The Fraction of Freestanding Wood-Fueled Stoves in Current Use That are U.S. 

EPA Certified Cordwood Stoves and Wood Pellet Stoves 

Prepared for: 

John Crouch 

Hearth, Patio & Barbecue Association 

7509 Madison Ave, Suite 204D 

Citrus Heights, CA 95610 

Prepared by: 

James E. Houck, Ph.D. 

7494 SW 48th Ave. 

Portland, OR 97219-1404 

(503) 244-8543 

jbchouck@comcast.net

July 23, 2011
i 

Executive Summary 

The magnitude of the future potential reduction in air emissions from the replacement of 

pre-certified cordwood stoves with certified cordwood stoves or pellet stoves and the 

concomitant future sales opportunities for new cordwood or pellet stoves are in large part 

dependent on the fraction of stoves already in use that are certified cordwood stoves or 

that are pellet stoves versus the fraction that are older pre-certified cordwood stoves and 

still in use. 

This review focused on freestanding wood stoves. The term “wood stove” included both 

freestanding cordwood- and freestanding pellet-fueled heaters. Both certified and 

uncertified freestanding pellet stoves, as they both have low air emissions, were grouped 

together and simply referred to as “pellet” stoves. Freestanding certified cordwood 

stoves and freestanding pellet stoves together are referred to as “high-technology” stoves. 

Surveys of home occupants who are cordwood stove users have not been very helpful in 

providing accurate estimates of the fraction of cordwood stoves that are certified 

primarily due to home occupants commonly not knowing the certification status or age of 

their wood heater. Further, because many home occupant surveys that include questions 

relating to stove certification status have been local or regional in scope and have 

generally been focused in areas where wood stove usage has been a topical issue, the 

results of these high-visibility area surveys, even if accurate, are not representative of the 

Nation as a whole. Often there have been programs encouraging or requiring change outs 

to new stoves in these areas. Nearly three quarters of wood stoves that are used are in 

rural areas, many of which are in rural areas of the South and Mid-Atlantic states, where 

there are few if any wood stove regulations or voluntary programs for the purchase of 

new lower-emitting wood stoves. Consequently, again even if accurate, the results of the 

“focused” surveys tend to over predict the national average fraction of stoves that are 

high-technology stoves. 

To obtain a national estimate of the fraction of freestanding wood stoves that are 

currently certified cordwood or pellet stoves, hearth industry manufacturing (shipment) 

records tabulated since 1989 and supplied by the Hearth, Patio and Barbecue Association 

(HPBA) were compared to total wood stove ownership data. To avoid “double 

counting,” the HPBA shipment data were adjusted (reduced) by an estimate of the 

freestanding certified stoves and pellets stoves that have been replaced by newer 

freestanding certified cordwood stoves or pellet stoves since 1987. These estimates were 

obtained by a survey of 22 well-established hearth dealers geographically distributed 

throughout the United States. Total wood stove ownership data were obtained from 

multiple credible sources. These were: (1) American Housing Survey biennial reports, 

(2) HPBA biennial consumers surveys, (3) Mediamark Research, Household and 

Personal Appliances annual reports, and (4) Simmons Market Research Bureau, Inc. 

annual surveys. 
ii 

In addition to freestanding stove ownership estimates, estimates of the current (2010) 

national particulate emissions for each freestanding stove category were made from the 

number of stoves used (used in contrast to owned), standard emission factors, and 

average annual national fuel usage per unit. The stove categories were: (1) freestanding 

uncertified conventional cordwood stoves, (2) freestanding non-catalytic certified 

cordwood stoves, (3) freestanding catalytic certified cordwood stoves, and, (4) 

freestanding pellet stoves. Except for pellet stoves, emission factors were from the 

standard U.S. EPA AP-42 emission factor compilation document. Pellet stove emission 

factors were obtained from various literature sources as the AP-42 data are from two old 

studies with long obsolete pellet stove models. Annual national average fuel usage 

values per stove were obtained from U.S. DOE reports and adjusted by stove category 

with efficiencies provided in AP-42. 

Figure ES1 shows the estimated cumulative number of freestanding certified cordwood 

stoves, the estimated cumulative number of freestanding pellet stoves and the sum of 

both. The data is shown by year since 1987 when pellet stoves and certified or certifiable 

cordwood stove models first appreciably became available. As of the end of 2010, the 

cumulative number of freestanding certified cordwood stoves was estimated as 

2,397,602, the cumulative number of pellet stoves as 981,488 and the sum of both as 

3,379,090. 

Figure ES2 is a comparison of the cumulative number of freestanding high-technology 

stoves and the number of total freestanding stoves. The total number of freestanding 

wood stoves in use fluctuated modestly from 1987 to 2010 in part due to the ebb and 

wane of wood stove popularity in response to such factors as fossil fuel prices, the 

increase in natural gas availability, and interest in renewable resources. Also part of the 

variability is from the uncertainty in survey results and from the statistical bias among the 

different survey organizations’ methods and surveyed population. It also needs to be 

remembered that many high-technology wood stoves are replacement units for existing 

pre-certified cordwood units and even some certified units. The mean number of 

freestanding cordwood stoves for the time period between 1987 and 2010 was 9,147,500 

with a year-to-year standard deviation of 976,000. 

The percentage of total freestanding wood stoves that were either certified cordwood 

stoves or pellets stoves are shown by year in Figures ES2 and ES3. As of the end of 

2010, 35.4% of the total freestanding wood stoves owned in the United States were either 

freestanding certified cordwood stoves or pellet stoves. 

Figure ES4 shows the national annual particulate emissions for freestanding wood stoves 

by category. In 2010, uncertified cordwood stoves were responsible for 86% of the 

particulate emissions. It is difficult to judge the effectiveness of the NSPS and new 

technology stoves in reducing particulate emissions because of changes in overall wood 

stove usage independent of the NSPS due, as previously noted, to the ebb and wane of 

wood stove popularity in response to such factors as fossil fuel prices, the increase in 

natural gas availability, and interest in renewable resources. However, if it is assumed 
iii 

that the same number of freestanding stoves would be in use today without the NSPS, 

i.e., all the freestanding stoves were uncertified conventional cordwood stoves, the annual 

hypothetical 2010 emissions would have been 209,742 rather than the actual 157,069 tons 

or 34% higher. 
iv 

Figure ES1. Cumulative Number of Certified Freestanding Cordwood Stoves and 

Freestanding Pellet Stoves. 

Figure ES2. Comparison of the Cumulative Number of Certified Freestanding Cordwood 

Stoves Plus Pellet Stoves with the Total Number of Freestanding Wood Stoves Owned. 
v 

Figure ES3. Percent of Total Freestanding Wood Stoves That Are Certified Freestanding 

Cordwood Stoves and Pellet Stoves. 

Figure ES4. 2010 National Particulate Emissions by Freestanding Stove Category. 
vi 

Table of Contents 

Section Page 

Executive Summary i 

List of Tables vii 

List of Figures ix 

1. Introduction 1 

2. Methodology and Database 3 

 2.1. Total Freestanding Stoves – AHS 3 

 2.2. Total Freestanding Stoves – HPBA 9 

 2.3. Total Freestanding Stoves – Mediamark Research 11 

 2.4. Total Freestanding Stoves – Simmons Market Research 14 

2.5. Certified Freestanding Cordwood Stove and Freestanding 

Pellet Stove Ownership 15 

2.6. Particulate Emission Factors and Wood Usage 29 

3. Results 30 

4. References 34 
vii 

List of Tables 

Table Page 

Table 1. NSPS Certification Program Timeline 1

Table 2. Vacation/Secondary Home Fireplace and Freestanding Wood 

Stove Ownership Usage 5 

Table 3. Cordwood Stove Usage 5 

Table 4. Multiple Freestanding Cordwood Stove Ownership 6 

Table 5. Year-Around Occupied Housing Units, Vacant Housing 

Units, and Seasonal Housing Units 7 

Table 6. Freestanding Wood Stoves Owned Based on American Housing 

Survey Data 8 

Table 7. Freestanding Wood Stoves Owned Based on Hearth, Patio and 

Barbecue Association Data 10 

Table 8. Freestanding Wood Stoves Owned Based on Mediamark 

Research Data 12 

Table 9. Freestanding Wood Stoves Owned Based on Simmons 

Market Research Bureau Data 15 

Table 10. Certified Freestanding Cordwood Stove Shipments (Sales) 17 

Table 11. Freestanding Pellet Stove Shipments (Sales) 18 

Table 12. Pellet-Fueled Fireplace Insert Shipments (Sales) 19 

Table 13. List of Retailer Questions 21 

Table 14. Results of the Survey Questions from Twenty-Two 

Wood Stove Retailers 22 

Table 15. Freestanding Certified Cordwood Stoves That Were Replaced 

by New Freestanding Certified Cordwood Stoves or Pellet Stoves and 

That were Taken Out of Service through 1999 24 
viii 

Table 16. Freestanding Certified Cordwood Stoves That Were 

Replaced by New Freestanding Certified Cordwood Stoves or Pellet 

Stoves and That were Taken Out of Service from 2000 to 2010 25 

Table 17. Freestanding Pellet Stoves that Were Replaced by New 

Freestanding Pellet Stoves and That Were Taken Out of Service 

through 1999 25 

Table 18. Freestanding Pellet Stoves that Were Replaced by New 

Freestanding Pellet Stoves and That Were Taken Out of Service 

from 2000 to 2010 26

Table 19. Summary of the Replacement of Existing Freestanding 

Certified Cordwood Stoves and Pellet Stoves with New Freestanding 

Certified Cordwood Stoves and Pellet Stoves as of 2010 27 

Table 20. Certified Freestanding Cordwood Stoves in Homes 28 

Table 21. Freestanding Pellet Stoves in Homes 29 

Table 22. Number of Freestanding Stoves in Homes by Category 

(2010), Emission Factors, Efficiencies, and Fuel Usage 30 

Table 23. Summary of Freestanding Wood Stove Ownership Estimates 31 

Table 24. Cumulative Data, Number of Freestanding Wood Stoves 

Owned, and Percent of the Total Freestanding Wood Stoves Owned 

That Are Certified Freestanding Cordwood Stoves and Freestanding 

Pellet Stoves 32 

Table 25. Particulate Emissions by Freestanding Stove 

Category (2010) 33 
ix 

List of Figures 

Figure Page 

Figure ES1. Cumulative Number of Certified Freestanding 

Cordwood Stoves and Freestanding Pellet Stoves iv 

Figure ES2. Comparison of the Cumulative Number of Certified 

Freestanding Cordwood Stoves Plus Pellet Stoves with the Total 

Number of Freestanding Wood Stoves Owned iv 

Figure ES3. Percent of Total Freestanding Wood Stoves That Are 

Certified Freestanding Cordwood Stoves and Pellet Stoves v 

Figure ES4. 2010 National Particulate Emissions by Freestanding 

Stove Category v 

Figure 1. Map of the U.S. Showing Geographical Distribution of Survey 

Respondents 20 

Figure 2. Cumulative Number of Certified Freestanding Cordwood 

Stoves Replaced by New Certified Freestanding Cordwood Stoves 

or Pellet Stoves 27 

Figure 3. Cumulative Number of Freestanding Pellet Stoves Replaced by New 

Freestanding Pellet Stoves 27 
1 

1. Introduction 

The magnitude of the future potential reduction in air emissions from wood stove change 

outs and the future sales opportunities for new cordwood or pellet stoves are in large part 

dependent on the fraction of stoves currently already in use that are certified cordwood 

stoves or that are pellet stoves versus those that are older pre-certified cordwood stoves. 

It needs to be emphasized that most pre-certified cordwood stoves were generally 

constructed with cast iron or heavy gage plate steel with rudimentary internal components 

and hence can have a significant lifetime under normal usage. 

Surveys of home occupants who are cordwood stove users have not been very helpful in 

providing accurate estimates of the fraction of cordwood stoves that are certified for a 

number of reasons. Notably these are: (1) Many consumers simply do not know if the 

stove is certified or not. (2) Many do not know the date when the stove was purchased. 

(Stoves purchased after July 1, 1990 were required to be certified by the NSPS.) (3) 

Many confuse safety labels attached to the stove as verification of certification. (4) The 

NSPS requirements were phased in over a four year period which has caused some 

confusion with the certification status of units bought during that period or in the years 

immediately proceeding the action dates due to some manufacturers being proactive and 

manufacturing heaters that were certifiable before the deadlines. (See Table 1 for dates.) 

Table 1 

NSPS Certification Program Timeline 

Date Action 

July 1, 1988 All wood heaters manufactured must meet Phase I emission limits 

July 1, 1989 Manufacturing extension for small manufacturers 

July 1, 1990 All wood heaters manufactured must meet Phase II emission limits 

All wood heaters sold must meet Phase I or Phase II emission limits 

July 1, 1992 All wood heaters sole must meet Phase II emission limits 

Pellet heaters can be either certified or non-certified. They entered the marketplace circa 

1989. Both certified and non-certified models have low emissions and are grouped 

together here as simply pellet stoves. 

Because many home occupant surveys that include questions relating to stove 

certification status have been local or regional in scope and have generally been focused 

in areas where wood stove usage has been a topical issue, the results of these highvisibility area surveys, even if accurate, are not representative of the Nation as a whole. 

For example, notable surveys have been conducted in the Bay Area of California, in the 

Puget Sound area of Washington, in Colorado towns and cities, and in other western 

communities where historically wood stove usage has been high and there has been a 

long-term particulate problem with a corresponding high public awareness. Often there 

have been regulatory programs encouraging or requiring change outs to new stoves in 

these areas. 
2 

It needs to be remembered that according to the American Housing Survey (AHS) that 

nearly three quarters of wood stoves that are used are in rural areas many of which are in 

rural areas of the South and Mid-Atlantic states where there are few if any wood stove 

regulations or programs encouraging the purchase of new lower-emitting wood stoves. 

Rural areas also tend to be areas with lower average household incomes which make the 

purchase of a new wood stove, typically in the $1500 to $3000 price range, less common. 

Consequently, even if accurate, the results of the “focused” surveys would tend to over 

predict the national average fraction of stoves that are high-technology stoves. 

To obtain a national estimate of the fraction of freestanding wood stoves that are certified 

cordwood or pellet stoves, hearth industry manufacturing (shipment) records tabulated 

since 1989 and supplied by the Hearth, Patio and Barbecue Association (HPBA) were 

compared to total wood stove ownership data. To avoid “double counting,” the HPBA 

shipment data were adjusted (reduced) by an estimate of the freestanding certified stoves 

and pellets stoves that have been replaced by newer freestanding certified cordwood 

stoves or pellet stoves since 1987. These estimates were obtained by a survey of 22 wellestablished hearth dealers geographically distributed throughout the United States. Total 

wood stove ownership data were obtained from four sources. These were: (1) American 

Housing Survey biennial reports, (2) HPBA biennial consumers surveys, (3) Mediamark 

Research, Household and Personal Appliances annual reports, and (4). Simmons Market 

Research annual surveys. Ancillary data needed for the calculations of ownership of 

multiple wood stoves by some households and the fraction of wood stoves that are owned 

that are actually used were obtained from a review of various national, state and local 

surveys. 

As per instructions provided by the HPBA, this report covers freestanding wood stoves 

only. It does not cover fireplace inserts or EPA certified fireplaces. This is due primarily 

to the fact that the term “fireplace insert” is nebulous covering many devices associated 

with a fireplace and hence the ownership data based on household surveys is not well 

defined. In the case of EPA certified fireplaces, while they are actually wood heaters 

under the NSPS, they are designed to look like a fireplace and mounted into the wall. 

Because an attempt to include certified fireplaces in this study would have confounded 

the analysis due to the confusion at the user/home owner level about what these 

appliances are, they were not included. Further the numbers of “certified fireplaces” are 

small compared to freestanding stoves and their impact on the overall results would likely 

be insignificant. 

In addition to freestanding stove ownership estimates, estimates of the current (2010) 

national particulate emissions by freestanding stove category were made from the number 

of stoves used (used in contrast to owned), standard emission factors, and average annual 

national fuel usage per unit. The stove categories were: (1) freestanding uncertified 

conventional cordwood stoves, (2) freestanding non-catalytic certified cordwood stoves, 

(3) freestanding catalytic certified cordwood stoves, and, (4) freestanding pellet stoves. 

Except for pellet stoves, emission factors were from the standard U.S. EPA AP-42 

emission factor compilation document. Pellet stove emission factors were obtained from 
3 

various literature sources as the AP-42 data are from two old studies with long obsolete 

pellet stove models. Annual national average fuel usage values per stove were obtained 

from U.S. DOE reports and adjusted by stove category with efficiencies provided in AP42. 

2. Methodology and Database 

Section 2.1 (Total Freestanding Stoves – AHS) describes the database and method used 

to calculated freestanding stove ownership obtained from the American Housing Surveys. 

Section 2.2 (Total Freestanding Stoves – HPBA) describes the database and method used 

to calculate the freestanding stove ownership obtained from the Hearth, Patio and 

Barbecue Association consumers’ surveys. Section 2.3 (Total Freestanding Stoves – 

Mediamark Research) describes the database and method used to calculate the 

freestanding stove ownership obtained from the Mediamark Research annual reports. 

Section 2.4 (Total Freestanding Stoves –Simmons) describes the database and method 

used to calculate the total ownership obtained from Simmons Market Research surveys. 

Section 2.5 (Certified Freestanding Cordwood Stove and Freestanding Pellet Stove 

Ownership) describes the database and method used to calculate the ownership of 

certified freestanding cordwood stoves and freestanding pellet stoves from 

manufacturers’ shipment data compiled by the HPBA and the survey used to make 

adjustments for the replacement of certified cordwood stoves and pellet stoves already in 

homes with newer certified cordwood or pellet models. Section 2.6 (Particulate Emission 

Factors and Wood Usage) describes the method used to calculate total annual particulate 

emissions for 2010 from the results of this analysis and standard emission factor and fuel 

usage data from U.S. EPA, U.S. DOE, and other published literature sources. 

2.1. Total Freestanding Stoves – AHS 

The U.S. Census Bureau conducts surveys referred to as American Housing Surveys 

(AHS) to obtain up-to-date housing statistics for the Department of Housing and Urban 

Development (HUD). Title 12, Section 1701Z-10 of the U.S. Code mandates the 

collection of the data for the AHS. Both national and metropolitan area American 

Housing Surveys are conducted. The national surveys are conducted every two years, 

with the most recent data compiled for 2009. Data on housing, including apartments, 

single-family homes, mobile homes, vacant housing units, household characteristics, 

income, housing and neighborhood quality, housing costs, equipment and fuels, size of 

housing unit, etc., are collected. “Main Heating Equipment – Stoves” and “Other Heating 

Equipment – Stoves” are among the many categories for which data are collected. 

In addition to year-around housing units, the American Housing Survey tabulates the 

number of vacant housing units and seasonal housing units separately. It does not, 

however, provide information on stove ownership in them. It was assumed that stove 

ownership percentage was the same in vacant housing units as year-around housing units. 

In the case of seasonal housing units there was a small adjustment factor for stove 
4 

ownership housing units as compared to year-around occupied housing units based on 

HPBA surveys. (See Table 2.) 

The term “stove” is defined in the AHS glossary as, “Stove refers to any range or stove 

that burns solid fuel including wood burning, pot belly, and Franklin stoves.” 

The number of occupied housing units reporting stoves as “main” heating equipment was 

added to the number of occupied housing units reporting stoves as “other” heating 

equipment to obtain the total number of housing units using stoves as heat. The term 

“other” is the sum heating appliances used as supplemental and parallel heating sources. 

Once the total number of housing units that used stoves as a heating source was 

determined, it was then adjusted to the total number of wood stoves owned by dividing 

by the fraction of stoves owned that are used for heat (Table 3) and multiplied by the 

multiple ownership factor (Table 4). These two adjustment factors are needed because 

some stoves are not used and because some homes own multiple stoves. Data in Tables 3 

and 4 were obtained by reviewing various national, regional and local surveys. Table 5 is 

a tabulation of year-around occupied housing units, vacant housing units, and seasonal 

housing units. Table 6 is a tabulation of the number of stoves owned determined from 

data from each biennial AHS survey since 1987. 

Three small factors should be noted: (1.) The multiple pellet stove ownership factor that 

was used was unity (one). (2.) The reported percent of pellet stoves that were used versus 

owned varied substantially from study to study probably due to the small sample size for 

pellet stoves. In some cases the value was higher for pellet stoves than for freestanding 

cordwood stoves and in some cases lower. In general it was close and because the effect 

would be small the same overall all percentage was used for all freestanding stoves 

(cordwood plus pellet). (3.) The stoves in vacant houses were included in the tabulations 

of stove ownership but were not included in the calculation of total particulate emissions 

as they are not in use. The vacancy rate in 2009 was 10.5%. 
5 

Table 2 

Vacation/Secondary Home Fireplace and Freestanding Wood Stove Ownership1

Survey

Year 

Own Vacation 

or Secondary 

Home 

Have Fireplace or 

Freestanding Wood 

Stove in Primary 

Home 

Have Fireplace or 

Freestanding Wood 

Stove in Vacation or 

Secondary Home 

Ownership 

Ratio of 

Vacation or 

Secondary 

Home to 

Primary Home 

2006 13% 50% 50% 1.00 

2008 13% 53% 61% 1.15 

2010 10% 52% 56% 1.08 

Mean 12% 52% 56% 1.07 

1Data from references 11-13. 

Table 3 

Cordwood Stove Usage1

Survey Area Sponsor Year(s) Percent2

Minnesota MPCA 2007-08HS3 83.0 

Bay Area, CA BAAQMD 2004 84.2 

2005 74.4 

2006 81.8 

2007 80.0 

Puget Sound Area, WA PSCAA 2007 72.5 

Total U.S. USCPSC 1989 88.4 

Idaho, Washington, Oregon IDEQ 2001 86.0 

Colorado Springs, CO CDH 1992 95.0 

Denver, CO CDH 1988 83.0 

Washoe County, NV WCAQMD 1995-96HS3 77.1 

Mean 82.3 

1Data from references 1-9 

2

(Woodstoves Used)/(Woodstoves Owned) X 100% 

3HS = Heating Season 

MPCA = Minnesota Pollution Control Agency 

BAAQMD = Bay Area Air Quality Management District 

PSCAA = Puget Sound Clean Air Agency 

USCPSC = U.S. Consumer Products Safety Commission 

IDEQ = Idaho Department of Environmental Quality 

CDH = Colorado Department of Health 

WCAQMD = Washoe County Air Quality Management Division 
6 

Table 4 

Multiple Freestanding Cordwood Stove Ownership1

Survey Area Sponsor Year Multiplication 

Factor 

Total U.S. HPBA 2010 1.2 

2008 1.4 

2006 1.3 

2004 1.3 

Puget Sound Area, WA PSCAA 2007 1.1 

Bay Area, CA BAAQMD 2007 1.07 

2006 1.02 

2005 1.13 

2004 1.11 

Total U.S. USPSC 1989 1.09 

Albuquerque, NM CAEHD 1998 1.06 

Wisconsin NCHPA 2000 1.03 

Mean 1.16 

1Data from references 3, 4, 10-15 

HPBA = Hearth, Patio and Barbecue Association 

PSCAA = Puget Sound Clean Air Agency 

BAAQMD = Bay Area Air Quality Management District 

CAEHD = City of Albuquerque Environmental Health Department 

NCHPA = North Central Hearth Product Association 
7 

Table 5 

Year-Around Occupied Housing Units, Vacant Housing Units, and Seasonal 

Housing Units1

Year Total 

Housing 

Units 

(X 1000) 

Year-Around 

Occupied 

Housing Units 

(X 1000) 

Vacant Housing 

Units (X 1000) 

Seasonal 

Housing Units 

(X 1000) 

2010 131,070 112,364 13,977 4726 

2009 130,112 111,806 13,688 4618 

2008 129,157 111,248 13,399 4510 

2007 128,203 110,692 13,109 4402 

2006 126,290 109,782 12,384 4124 

2005 124,377 108,871 11,660 3845 

2004 122,577 107,357 11,514 3706 

2003 120,777 105,842 11,369 3566 

2002 119,486 105,639 10,537 3310 

2001 118,196 105,435 9705 3055 

2000 116,724 104,119 9597 3008 

1999 115,253 102,803 9489 2961 

1998 113,805 101,145 9597 3064 

1997 112,357 99,487 9704 3166 

1996 110.907 98,590 9207 3110 

1995 109,457 97,693 8710 3054 

1994 108,034 96,209 8754 3071 

1993 106,611 94,724 8799 3088 

1992 106,102 93,936 9258 2908 

1991 105,592 93,147 9717 2728 

1990 105,627 93,415 9407 2805 

1989 105,661 93,683 9097 2881 

1988 104,157 92,286 9012 2859 

1987 102,652 90,888 8927 2837 

1Data for even years from references 16-28. Data for odd years are the averages of the proceeding and 

following years. Data for 2010 extrapolated from 2008 and 2009 values. 
Table 6 

Freestanding Wood Stoves Owned Based on American Housing Survey Data1

Year Total Year-Around Occupied Housing Units Vacant 

Housing Units – Freestanding Wood Stoves Owned (X 1000 stoves)†

Seasonal Housing Units – Freestanding Wood Stoves Owned (X 1000 stoves)†

Freestanding Wood Stoves, Main Heating (X 1000 housing units) 

Freestanding Wood Stoves, Other Heating (X 1000 housing units) 

Freestanding Wood Stoves, All Heating (X 1000 housing units) 

Freestanding Wood Stoves Owned (X 1000 stoves)* 

2009 1035 4165 5200 7327 897 323 2007 945 4141** 5086 7169 848 305 2005 896 4117 5013 7063 757 267 2003 1040 4161 5201 7328 787 264 2001 1119 4787 5906 8321 766 258 1999 1113 4599 5712 8048 743 247 1997 1142 4566 5698 8028 777 271 1995 2320 3305 5625 7925 7706 262 1993 2831 3516 6347 8943 831 312 1991 2687 3548 6232 8781 822 276 1989 3087 3871 6958 9804 955 323 1987 3762 3873 7735 10,898 1143 363 1Data from references 16-28 *Total stoves owned = (total occupied housing units using wood stoves for heating) X (1.16 multiple ownership factor/0.823 fraction u

**The 2007 datum for the “other heating” value reported appears to be a typographical error or an outlier and the average of the 2005 a

in place of it and is shown in the table. 

†The same ratio of freestanding woodstoves in occupied housing units to total occupied housing units was applied to the number of vac

seasonal housing units. A further correction was made for seasonal housing units as there appears to be a slightly higher fraction of thewood stoves (See Table 2).
9 

2.2. Total Freestanding Stoves – HPBA 

The Hearth, Patio and Barbecue Association (HPBA) has conducted a “Fireplace and 

Freestanding Stove Lifestyle, Usage and Attitude Study” every other year since 2002 

(2002, 2004, 2006, 2008 and 2010). The results are provided to HPBA members. The 

goal of the studies is to understand how consumers relate to the hearth products produced 

by the hearth industry. The hearth industry uses the data to improve 

marketing/advertising programs and product development strategies. HPBA uses the 

results to promote/protect the hearth industry. 

Data from the 2006, 2008 and 2010 studies provided the fraction of occupied housing 

units in the U.S. that owned a freestanding cordwood stove and a pellet stove. Because it 

is probable that if a home occupant had a pellet insert it would be viewed as a pellet 

“stove” the pellet stove fraction provided in the 2006, 2008, and 2010 surveys was 

reduced by the ratio of freestanding pellet stoves to the sum of freestanding pellet stoves 

plus pellet-fueled fireplace inserts. The cumulative number of freestanding pellet stoves 

and pellet-fueled fireplace inserts shipped up to the years 2006, 2008, and 2010, 

respectively, obtained from hearth industry shipment records were used. (See Section 

2.5.) 

The fraction of consumer households that own a freestanding cordwood stove plus a 

freestanding pellet stove were multiplied by the number of housing units in each of the 

three years obtained from the U.S. Census Bureau data. These numbers where then 

multiplied by the multiple ownership factor determined from each survey. Table 7 is a 

compilation of results. As with the American Housing Survey data, adjustments for 

vacant housing units and seasonal housing units were made.
10 

Table 7 

Freestanding Wood Stoves Owned Based on Hearth, Patio and Barbecue 

Association Data1

Year Occupied 

housing 

units 

(X 1000) 

Fraction of 

consumers 

that own a 

freestanding 

cordwood 

stove 

Fraction 

of 

consumers 

that own a 

pellet 

“stove” 

Fraction of 

consumers 

that own a 

freestanding 

pellet stove2

Multiple 

ownership 

factor 

cordwood 

stoves3

Total 

freestanding 

wood stoves 

owned 

(X 1000) 

2010 113,000 0.0598 0.0130 0.0100 1.2 9241 

2008 111,249 0.0473 0.0111 0.0086 1.4 8319 

2006 109,782 0.0560 0.0090 0.0070 1.3 8753 

Table 7 (continued) 

Freestanding Wood Stoves Owned Based on Hearth, Patio and Barbecue 

Association Data1

Year Vacant 

housing 

units 

(X 1000 

stoves) 

Seasonal 

housing 

units 

(X 1000 

stoves) 

Vacant 

Housing Units 

– Freestanding 

Wood Stoves 

Owned 

(X 1000 

stoves)4

Seasonal 

Housing Units – 

Freestanding 

Wood Stoves 

Owned 

(X 1000 stoves)4

Total Housing 

Units – 

Freestanding 

Wood Stoves 

Owned 

(X 1000 stoves) 

2010 13,977 4726 1149 416 10,806 

2008 13,399 4510 1002 361 9682 

2006 12,384 4124 987 352 10,122 

1Data from references 11-13 

2

It was assumed that most survey respondents when ask if they owned a pellet stove would respond “yes” 

whether it was an insert or a freestanding unit. The fraction of consumers that owned a pellet stove was 

reduced by the ratio of freestanding pellet stoves to total pellet units sold based on HPBA shipment data. 

This ratio was: 1,048,681/(1,048,681 + 311,749) = 0.771 

3The individual multiple ownership factor for freestanding cordwood stoves determined from each survey 

was used rather than the average value of 1.16 determined from averaging the various national, state, local 

surveys (Table 4). A multiple ownership factor of 1 was used for pellet stoves. 

4The same ratio of freestanding woodstoves in occupied housing units to total occupied housing units was 

applied to the number of vacant housing units and seasonal housing units. A further correction was made 

for seasonal housing units as there appears to be a slightly higher fraction of them that have freestanding 

wood stoves (See Table 2). 
11 

2.3. Total Freestanding Stoves – Mediamark Research 

Mediamark has conducted surveys of demographics, product usage, and media exposure 

in the 48 contiguous states since 1979. The purpose of the surveys is to provide the 

advertising industry with detailed demographic and marketing segments of media 

audiences. In the “appliances for climate control” section of the survey the number of 

households having a “coal/wood stove” and a “wood pellet stove” are tallied. The 

number of coal stoves in the Unites States is insignificant as compared to the number of 

wood stoves and hence the “coal/wood stove” is primarily only wood stoves. Old reports 

for the years 1999, 1995, 1994, 1990, and 1989 were obtained from university libraries. 

The number of housing units was multiplied by the mean multiple use factor (See Table 

4.) to calculate the total freestanding wood stoves owned (Table 8).
Table 8 

Freestanding Wood Stoves Owned Based on Mediamark Research Data1 

Year Year-Around 

Occupied Housing Units ( X 1000) 

Vacant Housing Units ( X 1000) 

Seasonal Housing Units ( X 1000) 

Households that own a freestanding cordwood stove ( X 1000) 

Freestanding cordwood stoves in year-around occupied + seasonal housing units ( X 1000 stoves)2

Households that own a freestanding pstove + pellet insert ( X 1000) 

1999 102,803 9489 2961 5284 6922 523 1995 97,693 8710 3054 5342 6998 360 1994 96,209 8754 3071 5955 7801 532 1990 93,415 9407 2805 8400 11,004 ND 1989 93,683 9097 2881 7497 9821 ND 

Table 8 (continued) 

Freestanding Wood Stoves Owned Based on Mediamark Research Data1 

Year Freestanding 

pellet stoves in year-around occupied + seasonal units (X 1000 stoves)4

Freestanding wood stoves (pellet + cordwood) in year-around + seasonal units ( X 1000 stoves) 

Freestanding wood stoves (pellet + cordwood) in vacant units ( X 1000 stoves) 

Total freestanding wood stoves (pellet + cordwood) in housing units ( X 1000 stoves) 

1999 455 7377 661 8038 1995 406 7404 640 8044 1994 463 8264 728 8992 1990 - 11,004 961 11,965 1989 - 9821 925 10,746 
1Data from reference 29 2Cordwood stoves in year-around occupied and seasonal housing units = (households that own a freestanding cordwood stoves) X (1.16 

factor) X (1.13 for a second home). The 1.13 factor is calculated from 12% X 1.07 – See Table 2. 

3It was assumed that most survey respondents when ask if they owned a pellet stove would respond “yes” whether it was an insert or a 

fraction of consumers that owned a pellet stove was reduced by the ratio of freestanding pellet stoves to total pellet units sold based on 

This ratio was: 1,048,681/(1,048,681 + 311,749) = 0.771. 

4Pellet stoves in year around occupied and seasonal housing units = (households that own a pellet stove) X (1.0 multiple ownership fact

home). 
14 

2.4. Total Freestanding Stoves – Simmons Market Research 

Simmons Market Research was founded in 1950 and conducts regular surveys on 

lifestyles, media habits, and product/brand preferences of American families. One of the 

parameters tallied is the ownership of “wood-burning stove/heater”. As the results are 

tabulated per adult over 18 years of age the values need to be divided by 2.59 which is 

the average number of adults over 18 years old per household in the United States. Once 

the number of households owning a woodstove was determined that value was then 

multiplied by the average multiple use factor of 1.16 (See Table 4.) Data were obtained 

directly from Simmons. (See reference 30.) Table 9 is a compilation of the results for all 

years. 
15 

Table 9 

Freestanding Wood Stoves Owned Based on Simmons Market Research Bureau 

Data1

Year Adults 18+ 

yrs old that 

own a 

freestanding 

wood stove 

(X 1000) 

Households 

that own a 

freestanding 

wood stove 

(X 1000)2

Freestanding 

wood stoves 

owned in yeararound occupied 

+ seasonal units 

(X 1000 stoves) 

Freestanding 

wood stoves 

owned in vacant 

units (X 1000 

stoves 

Total 

freestanding 

wood stoves 

in housing 

units ( X 1000 

stoves) 

2010 14,601 5637 7384 882 8266 

2009 18,015 6956 9112 1071 10,183 

2008 17,976 6941 9093 1053 10,146 

2007 14,615 5643 7392 842 8234 

2006 16,716 6454 8456 919 9375 

2005 15,145 5847 7660 795 8455 

2004 15,351 5927 7764 690 7770 

2003 15,413 5951 7796 809 8605 

2002 15,377 5937 7777 752 8532 

2001 14,878 5744 7525 673 8198 

2000 14,305 5523 7235 648 7883 

1999 14,756 5697 7463 670 8133 

1998 14,961 5776 7567 697 8264 

1997 17,024 6573 8611 814 9425 

1996 18,467 7130 9340 845 10,185 

1995 15,297 5906 7737 669 8406 

1994 15,086 5825 7631 673 8304 

1993 15,285 5902 7732 695 8427 

1992 16,896 6524 8546 816 9362 

1991 14,835 5728 7504 764 8268 

1990 18,358 7088 9285 908 10,193 

1989 16,855 6508 8525 803 9328 

1988 16,277 6284 8232 780 9012 

1987 19,643 7584 9935 946 10,881 

1Data from reference 30 

2Average of 2.59 adults over the age of 18 per household 

3Multiple ownership factor of 1.16 and 1.13 for seasonal used 

2.5. Certified Freestanding Cordwood Stove and Freestanding Pellet Stove 

Ownership 

The annual manufacturers’ shipment records of hearth products have been maintained 

since 1989. It has been assumed that manufacturers’ shipment records are a reasonable 

surrogate for appliance sales in any given year. Records were compiled by the firm of 
16 

Smith, Bucklin & Associates for the HPBA from 1989 to 1997. Records have been 

compiled directly by the HPBA from 1999 to present. No records were compiled in 

1998. The data for 1999 were used to estimate 1998 data as per HPBA’s 

recommendation. No surveys were conducted in 1987 or 1988. Data for 1989 were used 

to estimate shipments for those two years. 

The NSPS requirements were phased in over a four year period which has caused some 

confusion with the certification status of units bought during that period or in the years 

immediately proceeding the action dates due to some manufacturers being proactive and 

manufacturing heaters that were certifiable before the deadlines. (See Table 1 for dates.) 

It was estimated that 50%, 70%, 80% and 90% of the freestanding cordwood models sold 

in the years of 1987, 1988, 1989, and 1990, respectively were certified or certifiable 

models. According to interviews with hearth industry personnel an insignificant number 

of pellet stoves were sold before 1989. Also according to interviews with hearth industry 

personnel is was estimated that the surveys conducted annually from 1989 to 1997 

captured approximately 75% of the units sold and the surveys conducted from 1999 to 

present captured approximately 90% of the units sold. Catalytic and non-catalytic 

tabulations were added to provide the total for freestanding cordwood stoves. Table 10 

lists the estimated number of certified freestanding cordwood stoves sold per year since 

1987. Table 11 lists the estimated number of pellet stoves sold per year since 1987. 

Table 12 lists the estimated number of pellet-fueled fireplace inserts sold per year since 

1987. The number of pellet-fueled fireplaces sold per year was not a direct part of this 

analysis but the numbers were needed to adjust the total number of pellet heaters sold to 

just freestanding units. (See Section 2.2.) 

To avoid “double counting,” the HPBA shipment data were adjusted (reduced) by an 

estimate of the freestanding certified stoves and pellets stoves that have been replaced by 

newer freestanding certified cordwood stoves or pellet stoves since 1987. These 

estimates were obtained by a survey of 22 well-established hearth dealers that have been 

in business since 1989 and that were geographically distributed throughout the United 

States. Overall, 22 surveys were completed. Table 13 is a list of the questions. Figure 1 

is a map showing the geographical distribution of the dealerships. The questions asked 

for the retailer’s best professional judgment of how frequently they replaced a certified 

freestanding cordwood stove or an existing pellet stove (certified or uncertified) with a 

certified cordwood stove or a new pellet stove. Further, the survey requested the retailers 

estimates of how many of those certified stoves and pellet stoves were completely 

removed from service and did not enter the used market. 

Table 14 is a tabulation of the responses to the questions. For retailers that did not sell 

pellet stoves a “na” (not applicable) is reported as a result. If a question referenced a 

preceding question with a zero percent response, a “na” was also reported. One outlier 

was removed because it is believed the retailer thought the surveyor was asking about 

uncertified wood stoves. In addition, there were three retailers (one in Georgia, two in 

Florida) who said they did not replace any existing certified stoves (many uncertified 

stoves were replaced) over the last 20 years. 
17 

Table 10 

Certified Freestanding Cordwood Stove Shipments (Sales)1

Year HPBA 

Shipment 

Data 

Assumptions Certified Units 

Shipped 

Cumulative 

Number 

Shipped 

1987 - 50% certified models, total 

shipment = 1989 shipment, 

75% data capture 

54,995 54,995 

1988 - 70% certified models, total 

shipment = 1989 shipment, 

75% data capture 

76,993 131,988 

1989 82,699 80% certified, 75% data 

capture 

87,992 219,980 

1990 111,747 90% certified, 75% data 

capture 

133,761 353,741 

1991 118,936 75% data capture 158,185 511,926 

1992 94,322 75% data capture 125,448 637,374 

1993 90,121 75% data capture 119.861 757,235 

1994 80,975 75% data capture 107,697 864,932 

1995 61,886 75% data capture 82,308 947,240 

1996 63,590 75% data capture 84,755 1,031,815 

1997 66,733 75% data capture 88,755 1,120,570 

1998 - total shipment = 1999 

shipment, 90% data 

capture 

134,222 1,254,792 

1999 134,223 90% data capture 134,222 1,389,014 

2000 85,528 90% data capture 94,936 1,483,950 

2001 124,570 90% data capture 138,273 1,622,223 

2002 82,601 90% data capture 91,687 1,713,910 

2003 77,224 90% data capture 85,719 1,799,629 

2004 79,009 90% data capture 87,700 1,887,328 

2005 98,219 90% data capture 109,023 1,996,352 

2006 101,586 90% data capture 112,760 2,109,112 

2007 74,710 90% data capture 82,928 2,192,040 

2008 127,124 90% data capture 141,108 2,333,148 

2009 95,938 90% data capture 106,491 2,439,639 

2010 86,852 90% data capture 96,407 2,536,046 

1Data from references 31 & 32. 
18 

Table 11 

Freestanding Pellet Stove Shipments (Sales)1

Year HPBA 

Shipment 

Data 

Assumptions Units Shipped Cumulative 

Number 

Shipped 

1987 - Insignificant number 

shipped 

- - 

1988 - Insignificant number 

shipped 

- - 

1989 5952 75% data capture 7916 7916 

1990 22,895 75% data capture 30,450 38,366 

1991 31,288 75% data capture 41,613 79,979 

1992 31,294 75% data capture 41,621 121,600 

1993 44,090 75% data capture 58,646 180,246 

1994 41,810 75% data capture 55,607 235,853 

1995 25,830 75% data capture 34,354 270,207 

1996 18,147 75% data capture 24,135 294,342 

1997 19,599 75% data capture 26,067 320,409 

1998 14,412 total shipment = 1999 

shipment, 90% data 

capture 

15,997 336,406 

1999 14,412 90% data capture 15,997 352,403 

2000 27,182 90% data capture 30,172 382,578 

2001 43,500 90% data capture 48,285 430,863 

2002 26,990 90% data capture 29,959 460,822 

2003 38,700 90% data capture 42,957 503,779 

2004 54,234 90% data capture 60,200 563,979 

2005 99,861 90% data capture 110,846 674,825 

2006 107,344 90% data capture 119,152 793,977 

2007 42,442 90% data capture 47,111 841,088 

2008 118,401 90% data capture 131,425 972,513 

2009 35,609 90% data capture 39,526 1,012,039 

2010 33,011 90% data capture 36,642 1,048,681 

1Data from references 31 & 32. 
19 

Table 12 

Pellet-Fueled Fireplace Insert Shipments (Sales)1 

Year HPBA 

Shipment 

Data 

Assumptions Units Shipped Cumulative 

Number 

Shipped 

1987 - Insignificant number 

shipped 

- - 

1988 - Insignificant number 

shipped 

- - 

1989 2739 75% data capture 3643 3643 

1990 12,736 75% data capture 16,939 20,582 

1991 15,061 75% data capture 20,031 40,613 

1992 16,867 75% data capture 22,433 63,046 

1993 19,078 75% data capture 25,373 88,419 

1994 18,631 75% data capture 24,779 113,196 

1995 9247 75% data capture 12,299 125,499 

1996 6400 75% data capture 8512 131,009 

1997 6439 75% data capture 8564 142,573 

1998 3948 total shipment = 1999 

shipment, 90% data 

capture 

4382 146,955 

1999 3948 90% data capture 4382 151,337 

2000 3788 90% data capture 4204 155,541 

2001 9973 90% data capture 11,070 166,611 

2002 6988 90% data capture 7757 174,368 

2003 9969 90% data capture 11,065 185,433 

2004 13,233 90% data capture 14,689 200,122 

2005 18,629 90% data capture 20,678 220,800 

2006 25,761 90% data capture 28,595 249,395 

2007 11,590 90% data capture 12,865 262,260 

2008 22,807 90% data capture 25,316 287,576 

2009 10,521 90% data capture 11,678 299,254 

2010 11,258 90% data capture 12,496 311,749 

1Data from references 31 & 32. 
Figure 1. Map of the U.S. Showing Geographical Distribution of the Survey Respondents. 
21 

Table 13 

List of Retailer Questions 

---------------------------------------------------------------------------------------------------------- 

 1. Between the years 1989 and 1999 what percentage of new freestanding certified 

cordwood stoves that you sold replaced already certified models? 

 2. Between the years 1989 and 1999 what percentage of new freestanding pellet stoves 

that you sold replaced already certified wood stoves? 

 3. Between 1989 and 1999 what percentage of those replaced EPA wood stoves are 

removed from service and do not enter the used market? 

 4. Between the year 2000 and present what percentage of new freestanding certified 

cordwood stoves that you sold replaced already certified models? 

 5. Between the years 2000 and present what percentage of new freestanding pellet stoves 

that you sold replaced already certified wood stoves? 

 6. Between the year 2000 and present what percentage of those replaced EPA woodstoves 

are removed from service and do not enter the used market? 

 7. Between the years 1989 and 1999 what percentage of new freestanding pellet stoves 

that you sold replaced existing pellet stoves?

 8. Between 1989 and 1999 what percentage of those replaced pellet stoves are removed 

from service and do not enter the used market? 

 9. Between the year 2000 and present what percentage of new freestanding pellet stoves 

that you sold replaced existing pellet stoves? 

 10. Between the year 2000 and present what percentage of those replaced pellet stoves 

are removed from service and do not enter the used market? 

 11. What percent of pellet stoves or certified freestanding wood stoves are replaced with 

gas appliances you sold? 

---------------------------------------------------------------------------------------------------------- 
Table 14 

Results of the Survey Questions from Twenty-Two Wood Stove Retailers (values are percen

Retailer City/Town State Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 

1 Fairbanks AK 1 na 50 2 5 80 na na 2 Oroville CA 1.5 1 100 15 20 95 na na 3 Wilmington DE 0 0 na 1 0 100 0 na 4 Tallahassee FL 0 na na 0 na na na na 5 Gainesville FL 0 na na 0 na na na na 6 Bremen GA 10 na 50 45 na 50 na na 7 Jefferson GA 0 na na 0 na na na na 8 Wichita KS 1 1 20 1 3 20 1 100 9 Auburn ME 25 10 50 20 35 15 1 0.5 

10 Cadillac MI 4 2 0 10 20 0 0 na 11 Minneapolis MN 10 na 5 50 na 80 na na 12 Missoula MT 0.5 0.5 100 3 1 100 50 100 13 Oakhurst NJ 0 0 na 10 5 0 0 na 14 Portland OR 5 2 5 8 7 0.5 5 6 15 Grants Pass OR 0.5 5 5 1 15 5 20 5 16 Pleasant Gap PA 13 5 5 35 15 55 10 0.5 17 Kingsley PA 7 10 2 15 20 10 8 5 18 Tyler TX 35 na 25 20 na 25 na na 19 Brattleboro VT 2 2 100 10 30 75 2 100 20 Laramie WY 2 10 0 10 20 0 10 50 21 Seattle WA 5 na 0 20 na 3 na na 22 Mt. Vernon WA 15 3 70 10 12.5 90 15 5 

Mean 6.25 3.68 34.53 13.00 13.90 42.29 9.38 37.20 

na – not applicable, nd – no data (if the retailer was short on time the 11th question was not asked as it did not directly pertain to the obj1See Table 13 for list of questions, data from reference 33. 
23 

The questions were broken up into to time blocks, 1989-1999 and 2000-present, as it was 

believed that there may be a significant difference in change out frequency in the first 

nominal decade as compared to the second as, on the one hand, the earliest certified 

cordwood stoves and pellets stoves are believed to have been less robust than more recent 

models but, on the other hand, it is reasonable to assume as the population of wood stoves 

ages more will be replaced by newer ones. The questions focused on the number of 

existing certified cordwood stoves being replaced by either new certified cordwood 

stoves or pellet stoves and the number of existing pellet stoves being replaced by new 

pellet stoves. It was believed that the number of existing pellet stoves that were replaced 

by new certified cordwood stoves was small and that question was not asked to simplify 

the survey. 

Table 15 shows the calculation of the number of freestanding certified cordwood stoves 

that were replaced by new freestanding certified cordwood stoves or pellet stoves and 

that were taken out of service through 1999. Table 16 shows the calculation of the 

number of freestanding certified cordwood stoves that were replaced by new freestanding 

certified cordwood stoves or pellet stoves and that were taken out of service from 2000 

through 2010. Table 17 shows the calculation of the number of freestanding pellet stoves 

that were replaced by new pellet stoves and that were taken out of service through 1999. 

Table 18 shows the calculation of the number of pellet stoves that were replaced by new 

pellet stoves and that were taken out of service from 2000 through 2009. 

Table 19 is a summary of the replacement of existing freestanding certified cordwood 

stoves and pellet stoves with new freestanding certified cordwood stoves and pellet 

stoves as of 2010. The results show that 138,444 freestanding certified cordwood stoves 

were replaced by new freestanding certified cordwood stoves or pellet stoves and taken 

out of service as of 2010 which is 5.46% of the total sold. For freestanding pellet stoves 

67,193 of those that have been sold have been replaced by new freestanding pellet stoves 

and have been taken out of service as of 2010 which is 6.40% of the total sold. 

From the survey data and the HPBA shipment data the cumulative net number of the 

certified cordwood stoves and pellet stoves increase in homes annually could be 

estimated. This was done by doing a best curve fit of the survey data (Figures 2 and 3) to 

obtain annual values of the number of certified cordwood stoves and pellet stoves 

replaced by new units and also taken out of service which was then subtracted from the 

annual shipment data. Table 20 shows the annual data for certified cordwood stoves. 

Table 21 shows the annual data for pellet stoves. 
24 

Table 15 

Freestanding Certified Cordwood Stoves That Were Replaced by New Freestanding 

Certified Cordwood Stoves or Pellet Stoves and That were Taken Out of Service 

through 1999

Description Numerical Values 

Cumulative certified freestanding stoves sold 

(shipped) through 1999 

1,389,014 

Cumulative freestanding pellet stoves sold (shipped) 

through 1999 

352,403 

Percent/Number of certified freestanding cordwood 

stoves sold that replaced existing freestanding 

certified cordwood stoves through 1999 

6.25% 

(0.0625 X 1,389,014) = 86,813 

Percent/Number of freestanding pellet stoves sold 

that replaced existing freestanding certified cordwood 

stoves through 1999 

3.68% 

(0.0368 X 352,403) = 12,968 

Total number of freestanding certified cordwood 

stoves that were replaced by either new certified 

cordwood stoves or pellet stoves through 1999 

86,813 + 12,968 = 99,781 

Percent/Number that were replaced and taken out of 

service (did not enter the used market) through 1999 

34.53% 

(0.3453 X 99,781) = 34,454
25 

Table 16 

Freestanding Certified Cordwood Stoves That Were Replaced by New Freestanding 

Certified Cordwood Stoves or Pellet Stoves and That were Taken Out of Service 

from 2000 to 2010

Description Numerical Values 

Cumulative certified freestanding stoves sold 

(shipped) from 2000 to 2010 

2,536,046 - 1,389,014 = 

1,147,032 

Cumulative freestanding pellet stoves sold (shipped) 

from 2000 to 2010 

1,048,681 – 353,403 = 696,278 

Percent/Number of certified freestanding cordwood 

stoves sold that replaced existing freestanding 

certified cordwood stoves from 2000 to 2010 

13.00% 

(0.1300 X 1,147,032) = 149,114 

Percent/Number of freestanding pellet stoves sold 

that replaced existing freestanding certified cordwood 

stoves from 2000 to 2010 

13.90% 

(0.1390 X 696,278) = 96,783 

Total number of freestanding certified cordwood 

stoves that were replaced by either new certified 

cordwood stoves or pellet stoves from 2000 to 2010 

149,1114 + 96,783 = 245,897 

Percent/Number that were replaced and taken out of 

service (did not enter the used market) from 2000 to 

2010 

42.29% 

(0.4229 X 245,847) = 103,990

Table 17 

Freestanding Pellet Stoves that Were Replaced by New Freestanding Pellet Stoves 

and That Were Taken Out of Service through 1999

Description Numerical Values 

Cumulative freestanding pellet stoves sold (shipped) 

through 1999 

352,403 

Percent/Number of freestanding pellet stoves sold 

that replaced existing pellet stoves through 1999 

9.38% 

(0.0938 X 352,403) = 33,055 

Percent/Number that were replaced and taken out of 

service (did not enter the used market) through 1999 

37.20% 

(0.3720 X 33,055) = 12,296
26 

Table 18 

Freestanding Pellet Stoves that Were Replaced by New Freestanding Pellet Stoves 

and That Were Taken Out of Service from 2000 to 2010

Description Numerical Values 

Cumulative freestanding pellet stoves sold (shipped) 

from 2000 to 2010 

1,048,681 – 352,403 = 696,278 

Percent/Number of freestanding pellet stoves sold 

that replaced existing pellet stoves from 2000 to 2010 

17.67% 

(0.1767 X 696,278) = 123,032 

Percent/Number that were replaced and taken out of 

service (did not enter the used market) from 2000 to 

2010 

44.62% 

(0.4462 X 123,032) = 54,897

Table 19 

Summary of the Replacement of Existing Freestanding Certified Cordwood Stoves 

and Pellet Stoves with New Freestanding Certified Cordwood Stoves and Pellet 

Stoves as of 2010 

Description Numerical Values 

Total freestanding certified cordwood stoves replaced 

by new freestanding certified cordwood stoves or 

pellet stoves and taken out of service (as of 2010)

34,454 + 103,990 = 138,444 

Total freestanding certified cordwood stoves in 

homes as of 2010 

2,536,046 – 138,444 = 2,397,602 

Percent of freestanding certified cordwood stoves that 

have been sold that have been replaced by new 

freestanding certified cordwood stoves or pellet 

stoves and have been taken out of service as of 2010 

(138,444/2,536,046) X 100% = 

5.46% 

Total freestanding pellet stoves replaced by new 

freestanding pellet stoves and taken out of service (as 

of 2010) 

12,296 + 54,897 = 67,193 

Total freestanding pellet stoves in homes as of 2010 1,048,681 – 67,193 = 981,488 

Percent of freestanding pellet stoves that have been 

sold that have been replaced by new freestanding 

pellet stoves and have been taken out of service as of 

2010 

(67,193/1,048,681) X 100% = 

6.40% 
27 

Figure 2. Cumulative Number of Certified Freestanding Cordwood Stoves Replaced by 

New Certified Freestanding Cordwood Stoves or Pellet Stoves. 

Figure 3. Cumulative Number of Freestanding Pellet Stoves Replaced by New 

Freestanding Pellet Stoves. 
28 

Table 20 

Certified Freestanding Cordwood Stoves in Homes 

Year Units shipped Cumulative 

Number 

Shipped 

Annual 

Number 

Replaced by 

New 

Freestanding 

Certified 

Cordwood 

Stoves or 

Pellet Stoves 

Cumulative 

Number 

Replaced by 

New 

Freestanding 

Certified 

Cordwood 

Stoves or 

Pellet Stoves 

Cumulative 

Number of 

Freestanding 

Certified 

Cordwood 

Stoves in 

Homes 

1987 54,995 54,995 0 0 54,995 

1988 76,993 131,988 0 0 131,988 

1989 87,992 219,980 0 0 219,980 

1990 133,761 353,741 868 868 352,873 

1991 158,185 511,926 1,440 2,308 509,618 

1992 125,448 637,374 2,013 4,321 633,053 

1993 119.861 757,235 2,585 6,906 750,329 

1994 107,697 864,932 3,157 10,063 854,869 

1995 82,308 947,240 3,730 13,793 933,447 

1996 84,755 1,031,815 4,302 18,095 1,013,720 

1997 88,755 1,120,570 4,875 22,969 1,097,601 

1998 134,222 1,254,792 5,447 28,416 1,226,376 

1999 134,222 1,389,014 6,038 34,454 1,354,560 

2000 94,936 1,483,950 6,573 41,027 1,442,923 

2001 138,273 1,622,223 7,164 48,191 1,574,032 

2002 91,687 1,713,910 7,736 55,928 1,657,982 

2003 85,719 1,799,629 8,309 64,236 1,735,393 

2004 87,700 1,887,328 8,881 73,118 1,814,210 

2005 109,023 1,996,352 9,454 82,571 1,913,781 

2006 112,760 2,109,112 10,026 92,597 2,016,515 

2007 82,928 2,192,040 10,598 103,196 2,088,844 

2008 141,108 2,333,148 11,171 114,366 2,218,782 

2009 106,491 2,439,639 11,743 126,110 2,313,529 

2010 96,407 2,536,046 12,334 138,444 2,397,602 
29 

Table 21 

Freestanding Pellet Stoves in Homes 

Year Units 

Shipped 

Cumulative 

Number 

Shipped 

Annual 

Number 

Replaced by 

New 

Freestanding 

Pellet Stoves 

Cumulative 

Number 

Replaced by 

New 

Freestanding 

Pellet Stoves 

Cumulative 

Number of 

Freestanding 

Pellet 

Stoves in 

Homes 

1987 - - 0 0 0 

1988 - - 0 0 0 

1989 7916 7916 0 0 7,916 

1990 30,450 38,366 243 243 38,123 

1991 41,613 79,979 389 632 79,347 

1992 41,621 121,600 579 1,211 120,389 

1993 58,646 180,246 790 2,001 178,245 

1994 55,607 235,853 1,021 3,022 232,831 

1995 34,354 270,207 1,272 4,294 265,913 

1996 24,135 294,342 1,543 5,838 288,504 

1997 26,067 320,409 1,834 7,672 312,737 

1998 15,997 336,406 2,146 9,818 326,588 

1999 15,997 352,403 2,478 12,296 340,107 

2000 30,172 382,578 2,829 15,125 367,453 

2001 48,285 430,863 3,201 18,326 412,537 

2002 29,959 460,822 3,593 21,919 438,903 

2003 42,957 503,779 4,005 25,924 477,855 

2004 60,200 563,979 4,438 30,362 533,617 

2005 110,846 674,825 4,890 35,252 639,573 

2006 119,152 793,977 5,363 40,614 753,363 

2007 47,111 841,088 5,855 46,470 794,618 

2008 131,425 972,513 6,368 52,838 919,675 

2009 39,526 1,012,039 6,901 59,739 952,300 

2010 36,642 1,048,681 7,454 67,193 981,488 

2.6 Particulate Emission Factors and Wood Usage 

The total annual particulate emissions by freestanding cordwood stove category can be 

calculated from: (1) the number of stoves owned by category, (2) the fraction of those 

that are owned that are used, (3) their respective emission factors, (4) their respective 

efficiencies which allows for the average national fuel usage in freestanding stoves to be 

adjusted appropriately (higher efficiency units use less fuel for the same heat demand), 

and, (5) the national average amount of fuel used per freestanding stove unit. Table 22 is 

a tabulation of these values. Except for pellet stoves, emission factors were from the 

standard U.S. EPA AP-42 emission factor compilation document. Pellet stove emission 
30 

factors were obtained from various literature sources as the AP-42 data are from two old 

studies with long obsolete pellet stove models. Annual national average fuel usage 

values per stove were obtained from U.S. DOE reports and adjusted by stove category 

with efficiencies provided in AP-42. 

Table 22 

Number of Freestanding Stoves in Homes by Category (2010), Emission Factors, 

Efficiencies, and Fuel Usage1

Category Number 

in 

Occupied 

Homes* 

(2010) 

Number 

in Use* 

Emission 

Factors 

(g/kg) 

Efficiency 

(%) 

Fuel/UnitYear 

Freestanding Uncertified 

Conventional Cordwood 

Stoves 

5,278,830 4,344,057 15.3 54 1.75 cords 

(2.04 dry 

tons) 

Freestanding Certified 

Catalytic Cordwood 

Stoves 

493,311 405,996 8.1 72 1.31 cords 

(1.62 dry 

tons 

Freestanding Certified 

Non-Catalytic Cordwood 

Stoves 

1,562,153 1,285,652 7.3 68 1.39 cords 

(1.52 dry 

tons) 

Freestanding Pellet 

Stoves 

841,429 692,496 1.5 78 1.41dry 

tons 

Total/Weighted Average 8,175,213 6,728,200 11.9 60 1.85 dry 

tons 

*Freestanding stoves in seasonal housing units were not included in the tabulations as seasonal homes 

represent only 4% of the total number of occupied housing units and in addition it is reasonable to assume 

that stoves in them are used less frequently than stoves in year-around occupied housing units. Based on 

HPBA shipment records for proportioned shipments between catalytic and non-catalytic stoves available 

for some years it was estimated that 24% of the certified cordwood stoves are catalytic and 76% are noncatalytic. The fraction of freestanding woodstoves owned that are used has been estimated as 0.823. The 

conversion factor from cords to dry tons used was 1.163 dry tons/cord. Data from references 34-40.

3. Results 

As four different sources of data were used to estimate the annual number of freestanding 

woodstoves owned each year, when data from more than one was available for a given 

year, the mean was calculated and used. Table 23 is a compilation of the estimates per 

year from each of the four sources and the mean value used for the calculation of 

percentage of freestanding stoves owned that are high-technology stoves (certified 

cordwood stoves plus pellet stoves). 

Table 24 is a summary compilation of: (1) cumulative certified freestanding cordwood 

stoves in homes by year since 1987, (2) cumulative freestanding pellet stoves in homes 

by year since 1987, (3) the sum of cumulative freestanding certified cordwood and pellet 
31 

stoves in homes by year since 1987, (4) the number of freestanding wood stoves owned 

each year since 1987, and, (5) the percent of total freestanding wood stoves that are 

certified cordwood and pellet stoves each year since 1987. As of the end of 2010, 35.4% 

of the total freestanding wood stoves owned in the United States were either freestanding 

certified cordwood stoves or pellet stoves. 

Table 23 

Summary of Freestanding Wood Stove Ownership Estimates1

 

Year Source of Data Mean 

(units X 

1000) 

AHS 

(units X 1000) 

HPBA 

(units X 1000)

Mediamark 

(units X 1000)

Simmons 

(units X 1000) 

1987 12,404 10,881 11,643 

1988 9012 9012 

1989 11,082 10,746 9328 10,385 

1990 11,965 10,193 11,079 

1991 9879 8268 9074 

1992 9362 9362 

1993 10,086 8427 9257 

1994 8992 8304 8648 

1995 8893 8044 8406 8448 

1996 10,185 10,185 

1997 9076 9425 9251 

1998 8264 8264 

1999 9038 8038 8133 8370 

2000 7883 7883 

2001 9345 8198 8772 

2002 8532 8532 

2003 8379 8605 8492 

2004 7770 7770 

2005 8087 8455 8271 

2006 10,122 9375 9749 

2007 8322 8234 8278 

2008 9682 10,146 9914 

2009 8547 10,183 9365 

2010 10,806 8266 9536 

1Data from references 11-13, 16-29, 31 
32 

Table 24 

Cumulative Data, Number of Freestanding Wood Stoves Owned, and Percent of the 

Total Freestanding Wood Stoves Owned That Are Certified Freestanding 

Cordwood Stoves and Freestanding Pellet Stoves 

Year Cumulative 

Certified 

Freestanding 

Cordwood 

Stoves in 

Homes 

Cumulative 

Freestanding 

Pellet Stoves 

in Homes 

Sum of 

Cumulative 

Freestanding 

Certified 

Cordwood 

and Pellet 

Stoves in 

Homes 

Number of 

Freestanding 

Wood Stoves 

Owned 

Percent of 

Total 

Freestanding 

Wood Stoves 

That Are 

Certified 

Cordwood and 

Pellet Stoves 

1987 54,995 0 54,995 11,643,000 0.5% 

1988 131,988 0 131,988 9,012,000 1.5% 

1989 219,980 7,916 227,896 10,385,000 2.2% 

1990 352,873 38,123 390,996 11,079,000 3.5% 

1991 509,618 79,347 588,965 9,074,000 6.5% 

1992 633,053 120,389 753,442 9,362,000 8.0% 

1993 750,329 178,245 928,574 9,257,000 10.0% 

1994 854,869 232,831 1,087,700 8,648,000 12.6% 

1995 933,447 265,913 1,199,360 8,448,000 14.2% 

1996 1,013,720 288,504 1,302,224 10,185,000 12.8% 

1997 1,097,601 312,737 1,410,338 9,251,000 15.2% 

1998 1,226,376 326,588 1,552,964 8,264,000 18.8% 

1999 1,354,560 340,107 1,694,667 8,370,000 20.2% 

2000 1,442,923 367,453 1,810,376 7,883,000 23.0% 

2001 1,574,032 412,537 1,986,569 8,772,000 22.6% 

2002 1,657,982 438,903 2,096,885 8,532,000 24.6% 

2003 1,735,393 477,855 2,213,248 8,492,000 26.1% 

2004 1,814,210 533,617 2,347,827 7,770,000 30.2% 

2005 1,913,781 639,573 2,553,354 8,271,000 30.9% 

2006 2,016,515 753,363 2,769,878 9,749,000 28.4% 

2007 2,088,844 794,618 2,883,462 8,278,000 34.8% 

2008 2,218,782 919,675 3,138,457 9,914,000 31.7% 

2009 2,313,529 952,300 3,265,829 9,365,000 34.9% 

2010 2,397,602 981,488 3,379,090 9,536,000 35.4% 

Table 25 lists the national particulate emissions by freestanding wood stove category for 

2010 and the percentage each represented of the total for freestanding wood stoves that 

year. In 2010, uncertified cordwood stoves were responsible for 86% of the particulate 

emissions. It is difficult to judge the effectiveness of the NSPS and new technology 

stoves in reducing particulate emissions because of changes in overall wood stove usage 

independent of the NSPS due to the ebb and wane of wood stove popularity in response 
33 

to such factors as fossil fuel prices, the increase in natural gas availability, and interest in 

renewable resources. However, if it is assumed that the same number of freestanding 

stoves would be in use today without the NSPS, i.e., all the freestanding stoves were 

uncertified conventional cordwood stoves, the annual hypothetical 2010 emissions would 

have been 209,742 rather than the actual 157,069 tons or 34% higher. 

Table 25 

Particulate Emissions by Freestanding Stove Category (2010) 

Category Number 

in Homes 

(2010)* 

Number 

in Use* 

Particulate 

Emissions 

(tons/year) 

Percent of Total 

Emissions from 

Freestanding Wood 

Stoves 

Freestanding Conventional 

Cordwood Stoves 

5,278,830 4,344,057 135,420 86% 

Freestanding Certified 

Catalytic Cordwood Stoves 

493,311 405,996 5016 3% 

Freestanding Certified NonCatalytic Cordwood Stoves 1,562,153 1,285,652 15,188 10% 

Freestanding Pellet Stoves 841,429 692,496 1445 1% 

Total 8,175,213 6,728,200 157,069 100% 

Hypothetical Emissions if 

All Freestanding Stoves were 

Conventional Cordwood 

Stoves 

8,175,213 6,728,200 209,742 134% 

*Freestanding stoves in seasonal housing units were not included in the tabulations as seasonal homes 

represent only 4% of the total number of occupied housing units and in addition it is reasonable to assume 

that stoves in them are used less frequently than stoves in year-around occupied housing units.
34 

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36 

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37 

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