The Fraction of Freestanding Wood-Fueled Stoves in Current Use That are U.S. EPA Certified Cordwood Stoves and Wood Pellet Stove s

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 48 th Ave. Portland, OR 97219-1404 (503) 244-8543 jbchouck@comcast.net

July 23, 2011i Executive Summary

The magnitude of the future potential reduction in air emissions from the replacement of pre-certified cordwood stoves with certified cordwo od stoves or pellet stoves and the concomitant future sales opportunities for new cord wood 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. T he term “wood stove” included both freestanding cordwood- and freestanding pellet-fuel ed heaters. Both certified and uncertified freestanding pellet stoves, as they bot h 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 us ers have not been very helpful in providing accurate estimates of the fraction of cor dwood stoves that are certified primarily due to home occupants commonly not knowin g the certification status or age of their wood heater. Further, because many home occu pant surveys that include questions relating to stove certification status have been lo cal or regional in scope and have generally been focused in areas where wood stove us age 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 quarter s of wood stoves that are used are in rural areas, many of which are in rural areas of th e South and Mid-Atlantic states, where there are few if any wood stove regulations or volu ntary programs for the purchase of new lower-emitting wood stoves. Consequently, agai n 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 fr eestanding wood stoves that are currently certified cordwood or pellet stoves, hear th industry manufacturing (shipment) records tabulated since 1989 and supplied by the He arth, Patio and Barbecue Association (HPBA) were compared to total wood stove ownership data. To avoid “double counting,” the HPBA shipment data were adjusted (re duced) by an estimate of the freestanding certified stoves and pellets stoves th at have been replaced by newer freestanding certified cordwood stoves or pellet st oves since 1987. These estimates were obtained by a survey of 22 well-established hearth dealers geographically distributed throughout the United States. Total wood stove own ership data were obtained from multiple credible sources. These were: (1) Americ an 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 estimat es, estimates of the current (2010) national particulate emissions for each freestandin g 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 s tove categories were: (1) freestanding uncertified conventional cordwood stoves, (2) frees tanding non-catalytic certified cordwood stoves, (3) freestanding catalytic certifi ed cordwood stoves, and, (4) freestanding pellet stoves. Except for pellet stov es, emission factors were from the standard U.S. EPA AP-42 emission factor compilation document. Pellet stove emission factors were obtained from various literature sourc es as the AP-42 data are from two old studies with long obsolete pellet stove models. An nual national average fuel usage values per stove were obtained from U.S. DOE report s 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 freestan ding pellet stoves and the sum of both. The data is shown by year since 1987 when pe llet stoves and certified or certifiable cordwood stove models first appreciably became avai lable. As of the end of 2010, the cumulative number of freestanding certified cordwoo d stoves was estimated as 2,397,602, the cumulative number of pellet stoves a s 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 f actors 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 resul ts and from the statistical bias among the different survey organizations’ methods and surveye d population. It also needs to be remembered that many high-technology wood stoves ar e replacement units for existing pre-certified cordwood units and even some certifie d units. The mean number of freestanding cordwood stoves for the time period be tween 1987 and 2010 was 9,147,500 with a year-to-year standard deviation of 976,000.

The percentage of total freestanding wood stoves th at were either certified cordwood stoves or pellets stoves are shown by year in Figur es ES2 and ES3. As of the end of 2010, 35.4% of the total freestanding wood stoves o wned in the United States were either freestanding certified cordwood stoves or pellet st oves.

Figure ES4 shows the national annual particulate em issions for freestanding wood stoves by category. In 2010, uncertified cordwood stoves were responsible for 86% of the particulate emissions. It is difficult to judge th e 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 previou sly noted, to the ebb and wane of wood stove popularity in response to such factors a s fossil fuel prices, the increase in natural gas availability, and interest in renewable resources. However, if it is assumediii

that the same number of freestanding stoves would b e 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 Freesta nding 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 Sto ves 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 Resear ch 11

2.4. Total Freestanding Stoves – Simmons Market R esearch 14

2.5. Certified Freestanding Cordwood Stove and Fre estanding Pellet Stove Ownership 15

2.6. Particulate Emission Factors and Wood Usage 29

3. Results 30

4. References 34vii List of Tables

Table Page

Table 1. NSPS Certification Program Timeline 1

Table 2. Vacation/Secondary Home Fireplace and Fre estanding Wood Stove Ownership Usage 5

Table 3. Cordwood Stove Usage 5

Table 4. Multiple Freestanding Cordwood Stove Owne rship 6

Table 5. Year-Around Occupied Housing Units, Vacan t Housing Units, and Seasonal Housing Units 7

Table 6. Freestanding Wood Stoves Owned Based on A merican Housing Survey Data 8

Table 7. Freestanding Wood Stoves Owned Based on H earth, Patio and Barbecue Association Data 10

Table 8. Freestanding Wood Stoves Owned Based on M ediamark Research Data 12

Table 9. Freestanding Wood Stoves Owned Based on S immons Market Research Bureau Data 15

Table 10. Certified Freestanding Cordwood Stove Sh ipments (Sales) 17

Table 11. Freestanding Pellet Stove Shipments (Sal es) 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 Twe nty-Two Wood Stove Retailers 22

Table 15. Freestanding Certified Cordwood Stoves T hat Were Replaced by New Freestanding Certified Cordwood Stoves or Pe llet Stoves and That were Taken Out of Service through 1999 24viii

Table 16. Freestanding Certified Cordwood Stoves T hat Were Replaced by New Freestanding Certified Cordwood Sto ves or Pellet Stoves and That were Taken Out of Service from 2000 to 2010 25

Table 17. Freestanding Pellet Stoves that Were Rep laced by New Freestanding Pellet Stoves and That Were Taken Out of Service through 1999 25

Table 18. Freestanding Pellet Stoves that Were Rep laced 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 F reestanding Certified Cordwood Stoves and Pellet Stoves with Ne w Freestanding Certified Cordwood Stoves and Pellet Stoves as of 2 010 27

Table 20. Certified Freestanding Cordwood Stoves i n Homes 28

Table 21. Freestanding Pellet Stoves in Homes 29

Table 22. Number of Freestanding Stoves in Homes b y Category (2010), Emission Factors, Efficiencies, and Fuel Us age 30

Table 23. Summary of Freestanding Wood Stove Owner ship Estimates 31

Table 24. Cumulative Data, Number of Freestanding Wood Stoves Owned, and Percent of the Total Freestanding Wood S toves Owned That Are Certified Freestanding Cordwood Stoves and Freestanding Pellet Stoves 32

Table 25. Particulate Emissions by Freestanding St ove Category (2010) 33ix List of Figures

Figure Page

Figure ES1. Cumulative Number of Certified Freesta nding Cordwood Stoves and Freestanding Pellet Stoves iv

Figure ES2. Comparison of the Cumulative Number of Certified Freestanding Cordwood Stoves Plus Pellet Stoves wit h the Total Number of Freestanding Wood Stoves Owned iv

Figure ES3. Percent of Total Freestanding Wood Sto ves That Are Certified Freestanding Cordwood Stoves and Pellet S toves v

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

Figure 1. Map of the U.S. Showing Geographical Dis tribution of Survey Respondents 20

Figure 2. Cumulative Number of Certified Freestand ing Cordwood Stoves Replaced by New Certified Freestanding Cordw ood Stoves or Pellet Stoves 27

Figure 3. Cumulative Number of Freestanding Pellet Stoves Replaced by New Freestanding Pellet Stoves 271

1. Introduction

The magnitude of the future potential reduction in air emissions from wood stove change outs and the future sales opportunities for new cor dwood or pellet stoves are in large part dependent on the fraction of stoves currently alrea dy 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 c ordwood stoves were generally constructed with cast iron or heavy gage plate stee l with rudimentary internal components and hence can have a significant lifetime under nor mal usage.

Surveys of home occupants who are cordwood stove us ers have not been very helpful in providing accurate estimates of the fraction of cor dwood stoves that are certified for a number of reasons. Notably these are: (1) Many co nsumers simply do not know if the stove is certified or not. (2) Many do not know th e 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 p eriod which has caused some confusion with the certification status of units bo ught 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 mee t Phase I emission limits July 1, 1989 Manufacturing extension for small manu facturers July 1, 1990 All wood heaters manufactured must mee t 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-certi fied. 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 que stions 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 a nd 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 requir ing change outs to new stoves in these areas.2

It needs to be remembered that according to the Ame rican 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 wh ere 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 averag e household incomes which make the purchase of a new wood stove, typically in the $150 0 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 tha t are high-technology stoves.

To obtain a national estimate of the fraction of fr eestanding wood stoves that are certified cordwood or pellet stoves, hearth industry manufact uring (shipment) records tabulated since 1989 and supplied by the Hearth, Patio and Ba rbecue Association (HPBA) were compared to total wood stove ownership data. To av oid “double counting,” the HPBA shipment data were adjusted (reduced) by an estimat e of the freestanding certified stoves and pellets stoves that have been replaced by newer freestanding certified cordwood stoves or pellet stoves since 1987. These estimate s were obtained by a survey of 22 wellestablished hearth dealers geographically distribut ed throughout the United States. Total wood stove ownership data were obtained from four s ources. 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 fra ction 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 repo rt covers freestanding wood stoves only. It does not cover fireplace inserts or EPA c ertified fireplaces. This is due primarily to the fact that the term “fireplace insert” is neb ulous 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 fi replace 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 th e numbers of “certified fireplaces” are small compared to freestanding stoves and their imp act on the overall results would likely be insignificant.

In addition to freestanding stove ownership estimat es, estimates of the current (2010) national particulate emissions by freestanding stov e category were made from the number of stoves used (used in contrast to owned), standar d 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 stove s, and, (4) freestanding pellet stoves. Except for pellet stoves, emission factors were fro m the standard U.S. EPA AP-42 emission factor compilation document. Pellet stove emission factors were obtained from3

various literature sources as the AP-42 data are fr om 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 categor y with efficiencies provided in AP42.

2. Methodology and Database

Section 2.1 (Total Freestanding Stoves – AHS) descr ibes the database and method used to calculated freestanding stove ownership obtained from the American Housing Surveys. Section 2.2 (Total Freestanding Stoves – HPBA) desc ribes the database and method used to calculate the freestanding stove ownership obtai ned from the Hearth, Patio and Barbecue Association consumers’ surveys. Section 2 .3 (Total Freestanding Stoves – Mediamark Research) describes the database and meth od used to calculate the freestanding stove ownership obtained from the Medi amark Research annual reports. Section 2.4 (Total Freestanding Stoves –Simmons) de scribes 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 t o calculate the ownership of certified freestanding cordwood stoves and freestan ding pellet stoves from manufacturers’ shipment data compiled by the HPBA a nd the survey used to make adjustments for the replacement of certified cordwo od stoves and pellet stoves already in homes with newer certified cordwood or pellet model s. Section 2.6 (Particulate Emission Factors and Wood Usage) describes the method used t o calculate total annual particulate emissions for 2010 from the results of this analysi s and standard emission factor and fuel usage data from U.S. EPA, U.S. DOE, and other publi shed 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 t he Department of Housing and Urban Development (HUD). Title 12, Section 1701Z-10 of t he U.S. Code mandates the collection of the data for the AHS. Both national and metropolitan area American Housing Surveys are conducted. The national survey s 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 u nits, household characteristics, income, housing and neighborhood quality, housing c osts, equipment and fuels, size of housing unit, etc., are collected. “Main Heating Eq uipment – Stoves” and “Other Heating Equipment – Stoves” are among the many categories f or which data are collected.

In addition to year-around housing units, the Ameri can 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 s mall adjustment factor for stove4

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 b elly, and Franklin stoves.”

The number of occupied housing units reporting stov es as “main” heating equipment was added to the number of occupied housing units repor ting stoves as “other” heating equipment to obtain the total number of housing uni ts using stoves as heat. The term “other” is the sum heating appliances used as suppl emental and parallel heating sources. Once the total number of housing units that used st oves as a heating source was determined, it was then adjusted to the total numbe r of wood stoves owned by dividing by the fraction of stoves owned that are used for h eat (Table 3) and multiplied by the multiple ownership factor (Table 4). These two adj ustment 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 numb er of stoves owned determined from data from each biennial AHS survey since 1987.

Three small factors should be noted: (1.) The mult iple pellet stove ownership factor that was used was unity (one). (2.) The reported percen t of pellet stoves that were used versus owned varied substantially from study to study prob ably 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 genera l 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 cal culation of total particulate emissions as they are not in use. The vacancy rate in 2009 w as 10.5%.5 Table 2 Vacation/Secondary Home Fireplace and Freestanding Wood Stove Ownership 1

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

1 Data from references 11-13.

Table 3 Cordwood Stove Usage 1

Survey Area Sponsor Year(s) Percent 2

Minnesota MPCA 2007-08HS 3 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 1995-96HS 3 77.1

Mean 82.3

1 Data from references 1-9

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

3 HS = 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 Divis ion6 Table 4 Multiple Freestanding Cordwood Stove Ownership 1

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

1 Data 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 De partment NCHPA = North Central Hearth Product Association7 Table 5 Year-Around Occupied Housing Units, Vacant Housing Units, and Seasonal Housing Units 1

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

1 Data for even years from references 16-28. Data fo r odd years are the averages of the proceeding and following years. Data for 2010 extrapolated from 2 008 and 2009 values.8Table 6Freestanding Wood Stoves Owned Based on American Housing Survey Data1YearTotal Year-Around Occupied Housing UnitsVacantHousingUnits –FreestandingWood StovesOwned(X 1000stoves)†SeasonalHousing Units– FreestandingWood StovesOwned(X 1000stoves)†Total HousingUnits –FreestandingWood StovesOwned(X 1000stoves)FreestandingWood Stoves,Main Heating(X 1000housing units)FreestandingWood Stoves,Other Heating(X 1000 housingunits)FreestandingWood Stoves,All Heating(X 1000housing units)FreestandingWood StovesOwned(X 1000stoves)*2009 1035 4165 5200 7327 897 323 85472007 945 4141** 5086 7169 848 305 83222005 896 4117 5013 7063 757 267 80872003 1040 4161 5201 7328 787 264 83792001 1119 4787 5906 8321 766 258 93451999 1113 4599 5712 8048 743 247 90381997 1142 4566 5698 8028 777 271 90761995 2320 3305 5625 7925 7706 262 88931993 2831 3516 6347 8943 831 312 10,0861991 2687 3548 6232 8781 822 276 98791989 3087 3871 6958 9804 955 323 11,0821987 3762 3873 7735 10,898 1143 363 12,4041Data from references 16-28*Total stoves owned = (total occupied housing unitsusing wood stoves for heating) X (1.16 multiple ownership factor/0.823 fraction used for heat)**The 2007 datum for the “other heating” value reported appears to be a typographical error or an outlier and the average of the 2005 and 2009 values were usedin 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 vacant housing units andseasonal housing units. A further correction was made for seasonal housing units as there appears tobe a slightly higher fraction of them that have freestandingwood stoves (See Table 2).9

2.2. Total Freestanding Stoves – HPBA

The Hearth, Patio and Barbecue Association (HPBA) h as conducted a “Fireplace and Freestanding Stove Lifestyle, Usage and Attitude St udy” 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 t he data to improve marketing/advertising programs and product developm ent 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 cordwoo d stove and a pellet stove. Because it is probable that if a home occupant had a pellet in sert it would be viewed as a pellet “stove” the pellet stove fraction provided in the 2 006, 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 cumulati ve number of freestanding pellet stoves and pellet-fueled fireplace inserts shipped up to t he years 2006, 2008, and 2010, respectively, obtained from hearth industry shipmen t records were used. (See Section 2.5.)

The fraction of consumer households that own a free standing cordwood stove plus a freestanding pellet stove were multiplied by the nu mber of housing units in each of the three years obtained from the U.S. Census Bureau da ta. These numbers where then multiplied by the multiple ownership factor determi ned from each survey. Table 7 is a compilation of results. As with the American Housi ng Survey data, adjustments for vacant housing units and seasonal housing units wer e made.10 Table 7 Freestanding Wood Stoves Owned Based on Hearth, Pat io and Barbecue Association Data 1

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 stove 2 Multiple

ownership factor cordwood

stoves 3 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, Pat io and Barbecue Association Data 1

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

1 Data from references 11-13

2 It was assumed that most survey respondents when as k if they owned a pellet stove would respond “yes” whether it was an insert or a freestanding unit. T he 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 d ata. This ratio was: 1,048,681/(1,048,681 + 311,749) = 0.771

3 The individual multiple ownership factor for freest anding cordwood stoves determined from each survey was used rather than the average value of 1.16 dete rmined from averaging the various national, state, local surveys (Table 4). A multiple ownership factor of 1 was used for pellet stoves.

4 The same ratio of freestanding woodstoves in occupi ed housing units to total occupied housing units wa s applied to the number of vacant housing units and s easonal housing units. A further correction was ma de for seasonal housing units as there appears to be a slightly higher fraction of them that have freesta nding wood stoves (See Table 2).11

2.3. Total Freestanding Stoves – Mediamark Researc h

Mediamark has conducted surveys of demographics, pr oduct usage, and media exposure in the 48 contiguous states since 1979. The purpos e 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 p ellet stove” are tallied. The number of coal stoves in the Unites States is insig nificant as compared to the number of wood stoves and hence the “coal/wood stove” is prim arily 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 m ean multiple use factor (See Table 4.) to calculate the total freestanding wood stoves owned (Table 8).12Table 8Freestanding Wood Stoves Owned Based on Mediamark Research Data1YearYear-AroundOccupiedHousing Units( X 1000)VacantHousingUnits( X 1000)SeasonalHousing Units( X 1000)Householdsthat own afreestandingcordwood stove( X 1000)Freestandingcordwood stovesin year-aroundoccupied +seasonal housingunits ( X 1000stoves)2Householdsthat own afreestanding pelletstove + pelletinsert( X 1000)Householdsthat own afreestandingpellet stove( X 1000)31999 102,803 9489 2961 5284 6922 523 4031995 97,693 8710 3054 5342 6998 360 3591994 96,209 8754 3071 5955 7801 532 4101990 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 Data1YearFreestandingpellet stoves inyear-aroundoccupied +seasonal units (X1000 stoves)4Freestandingwood stoves(pellet +cordwood) inyear-around +seasonal units( X 1000 stoves)Freestandingwood stoves(pellet +cordwood) invacant units ( X1000 stoves)Total freestandingwood stoves (pellet +cordwood) in housingunits ( X 1000 stoves)1999 455 7377 661 80381995 406 7404 640 80441994 463 8264 728 89921990 - 11,004 961 11,9651989 - 9821 925 10,746131Data from reference 292Cordwood stoves in year-around occupied and seasonal housing units = (households that own a freestanding cordwood stoves) X (1.16 multiple ownershipfactor) 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 freestanding unit. Thefraction of consumers that owned a pellet stove wasreduced by the ratio of freestanding pellet stovesto total pellet units sold based on HPBA shipmentdata.This ratio was: 1,048,681/(1,048,681 + 311,749) =0.771.4Pellet stoves in year around occupied and seasonalhousing units = (households that own a pellet stove) X (1.0 multiple ownership factor) X (1.13 for a secondhome).14

2.4. Total Freestanding Stoves – Simmons Market Re search

Simmons Market Research was founded in 1950 and con ducts regular surveys on lifestyles, media habits, and product/brand prefere nces of American families. One of the parameters tallied is the ownership of “wood-burnin g 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 det ermined 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 Mar ket Research Bureau Data 1

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 stovesowned 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

1 Data from reference 30

2 Average of 2.59 adults over the age of 18 per house hold

3 Multiple ownership factor of 1.16 and 1.13 for seas onal used

2.5. Certified Freestanding Cordwood Stove and Fre estanding Pellet Stove Ownership

The annual manufacturers’ shipment records of heart h 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. R ecords were compiled by the firm of16

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 ye ar period which has caused some confusion with the certification status of units bo ught 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, respect ively were certified or certifiable models. According to interviews with hearth indust ry personnel an insignificant number of pellet stoves were sold before 1989. Also accor ding to interviews with hearth industry personnel is was estimated that the surveys conduct ed annually from 1989 to 1997 captured approximately 75% of the units sold and th e surveys conducted from 1999 to present captured approximately 90% of the units sol d. Catalytic and non-catalytic tabulations were added to provide the total for fre estanding cordwood stoves. Table 10 lists the estimated number of certified freestandin g cordwood stoves sold per year since 1987. Table 11 lists the estimated number of pelle t stoves sold per year since 1987. Table 12 lists the estimated number of pellet-fuele d 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 p ellets stoves that have been replaced by newer freestanding certified cordwood stoves or pel let stoves since 1987. These estimates were obtained by a survey of 22 well-esta blished 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 t he dealerships. The questions asked for the retailer’s best professional judgment of ho w frequently they replaced a certified freestanding cordwood stove or an existing pellet s tove (certified or uncertified) with a certified cordwood stove or a new pellet stove. Fu rther, 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 mar ket.

Table 14 is a tabulation of the responses to the qu estions. For retailers that did not sell pellet stoves a “na” (not applicable) is reported a s 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 tho ught the surveyor was asking about uncertified wood stoves. In addition, there were t hree 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 (Sa les) 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

1 Data 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

1 Data 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

1 Data from references 31 & 32.20cordwood / pelletcordwood onlyFigure 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 cert ified models?

2. Between the years 1989 and 1999 what percentage of new freestanding pellet stoves that you sold replaced already certified wood stove s?

3. Between 1989 and 1999 what percentage of those replaced EPA wood stoves are removed from service and do not enter the used mark et?

4. Between the year 2000 and present what percenta ge of new freestanding certified cordwood stoves that you sold replaced already cert ified models?

5. Between the years 2000 and present what percent age of new freestanding pellet stoves that you sold replaced already certified wood stove s?

6. Between the year 2000 and present what percenta ge 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 percenta ge of new freestanding pellet stoves that you sold replaced existing pellet stoves?

10. Between the year 2000 and present what percent age of those replaced pellet stoves are removed from service and do not enter the used market?

11. What percent of pellet stoves or certified fre estanding wood stoves are replaced with gas appliances you sold?

--------------------------------------------------- --------------------------------------------------- ----22Table 14Results of the Survey Questions from Twenty-Two Wood Stove Retailers (values are percentages)1RetailerCity/TownStateQ1Q2Q3Q4Q5Q6Q7Q8Q9Q10Q111 Fairbanks AK 1 na 50 2 5 80 na na 0 na nd2 Oroville CA 1.5 1 100 15 20 95 na na 15 98 403 Wilmington DE 0 0 na 1 0 100 0 na 1 100 354 Tallahassee FL 0 na na 0 na na na na na na nd5 Gainesville FL 0 na na 0 na na na na na na nd6 Bremen GA 10 na 50 45 na 50 na na na na 207 Jefferson GA 0 na na 0 na na na na na na nd8 Wichita KS 1 1 20 1 3 20 1 100 2 80 609 Auburn ME 25 10 50 20 35 15 1 0.5 10 5 2510 Cadillac MI 4 2 0 10 20 0 0 na 15 2 2011 Minneapolis MN 10 na 5 50 na 80 na na na na 5012 Missoula MT 0.5 0.5 100 3 1 100 50 100 50 97 2013 Oakhurst NJ 0 0 na 10 5 0 0 na 0 na 2014 Portland OR5 2 5 8 7 0.5 5 6 10 3 1015 Grants Pass OR0.5 5 5 1 15 5 20 5 20 5 1516 Pleasant GapPA 13 5 5 35 15 55 10 0.5 55 3 2017 Kingsley PA 7 10 2 15 20 10 8 5 25 50 3518 Tyler TX 35 na 25 20 na 25 na na na na nd19 Brattleboro VT 2 2 100 10 30 75 2 100 30 100 2020 Laramie WY 2 10 0 10 20 0 10 50 15 33 2021 Seattle WA 5 na 0 20 na 3 na na na na nd22 Mt. Vernon WA 15 3 70 10 12.5 90 15 5 17 4 40Mean 6.25 3.68 34.53 13.00 13.90 42.29 9.38 37.20 17.67 44.62 28.13na – not applicable, nd – no data (if the retailerwas short on time the 11thquestion was not asked as it did not directly pertain to the objective of the study,1See Table 13 for list of questions, data from reference 33.23

The questions were broken up into to time blocks, 1 989-1999 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 ques tions focused on the number of existing certified cordwood stoves being replaced b y 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 fre estanding certified cordwood stoves that were replaced by new freestanding certified co rdwood 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 th at 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 th e number of freestanding pellet stoves that were replaced by new pellet stoves and that we re taken out of service through 1999. Table 18 shows the calculation of the number of pel let stoves that were replaced by new pellet stoves and that were taken out of service fr om 2000 through 2009.

Table 19 is a summary of the replacement of existin g freestanding certified cordwood stoves and pellet stoves with new freestanding cert ified cordwood stoves and pellet stoves as of 2010. The results show that 138,444 f reestanding certified cordwood stoves were replaced by new freestanding certified cordwoo d stoves or pellet stoves and taken out of service as of 2010 which is 5.46% of the tot al sold. For freestanding pellet stoves 67,193 of those that have been sold have been repla ced 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 increas e 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 cor dwood 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 da ta for certified cordwood stoves. Table 21 shows the annual data for pellet stoves.24 Table 15 Freestanding Certified Cordwood Stoves That Were Re placed 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 cordw ood 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 199 9 34.53% (0.3453 X 99,781) = 34,45425 Table 16 Freestanding Certified Cordwood Stoves That Were Re placed 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 cordw ood 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 t o 2010 42.29% (0.4229 X 245,847) = 103,990

Table 17 Freestanding Pellet Stoves that Were Replaced by Ne w 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 199 9 37.20% (0.3720 X 33,055) = 12,29626 Table 18 Freestanding Pellet Stoves that Were Replaced by Ne w Freestanding Pellet Stoves

and That Were Taken Out of Service from 2000 to 201 0

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 2 010 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 t o 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 C ordwood Stoves and Pellet Stoves as of 2010

Description Numerical Values Total freestanding certified cordwood stoves replac ed 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 t hat 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 201 0 (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 201 0 1,048,681 – 67,193 = 981,488 Percent of freestanding pellet stoves that have bee n 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 Freestand ing Cordwood Stoves Replaced by New Certified Freestanding Cordwood Stoves or Pelle t 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 2,397,60229 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 freestand ing 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 p er freestanding stove unit. Table 22 is a tabulation of these values. Except for pellet st oves, emission factors were from the standard U.S. EPA AP-42 emission factor compilation document. Pellet stove emission30

factors were obtained from various literature sourc es as the AP-42 data are from two old studies with long obsolete pellet stove models. An nual national average fuel usage values per stove were obtained from U.S. DOE report s 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 Usage 1

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 h ousing units and in addition it is reasonable to as sume that stoves in them are used less frequently than s toves in year-around occupied housing units. Based on HPBA shipment records for proportioned shipments be tween catalytic and non-catalytic stoves available for some years it was estimated that 24% of the cer tified cordwood stoves are catalytic and 76% are no ncatalytic. The fraction of freestanding woodstoves owned that are used has been estimated as 0.823. T he 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 esti mate the annual number of freestanding woodstoves owned each year, when data from more tha n one was available for a given year, the mean was calculated and used. Table 23 i s a compilation of the estimates per year from each of the four sources and the mean val ue used for the calculation of percentage of freestanding stoves owned that are hi gh-technology stoves (certified cordwood stoves plus pellet stoves).

Table 24 is a summary compilation of: (1) cumulati ve 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 frees tanding certified cordwood and pellet31

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 sinc e 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 Estima tes 1

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

1 Data from references 11-13, 16-29, 3132 Table 24 Cumulative Data, Number of Freestanding Wood Stoves Owned, and Percent of the Total Freestanding Wood Stoves Owned That Are Certi fied 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 b y freestanding wood stove category for 2010 and the percentage each represented of the tot al for freestanding wood stoves that year. In 2010, uncertified cordwood stoves were re sponsible for 86% of the particulate emissions. It is difficult to judge the effectiven ess 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 response33

to such factors as fossil fuel prices, the increase in natural gas availability, and interest in renewable resources. However, if it is assumed tha t 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 annua l hypothetical 2010 emissions would have been 209,742 rather than the actual 157,069 to ns or 34% higher.

Table 25 Particulate Emissions by Freestanding Stove Categor y (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 h ousing units and in addition it is reasonable to as sume that stoves in them are used less frequently than s toves in year-around occupied housing units.34

4. References

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