Which Fireplace Is Best for the Environment? Wood, Gas, Electric, Pellet or Alcohol?

Free hovering fireplace in a white and glass room

Dominique Imbert

Fireplaces are a great way of keeping warm, but there are many kinds to choose from, with unique strengths and weaknesses. This article will look at different types of fireplaces (in sleek European designs) to help you determine which is best for you.

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Wood Burning Fireplaces

Free floating fireplace in a glass and white room

Dominique Imbert

Wood burning fireplaces are the most traditional, but they can still be stylish. The Gyrofocus was designed by Dominique Imbert in 1968, and in 2009, was voted "The world's most beautiful object."

But like all open wood-burning fireplaces, it is very inefficient. An open fireplace can draw as much as 300 cubic feet of heated room air up the chimney every minute.

They also produce a lot of particulate pollution, so much so that the City of Montreal has banned them and wants them all eliminated by the end of the decade. Fireplaces can be improved by bringing in outside air for combustion and having glass doors, but they still are quite ineffective.

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Wood Burning Stoves

Black vertical wood stove against a graffitied brick wall

 Stuv

Engineered wood-burning stoves have higher efficiency. EPA-certified stoves are a huge improvement and reduce the fine particle pollution significantly. However, the new EPA stoves can get expensive; according to the US Department of energy they work hard to get those high efficiencies and low pollution numbers.

Advanced combustion woodstoves provide a lot of heat but often only work efficiently when the fire burns at full throttle. Also known as secondary burn stoves, they can reach temperatures of 1,100°F—hot enough to burn combustible gases. These stoves have several components that help them burn combustible gases, as well as particulates, before they can exit the chimney. Components include a metal channel that heats secondary air and feeds it into the stove above the fire. This heated oxygen helps burn the volatile gases above the flames without slowing down combustion.
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Masonry Heaters

Gray stone fireplace in a beige and white room

Tulikivi

Masonry heaters are traditional in Scandinavia. The nicest ones are built out of soapstone but others are made of more conventional masonry and even rammed earth. According to Wikipedia, they are:

A vented heating system of predominantly masonry construction having a mass of at least 800 kg (1760 lbs), excluding the chimney and masonry heater base. In particular, a masonry heater is designed specifically to capture and store a substantial portion of the heat energy from a solid fuel fire in the mass of the masonry heater.

In short, they have the thermal mass to radiate heat long after the fire has gone out. However, they are very heavy and expensive to build.

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Pellet Stoves

Gray rectangular pellet stove against a white wall

 RIKA Pellet stove

Pellet stoves are quite efficient, (75 to 90%) and have low emissions. The pellets, made from waste sawdust, are consistent and convenient. According to Popular Mechanics,

Pellet fuel offers many advantages over cordwood: It has a moisture content of less than 8 percent, compared to 20 percent or more for seasoned wood and 50 to 60 percent for unseasoned wood. (Btus are wasted in vaporizing moisture.) Dry pellet fuel is inert and nontoxic. It has an infinite shelf life, and it doesn't harbor bacteria, fungus, bugs or mice. Its energy density rivals that of coal, but it doesn't produce as much ash as either coal or wood.

However, when the Great Recession hit, the drop in housing production and manufacturing dried up the supply of waste sawdust and the price of pellets doubled, to $250 per ton.

The stoves also need electricity to operate the feeder and the fans inside, so it won't keep you warm in a blackout unless you have backup power. They are popular in Europe for space heating needs where the heating season is short; the pellets are easier to carry and store than wood.

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Gas Fireplaces

Rectangular gas fireplace with a gray steel border

 phototropic / Getty Images

Gas fireplaces can be effective space heaters. But they are certainly not an efficient way to heat with gas running at about 65% and the rest of the heat leaving up the flue.

A high-efficiency furnace can be up to 95% efficient, which is a much better way to get your heat. However, proper insulation and sealing are still more efficient.

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Electric Fireplaces

Electric fireplace with white exterior detailing against a blue wall

 maxsime / Getty Images

All electric heaters are 100% efficient at converting electricity to heat; the difference is how effectively they get the heat to you. An electric heater is much more effective than a faux fireplace.

An electric fireplace can be zero-emission depending on where you are and how you get your power; if it is from coal, like 47% of America, you are not burning a clean fuel. If you are just doing it for the looks, you are better off putting a video of a real roaring fire up on that big screen.

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Ethanol Fireplaces

A rectangular fireplace, with a black modern table in the foreground

A-Fire

Ethanol fireplaces produce a real flame without any flue. That's because alcohol burns extremely cleanly, producing primarily water vapor and a little bit of CO2. But it does make that water vapor by taking oxygen out of the air.

This means that ethanol fireplaces come with all kinds of safety devices like a built-in CO2 detector that shuts it off. And they say, "Running on bio-alcohol, an eco-friendly and renewable energy, these fire spaces do not produce smoke or smell. AFIRE Bio-fireplaces is the simplest way of appreciating a real fire."

There are smaller units that sit on your table; these come with warnings that there should be adequate ventilation. But they can still be dangerous; studies agree:

As a rule, ethanol does not burn out completely. Rather, the incineration process results in CO2 – along with poisonous gases (like carbon monoxide, a respiratory toxin), organic compounds (like benzene, a carcinogen), and irritant gases (like nitrogen dioxide and formaldehyde), as well as ultrafine combustion particles.
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Flueless Gas Fireplaces

Silver fireplace inset into a black and white wall

 Ekofire

Another type of fireplace is the catalytic flueless gas fireplace. These are legal in the UK and the United States, but not in Canada. These units burn natural gas and then put it through a catalytic converter to theoretically remove noxious fumes.

They have all kinds of safety devices from oxygen detectors to CO2 detectors. Some have makeup air vents, and others do not, relying on the leakiness of your house. The manufacturers claim they are safe, but others do not.

In the UK, where they are common, this building expert advises that:

All gas heaters produce water vapour and carbon dioxide, and — in the event of an insufficient supply of oxygen – some carbon monoxide too. That’s why they need flues, to get all that stuff vented to the outside. Flueless gas heaters just chuck it all into the air inside the house. The water vapour produced will raise the relative humidity and increase the likelihood of condensation; the carbon dioxide will make you feel sleepy, and the carbon monoxide – if present – could damage your health.

Flue-based systems appear to be healthier, even if they are more expensive.

Which Fireplace Should I Buy?

Chart of clean energy options

Puget Sound Clean Energy Agency

The most efficient solution is to wear warm clothing. Failing that, the natural gas or propane stove is, from a pollution point of view, the best bet. From a fuel cost point of view, it's best to look at the cost per million BTU. Gillespie did the comparison in SFGATE,

At a fuel cost of $250 per ton and an efficiency rating of 85%, a pellet-stove heat costs about $18 per million BTU. At a 75% efficiency rating, the cost increases to more than $20 per million BTU. On a cost-per-BTU basis, pellet stoves are significantly more expensive than wood stoves, which cost about $13 per million BTU. Natural gas furnaces are almost as inexpensive as wood stoves, at $13.52 per million BTU, and coal-fired systems are much less expensive, at $10.89 per million BTU.

But in the long run, the best place to spend your money is on insulation and sealing, along with a professionally designed and installed central heating system, so you don't need supplementary heat in the first place. Because none of these are perfect.