I recently discovered some heaters based on "bio fuel" (ethanol).

Many products seem to be decorative and often present a modern design.

Some ethanol burners can be used in empty fireplaces and can deliver some moderate heating power.

It seems also that the emissions are very low, and there's usually no need for using a chimney.

Do you think that a solution based on ethanol can be used as a main heating source for a flat?

  • If one of your motives is to be green, be advised that not all biofuel is green (in its production). Jan 12, 2023 at 1:53

4 Answers 4


Anything that burns will provide some heat, it will also provide some exhaust.

At today's prices you can save a dollar per gallon by using ethanol over home heating oil. The problem is that you really shouldn't care about price per gallon, you should care about price per amount of energy released.

Heating oil is about 141 Mega-Joules per gallon. Ethanol is about 70 Mega-Joules per gallon 100% Ethanol.

At $3.60 / gallon for heating oil, it is a bargain compared to $2.72 for 85% ethanol, because you would need to buy two gallons to equal the amount of theoretical heat available in one gallon of heating oil. It is even more of a bargain than 95% ethanol (denatured), at $29.31 per gallon. Note that we won't consider 100% ethanol, as opening the container tends to suck enough humidity from the air to make it 95%.

 $3.60 for ~141 MegaJoules of heating oil (1 gallon) 
 $6.40 for ~141 MegaJoules of 85% ethanol (2.35 gallons)
 $62.15 for ~141 MegaJoules of 95% ethanol (2.12 gallons)

It is not a fuel with a high energy capacity, so you'll need a lot of it. Cheap sources are not very pure, and are poisoned (to prevent sales on the alcohol market) that means that "burns cleanly" isn't going to apply unless you want even more expensive forms of ethanol.

Some claim that one can recover more heat from burning ethanol as all of the combustive products (including all of the heat) can be captured in the room. This is highly inadvisable unless you use a double-burn setup, guaranteeing the complete combustion of Ethanol. Partial oxidation of Ethanol produces acetaldehyde which is quite harmful to lungs and belongings. Also, most Ethanol is denatured, meaning it has poisons purposefully added to it to prevent consumption (avoiding the alcohol taxes). The by products of burning the denatured additives are varied and generally unwanted (if not also poisonous).

Partial combustion by-products, like acetaldehyde, are very damaging to certain plastics, making installation costs higher (or hiding those costs in future repair bills).

It makes sense in some places, but in home heating it's not a winning choice unless other factors increase the costs of more mundane solutions.

  • My calculations are approximate, and I could have made a mistake, but by all means, check them for yourself!
    – Edwin Buck
    Sep 28, 2012 at 17:09
  • 1
    A lot of less reputable bio-fuel advocates hide costs in promotion of their favorites. For example, I knew of one person who told of the virtues of used french-fry oil. The only problem is that he was basically stealing it, thinking "it's free" when in reality it is sold back to reprocessing plants. If he paid for his own oil at market prices for used french fry oil, it would have been very expensive.
    – Edwin Buck
    Sep 28, 2012 at 17:12
  • 2
    I will add, even if combustion were 100% efficient with no by-products of any kind, you still would be pumping water vapor into the living area... a LOT of water vapor... almost a gallon (.93 gallons actually), for every gallon of ethanol you burn. That assumes E100 and perfect combustion of course. When that vapor hits anything cold, it will condense. That will lead to mold and other issues. This is another significant reason to never vent combustion into an interior space! Mar 4, 2015 at 20:02
  • This probably has a lot to do with why E85 gasoline is now an endangered species. People figured out that they were getting significantly lower mileage from their "cheaper" fuel, meaning they were buying more of it and not saving any money in the long run. And let's face it - "saving the planet" is a grand & noble ideal, but most people will drop it in a heartbeat if it's significantly more expensive.
    – FreeMan
    Jan 12, 2023 at 15:37
  • @FreeMan Alas, I believe that E85 gasoline is here to stay. You are right about a lot, but you are forgetting that he US Dept of Agriculture is very powerful. It promotes Ethanol gas blends in cars, to create a new consumer of corn (automobiles). This waste of food resources is pitched as "green" and "bio-renewable" even when some of the logic is sketchy. E85 engines use acid resistant rubber and plastic to handle the acidic by-products of ethanol. That's why E15 is only 15%, it only generates enough acid that it seems safe for expected car lifetimes. E85 is, in my opinion, the new hydrogen.
    – Edwin Buck
    Jan 12, 2023 at 17:40

This is a great article. I took a semester off of college two semesters ago to try to find all the right resources to make this venture possible. But, as Edwin ran the numbers, which I would agree are pretty accurate considering the price fluctuations, it is hard to make money trying to sell ethanol as a means of heat for buildings.

After traveling to SP, Brazil and negotiating prices with E85 producers the cost per gallon/liter is too high. Plus the E85 tariff the US places on sugar cane ethanol from Brazil and the boiler system every building would have to replace.

One suggestion would be to find a different means of bio-fuel. Keep in mind that people don't want to replace what they already have for something that isn't going to save them money or fuel less at twice the cost, granted it is better for the environment. Let's face it, it all comes down the impact it has on our wallets.

  • 4
    Biofuel isn't necessarily better for the environment. It can lead to monoculture and, in the case of Brazil, rain forest deforestation.
    – DA01
    Oct 31, 2012 at 8:11
  • Note that my prices are for E85, but my energy calculations are for E100. I was trying to give the maximum benefit of a doubt, but the numbers really don't support the effort. True prices are worse than I published.
    – Edwin Buck
    Nov 13, 2012 at 17:24

One thing you need to consider in the comparison between e-85 ethanol versus heating oil, propane, and natural gas, is that while the energy in Mega-Joules is higher for the last three, heating oil, propane, and natural gas all produce Carbon Monoxide and other waste products which have to be exhausted to the outdoors.

A huge amount of heat (energy) is lost when these fuels have to be isolated by heat exchangers and additional exhaust fans to move the exhaust out and the air past the exchangers, as well as water systems. With ethanol it is possible with only light air intake (to avoid asphyxiation) to directly generate heat energy with very little carbon monoxide. Yes, there is 15 percent gasoline in e85, but the amount is quite usable in indoor environments. Operation of such devices require sensors to avoid CO and oxygen deprivation, and there are small amounts of other bi-products associated with ethanol, but with electronically controlled burner systems, these products can be safely minimized.

I have personally experimented with e-85 heating to heat a two bedroom, one bath, one kitchen apartment. I was able to keep a reasonably comfortable temperature, in fact, sometimes too hot, for about $10 per month!! This is in the dead of winter in Wisconsin, USA, with temperatures outside at -22F in 2013 and early 2014.

The reason why there are few manufacturers of these heaters is that consumers could accidentally or intentionally put gasoline in these units, which can quickly kill them with Carbon Monoxide. My controller was mechanical, and electronics would probably increase the efficiency quite a bit. If you used it alot, you could conceivably obtain unsafe levels of CO from the gasoline component in most e85, although sensors both mechanical and electronic can make operation safe. A small momentary exhaust fan would improve the product, venting out the cool down alcohol vapors when the unit is turned off.

I filled a one gallon gasoline tank twice a month. My system was a direct open air dual burner, with heat shielding. Just experimental, I had problems with start up and controlling the fuel pressure, as the fuel would burn differently from cold to warm. The initial setup, and my future electronically controlled system would use vehicle fuel injectors, a fuel pump, a small air blower, and temperature sensors.

When I used this system, my apartment smelled weakly like hops, without the strong sugary component. One person even asked me if I was making beer!


It's an interesting idea. Conceivably, any combustible fuel could be used for home heating. In practice, the dominant fuels for home heating are natural gas (methane), propane gas, home heating oil, and electricity. Wood stoves and built-in heaters powered by fuels such as kerosene are also available, but typically used as accessory heat or used in locations where other fuels are unavailable.

After some googling, it doesn't look like ethanol-fueled home furnaces or boilers are mass-produced. I can imagine a couple of reasons for this:

  1. People want a cheap, readily available fuel source for home heating. Until there are delivery services or pipelines for a fuel, it will be inconvenient to use.
  2. Ethanol is inefficient for large-scale heating use. The production of ethanol involves distillation which requires heat; it might be more efficient to simply use that fuel to produce the heat you need than to produce and then consume ethhanol.

There may be other reasons as well. Overall, it looks like if you want to use ethanol for built-in whole-house heating, you will be undertaking an unusual experiment. If you have a low cost source of ethanol, perhaps you can achieve most of your heating needs using portable ethanol burners. However, if you want to be able to sell your flat, it would be wiser to invest in a more mainstream heating system for whole-house heat.

  • The flat at the moment has only electricity as a main source.. The current radiators seem to be expensive and not really "smart".. I am thinking of using heated floors + ethanol.
    – Rdpi
    Sep 28, 2012 at 15:46
  • A problem with ethanol are the running costs. In the UK I am able to find many different burners, but the "fuel" isn't really cheap (on long term)
    – Rdpi
    Sep 28, 2012 at 15:46
  • To prove efficiency of electric heating, consider installing a heat pump system. MUCH more efficient than electric radiant heating. And many such systems give you air conditioning too, since that's basically a matter of what direction you run the compressor.
    – keshlam
    Jan 11, 2023 at 22:59

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