Mapping wood heating and wood smoke in the United States

Updated, Dec., 2020: Wood heating has made a comeback in the United States and has been the fastest growing heating fuel for most years between 2005 and 2015, according to US Census figures. Currently, 2.36 million homes in the United States use wood as a primary heating fuel (ACS, 2015, 1-year estimates). And 8.8 U.S. million homes use it as a secondary heating fuel (EIA, RECS, 2009). Wood was the dominant residential heating fuel in the United states until coal began to take over in the 1880s. After that, heating oil and then gas became popular. The percent of the population primarily heating with wood dropped from 23% in the 1940s, when the US Census first began tracking heat, to a low point of 1.3% in 1970, when fossil fuels were cheap and popular.

Wood smoke follows wood heater installations and the first map shows shows county level particulate matter from residential wood combustion based on the 2011 National Emissions Inventory, Version 1.5.  The EPA should be releasing data from the 2014 National Emissions Inventory this year, so that residential wood smoke changes can be compared from 2011 to 2014.  Emissions from fireplaces - and more recently from outdoor fire pits - mix with smoke from residential wood heaters, and complicate assessing the impact of wood stoves and boilers.

This second map also shows PM 2.5 emissions from residential wood combustion by county, but its on a per capita basis according to the 2008 National Emissions Inventory, in this  EPA report, "New Methodology for Estimating Emissions from Residential Wood Combustion." It appears to show the densest per capita concentrations of PM2.5 in Wisconsin and Minnesota where the most outdoor wood boilers are made and installed.

The third map, from the same 2008 EPA, report provides further detail on the source of PM 2.5 emissions by appliance type. Each appliance type is represented by a different color. Red represents fireplaces, green represents fireplaces with inserts, dark blue represents woodstoves, light blue represents indoor furnaces, magenta represents outdoor hydronic heaters, and yellow represents wax/sawdust firelogs. While the terminology is somewhat confusing, the map shows some interesting trends.  For instance, wood stoves emit the majority of PM in the Northeast, while outdoor hydronic heaters are the largest source in the Great Lake states (outdoor wood boilers continued their popularity in these states after the 2008 EPA report). Fireplaces with inserts are the largest emitter in most of the south and California. Indoor furnaces are the most common source of PM pollution in Ohio, Indiana, and Illinois.

The next map was produced by the Census Bureau, showing per capita use of wood stoves. It shows 17.8% of homes in Vermont use wood or pellets as a primary heat source in 2012. Maine had the second highest percentage at 13.7% of homes. Out West, Montana has the highest percentage with 9.2% of homes, followed by Idaho at 7.9% and Oregon at 7.1%. On the US mainland, the states with the least wood heating are predictably Florida, at 0.2% of the population and then Texas at 0.4%.

The Alliance for Green Heat produced a map using Census data to show the continued growth of wood heating between 2000 and 2012. By 2010, the growth trend was well established, due in part to the housing crisis and recession. In that period, wood heat doubled in about 10 states, mostly in the Northeast.

This map below, made the Alliance for Green Heat, also uses Census data but breaks down primary wood heating households by Congressional districts. This provides a much more detailed look at the geography of wood heating compared to state level details. Presumably, a map showing wood usage at the county level could also be produced.  

This last map shows a curious phenomenon in 1950 where the Census Bureau found higher rates of primary wood heating in southern states than in many northern ones. This is likely due to the quicker penetration of fossil fuels in northern states, whereas room heaters in southern states, including those in many poor, rural black and white households, continued to operate on cordwood.

This map shows a per capita use of primary wood heat in impoverished counties.  Note the hot spots in northern Maine, West Virginia, Arkansas and the Navajo reservation in New Mexico.  We are unclear if Native American populations are among the hot spots in Washington, Oregon, and Northern California.

This final map of oil and gas heating use per capita generally correlates with heating costs, or at least it did before gas and oil prices plunged in 2019 - 2020.  Where there is high use of oil and gas, there is generally high use of wood heat in rural areas.

2012 Census Shows Wood Heating Continues Growth Streak

Alliance for Green Heat, Sept. 25, 2013 - According to recently released U.S. Census statistics, 63,566 more families used wood or pellets as a primary heating fuel in 2012 compared to 2011, which amounts to an increase of 2.6%, making wood again the fastest growing heating fuel in America.

From 2000 to 2010, wood and pellet home heating grew by 34%, faster than any of the other heating fuels, including solar and natural gas. Oil and propane use declined between 2000 and 2010, and the decline continued in 2012.

Today, 2.1% of Americans use wood or pellets as their primary heating fuel, up from 1.6% in 2000. An additional 7.7 % of U.S. households use wood as a secondary heating fuel, according to the 2009 EIA Renewable Energy Consumption Survey.

Nearly 2.5 million households use wood as a primary heating fuel, making it, by far, the dominant residential source of renewable energy in the United States. In comparison, only about 500,000 of U.S. homes have solar panels and less than 50,000 use solar thermal heating. Solar thermal heating dropped by 2% in 2012 from 2011, according to the new Census numbers.

The states with the biggest growth in wood heat from 2011 - 2012 are Delaware (35.1%), Rhode Island (29.6%), Nebraska (24.6%), New Hampshire (18.5%) and New Jersey (17.7%). However, other states experienced declines. Among the important wood heating states of Washington, Oregon and California, the decline was very small, but there were more significant declines in Illinois (5.2%), Idaho (5%) and Colorado (4.8%). Over a 12-year period, the prevalence of wood heating has increased, often very significantly, in every state except Louisiana, Mississippi, Florida and Hawaii.

Since the U.S. Census Bureau started tracking heating data in 1950, wood heating has had wide swings. Starting at 10% of the population in 1950, it dropped to 1.3% of the population in 1970, an all-time low. By 1990, wood had climbed back to 3.9%, only to drop back to 1.6% in 2000. The biggest growth story in heating fuel is electricity, which went from under 1% in 1950 to 36% today.

The environmental costs of using electricity for heating is high in most states, where the majority of electricity is still made with coal. The environmental cost of drilling and transporting other fossil fuels like oil and gas can also be high. Wood heating has an environmental cost from the particulate matter in the smoke, particularly from older stoves in more densely inhabited areas, and, in some states, from growing numbers of outdoor wood boilers. The EPA has proposed stricter emission standards for wood and pellet stoves and boilers and the Office of Management and Budget is reviewing them now.

Some of the growth in wood heating can be attributed to households that already had stoves, but now use them as primary heaters, instead of a secondary ones. Other households may have bought and installed stoves they found on the second hand market, which is legal in all states except Washington and Oregon.

The trend towards greater use of wood and pellets is mainly due to the lower operating costs compared to oil, propane and electricity. Three states – New Hampshire, Massachusetts and Maine – have provided generous rebates for pellet boilers to help residents replace costly oil heating systems and keep their heating dollars local. Maryland recently established a rebate for the cleanest wood and pellet stoves for rural homes that do not have access to natural gas.

For more info on 2012 U.S. Census data and on trends from 2000 - 2010, and more details about wood heat in the 2000 – 2010 Census.

2010 Census Shows Wood is Fastest Growing Heating Fuel in US

Rural low-income families the new growth leaders in renewable energy production

October 10, 2011 - Recently released US Census figures show the number of households heating with wood grew 34% between 2000 and 2010, faster than any other heating fuel. Electricity showed the second fastest growth, with a 24% increase over the last decade.

In two states, households using wood as a primary heat source more than doubled - Michigan (135%) and Connecticut (122%). And in six other states, wood heating grew by more than 90% - New Hampshire (99%), Massachusetts (99%), Maine (96%), Rhode Island (96%), Ohio (95%) and Nevada (91%).

Census data also shows that low and middle-income households are much more likely to use wood as a primary heating fuel, making low and middle-income families growth leaders of the residential renewable energy movement. According to the EIA, residential wood heat accounts for 80% of residential renewable energy, solar 15% and geothermal 5%.

“Heating with wood may not be hip like solar, but it’s proving to be the workhorse of residential renewable energy production,” said John Ackerly, President of the Alliance for Green Heat, a non-profit organization based in Maryland.

The rise of wood and wood pellets in home heating is driven by the climbing cost of oil, the economic downturn and the movement to use renewable energy. The Census Bureau does not track the reason people switch fuels but in states like Maine and New Hampshire where rising oil prices are squeezing household budgets, it is clear that many families simply feel the need to cut heating costs.

“The rise of wood heat is good news for offsetting fossil fuels, achieving energy independence, creating jobs and helping families affordably heat their homes,” said Mr. Ackerly.

“However, Wood heat’s rapid rise is not just from people using clean pellet and EPA certified wood stoves. Many people are also dusting off old and inefficient stoves and in some states installing outdoor boilers that create too much smoke,” cautions Ackerly.

Over the last decade, the number of households using two of the most expensive heating fuels significantly declined: propane dropped 16% and oil heat dropped 21%. Some of those homes undoubtedly switched to wood. Switching from fossil fuels to commercially purchased wood heat can reduce a home’s heating bills by half or more. Those who cut or collect their own wood save much more, using their labor to zero out heating bills.

Currently about 25-30% of the 12 million stoves in the U.S. are clean burning pellet stoves or EPA certified wood stoves, according to the EPA and other sources. Americans have installed about one million pellet stoves since the 1980s when they were invented.

Wood now ranks third in the most common heating fuels after gas and electricity for both primary and secondary heating fuel use, but ranks fifth, after oil and propane as well, when only primary heat fuel is considered. As of 2010, 2.1% of American homes, or 2,382,737 households, use wood as a primary heat source, up from 1.6% in 2000. About 10 - 12% of American households use wood when secondary heating is counted, according to the US Census Bureau and the Energy Information Agency (EIA).

The rapid rise in wood heat as a primary heating fuel is mainly a rural phenomenon, and to a lesser extent a suburban trend. According to the US census, 57% of households who primarily heat with wood live in rural areas, 40% in suburban areas and only 3% in urban areas.

# # #

The Alliance for Green Heat promotes wood and pellet heat as a low-carbon, sustainable and affordable energy solution. The Alliance works toward cleaner and more efficient wood heating appliances, particularly for low and middle-income families. The Alliance is a 510c3 non-profit organization based in Maryland.

To download the full press release, visit: http://www.forgreenheat.org/resources/press.pdf

Facts and Analysis on 2010 Census Heating Fuel Data

· The top ten states of per capita primary wood heating are: Vermont (15%), Maine (12%), Montana (8%), New Hampshire (8%), Oregon (7%), Idaho (7%), West Virginia (6%), Alaska (5%) and Wyoming (5%).

· Four of the eight most populous states - New York, Pennsylvania, Ohio and Michigan - experienced increases in wood heat of at least 65%.

· Rapid rise in wood heat is not just confined to states with very high use of heating oil. In Michigan and Ohio, for example, where the relatively inexpensive natural gas is dominant, wood heat still soared.

· West Coast states, where laws regulating wood heating tend to be stronger, had modest increases in wood heating (6 – 12%) but it is unclear to what extent those regulations kept wood heat growth in check and to what extent other factors were responsible.

· The only part of the country where wood fell as a primary heating fuel was the Deep South, where states experienced a 2 – 13% decline with the exception of Florida that declined 21%.

· In a significant milestone, since 2000 wood has overtaken propane as a primary heating fuel in three eastern states: Maine, Vermont and West Virginia. This is the first time that wood has topped propane in an eastern state since 1970.

· In Europe there has also been a rapid rise in wood and pellet heating, which has more to do with generous government incentives to help homes reduce fossil fuel use. Many European countries have had 25 to 50% incentives for much of the previous decade.

· The US had a 30% tax credit up to $1,500 for only two years, 2009 and 2010. Currently the tax credit is only for 10% with a maximum of $300.

· The number of homes heating with wood fluctuates much more quickly than other fuels because most families who use wood as a primary heat source also have a fossil fuel back-up which they use more of when or if that fossil fuel is more affordable.

· According to the US Forest Service reports, a majority of Americans who heat with wood cut or collect their wood.

· Some states with a more than 90% rise in wood heat have very high unemployment, such as Michigan and Nevada, ranked 1 and 3 for highest unemployment rates. But in New Hampshire, which also had more than 90% rise, unemployment is among the lowest in the US.

· A disturbing trend is that in some of the states with the greatest increase in wood heat, inefficient traditional outdoor hydronic heaters that often create excessive smoke are still allowed to be installed, such as Ohio, Michigan, Wisconsin and Minnesota. These four states have more than half of all such outdoor heaters in the US according to a 2006 NESCAUM report. (13 states, mainly from the Northeast and the West Coast, ban the installation of these devices but most allow cleaner, EPA qualified ones to be installed.)

Sources:

2010 US Census, American Community Survey data: http://factfinder2.census.gov/faces/nav/jsf/pages/searchresults.xhtml?refresh=t

2000 US Census, American Community Survey data: http://factfinder.census.gov/servlet/ACSSAFFHousing?_sse=on&_submenuId=housing_1

Historical: http://www.census.gov/hhes/www/housing/census/historic/fuels.html

Urban/rural data: http://0-www.census.gov.iii-server.ualr.edu/housing/ahs/data/ahs2009.html

EIA Residential Energy Consumption Survey, 2009, Table HC1.1 &Table HC2.4: http://205.254.135.24/consumption/residential/data/2009/

Background on government incentives: http://forgreenheat.org/toolkit.html