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!