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In defence of wood burning stoves

I sell wood burning stoves for a living.

For some, that would in and of itself negate the legitimacy of my opinion. Of course, this is a reason for scepticism, and I make no claim to be an expert on respiratory health or on air pollution, but there are, if you read into the subject, as I have, strong grounds for challenging much of the current narrative on woodburners.

Like any conscientious salesman, I believe in the integrity and wholesomeness of the product we sell. For someone with a strong social conscience and a deep desire to minimise human impact on the environment, I feel truly privileged to have a job that accords strongly with my ethics. Our customers regularly say that installing one of our fabulous woodburners has been the best investment they have ever made. Because most of our customers only buy one, and because a good wood burner will last up to thirty years or more, most of our new business comes from word-of-mouth.

Among those customers, we have always been proud to include a disproportionately high rate of doctors, as well as academics, science teachers, and, on one occasion, a couple who both worked in academic posts specifically oriented towards air quality. It’s always been a reassuring heuristic to suggest that not only are we selling the right kind of stove for a discerning market, but that this highly-educated portion of our clientele have few reservations about the health effects of using our products.

Our sales environment is, however, also shaped by the media environment, and at the moment the narrative about wood-burning stoves is almost entirely negative. Stories about air pollution, and especially tiny particulates that can penetrate deep into the lungs, are rarely out of the news cycle, with the government suggesting that this source of pollution is the contributory factor in 29,500 premature deaths per year, and Sadiq Khan, the mayor of London, claiming that 10,000 Londoners a year die early as a result.

The tenor of the articles veer wildly from alarmist reports that stoves are going to be banned, for which there is currently no evidence whatsoever, to insinuations that wood burning stoves are killing people and ruining the health of the population. (“More deaths in Bristol from pollution than car crashes, Centre for Cities report finds” https://www.bristolpost.co.uk/news/bristol-news/more-deaths-bristol-pollution-car-3809538, ‘More people die from polluted air than car crashes in UK towns and cities’ https://www.salisburyjournal.co.uk/news/national/18188592.more-people-die-polluted-air-car-crashes-uk-towns-cities/ This is of course a ridiculous comparison: not many people die in road accidents anymore, and a sudden mid-life death from massive trauma is a quite different proposition from an incrementally shorter life from environmental factors.)

The narrative is further confused, certainly for the layman, by the conflation of many types of pollution, from greenhouse gases to nitrogen dioxide, but even within the narrow parameters of small-particulate pollution, emissions from vehicles, domestic solid-fuel use for heating, and industry are often conflated, when there are significant differences both in the nature of the emissions and in where they are delivered. These nuances are rarely reflected in the clickbait reporting in the media, and there are some shocking misrepresentations, which normally cast stoves as the villain of the piece. This sensationalist bias no doubt helps to sell newspapers, and also, I would suggest, shift the focus of the pollution story away from the car industry in particular, this being one of the highest-spending sectors in print and digital advertising, and relies on some very dubious statistics and routine misreporting of the available facts.

Despite the creeping news agenda on woodburners, no doubt exacerbated by the feedback mechanism of consequent click rates on sensationalist stories, the wood burning stove industry has been slow to react, and we have been generally surprised by the vehemence of the reaction. The two ostensible outriders of the news cycle have been Michael Gove’s much-trumpeted Clean Air Strategy and the forthcoming implementation of Ecodesign 2022, a new standard for stove efficiency and performance which is currently being phased in.

At the company where I work, we have been selling stoves for over forty years. We’re one of the oldest stove retailers in the UK, and one of the earliest. The early models we sold were certainly less efficient than modern stoves, but were revolutionary in their improvement on open fires, which were more prevalent (and incredibly wasteful) at the time. Nonetheless, the top-tier stoves we sold then – from Jotul, Vermont Castings, and, providing a step-change in performance, Clearview Stoves – still achieved very high efficiencies,and those we sell now, from Clearview, Chesney’s, Contura, Chilli Penguin and Barbas are rightfully considered best-in-class on a wide range of parameters, and we have confidently promulgated their performance characteristics over the years.

Ecodesign is another step-change, driven by often political and commercial considerations, which will probably elevate performance across the board, though there will be casualties, and not all of them deserved: it will penalise some excellent manufacturers whose products don’t currently conform in exactly the required way, and it will allow market entry to some very poor stoves, which will perform inadequately but meet the criteria. Hopefully, these latter will ultimately be weeded out by market pressures, but at significant expense for those consumers who are persuaded to install them on the basis of their regulatory credentials. Nonetheless, regulation does provoke innovation, and as the various brands try to modify their designs to meet the new rules, some radical improvements in performance will be achieved. We know this, because many of them are already here. We have them under fire in our shop, they light easily enough, burn beautifully and consume less fuel, and we know that they produce fewer particulates because they have been put through rigorous testing. The standards required are very high, and very difficult to meet, and we can only applaud the brilliant engineering prowess that has produced these new stoves.

For us, this process has been a natural market evolution, much as emissions requirements have become more stringent for cars or gas boilers. Newer, more-efficient models enter the market; older models become obsolete and are replaced over time, leading to gradual, but significant improvements for the environment and the people who live in it. So far, so uncontroversial. There is rarely a furore when new standards are introduced for cars or gas boilers, or calls for old models to be banned or ripped out of people’s homes. An exception would be the end of manufacture of the iconic Land Rover Defender, but most petrolheads understood the reasoning, even if they didn’t like the result. Nonetheless, there are still plenty of Defenders on the road, just as there are still plenty of classic cars. Being based near Beaulieu Car Museum, we frequently get stuck behind them in traffic. If you end up behind one in the queue at the level crossing in Brockenhurst, you can get a cracking headache in just a couple on minutes, but they are statistical outliers, and in aggregate a pretty minor, and charming, inconvenience that brings enormous pleasure to heritage motoring enthusiasts. No politician would dare suggest outlawing them outright. The other recent furore concerns emissions cheating by the car industry, but the consequences of that are fully deserved and not nearly punitive enough.

It is thus hardly surprising that, as the tobacco industry has done before them, car manufacturers would seek to deflect attention away from their own egregious pollution and corruption towards a convenient bogeyman, which produces a visible and smellable waste-product: wood-smoke. As Jaguar Land Rover boss Jeremy Hicks said in 2017, right at the zenith of dieselgate: “I don’t want to stereotype, but I can imagine the well-intentioned London dweller deciding against buying a diesel car for environmental reasons as they sling another log into the wood-burning stove thinking they are returning to nature…They are not. They are doing harm. Oblivious to what they are doing.” (https://www.dailymail.co.uk/news/article-4623828/Stop-demonising-diesel-demands-boss-Jaguar.html “Mr Hicks said that the trendy wood-burners beloved of environmental campaigners are actually just as bad as the worst-polluting cars.”)

The backlash against stoves, emerging from nebulous and apparently innocuous developments, has been vicious, immediate and largely unwarranted. Why? I would argue that stoves are an easy, high-visibility target, with an easily-demonised class of aspirational users, and represent an easy distraction for hegemonic industrial behemoths who would prefer to face diminished scrutiny by shifting the focus of the pollution narrative onto a tiny sector of the economy which has all the PR effectiveness of a knitting convention.

The car industry, like the tobacco industry before them, is particularly keen, with its deep pockets, to obfuscate the issue, and many of its representatives have desperately slung mud at the tiny wood-burning stove industry, often just days before their own companies get hit with massive fines for lying to the public about the toxic emissions of their vehicles, in an effort to distract scrutiny from their woeful misrepresentations and deceits, and consequent legal and regulatory exposure.

The slow PR machinery of the wood burning stove industry has largely responded by pushing its latest-generation appliances, which promise to minimize particulate emissions. This is a partial, and slightly misleading, panacea, and does little to defang or even interrogate the charge with which it is faced: that stoves make an outsize contribution to air pollution and damage human health. In effect, the tacit admission is: yes, we pollute, but our new stoves pollute less.

The tenor of the clickbait that has filled the popular press in the last couple of years has become more and more shrill in this regard, both in the inflammatory language it deploys (stoves “kill”) and in the total absence of analysis of the data it regurgitates. The latest round of headlines have been kicked off by a report from the Centre for Cities, which states:

  • 1 in 9 deaths in the UK are linked to air pollution
  • The two biggest sources of PM 2.5 are road traffic and domestic combustion for heating
  • 50% of PM 2.5 in cities is from domestic burning
  • Recommends legally-binding commitments on emissions in cities, leading to a ban on wood-burning.

Some of these statistics correlate, at least partially, with the government’s figures compiled for its Clean Air Strategy.

The Clean Air Strategy has been controversial insofar as it has highlighted the increasing popularity of wood-burning for domestic heating, with the corollary of dramatically increased particulate emissions, which suggests that this single source now contributes 38% of all particulates in UK emissions. The statistics used to produce this report, dissected recently by Tim Harford’s ‘More or Less’ radio program https://www.bbc.co.uk/programmes/p070d4xz , relied on a 2015 national survey based on the number of homes burning wood, and an average amount of assumed pollution per wood-burning home.

The assumptions made in producing these statistics were that most stoves in use are of an older, more-polluting variety and that the average user burns her or his stove 40 hours per week in the winter and 20 hours per week in the summer.

Because there is no national register of which stoves people have installed, the first assumption is hard to verify, but doesn’t accord with our experience, nor with our historic sales. Where people have installed cheap stoves (of the kind we don’t sell, but which are widely available online or from budget outlets) – usually built in countries with low manufacturing costs and minimal environmental regulation and without any stove-engineering pedigree – the consequences usually become apparent fairly quickly. They are difficult to light, burn badly, the glass windows brown up throughout the burn cycle, the welds often become translucent during use, and because of the variable quality of the (usually recycled) iron used in construction, they often fall apart within five to ten years.

The second assumption is also hard to verify, but seems questionable. The vast majority of our customers buy stoves as a lifestyle addition, and use their stoves as a convenience and pleasure. That they would run it on average for forty hours a week in winter seems incredibly unlikely, and the proportion who would use their stoves at all in summertime would probably be in single figures.

The government themselves, according to Harford, accept that their estimates may be wrong by a factor of ten. This is unlikely to vary to the upside, as there are limits to the possible pollution attributable to domestic wood-burning based on direct measurements of air-pollution, but it does mean that instead of 38%, we could feasibly be looking at a figure as low as 3.8%. That is a massive difference, and certainly an anomaly that should make any politician wary of using the statistics as the basis for designing policy.

On top of this, even if we are to accept other nebulous assertions, Stove Industry Alliance figures show that forty percent of domestic wood burning is still done on open fires, rising to seventy percent in London, where it is illegal anyway. As open fires are profligate consumers of logs, using at least four times as much wood as even the dirtiest kind of stove, this skews the emissions figures massively, and emphasises both the pitiful enforcement of existing regulations and the enormous contribution that stoves can still play in moderating the output of potentially harmful particulates.

The stove template for Ecodesign is basically a step-up from existing DEFRA requirements for wood burning in smokeless zones, which will then be applied across the board, not just in cities. Unsurprisingly, most of the ongoing argument about stove use does concern their use in urban areas.

We sell stoves mostly for the rural market, but a high proportion also go to homes in the urban sprawl of Bournemouth, and into our local smoke-control zone of Southampton, which WHO have described as one of the most air-polluted cities in the UK. Southampton has several problems in this regard, some ubiquitous, others specific to its maritime identity. Familiar to any urban dweller in a city with pitiful public transport is the prevalence of traffic in Southampton, heavy everywhere, often gridlocked, spewing fumes from cold engines at an ideal height to be sucked straight into lungs (unlike stove emissions, which are generally delivered via chimneys into clear air at between eight and ten metres altitude). There is also significant industrial pollution, not least from the Fawley refinery across the river. Southampton also suffers from massive maritime traffic, which sends a constant pall of exhaust fumes from the very dirtiest of diesel fuels (which don’t have to conform to any of our domestic regulations) over the city. This is exacerbated by the presence of cruise ships, which keep their engines running in dock in order to keep running onboard services for their customers. (https://www.bbc.co.uk/news/uk-england-hampshire-39181972 “World Health Organisation (WHO) called Southampton one of the most polluted cities in the UK…The city's port welcomes thousands of ships a year, including some of the biggest cruise liners and container ships in the world…The vessels leave their engines running while docked to power their electrics...”)

No doubt, somewhere in the mix, woodburners also make their contribution, but it must be negligible by comparison, and unless you were searching for a straw man to knock down, they would feature fairly far down on the list of culprits to tackle if you were genuinely concerned with improving air quality.

The other crucial variable in controlling particulate emissions is the wood that is burnt. Unlike car fuel, for instance, which is standardised, logs vary by species of tree, in density, sap content, dimensions and dryness. The last factor is absolutely critical, because only very dry wood should ever be used on stoves. Damp or unseasoned wood will burn very badly, if at all, and produce plumes of smoke. A similar effect can be achieved by improper stove use – by smouldering wood with insufficient oxygen allowed to enter the combustion chamber. It doesn’t matter how good a stove you buy if you misuse it or burn inappropriate fuel, so Ecodesign is only ever going to be a partial panacea to air pollution. What is required is meaningful regulation and enforcement, which the Clean Air Strategy is moving towards, though it will depend on rigorous and responsible implementation. European countries with more mature traditions of stove use manage this successfully with a firm but light touch; it remains to be seen whether or not a UK government is capable of administering a similarly balanced regime, but it is something that we as a company, and that the better part of the stove industry, would welcome.

Another bone of contention is just how harmful wood burning emissions actually are. Some three billion people on the planet burn biomass of one sort or another for heat, cooking or both. Humanity as a whole has been living around fire for tens of thousands of years; the oldest-recorded hearth is 300,000 years old (“New species of early human cooked there 300,000 years ago, say archaeologists.” https://www.nationalgeographic.com/news/2014/1/140129-oldest-hearth-israel-cave-new-human-species-discovery-archaeology-science/)

As an anthropology enthusiast, I’ve been scrabbling around to see what data there is on subsequent health outcomes. Where burning is practised indoors, with insufficient ventilation, often by peoples dispossessed of their lands and traditional lifestyles, where homes are filled with smoke on a daily and continual basis, the health impact is routinely catastrophic, disproportionately on the women who are routinely confined indoors, which is well-documented. Less studied from this perspective are those who live outdoors, and who gather in close proximity around fires on a daily basis.Here there is a remarkable absence of evidence – remarkable in contrast to the volume of studies of polluted homes and dwellings – of respiratory problems from the daily, close-quarters inhalation of wood smoke. In general, bushmen and aboriginal people, where they have been allowed to live as they have for the previous thousands of years, are actually remarkably healthy.

This accords with recent Danish research which deliberately exposed healthy individuals to high levels of wood smoke in enclosed spaces for up to three hours. One, conducted by the Aarhus University’s Department of Public Health, found, “This experimental exposure study confirmed that only limited effects could be observed after a 3-hour wood smoke exposure in the 2 to 400 μg/m3 fine particle range in healthy atopic volunteers.”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921260/

Another study from Copenhagen University studied the bodies of the same subjects to evaluate the extent to which wood smoke affected aspects other than lung function, by, for instance, stressing their DNA, creating inflammations in the body or affecting blood vessels – noxious effects which were strikingly evident in studies related to traffic-related pollutants.

“We have previously observed an effect of traffic pollution at lower concentrations, albeit over a longer period, so we were expecting to be able to measure something here too. But we found no effect at all from exposing people to wood smoke for three hours at a relatively high concentration,” says Professor Steffen Loft, of Copenhagen University’s Department of Public Health. “The results of the examination of the participants’ bodies were just as clear as the examination of their airways: hour-long periods in a room filled with wood smoke does not affect the body – outside of the airways – to a degree that can be measured.”

The conclusion of the two studies shows “that if people are exposed to large amounts of wood smoke for three hours, it is certainly uncomfortable and it irritates the lungs, but it has no long-term effect on the lungs’ ability to function, or on our cells or any of our other bodily functions.” http://sciencenordic.com/no-serious-harm-breathing-wood-smoke

This contrasts strongly with, for example, a paper that was recommended to me by an interlocutor on Twitter: “Adverse effects of wood smoke PM2.5 exposure on macrophage functions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4757468/ which consists almost entirely of data extracted from tests on mice. There is no evolutionary reason why mice would have any tolerance for woodsmoke; for humans, it is overwhelming.

So it is not really fair to conflate wood burning stove emissions with those from vehicles. This finding would accord with earlier research which suggests that homo sapiens, exclusively among mammals and even earlier hominid species, has developed resistance to the worst toxins in wood smoke and is able to eliminate many of them through excretion. https://www.theguardian.com/science/2016/aug/02/smoke-signals-dna-adaptation-helped-early-humans-deal-with-toxic-fumes

For additional perspective on mortality rates from particulate emissions, which you will remember are counted in the tens of thousands, it is worth listening to the recording of the words of the late Professor Anthony James Frew, of the Allergy and Respiratory Medicine Department at the Royal Sussex Medical Centre, as played on Harford’s radio program. Contesting Sadiq Khan’s provocative 10,000-deaths figure, he points out that the threat of loss of life is primarily to those at the end of life, and is measured in days rather than months or years. If, for instance, an immediate reduction in particulate emissions of one μg/m3 could be achieved instantaneously and across the board in the United Kingdom, it would improve life expectancy by 20 days, so that someone expecting to die at 85, might then reasonably expect to live to 85 years and 20 days.

To translate this to our local Southampton example, I took a sample from the daily air quality index for central Southampton at midday on the 5th February 2020, which gave as the running 24-hour mean for PM2.5 particles as9 μg/m3. (https://uk-air.defra.gov.uk/latest/currentlevels?period=current®ion=15#levels) Extrapolating from Professor Frew’s metric, this would mean, variously, that using the Centre for Cities’ 50% figure, the government’s 38%, or the statistically possible 3.8% (government figures could be wrong by a factor of 10), an average life expectancy might be increased by 90 days, 68.4 days or 6.84 days by banning all domestic combustion for heating purposes. And that is taking equivalence between wood smoke and other pollutants at face value.

By contrast, smoking, which far too many people do, but which is still legal, reduces life expectancy by 10 years. Sedentary lifestyle, which most people do, reduces life expectancy by about the same margin. Moderate drinking reduces life by one to two years, more than two drinks a day reduces it by 4 to 5 years. Moderate obesity = 3 years. Severe obesity = 10 years.

Dealing with threats to public health is a bit like whack-a-mole, driven largely by the news cycle, but it’s fair to say that the government routinely ignores the greatest threats to life in obeisance to commercial interests that swell their party coffers, give employment to their constituents and flush the City (and sometimes, though increasingly less so, the Exchequer) with cash. But woodburners are demonstrably a minor part of the equation, even if the accusations against them held water, which we don’t think they do.

This is not to sniff at the value of an extra few days, or even three months, of life, nor to diminish the value of the lives of the elderly, but to put in perspective the benefits that might accrue from significant action on reducing this particular form of pollution. Of course, Professor Frew says, we want to reduce pollution, but we need to have an idea of where an acceptable level might be reached. Yes, there needs to be regulation and enforcement, but (and here he’s talking mostly about cars) putting the brakes on too hard would de-rail the economy, destroy the tax-base, put all our efforts at efficiency into reverse and itself, through loss of government revenue and further austerity, bring about catastrophic health- and life-expectancy outcomes.

Which brings us neatly back to the press campaign against wood burning stoves. The most recent derogatory article I read was from the Mail. The online version was bracketed exclusively by advertisements for new cars. It is certainly tempting to think that the car lobby, like the tobacco industry before it, having been hammered for lying and misrepresenting their own data, and for contributing to terrible street-level pollution, are helping useful idiots – sorry, uninformed journalists – to obfuscate the issues surrounding particulate emissions and steer public ire towards what is still in many ways a cottage industry. Who pays the piper, as they say, calls the tune.

We are only a small company, one of a few hundred serving the wood burning market in the country. Over-represented in our ranks are eccentrics, non-comformists, amateur enthusiasts and brilliant autodidacts, but on the whole, we care passionately about people and the planet. Many of the products we sell are from hugely successful British manufacturers, who are at the forefront of new stove technology and make a great contribution to the UK economy, often, as in the case of Clearview and Chilli Penguin, building their stoves in the UK, and even sourcing the materials – including the steel – domestically too. Downstream from us are a massive network of very experienced installers, some with decades of work under their belts, who depend on a continuous throughput of work for their livelihood, as well as a contingent supply network of builders, chimney sweeps, log suppliers and tree surgeons who represent a highly-localised economic nexus, earning and spending their pounds locally.

We have been deeply damaged by the negative tone of reporting in the British press, which represents a shameful neglect for the truth, with a total absence of thought for the consequences of their misrepresentations. It would be nice to see a little more professionalism and conscience.

If you enjoyed this, try our previous blog post: https://www.woodburners.com/about-us/blog/2020/02/05/nine-reasons-why-buying-a-wood-burning-stove-from-us-is-still-ecologically-friendly/