As far as climate change and human health are concerned, no wood stove is the best wood stove, according to some experts.
The negative impacts to human health associated with particulate matter emitted from residential wood stoves aren't disputed, said Michael Mehta, a professor of geography and environmental studies at Thompson Rivers University in Kamloops, B.C.
Yet, the myth persists that wood-burning as a residential heat source, particularly in rural areas or smaller communities, is natural and green, said Mehta, a specialist in environmental and health risk issues.
“The problem is there's been this false presentation of environmental performance as carbon neutral, when it's not,” Mehta said.
Proponents of burning wood as an energy source, particularly wood pellets, argue it’s a low-carbon fuel. The argument is that carbon released when trees are cut down and burned will be recaptured by new trees that grow in their place.
But recycling carbon with forests while burning wood is more complicated than presented, and it encourages people to use wood rather than switching to healthier and more sustainable heating methods, Mehta said.
What people are reading
It can be argued that burning wood is renewable, but that doesn’t mean it’s sustainable in terms of curbing climate change, he added.
“People seem to think that they can just harvest trees and burn them and it's a wash,” Mehta said.
“But, we’ll never be able to get at climate change in time if we think that way.”
Burning wood releases carbon immediately, but it takes upwards of 40 years for a tree to start capturing any significant amount of carbon, he said.
Yet in the short term, all the atmospheric carbon will continue to accelerate climate change, already an urgent problem.
“The second problem is when you burn wood from trees, you release a very potent short-lived climate pollutant called black carbon,” Mehta said.
In essence soot, black carbon is a component of fine particulates (PM2.5) emitted during wood burning that contribute to air pollution and are of particular concern to human health.
Black carbon from wood stoves can travel long distances and has a climate-warming effect, Mehta said.
The material absorbs sunlight in the atmosphere and heats it surroundings, he said. And if deposited on ice or snow, it reduces the materials’ ability to reflect sunlight, increasing glacial melting and accelerating global warming, he added.
Rather than using a wood stove, people would do more for the environment and their own health, and that of their neighbours, by switching to other heating options, said Mehta.
The B.C. government funds a wood stove exchange program in conjunction with a number of municipalities and regional districts that offers rebates to replace older, dirty wood stoves with new and cleaner sources of heat, such as electric heat pumps, gas or pellet stoves, or cleaner-burning emission-certified wood stoves.
The annual program has helped replace about 9,000 old stoves with cleaner options since its inception in 2008.
A total of 19 B.C. communities have funding in the coming year for the wood stove rebates, including the Strathcona Regional District, along with five other Vancouver Island regional districts.
Eligible households can apply and get $250 towards a certified wood stove, or $400 towards a qualifying electric heat pump, gas or propane or pellet stove.
Homes in “red zone” communities, where the fine particulate pollution exceeds federal air-quality standards, may be eligible for $500.
However, Mehta is concerned the program still provides the option of substituting one wood stove for another, regardless of the fact it’s certified and releases fewer emissions.
“It gives people the impression that their new wood stove is so clean that they can burn with impunity whenever they want and whatever they want,” he said.
Many people don’t have access to high-quality, dry seasoned wood necessary to limit harmful emissions, he added.
Wood stoves still have value as a secondary heat source in rural or isolated communities during extended power outages, Mehta said, but fundamentally, there are better heating technologies available.
“For everyday use, an electric heat pump, or mini-split heat pump, is the best technology,” he said.
“It's a technology that's been around for decades. There are tens of millions of them deployed around the world.”
Markus Kellerhals, a senior air quality science officer for B.C.'s Ministry of Environment and Climate Change Strategy, said the intent of the wood stove exchange program is to encourage people to switch out their wood stove for alternative heating methods.
“That’s reflected in the (financial) incentives offered by the program,” Kellerhals said.
In terms of air quality and health impacts, there is no minimum safe level of particulate emissions from wood stoves, he said.
“But on the other side of the coin, if someone with a dirty wood-burning appliance replaces it with a cleaner-burning stove, it won’t eliminate emissions, but it will significantly reduce them,” Kellerhals said.
And, for some lower-income households, the higher investment options — such as a heat pump, which can range in the thousands of dollars — aren’t viable options, he said.
“There’s a proportion of the population where heating a house in winter is a significant financial burden and who can't obtain cheap or free wood,” Kellerhals said.
“And those people are going to be less likely to switch to a heat pump, or any gas infrastructure either.”
Many people who own their own homes and use wood as a primary heat source have sufficient capital to cover the higher initial cost of a heat pump, especially when factoring in the energy savings that follow and taking advantage of rebates offered by BC Hydro, Mehta said.
And there are often significant economic costs associated with heating with wood, he said
Some residents with large forested properties, or who live in isolated areas, may have ready access to free or low-cost wood, but many households using the stoves as the primary heat source purchase wood, Mehta said.
That can cost as much as $1,800 or more in the winter, he said.
Over the course of history, people moved away from burning wood due to the threat to human health and because it was an inferior heating method, he added.
“And now ... people are moving back to burning wood, which has the lowest energy density and is the highest polluting source of energy that you could have in your home.”
Rochelle Baker / Local Journalism Initiative / Canada's National Observer
We built our rural NE Ontario
We built our rural NE Ontario home over 33 years ago. We put in a serious wood stove in the basement, which can heat the whole house, and a small air-tight upstairs, for desperately cold mornings.
Several years later, we replaced the old stove with one that's EPA approved, to lower the environmental impact.
The heating alternatives here are oil, gas, electric. All of which seemed to us to be much more perilous than wood, a renewable resource.
There is no duct or other circulation system in our house. Switching to another heat source would require the installation of one.
I've been looking, for the last couple of years, for a better alternative to wood, without success.
I would very much appreciate additional coverage of this issue, with alternatives discussed.
Kathy, I live in Eastern
Kathy, I live in Eastern Ontario in a house with no ducting. I have heated with a high-efficiency gas-fired boiler with radiant baseboards in the old part of the house (1910) and radiant floors in the back addition. It is pretty well insulated. Late this past summer we had 2 air-to air heat pumps (ductless minisplits) installed - one upstairs, one down- which cost about $60/mo. to run in this milder winter (so far). It will be somewhat more expensive when the weather gets really colder. (-25C). We have a gauge attached to the breaker that tells us how many kWh the system draws, so we have a pretty good idea of what it costs. We were careful to ask our installer to provide units that were good to at least -23C. There are ones that are good to -25C and -30C but that means research and some wait time. It's worth it. Our indoor units are mounted higher on a wall and the compressor that runs them from outside can be mounted on the ground or on the outside wall. You can get compressors that run 1 to 4 or 5 indoor units depending. We get air-conditioning and dehumidifying as well in summer. The tubing from the compressor has to be closed in inside and outside the house. We put crown moulding along one bedroom wall to get it the wall unit more centrally located. Some people just mount them on an outside-facing wall so there is no indoor tubing. There are kits to cover the outside tubing or a wood or metal run can be made to enclose.
Our next step to get off fracked fossil fuels in the future is to replace the boiler with an air to water heat pump that hooks into the current piping systems. If this technology existed in its current state when I was renovating the house in 2005, I would have insulated all the PEX piping installed so that this kind of heat pump could be also used as a chiller in summer. No dehumidification though with that.
It's disappointing that this
It's disappointing that this article simply says "No" - your wood stove isn't green. This fails to differentiate among different types of wood stoves. EPA certified wood stoves and pellet stoves are much better than uncertified stoves - combustion efficiency is the main factor affecting emissions and automatically operated appliances provide the most effective combustion. Wood fireplaces are highly inefficient and should be banned. The following paper http://woodheat.server296.com/attachments/article/hpawma.pdf provides a more balanced comparison of wood and other heating fuels.
Thanks for sharing that paper
Thanks for sharing that paper, Ole; good reading. The paper's note that "... electricity is
not a primary source of power and it is in turn is produced principally by fossil fuel combustion..." is not at all true in Ontario -- we decommissioned our last such plant about a decade ago. The paper was presented in 1998 when Ontario had six plants generating electricity from fossil fuels, so at least that aspect of the overall picture may have changed somewhat in the twenty years since the paper was presented.
"..many households using the
"..many households using the stoves as the primary heat source purchase wood, Mehta said. That can cost as much as $1,800 or more in the winter, he said."
For reference the electricity to supplement our geothermal furnace costs us more than that every winter. That is with Ontario's cap on the price of electricity. Perhaps Dr. Mehta is focussing on BC or overall Canadian statistics which are highly skewed towards our major cities near Canada's southern border; in rural Ontario electricity and the electricians with the government certification to install those systems are stupid expensive, and government support programs can disserve homeowners. For example the windows replacement program requires demolishing the windows back to the bare brick and the few contractors approved by the government jack up their prices so that the supported solution is still several times more expensive to implement (after receiving the government support) than double-glazed argon-filled sealed windows (which are only a couple percent less efficient than those of the government program). The devil is in the detaiils.
Rob, I believe that air to
Rob, I believe that air to air ductless minisplits are significantly cheaper to run (and install) than geothermal unless you have a pretty large house (mine is 1800 sq.ft. and pretty well insulated). Although geothermal supplies hot water also? I used 1117 kWh in December on TOU rates heating primarily with 2 minisplits with a small amount of radiant backup in 2 rooms (bathroom/kitchen). More in my comment to Kathy above.
Sorry Rob Campbell and Kathy,
Sorry Rob Campbell and Kathy,
It was actually 999 kWh used in December for the whole house and electric car charging (not hot water) on TOU. (Jan. also included on Hydro bill). The actual 'Electricity' portion of the bill cost $129 for December. 700kWh is off-peak. For Dec. we used 274 kWh for minisplit heat which is about 27.5% of the electricity portion of the bill so conservative cost estimate is $35.47 for running minisplits for December. Plus other Hydro and HST charges.
We have used 140 kWh so far this month (to Jan. 17 afternoon) according to our gauge, which would cost $23.29 @ .085kWh new rates. Imagine if solar panels plus lithium battery backup were powering this!
The kitchen/bathroom floors are hydronic radiant fired by gas boiler- to be converted to air to water Heat pump later. I think some infill heat is needed with my minisplit system and don't want to write off the investment I made in radiant heating infrastructure. The house is 110 years old so hard to totally retrofit and eliminate all air leaks and cold floors.