99 

83% AFUE - w/time delays 140,000 117,613 0 83 0.22 0.07 0.045 26.00 70 956 393 133.89 

83%AFUE - Interrupted Ignition 140,000 117,613 0 83 0.22 0.07 0.025 0.75 70 960 280 134.36 

84% AFUE - w/time delays 140,000 119,013 0 84 0.22 0.07 0.045 26.00 70 945 388 132.31 

84%AFUE - Interrupted Ignition 140,000 119,013 0 84 0.22 0.D7 0.025 0.75 70 948 277 132.77 

85% AFUE - w/time delays 140,000 120,413 0 85 0.22 0.07 0.045 26.00 70 934 384 130.77 

85%AFUE - Interrupted Ignition 140,000 120,413 0 85 0.22 0.07 0.025 0.75 70 937 274 131.21 

86% AFUE - w/time delays 140,000 121,813 0 86 0.22 0.07 0.045 26.00 70 923 379 129.26 

86%AFUE - Interrupted Ignition 140,000 121,813 0 86 0.22 0.07 0.025 0.75 70 926 270 129.69 

90% AFUE - w/time delays 140,000 127,413 0 90 0.22 0.07 0.045 26.00 70 883 363 123.56 

95% AFUE - w/time delays 140000 134413 0 95 0.22 0.07 0.045 26.00 80 956 393 133.84 

T a bi e D .. 412 E nergy U R se esu It s ~ or H o -t W a t er 0"1 I B o il ers (T wo-St age C on t ro I) s 

Description QrN QOITT Qp EFFYH~ BEH BE" PErc: T1G RDHR BOHss BOHR E\E EF 

Oil Boiler, 82% Fan Atomized Burner wi Two- 140,000 116,213 0 82 0.070 0.030 0.045 26.00 70 964 1417 465 134.91 

stage Modulation 

Oil Boiler, 83% Fan Atomized Burner wi Two- 140,000 117,613 0 83 0.070 0.030 0.045 26.00 70 952 1400 459 133.31 

stage Modulation 

Oil Boiler, 84% Fan Atomized Burner wi Two- 140,000 119,013 0 84 0.070 0.030 0.045 26.00 70 941 1384 454 131.74 

stage Modulation 

Oil Boiler, 85% Fan Atomized Burner wi Two- 140,000 120,413 0 85 0.070 0.030 0.045 26.00 70 930 1368 449 130.21 

stage Modulation 

Oil Boiler, 86% Fan Atomized Burner wi Two- 140,000 121,813 0 86 0.070 0.030 0.045 26.00 70 919 1352 443 128.71 

stage Modulation 

D-12 
REFERENCES

1. U. S. Department of Energy, Title 10, Code of Federal Regulations, Chapter II Part 430

Appendix N, Subpart B-Uniform Test Method for Measuring the Energy Consumption of

Furnaces and Boilers, January 1, 2007.

2. Honeywell Inc., Hot Surface Modules: S89C, D, G, H, J and S890C, D, G, H, J, 1989.

Form Number: 68-0079-1.

3. Comparison of Burner Operating Options, 1994. Brookhaven National Laboratory.

4. Gas Appliance Manufacturers Association (GAMA), GAMA Directory March 2005,

2005. (Last accessed March, 2005.)

<http://www. gamanet. org/gama/inforesources. nsf/vAllDocs/Product+Directories?OpenD

ocument>

5. Taco Inc., 110-120 Red Baron Circulators, 2003.

6. American Society for Heating Refrigeration and Air-Conditioning Engineers, Method of

Testing for Annual Fuel Ultilization Efficiency of Residential Central Furnaces and

Boilers, 1993. ANSI/ASHRAE. Atlanta, GA. Report No. Standard 103-1993.

7. 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.

8. Kweller, E., A Study of Three Measuresfor Energy Efficiency of Fossil Fueled Furnaces

and Boilers, October, 1987. National Bureau of Standards . Report No. NBSIR87-3645.

9. Liu, S. T., Proposed Revisions of Part ofthe Test Proceduresfor Furnaces and Boilers in

ASHRAE Standard 103-1993, September, 2002. U.S. Department of Commerce, National

Institute of Standard and Technology. Gaithersburg, MD. Report No. NISTIR 6913.

 EE-RM/STD-01-350 COMMENT 164

REFERENCES 

1. U.S. Department of Energy, Title 10, Code o/Federal Regulations, Chapter II Part 430 

Appendix N, Subpart B-Uniform Test Method/or Measuring the Energy Consumption 0/ 

Furnaces and Boilers, January 1,2007. 

2. Honeywell Inc., Hot Surface Modules: S89C, D, G, H, J and S890C, D, G, H, J, 1989. 

Form Number: 68-0079-1. 

3. Comparison 0/ Burner Operating Options, 1994. Brookhaven National Laboratory. 

4. Gas Appliance Manufacturers Association (GAMA), GAMA Directory March 2005, 

2005. (Last accessed March, 2005.) 

<http://www. gamanet. orgl gama/inforesources.nsf/v AllDocs/Product+ Directories ?OpenD 

ocument> 

5. Taco Inc., 110-120 Red Baron Circulators, 2003. 

6. American Society for Heating Refrigeration and Air-Conditioning Engineers, Method 0/ 

Testing/or Annual Fuel Ultilization Efficiency o/Residential Central Furnaces and 

Boilers, 1993. ANSI/ASHRAE. Atlanta, GA. Report No. Standard 103-1993. 

7. American Society of Heating Refrigerating and Air-Conditioning Engineers Inc., Method 

o/Testing/or Annual Fuel Utilization Efficiency 0/ Residential Central Furnaces and 

Boilers, October, 2003. Atlanta, GA. Report No. BSRlASHRAE Standard 103-1993R. 

First Public Review. 

8. Kweller, E., A Study o/Three Measures/or Energy Efficiency o/Fossil Fueled Furnaces 

and Boilers, October, 1987. National Bureau of Standards. Report No. NBSIR87-3645. 

9. Liu, S. T., Proposed Revisions 0/ Part o/the Test Procedures/or Furnaces and Boilers in 

ASH RAE Standard 103-1993, September, 2002. U.S. Department of Commerce, National 

Institute of Standard and Technology. Gaithersburg, MD. Report No. NISTIR 6913. 

D-13