APPENDIX V. ASSIGNMENT OF GAS FURNACE EFFICIENCY IN THE BASE CASE

TABLE OF CONTENTS

V.1 NOPR Method ....................................................... V-1

V.2 Revised Analysis for Final Rule ......................................... V-1

TABLES

Table V.2.1 Percent of Condensing Furnaces in Census Divisions (NOPR and Final Rule

Analysis) ..................................................... V-3

FIGURES

Figure V.2.1 NOPR Analysis HDD Percentile Ranking of Households and AFUE

Percentile Ranking of Shipments (Division 4) ........................ V-4

Figure V.2.2 HDD Percentile Ranking of Households and AFUE Percentile Ranking of

Shipments (Division 4; greater than 6000 HDD) ...................... V-4

Figure V.2.3 HDD Percentile Ranking of Households and AFUE Percentile Ranking of

Shipments (Division 4; less than 6000 HDD) ......................... V-4

 EE-RM/STD-01-350 COMMENT 164

APPENDIX V. ASSIGNMENT OF GAS FURNACE EFFICIENCY IN THE BASE CASE 

TABLE OF CONTENTS 

V.l NOPR Method ............. . ............ . ......... . ........... . ...... V-I 

V.2 Revised Analysis for Final Rule ...................... . .................. V-I 

TABLES 

Table Y.2.1 Percent of Condensing Furnaces in Census Divisions (NOPR and Final Rule 

Analysis) .. . .................................................. V-3 

FIGURES 

Figure V.2.l NOPR Analysis HDD Percentile Ranking of Households and AFUE 

Percentile Ranking of Shipments (Division 4) ........................ V-4 

Figure Y.2.2 HDD Percentile Ranking of Households and AFUE Percentile Ranking of 

Shipments (Division 4; greater than 6000 HDD) ...................... V-4 

Figure V.2.3 HDD Percentile Ranking of Households and AFUE Percentile Ranking of 

Shipments (Division 4; less than 6000 HDD) ......................... V-4 

V-i 
APPENDIX V: ASSIGNMENT OF GAS FURNACE EFFICIENCY IN THE BASE CASE

This appendix describes DOE's method for assignment of non-weatherized gas furnace

(NWGF) efficiencies to sample households in the base case.

V.1 NOPR Method

For the NOPR analysis, DOE derived the base case furnace assignment from data that

GAMA provided on the percentage of furnace sales in each State that are condensing furnaces.'

DOE combined the State -level GAMA data into Census divisions, and then assumed condensing

gas furnaces were installed in households solely on the basis of climate.

DOE assumed that the heating degree -day (HDD) profile correlates with the AFUE

shipment profile. For each Census division, the AFUE ofthe furnace for each sample household

was assigned by determining the percentile associated with the household's HDD and matching

it to the same percentile in the AFUE profile. In other words, all households in the division

sample were rank ordered from highest HDD to lowest, and furnace efficiencies were assigned to

them in order from highest to lowest, to match the distribution of efficiencies in the division.

Figure V.2.1 illustrates this approach for Census division four (West North Central).

This Figure shows the percentile of households and the distribution of AFUE in the shipments.

First, the LCC spreadsheet samples a household, determines the HDD percentile and assigns an

AFUE from the corresponding percentile. For example, for a household with 8000 HDD (100

percentile), the assigned AFUE was 96%. For a household with HDD of 6000, the HDD

percentile was 68% and the assigned AFUE is 92%. Consequently, all households in this Census

division having HDDs greater than 6000 were assigned furnaces with efficiencies of at least 92

AFUE. Households with HDD below 4800 (dashed horizontal line) were assigned furnaces with

AFUE below 90%.

V.2 Revised Analysis for Final Rule

Upon review, DOE determined that the assumption that the existing (and future) market

for condensing furnaces (absent a standard) was likely to be concentrated in the coldest states

was not an accurate reflection of the state-by-state sales data that GAMA provided. DOE found

that in several Census divisions for which the average HDD is greater than 6000, some states

within the division have average HDD lower than 6000.$ Therefore, in Steps 1 and 2 of the

revised analysis, DOE split each of these Census divisions into two climate zones-states with

average HDDs of above 6000 and below 6000. Using the state-level shipments data provided by

GAMA, DOE matched the household HDD percentile with the AFUE percentile within each

climate zone rather than for the whole division to assign the efficiency of the base case furnace.

This matching of HDD and AFUE by climate zone is illustrated in Figures V.2.2 and V.2.3.

a These are Census divisions 3, 4, 8, and 9.

V-1

 EE-RM/STD-01-350 COMMENT 164

APPENDIX V: ASSIGNMENT OF GAS FURNACE EFFICIENCY IN THE BASE CASE 

This appendix describes DOE's method for assignment of non-weatherized gas furnace 

(NWGF) efficiencies to sample households in the base case. 

V.I NOPR Method 

For the NOPR analysis, DOE derived the base case furnace assignment from data that 

GAMA provided on the percentage of furnace sales in each State that are condensing furnaces. 1 

DOE combined the State-level GAMA data into Census divisions, and then assumed condensing 

gas furnaces were installed in households solely on the basis of climate. 

DOE assumed that the heating degree-day (HDD) profile correlates with the AFUE 

shipment profile. For each Census division, the AFUE of the furnace for each sample household 

was assigned by determining the percentile associated with the household's HDD and matching 

it to the same percentile in the AFUE profile. In other words, all households in the division 

sample were rank ordered from highest HDD to lowest, and furnace efficiencies were assigned to 

them in order from highest to lowest, to match the distribution of efficiencies in the division. 

Figure V.2.1 illustrates this approach for Census division four (West North Central). 

This Figure shows the percentile of households and the distribution of AFUE in the shipments. 

First, the LCC spreadsheet samples a household, determines the HDD percentile and assigns an 

AFUE from the corresponding percentile. For example, for a household with 8000 HDD (100 

percentile), the assigned AFUE was 96%. For a household with HDD of6000, the HDD 

percentile was 68% and the assigned AFUE is 92%. Consequently, all households in this Census 

division having HDDs greater than 6000 were assigned furnaces with efficiencies of at least 92 

AFUE. Households with HDD below 4800 (dashed horizontal line ) were assigned furnaces with 

AFUE below 90%. 

V.2 Revised Analysis for Final Rule 

Upon review, DOE determined that the assumption that the existing (and future) market 

for condensing furnaces (absent a standard) was likely to be concentrated in the coldest states 

was not an accurate reflection of the state-by-state sales data that GAMA provided. DOE found 

that in several Census divisions for which the average HDD is greater than 6000, some states 

within the division have average HDD lower than 6000.a Therefore, in Steps 1 and 2 of the 

revised analysis, DOE split each of these Census divisions into two climate zones-states with 

average HDDs of above 6000 and below 6000. Using the state-level shipments data provided by 

GAMA, DOE matched the household HDD percentile with the AFUE percentile within each 

climate zone rather than {or the whole division to assign the efficiency of the base case furnace. 

This matching ofHDD and AFUE by climate zone is illustrated in Figures V.2.2 and V.2.3. 

a These are Census divisions 3, 4, 8, and 9. 

V-I 
Figure V.2.2 illustrate the changes in Step 2 for the revised assignment of furnace AFUE

for households in Census division four in the climate zone with HDDs of 6000 or higher. This

Figure shows that 38% (dashed horizontal line) of shipments in this climate zone are noncondensing and 62% of the shipments in this climate zone are condensing, based on state-level

GAMA data. Accordingly, in Step 3, DOE assigned condensing furnaces to 62% of the

households in this climate zone with highest HDDs (these are the household above the dashed

line in Figure V.2.2). (After adjusting for the RECS household weights, this appears as 63.7% in

Table V.2.1. The small number of households in the RECS survey causes the percentiles to

differ slightly from the GAMA percentiles.)

DOE used the same approach for households in Census division four in the climate zone

with HDDs below 6000 HDD (see Figure V.2.3). In this climate zone, 24% of shipments are

condensing furnaces. Accordingly, DOE assigned condensing furnaces to 24% of the

households in this climate zone with the highest HDDs (these are the household above the

dashed line in Figure V.2.3). (After adjusting for the RECS household weights, this appears as

25.8% in Table V.2.1. The small number of households in the RECS survey causes the

percentiles to differ slightly from the GAMA percentiles.)

Table V.2.1 shows the percent of total NWGF that were condensing furnaces in the

NOPR analysis and in the revised analysis for the final rule. For those states having more than

6000 HDD (subsets of some divisions), the NOPR analysis assumed that almost all households

with more than 6000 HDD had condensing furnaces. In contrast to the NOPR analysis, the

revised analysis has lower shares of condensing furnaces in most states with more than 6000

HDD and higher shares of condensing furnaces in most states with less than 6000 HDD. The

results of the revised analysis correspond to the shares of condensing furnaces reported in

GAMA state-level data.

 EE-RM/STD-01-350 COMMENT 164

Figure V.2.2 illustrate the changes in Step 2 for the revised assignment of furnace AFUE 

for households in Census division four in the climate zone with HDDs of 6000 or higher. This 

Figure shows that 38% (dashed horizontal line) of shipments in this climate zone are noncondensing and 62% of the shipments in this climate zone are condensing, based on state-level 

GAMA data. Accordingly, in Step 3, DOE assigned condensing furnaces to 62% of the 

households in this climate zone with highest HDDs (these are the household above the dashed 

line in Figure V.2.2). (After adjusting for the RECS household weights, this appears as 63.7% in 

Table Y.2.1. The small number of households in the RECS survey causes the percentiles to 

differ slightly from the GAMA percentiles.) 

DOE used the same approach for households in Census division four in the climate zone 

with HDDs below 6000 HDD (see Figure V.2.3). In this climate zone, 24% of shipments are 

condensing furnaces. Accordingly, DOE assigned condensing furnaces to 24% of the 

households in this climate zone with the highest HDDs (these are the household above the 

dashed line in Figure V.2.3). (After adjusting for the RECS household weights, this appears as 

25.8% in Table V.2.1. The small number of households in the RECS survey causes the 

percentiles to differ slightly from the GAMA percentiles.) 

Table V.2.l shows the percent of total NWGF that were condensing furnaces in the 

NOPR analysis and in the revised analysis for the final rule. For those states having more than 

6000 HDD (subsets of some divisions), the NOPR analysis assumed that almost all households 

with more than 6000 HDD had condensing furnaces. In contrast to the NOPR analysis, the 

revised analysis has lower shares of condensing furnaces in most states with more than 6000 

HDD and higher shares of condensing furnaces in most states with less than 6000 HDD. The 

results of the revised analysis correspond to the shares of condensing furnaces reported in 

GAMA state-level data. 

V-2 
Table V.2.1 Percent of Condensing Furnaces in Census Divisions (NOPR and Final Rule

Division GAMA NOPR Analysis Final Rule Analysis

Shipments

(2015)* National >= 6000

HDD

< 6000

HDD

>= 6000

HDD

< 6000

HDD

1 65.2% 65.2% 100.0% 70.5% 66.1%

2 51.2% 51.2% 100.0% 50.2% 52.6%

3 50.7% 50.7% 100.0% 28.7% 52.6% 51.0%

4 54.3% 54.3% 100.0% 31.0% 63.7% 25.8%

5 32.6% 32.6% 32.6% 34.5%

6 32.8% 32.8% 32.8% 34.6%

7 9.0% 9.0% 9.0% 11.5%

8 23.5% 23.5% 49.9% 0.0% 30.5% 17.4%

9 30.3% 30.3% 100.0% 27.1% 27.8% 32.4%

10 43.4% 43.4% 98.3% 0.0% 44.9%

11 14.5% 14.5% 100.0% 12.1% 16.8%

12 7.1% 7.1% 7.1% 9.6%

13 5.5% 5.5% 5.5% 8.0%

USA 35.6%

* The GAMA 2003 shipment data were adjusted in two ways: first, on the assumption that the share of condensing

furnaces increases over time from 31.4% in 2003 (original GAMA data) to 35.6% in 2015; and second, to account

for household sample weights by division in RECS 2001 (small numbers of households in some divisions causes a

coarser representation).

Analysis

 EE-RM/STD-01-350 COMMENT 164

Table V.2.t Percent of Condensing Furnaces in Census Divisions (NOPR and Final Rule 

Analysis) 

Division GAMA NOPR Analysis Final ~ule Analysis 

Shipments 

(2015)* National >=6000 <6000 >=6000 <6000 

HDD HDD HDD HDD 

1 65.2% 65.2% 100.0% 70.5% 66.1% 

2 51 .2% 51.2% 100.0% 50.2% 52.6% 

3 50.7% 50.7% 100.0% 28.7% 52.6% 51.0% 

4 54.3% 54.3% 100.0% 31.0% 63.7% 25.8% 

5 32.6% 32.6% 32.6% 34.5% 

6 32.8% 32.8% 32.8% 34.6% 

7 9.0% 9.0% 9.0% 11.5% 

8 23.5% 23.5% 49.9% 0.0% 30.5% 17.4% 

9 30.3% 30.3% 100.0% 27.1% 27.8% 32.4% 

10 43.4% 43.4% 98.3% 0.0% 44.9% 

11 14.5% 14.5% 100.0% 12.1% 16.8% 

12 7.1% 7.1% 7.1% 9.6% 

13 5.5% 5.5% 5.5% 8.0% 

USA 35.6% 

* The GAMA 2003 shipment data were adjusted m two ways: first, on the assumptIOn that the share of condensmg 

furnaces increases over time from 31.4% in 2003 (original GAMA data) to 35.6% in 2015; and second, to account 

for household sample weights by division in RECS 2001 (small numbers of households in some divisions causes a 

coarser representation). 

V-3 
NOPR AFUE Percentile Ranking of Shipments

(Division 4)

5500 6000 6500 7000

Heating Degree Days (HDD)

7500 8000 8500

^f I I I

Condensin

Nonr.mr•.r^

K 50%

10%

0%

78% 80% 81% 90% 91%

AFUE

92% 93% 96%

Figure V.2.1 NOPR Analysis HDD Percentile Ranking of Households and AFUE Percentile

Ranking of Shipments (Division 4)

AFUE Percentile Ranking of Shipments

(Division 4; greater than 6000 HDD)

100%

90%

8 80%

70%

60%

L

j--^-{ Condensinq i

12 50%

30%

20 Non- I.

I' Lnna ^Ynsno ^

0% ± -F-^

78% 80% 81% 90% 91%

AFUE

92% 93% 96%

Figure V.2.2 HDD Percentile Ranking of Households and AFUE Percentile Ranking of

Shipments (Division 4; greater than 6000 HDD)

HDD Percentile Ranking of Households

(Division 4; less than 6000 HDD)

5500 6000 6500 7000

Heating Degree Days (HDD)

AFUE Percentile Ranking of Shipments

(Division 4; less than 6000 HDD)

100%

90% Condensing

70%

60%

50%

Non- 40%

Condensing I

30%

20%

10%

0%

78% 80%

I I

_

I

81% 90% 91%

AFUE

Figure V.2.3 HDD Percentile Ranking of Households and AFUE Percentile Ranking of

Shipments (Division 4; less than 6000 HDD)

 EE-RM/STD-01-350 COMMENT 164

NOPR HDD Percentile Ranking of Households 

(Division 4) 

Heating Oegr •• Days (HOD) 

NOPR AFUE Percentile Ranking of Shipments 

, (Division 4) 

'~~~ H I I I I ! = 

l 80% . 1 I _ I I I i

l - ~ 70% t CondenslnQ 

~ :~ ~ -f +-=-' 1 _ _ I "' -=- ~ ~ ~~~r f~D~r- -" .. - - 1-::- - -

.. 10% r--n "..uJIWl"',", , f-+--

0% 1--+ I I I 1 - ,-

78% 80% 81% 90% 91 % 92% 93% 96% 

AFUE 

Figure V.2.t NOPR Analysis HDD Percentile Ranking of Households and AFUE Percentile 

Ranking of Shipments (Division 4) 

HDD Percentile Ranking of Households AFUE Percentile Ranking of Shipments 

(Division 4; greater than 6000 HDD) (Division 4; greater than 6000 HDD) 

" 

.- .... -... .... -- ........ \ 

100% / ' .. .r 100% 

r- ',' ;:-1 90% .,- - ! 90% 1-1- t- + ~ 80% / !f ! l I 

/ 11 / 80% J. g> 70% gt 70% Condensing I _ 

" r- j ~ 60% i I ~ 60% -,- t:. SO'I. f / 50'1. 1 I I I = ~ _1:1'- 40% -_ ..... ..... _ . --- ' ... ,..- -- - --' . -)' - --.-- . 

~~~~rn t -- - ;;- 1' '"- 1 ~ 30% , l " 

830% , - 1.- I 

.. 20% t20% H NOll- , - I / a. t!.gndens'mlJ' I I 10% ~~ !::I T -L J- , t- 0% \ .... -.-,-- i--" ... ~~ 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 78% 80% 81% 90% 91% 92% 93% 96% 

Heating Oegr •• Days (HOD) AFUE 

Figure V.2.2 HDD Percentile Ranking of Households and AFUE Percentile Ranking of 

Shipments (Division 4; greater than 6000 HDD) 

HDD Percentile Ranking of Households AFUE Percentile Ranking of Shipments 

(Division 4; less than 6000 HDD) (Division 4; less than 6000 HDD) 

100% 

90% 

~ [~ 90% Condensing ! I .L i'-H l 80% / 

. .t. ~~ .• '+! [tC i""' f -'i --- )'- r --- - - -, ... -.- - ... --- - -... - .". .... - - '~ ~ --' g> 70% r / ~ 70% !---1 - 1--

~ 60% 

.- L- =C l I 

I J I t:. 50% 

/ t:. 50% r-- l- f ~ 40% . 40% r-- Non- - 1-- - $ 30% I / ~ 30% r ~ Condensing , I ~ 

20% 5= / j If ] 20% I II · I- - - 10% /' 10% I ' I' - I- I- - I 0% 0% , , 

4000 "--4500 SOOO 5500 6000 6500 7000 7500 8000 8500 78% 80% 81% 90% 91% 92% 93% 96% 

Heating Oegree Days (HOD) AFUE 

Figure V.2.3 HDD Percentile Ranking of Households and AFUE Percentile Ranking of 

Shipments (Division 4; less than 6000 HDD) 

V-4 
REFERENCES

1. Gas Appliance Manufacturers Association (GAMA), Updated Shipment Data for

Residential Furnaces and Boilers, personal communication. April 25, 2005.

 EE-RM/STD-01-350 COMMENT 164

REFERENCES 

1. Gas Appliance Manufacturers Association (GAMA), Updated Shipment Data for 

Residential Furnaces and Boilers,personai communication. April 25, 2005. 

V-5