Company makes 2020 certified warm air furnace for under $2,000 - and stirs controversy

Paul Van Der Eems, Dan Haynes,
and David Walters of HY-C accept
a Vesta Award for their furnace.

Updated on April 5, 2019 - Many said it could not be done.  A competitor called it “preposterous.” But HY-C, a Missouri company that makes a budget line of warm air wood-fired furnaces, is well on their way to being ready for June 2020, when stricter EPA regulations come into effect.  

Their first 2020 compliant model, their smallest unit, was certified at 0.106 lb/MMBtu Output, well under the .15 allowable. The suggested retail price is $1,899 which is only $100 more than the previous unit that was certified to the 2017 standards.  HY-C won a Vesta Award for the furnace at the industry’s annual expo in Dallas last week.

In 2014, HY-C went to the EPA and urged them to adopt a laddered approach, giving companies several years to get certified and several more to meet a stricter standard. “The EPA was responsive, giving us a total of 5 years,” David Walters, President of HY-C recalled in a phone interview.  David said that  when they bought the company in 2011, the NSPS process was well underway, and they knew they would have to change and clean up.  “It wasn’t easy, but we did it, and that is good for the environment, for consumers, and for us, the manufacturer,” David said.

The HY-C FC100E is the first
low-cost wood fired forced air
furnace to meet the strict EPA
2020 emission standards.

The EPA won’t list a certified unit on the list of certified appliances until the company posts their lab test report on their website.  Parts of those reports are highly technical but provide key information for consumers and others. The HY-C report said the unit achieved 50% delivered efficiency and a stack loss efficiency of 71%. It was certified using a modified test protocol that had been approved in advance by the EPA.  Intertek laboratories did the testing using about 36-pound loads of cord wood that had about 22% moisture content.  The five tests ran 3 to 6 hours.  Their target output was 13,000 – 37,000 BTUs but the certification test obtained 20,000 – 34,000, due in part to the modified test protocol. 

To date, the only other company to have a 2020 compliant forced air furnace is Lamppa Manufacturing, which hit .09 lbs/MMBtu several year ago and a stack loss efficiency of 79%, far above the HY-C.  The Lamppa unit, the Vapor-Fire 100 is currently priced at $5,695 and also obtained a test protocol variance from the EPA in the test protocol.  The Vapor Fire weights 670 pounds, which may indicate thicker and more durable materials compared to the HY-C unit at 435 pounds.  (Update: SBI has certified a third wood furnace, under the Caddy brand.)

The Lamppa Vapor Fire
100 is the only other 2020
compliant wood furnace,

Another big player in the forced air furnace space is US Stove, and it’s unclear when they will have a 2020 compliant unit.  Of their eight units certified to the 2017 standards, one came in at 33% efficiency and an average of 60% efficiency. US Stove is urging the EPA to repeal the Step 2 standards for forced air furnaces, arguing that agency picked a “compliance limit out of thin air with not [sic] real data to support it.”  In a filing with the EPA, they said that the EPA’s timeline of going from an uncertified appliance category to meeting .15 mmBTU “is preposterous and unrealistic.”  HY-C appears to have just proved otherwise.

However, the willingness of the EPA to approve alternative test methods can be controversial, and companies often claim a competitor got an unfair advantage with a particular variance.  The EPA is not supposed to approve variances that make the protocol easier to pass, but that may just what is happening in some instances.  Variances are a critical tool for the EPA to allow for innovative products to be fairly tested and they also create a precedent for others to receive similar variances.

The largest player in the Canadian forced air furnace market is Stove Builders International (SBI) and they do not directly compete in the budget market with US Stove or HY-C.  SBI is also working on certifying furnaces to the 2020 standards but “we are trying to achieve the desired performance without using the alternative test method that the EPA has granted to others,” said Marc-Antoine Cantin, of SBI.  “We want to put out a product that cycles combustion and doesn’t just cycle the blower, while the unit is kept burning at a single burn rate,” Cantin said.  

HY-C sells their furnaces through a variety of distributors and retailers, including many big box stores. They provide all of their own customer services and have tens of thousands of units in the field that provide them with intensive customer feedback.  They make all of their furnaces in St. Louis Missouri and have extremely little inventory of non-2020 inventory left and expect to start shipping 2020 compliant units in July.  “We worked hard with distributors, so the pipeline of older units is dry,” Walter told us.  As a result, they have abstained from the debate as to whether the wider industry needs a 2-year sell through for units that are not 2020 compliant.  Lamppa has been an outspoken defender of the original timelines, arguing that a 2-year sell through would be unfair. Click here for more on that debate.

The EPA exempt US Stove 
1357 Hotblast  "coal only" furnace 
also advertises "21 in. log 
capacity" at Home Depot (Home
Depot discontinued the unit
a week after the story appeared.)

Both US Stove and HY-C say that their customer base is very price sensitive and need a furnace under $2,000, if not close to $1,500.  Other industry experts have questioned how so many people came to expect a whole house furnace for less than the price of an average wood stove and assumed that price would have to climb substantially to meet 2020 emission standards.  At the core of the fight between industry, states and air quality agencies is whether the price of wood appliances and costs to manufacturers should drive EPA standards more than other factors.  While HY-C was able to meet both the timeline and the emission standards, it is still unclear how well it will be received by the general public.  US Stove also make “coal only” units that are exempt from EPA emissions and sell side-by-side in many stores with the regulated wood units. HY-C has a coal only unit but only sells a few each year direct to consumers and not through retailers.

According to one industry insider, Tractor Supply Company stores is the biggest seller of wood furnaces from their 1,700 US stores.  Floor staff at chain hardware stores like this have reportedly been trained to inform consumers that the “coal only” units can burn wood perfectly well.  Companies that make both wood and coal units benefit from this and can sustain market share, even as EPA standards tighten.

Certifying to 2020 standards appears to have led to shorter burn times and more finicky furnace and boilers for some units.  HY-C advertised up to 12-hour burn time and a maximum of 130,000 BTU output for the unit as certified to 2017 emission standards.  The EPA listed BTU output up to 45,000.  The 2020 version only had up to 6-hour burn times in the lab and a maximum of 34,000 BTU output.  Both the 2017 and the 2020 model accept 20-inch logs.  Can the 2020 version meet consumer expectations at virtually the same price? 

But for now, HY-C achieved what they set out to. “We planned to build a better mouse trap and we feel that we succeeded, with advice from industry experts and our consumers,” David Walter said.  “In America, we should not take for granted that we have clean air and water, thanks to Congress and decades of work by the EPA,” Walter continued.  If anyone thinks the EPA efforts are a waste of time, Walters says all you have to do is visit Shanghai or some other foreign cities. “It’s so polluted you can barely walk outside and see the other side of the street,” he said.

Meet the teams: Entrepreneur at Stove Design Competition tackling China’s massive wood stove market

This post is the eleventh in a series introducing the 12 teams participating in the 2018 Wood Stove Design Challenge in November.

By John Ackerly and Shoshana Rybeck, Alliance for Green Heat

Founding of Cygnoides Smart Energy Tech Co

Cygnoides Smart Energy Tech Co.
engineers with local university student
volunteers working for a public welfare
project in Guizhou mountain area. 

In the US, the 60 million rural residents own about 5 – 7 million old, uncertified stoves. In China, there are nearly 600 million rural residents and up to 100 million old, polluting stoves. The market for cleaner wood stove is huge.

When Min Chen returned to China after getting his doctorate in engineering in Denmark in 2013, he dedicated himself to making a wood heating stove that rural Chinese would buy. To do this, he knew he had to keep the price around a few hundred dollars and it had to make enough electricity to light up a small home and provide hot water. Without providing electricity, a cleaner stove in and of itself was not going to sell. Scores of “improved” stove models have been tried in China, but the problem is so vast that its hard to know if they even made a dent.

Min also has to face major changes in national energy policy that can open up, or close down markets for tens of millions of stoves. China set a goal of banning coal heat by winter of 2017 in a bid to switch hundreds of towns and cities to gas. The ban had to be rescinded to avert a heating crisis but it spurred innovation in biomass stoves. Biomass was seen as much better than coal, and there still appears to be significant policy support for biomass, but gas and electricity are ultimately seen as the solution. A World Bank study found in China that replacing current wood stoves  for heating with pellet stoves and replacing chunk coal fuel with coal briquettes could provide significant climate benefits.

Nearly 100% of Chinese homes have electricity, but the problem Min says is that is that “there is still no reliable electricity” in millions of homes. Electricity is often spotty, thus Min understands that an inexpensive stove that provides indoor lighting will have a huge market. Min says that he “made a lot of generator toys and stove simulators when he was in the academy, but wanted to make this toy practical and really usable”. Min and his four other team members found investors and have designed their model that will consistently create heat, hot water for drinking, and electricity.

Wood stove similar to the ReBao

Stove making in China is complicated by the fact that Chinese use a wide variety of feedstocks. In fact, it is illegal to harvest firewood in most stoves use branches and agricultural residue like corn cobs – and lots of coal. Min’s stove is designed to used pelletized fuel or briquettes made of sawdust.  China has a large amount of agricultural and forestry residues that can be used as energy, and biomass densified solid fuel (BSDF) is an important pathway to use them as energy, especially for heating.

ReBao

Rebao uses an innovative converter as a voltage regulator to convert the stove’s input energy to output energy, and can be manually or automatically run. However, the stove runs on its own with full automatic operation, and can produce up to 100w of electricity with a few kw of heat, which Min says is enough heat to keep a small home comfortably heated and meet part of the electric load in the winter. 

Since he is trying to develop a product that will help people in their everyday lives, Min says “price is the most important part of the product”. He does not see why he should work so hard on developing a technology for people if they would even be able comfortably afford it. The stove has been sold in small quantities and currently costs around a few hundred dollars US dollars. Min reports that all units have worked well and continues to be optimistic about the future of the stove’s price and market success.

Further developments

China has a vibrant stove manufacturing industry for
domestic stoves for both heating and cooking, but most
are basic with little secondary PM reduction technology.

The development of ReBao is ongoing, and Min says that he would like to try to make the stove even more user friendly by developing smart functions on the stove that are wifi enabled. Heating stoves have to be emission certified in China by the national agricultural energy association but they can be continually improved without having to go back to the test lab for expensive certification tests. A stove with a cost of a few hundred $ that also heats water and makes electricity will probably not be the cleanest stove at the competition. But the competition seeks to include innovative heatings stoves that are fully or partially automated for markets that are much larger than the North American market. 

Contact the team

Min Chen

chenminmike@gmail.com

Coal Heating in the United States

By John Ackerly & Melissa Bollman
Alliance for Green Heat
This paper was prepared for the Warsaw Stove Summit which brought AGH and scores of experts in coal and wood heating from 19 countries to Poland in May 2017.

Summary
The US Census Bureau estimates that approximately 127,000 households used coal as a primary heating fuel in 2015, or about 0.1% of American homes. Residential coal heating dropped rapidly until 2000 and since then has been relatively stable.

More than half of homes using coal heat are concentrated in Pennsylvania and New York, right where it is mined. It appears to be based on cultural traditions and local support for local jobs because its still a very inexpensive way to heat and easy to transport. Most of the United States has no restrictions on coal heating and there have been few attempts to restrict it. Rather, it seems to have gradually died out except in pockets of states where anthracite is mined. Bituminous and sub-bituminous coal is much more widely dispersed but it is used far less than anthracite.

Coal stoves, particularly those fueled with anthracite coal that principally comes form Pennsylvania, typically have less particular matter than wood or possibly even pellet stoves. However, their health impacts may be far worse, as coal often emits high levels of SO2 and oxides from nitrogen.  In addition, coal often has poisonous toxins such as flourine, arsenic, selenium, mercury and lead.  For more on health impacts of coal and wood heating in the US and Europe, we excerpted key parts of a World Health Organization report here.

Who heats with coal and why?

Homes that heat with coal tend to be concentrated near anthracite coal mines and in homes with lower or mid level incomes. In the wealthier and more urban counties of Pennsylvania that are within 100 miles of anthracite mines, virtually no households heat with coal. High use of coal heat does not correlate with high use of wood heat. Both coal and wood are favored by rural, lower-income populations but coal appears to be favored near anthracite mines, and wood is favored in nearby, rural counties, according to data from the US census. The highest percentage of homes heating with coal at the county level is about 13%.

A prominent 2008 New York Times article reported that residential coal heating was on the rise, but rise was modest, and petered out a few years later. That rise corresponded with a major recession from 2007 – 2009 during which rates of wood heat soared far higher than coal. The New York Times also reported that an additional 80,000 homes use coal as a secondary heat source and the US Census reported 104,000 used it as a secondary heat source in 2005. Only 4,000 homes use it to cook with and 22,000 used it to heat domestic hot water in 2005, according to the US Census.

In 2015, the top five states for residential coal heating were Pennsylvania, New York, West Virginia, Kentucky, and Indiana. Over 50% of US homes that heat primarily with coal are located in Pennsylvania, where anthracite coal is mined.

The primary benefits of heating with coal, compared to wood, is 1. it burns for longer periods of time, so less reloading is needed and a home can easily stay warm overnight; 2. Like pellets, it can be delivered in bags on pallets by a forklift, and does not need the time consuming splitting, stacking and seasoning that cordwood needs; 3. It is even more inexpensive per BTU (assuming you don’t cut the wood yourself); and 4. It is a very dense fuel, and takes up half the space that the same amount of wood takes, per BTU.

The downside of heating with coal is 1. The odor, which most people find moderately unpleasant; 2. The black dust which is harder to clean than dirt and wood pieces from cordwood; and 3. Its hard to light, requiring most people to start the fire with wood, before switching to coal.

While the above pros and cons are widely agreed upon, other less tangible factors play a role. Coal has increasingly gained a stigma as a dirty, non-renewable fuel, whereas wood is regarded as far more environmentally friendly (even though particulate matter from wood can be equally high). On the other hand, the dwindling economic prospects of coal towns and counties tends to make those populations want to support the fuel to combat what they often see as an unfair bias against coal.

Coal and coal stoves

Coal stoves are either stokers or batch. Stokers automatically feed coal pellets (much like pellet stoves) into the stove, require electricity and only use anthracite. Batch stoves are loaded by hand and can take anthracite or bituminous.

Most coal used for heating in the US is anthracite but anecdotal estimates by experts say that no more than 25% is bituminous, primarily in areas where its abundant.

The EIA stopped collecting data on residential coal consumption in 2008. In 2007, the EIA reported that US residents consumed 353,000 short tons (320,171 metric tons) of coal, which represented only 0.03% of the nation’s annual coal use (1.1 billion short tons or around 1 billion metric tons). The overwhelming majority of course (93%) of US coal is used to generate electricity.

Usually coal is sold in 40 or 50 pound bags or by the ton. Coal may be sold directly to consumers from the mine, a fuel supplier, or a hardware store. Blaschak is one of the largest suppliers of bagged anthracite coal and sold 374,000 tons in 2014. Forty pound bags of anthracite coal (any size) from Pennsylvania usually run $6-$8. A ton of anthracite typically costs between $190 and $210 per ton, before delivery charges (which can increase price to $250-$300). One fuel seller, Central Maine Coal, sells about 200 short tons (181 metric tons) of residential coal per heating season.

Bituminous coal is usually considered a better coal for blacksmithing than heating, but can be burned in some coal stoves and is often only $80-$100 per ton.

Institutional heating with coal is somewhat relevant to residential coal heating and data indicates that institutional coal heating is declining much more rapidly that residential heating.

According to the EIA, US educational institutions consumed 700,000 short tons (634,900 metric tons) of coal in 2015, down from 2 million short tons (1.8 metric tons) in 2008. Twenty of the 57 US educational institutions that used coal in 2008 reported not using it 2015 due to sustainability initiatives. It is likely that most of the coal consumed at educational institutions is used to generate heat. Most US schools no longer heat with coal. Recent (2015-2016) news articles report that only five public schools heat with coal in West Virginia and four schools heat with coal in Cumberland, Maryland. One of the Maryland schools uses 517 tons of coal annually at a cost of $120 per ton.

Coal stove companies

Most coal stoves are made in Pennsylvania except for one big producer, Hitzer stoves located in eastern Indiana. Sales of coal stoves are reported to average 4,000 to 7,000 a year, but in 2008 they may have topped 10,000. In comparison, about 140,000 wood stoves are sold each year. There are about a dozen companies making coal stoves and one notable trend is that the larger wood stove companies are getting out of the coal stove business. Vermont Castings, Harman and Moreso used to sell coal stoves and now don’t. The one company that still focuses on both fuels is US Stove Company, based in Tennessee. Coal stoves cost about the same as wood stoves and range between $2,000 - $3,500.

Stove policy

Coal stoves remain exempt from EPA emission regulations. Coal stoves have never had a certification program at the EPA or at any state level, although the federal government and some states have indicated an interest in developing emission regulations. Regulation would likely drive up the cost of coal stoves and may reduce sales of coal stoves but other strategies may reduce their use faster and more economically. But without emission regulations, there is little data on coal stove emissions from various types of coal stoves, and there is little incentive for stove companies to try to produce cleaner stoves. Tests conducted in the 1980s suggested that wood stoves emitted higher levels of particulate matter than anthracite stoves, but lower levels than bituminous stoves (Houck, 2009). Of course, wood emits fewer other toxic chemicals than coal.

One significant policy change in 2015 was the ban on advertising dual coal/wood use in stoves unless the stove was certified with wood, and the company also tested for coal emissions and provided that data to the EPA. To our knowledge, no company has done this so no stove should advertise the ability to burn wood and coal any more.

The EPA is currently funding research on coal emissions and has developed an unofficial, draft test method at Robert Ferguson’s lab. However, this is being undertaken only because of an EPA program to change out coal stoves on the Navajo Indian reservation, not because it has any apparent mandate or serious plan to start regulating coal stoves.

It is unlikely under the Trump administration that any certification program would be initiated by the EPA, and the only state with enough coal stoves to justify the effort would be Pennsylvania, which is unlikely to do so.

Restrictions of the use of coal stoves

Unlike the United Kingdom, there has never been any national effort in the US to reduce reliance on coal stoves. Krakow, a major Polish city is banning coal stoves in 2019, after a multi-year effort to provide subsidies for alternative heating sources.

Two states – Washington and Oregon – effectively ban them because they only allow stoves that meet specific emission requirements, but those states would have very little coal heating anyway.

Many air districts that have poor air quality and high particulate matter levels employ temporary burn bans apply to coal stoves and well as wood stoves. A few jurisdictions, such as Fairbanks, Alaska, offer homeowners financial incentives to recycle their solid fuel burning appliance (including coal stoves) or replace it with a less polluting appliance (coal stoves are not eligible). However, most change out programs only remove old wood stoves and do not allow coal stoves to be replaced with wood stoves. A Pennsylvania county offered $200 to trade in old wood or coal stoves, but that program has been suspended.

Oregon is the only state where it is illegal to sell a coal stove, or any other uncertified solid fuel burning appliance. Oregon also requires uncertified solid fuel burning appliances, including coal stoves, to be removed and destroyed when a home is sold. According to the latest (2015) Census data, only 143 homes rely on coal for primary heat in Oregon.

At the local level, there may be a number of cities or counties that do not allow coal stoves, but the only one we could find is Summit County, Colorado that forbids the installation of a coal stove (uncertified solid fuel burning device) in a new home or as a replacement unit for an existing non-certified stove.

2021 update: more information about how some New Hampshire homes still heat with coal available here.

Key sources

Dr. James Houck, “Let’s Not Forget Coal,” Hearth & Home Magazine, December 2009, pp.

World Health Organization, “Residential heating with wood and coal: Health impacts and policy options in Europe and North America,” 2015.

Tom Zeller, “Burning Coal at Home Is Making a Comeback,” New York Times, Dec. 26, 2008 

Related stories

Residential Wood Heating in Russia (Aug. 2021)

Residential heating with wood and coal in the US and Europe (excerpts)

This blog contains excerpts from a very important and readable report published by the World Health Organization (WHO) in 2015.  It is primarily from a health and policy perspective and is very valuable for North American as it provides more of a European perspective and is balanced in its approach. The entire 58-page report can be downloaded here. 

The report is particularly interesting as it hits on many themes that were considered or included in the 2015 EPA wood heater regulations, some of which will be litigated in 2017. It addresses best available technologies, indoor air quality, efficiency standards, stove changeout programs, black carbon, carbon neutrality, HEPA filters and many other issues. One of the overarching conclusions is that national policy should strongly favor pellet over cord wood appliances, a transition that has already occurred in parts of Europe, but not in the US.

Authors include experts from the US, Austria, Canada, Finland and Germany.  This publication was prepared by the Joint WHO/United Nations Economic Commission for Europe (UNECE).

The report describes the health effects of and policy options for dealing with residential heating with wood and coal in Europe and the United States. The results presented indicate that it will be difficult to tackle problems with outdoor air pollution in many parts of the world without addressing this source sector. National, regional and local administrations, politicians and the public at large need a better understanding of the role of wood biomass heating as a major source of harmful outdoor air pollutants (especially fine particles). This report is intended to help increase such an understanding. 

Executive Summary:

Measures are available to reduce emissions of solid fuels for residential heating in most places. Encouraging fuel switching (away from coal and other solid fuels) and use of more efficient heating technologies (such as certified fireplaces or pellet stoves) can reduce the emissions from residential wood and coal heating devices. Educational campaigns may also be useful tools to reduce emissions from residential solid fuel heaters.

Furthermore, filters may reduce health effects from indoor air pollution. Existing regulatory measures include ecodesign regulations and labels in the European Union (EU) and technology based emission limits in the United States of America and Canada. Financial fuel switching and technology changeout incentives – as well as targeted “no burn” days and ecolabelling – are other tools available to policy-makers.

p. 2. Residential heating with wood is a sector in which PM2.5 and BC emissions can potentially be reduced with greater cost– effectiveness than many other emission reduction options. Nevertheless, within Europe and North America only a few countries or states have set legal limits for minimum combustion efficiency or maximum emissions of PM and harmful gaseous compounds like CO and gaseous organic compounds (see section 6).

Coal:

p. 8. In the USA 55% of homes used coal/coke for space heating in 1940, but this fell to 12% in 1960, below 5% in the early 1970s and below 1% from the early 1980s (Schipper et al., 1985; United States Census Bureau, 2011).

One study estimates that reductions in the use of bituminous coal for heating in the USA from 1945–1960 decreased winter all-age mortality by 1% and winter infant mortality by 3%, saving nearly 2000 lives per winter month, including 310 infant lives (Barreca et al., 2014).

Based on this and evidence that indoor emissions from household combustion of coal are carcinogenic to humans, the latest WHO indoor air quality guidelines strongly recommend against the residential use of unprocessed or raw coal, including for heating (WHO, 2014a).

Infiltration of smoke into homes

p. 10. A household with wood-burning appliances is likely to be surrounded by other homes with wood-burning appliances, and wood burning also tends to aggregate temporally; thus, on cold evenings and nights most homes in the area may be burning wood.

Given that most wood burning occurs in cold locations where homes are well insulated, buildings are expected to have low infiltration (meaning that relatively small amounts of outdoor air pollution, including wood-burning smoke, enter the house and contribute to indoor air pollution), especially during the heating season.

In North America heating-season outdoor temperature is an important determinant of infiltration, and infiltration levels are generally lower in the heating than the non-heating season, when doors and windows are likely to be open more (Allen et al., 2012). In British Columbia the mean infiltration fraction of PM2.5 in winter was found to be 0.28, compared to 0.61 in summer, although infiltration factors for individual homes in winter ranged from 0.1–0.6 (Barn et al., 2008); another study reported similarly low mean infiltration levels of 0.32 Å}0.17 during the winter (Allen et al., 2009). Combustion of wood in residential areas and often under cold, calm meteorological conditions can nonetheless lead to high exposure compared to other pollution sources, owing to the principle of intake fraction.

  

Indoor pollution

Modern wood stoves and fireplaces, when operated according to the manufacturers’ instructions, release some PM and gaseous pollutants directly into indoor air, although in most cases the evidence for substantial indoor emissions from these modern stoves is very limited. With poor operation, poor ventilation or backdrafting, however, elevated concentrations of combustion products (such as PM, CO, VOCs, NOx and aldehydes) may result indoors. Acute CO poisoning, which can sometimes even be fatal, may occur due to indoor wood burning and infiltration of dirty ambient air), especially when ventilation of the wood-burning appliance is not managed properly.

Stove Change outs

p. 21. Such change-out initiatives have potential limitations. The Canadian Council of Ministers of the Environment (CCME) – the association of environment ministers from the federal, provincial and territorial governments – evaluated 12 stove exchange and educational efforts conducted in Canada and concluded that exchange programmes may have limitations relating to both the cost of new technologies and the long service life of appliances once installed. The assessment supported the use of regulation effectively to curb the sale of high-emission appliances. This approach is used in a number of Canadian provinces and American states.

The Canadian National Collaborating Centre for Environmental Health found that emissions standards (based on best available technologies) are needed to ensure that the newer devices installed through change-out programmes are among the cleanest available in the marketplace. Without these standards, change-out programmes may, in fact, be lost opportunities to install the cleanest available wood-burning devices, which will be in use for years to come.

The study also found that removal of conventional noncertified appliances (through exchanges, time limits or prior to the sale or transfer of a property) was the most effective strategy included in a model municipal by-law for mitigation of residential wood smoke (Environment Canada, 2006) (see “Other regulations and voluntary measures” in section 6). [Click for more on stove change out programs - editor.]

HEPA Filters

While household or individual-level strategies are not typically part of air quality management programmes, two studies from Canada indicate that inhome HEPA filtration might reduce health impacts from wood smoke. An initial single-blind randomized crossover study of 21 homes during winter, in an area affected by residential wood combustion as well as traffic and industrial sources, reported a mean 55% (standard deviation = 38%) reduction in indoor PM levels when HEPA filters were operated (Barn et al., 2008). Use of the HEPA filters reduced indoor PM2.5 and levoglucosan concentrations by 60% and 75%, respectively. [Click for more on HEPA filters - editor.]

Regulatory Emission Limits

p. 26. Over the past decade, the European Commission has worked towards the possibility of regulating solid fuel local space heaters and boilers, particularly those that use various forms of woody biomass fuel (wood logs, pellets and biomass bricks), to create proposed ecodesign emissions limits.

According to the Commission proposals, implementation of ecodesign standards would lead to significant reductions of PM2.5 emissions from solid fuel local space heaters and boilers compared to baseline projections. The draft regulation for solid fuel local space heaters2 states that in 2030 the proposed requirements for those products, combined with the effect of the energy labelling, are expected to save around 41 petajoules (0.9 million tonnes of oil equivalent (Mtoe)) per year, corresponding to 0.4 million tonnes of CO2. They are also expected to reduce

PM emissions by 27 kilotonnes per year,

Voluntary Measures

p. 30. The Wood Stove Decathlon, an initiative of the Alliance for Green Heat, was organized in 2013 to focus creativity and resources on designing next generation wood stoves. The main goal was to challenge teams of combustion engineers, engineering students, inventors and stove manufacturers to build wood stoves that are low-emission, high-efficiency, innovative and affordable, in a common process that may point to commercially attractive next generation stove production (Alliance for Green Heat, 2013). 

Policy Needs

p. 31 Any renewable energy or climate change related policies that support combustion of wood for residential heating need to consider the local and global ambient air pollution impacts and immediately promote the use of only the lowest emission or best available combustion technologies.

Legal regulations for wood combustion efficiency in new heating appliances are urgently needed throughout the world. These will both slow down the current rapid speed of global warming (relating to BC in fine particles and VOCs that promote ozone formation) and reduce the great burden of disease caused by wood combustion-derived particles (especially organic compounds carried by BC). Such regulations should include tight – but technically achievable – limits in particular for the primary emissions of particulate mass, gaseous hydrocarbons and CO from new boilers and heaters.

p. 32. As new wood-burning devices become more energy efficient and emit less pollution (especially PM), national governments need to prepare heater exchange regulations or voluntary programmes. Municipalities, counties and states should consider requiring heater exchanges at the time of home remodels or sales. In many cases, these regulations will be most successful if financial compensation is offered to assist with the cost of replacing old heaters with those meeting tight energy efficiency or emission limits regulations.

“No burn” areas are needed. Especially with current combustion technologies, it is important to define urban areas with dense populations and/or geographical features (such as valleys between mountains) where residential heating or cooking with small-scale appliances burning solid fuels (wood and coal) is not permitted at all or is at least limited to registered models of low-emission wood combustion devices. Residential heating with coal in small-scale appliances should also be permanently prohibited, at least in communities of developed countries, as should the use of wood log burners for central heating without a sufficiently large water tank (which otherwise leads to badly incomplete combustion and very large emissions).

Co-benefits for health and climate

As wood is burned ... carbon is released back to the atmosphere, not only as CO2 but in most household combustion also in the form of short-lived greenhouse pollutants such as BC, CO and VOCs including CH4. Thus, to be perfectly “carbon neutral”, wood fuel has to be not only harvested renewably but also combusted completely to CO2. For both climate and health purposes, the form these fuels’ carbon takes when it is released matters greatly, since BC and CH4 are both strongly climate-warming.

p. 34. A World Bank study found that replacing current wood stoves and residential boilers used for heating with pellet stoves and boilers and replacing chunk coal fuel with coal briquettes (mostly in eastern Europe and China) could provide significant climate benefits.

Another study coordinated by the United Nations Environment Programme and the World Meteorological Organization found that widespread dissemination of pellet stoves (in industrialized countries) could improve health, since these interventions lead to reductions in PM2.5.

If Arctic climate change becomes a focus of targeted mitigation action (because of threats from rising sea levels, for example), widespread dissemination of pellet stoves and coal briquettes may warrant deeper consideration because of their disproportional benefit to mitigating warming from BC deposition in the Arctic (UNEP & WMO, 2011). The World Bank found that replacement of wood logs with pellets in European stoves could lead to a 15% greater cooling in the Arctic (about 0.1 ÅãC). For Arctic nations the modeling strongly indicates that the most effective

BC reduction measures would target regional heating stoves for both climate and health benefits (Pearson et al., 2013).

Conclusions

p. 35. Given that residential wood combustion for heating will continue in many parts of the world because of economic considerations and availability of other fuels, an urgent need exists to develop and promote the use of the lowest emission or best available combustion technologies.

 It may be preferable in many cases to focus on making biomass-based home heating more efficient and less polluting rather than transitioning away from biomass to fossil fuels, given the climate change implications of using fossil fuel for heating.

A reader responds to the wood vs. coal debate

In our October newsletter, we reprinted a column by Cory Hatch from the Jackson Hole News & Guide.  We found it to be a thoughtful piece by a person grappling with energy choices and trying to fairly weigh their costs and benefits.  We got a lot of positive feedback about the article but one reader, a former professor of thermodynamics thought it was important enough to clarify something the author said.

The column made many good points, and concluded:

"After you factor in the energy and associated emissions it takes to extract, refine and transport fossil fuels, wood starts to look pretty good again. If you harvest trees close to home, firewood is fairly efficient and renewable, even if storing that carbon again takes some time. Unfortunately, woodstoves have local impacts, too. Chimney smoke contains particulates, nitrogen oxides and other gasses that can degrade air quality and cause health problems, especially for people with respiratory or cardiovascular disease."

The author also noted: "according to the Sierra Club, burning coal for electricity is only about 35 percent efficient, whereas a modern wood stove is about 75 percent."

Professor Gael Ulrich took issue with that:

" It is true that wood is superior in that it is renewable and not a fossil fuel, and it does not contain sulfur or other elements that can be problems in coal stack emissions.  But his statement, attributed to the Sierra Club, implying that wood combustion is twice as efficient as coal combustion is incorrect.  The distinction is subtle and not appreciated by someone without a background in thermodynamics, but I will try to make the reason clear.  

Converting fuel energy to heat and then to electricity can never be done with 100% efficiency.  Even the most modern efficient power plants seldom succeed 40%.  Historically, that principle was elucidated by Carnot, and the theoretical maximum possible is known as the Carnot efficiency.  In short, electricity or "stored work” is a higher form of energy than heat.  Converting “heat" to “work” always represents an energy loss manifest as “waste heat.” 

Coal power plants probably don’t do much better that 35% as suggested, but wood-fired electricgenerators are even less efficient (for reasons that would require more explanation).  Converting the energy content of coal to heat can, on the other hand, be done with high efficiency, matching or exceeding that of biomass combustors.  

Thus, the statement as worded in Hatch’s column is misleading.  His arguments regarding global warming, etc. are ok.  

I thought you might be interested in the error in case someone else has not already called it to your attention."

Periodically we publish substantive comments such as this one on our blog. Scores of shorter comments are left on our Facebook site.  If you have a longer substantive comment, we can't promise to publish it but please don't hesitate to send to info@forgreenheat.org.