I can't remember if the 98% (or 95, or something close to 100%) efficient furnaces of various friends living in colder climes are gas or oil. Those friends(family) are huge greenies, so assume it's good.

I figure, if the exhaust pipe is regular PVC pipe from lowes, going out slightly inclined horizontal, it can't be too bad..  It's PVC because the gasses aren't hot -- that's how it's 98% efficient -- sucks all the heat out, so the gas isn't warm enough to melt the pipe.

I prefer gas.

• is "manufactured" right here in the good old US of A.
• Gas doesn't stink up you basement and become a waste management problem. If you have a gas "spill", just open the windows and DON'T SMOKE.
• You don't need to refill gas as $whatever for 200 gallons at a pop. The pain with gas is "death by a thousand cuts, while the pain with oil is the elephant stepping on your chest. Take you pick.
• When the oil in the tank runs out and you can't afford more, you're cold. When you can't pay your gas bill, it takes them awhile to cut you off and there are gas company sponsored assistance programs.
• In terms of efficiency, I imagine it's a wash with modern burners of either type being about equal. Are you heating water for radiators, or forcing hot air?

Geothermal is also very cool, will probably work well for heating and cooling in your climate, and can also be used to preheat your hot water at a very low cost. The installation costs will be >$20k, and you require enough land to drill a borehole or two (not recommended if you live over a subway line).

How well insulated is your house? That is another good place for long term savings. With better insulation, you might be able to get away with a slightly lower capacity furnace.

If you're thinking really long term, you might want a coal furnace :)

My parents have a kerosene setup.

I'd go with kerosene, it's cleaner, and they may refil 2 times in winter while my grandmother has to refill maybe 4 times.


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Click

clock makes fun of our little furnace up in the attic.  i remind him that we can't live well on the window a/c units his kind use up north.

Natural gas is essentially methane, or CH4 - four hydrogens to one carbon.  I read an article which held that the history of human use of energy was one of "decarbonization" - from wood to coal to oil to gas, each successively preferred fuel has had a higher hydrogen-to-carbon ratio.  I don't know the exact chemical composition of fuel oil, but I assume it's not as good as methane.  Perhaps eventually we'll have pure H2 coming in through the natural gas lines instead of CH4.

Now, if you REALLY wanted to be more environmentally friendly, you could get a wood stove - sure, wood smoke is dirty, but burning wood is a carbon-neutral activity - if you don't burn it, that carbon is just going to be released when the wood naturally rots anyway.  And if you can get a wood gasification thing going, you're basically back to burning methane, hooray.

Long story short, gas furnace.