gravity furnace

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A natural gas, or propane fired gravity hot air furnace has one very major advantage, if, it uses an atmospheric type burner, (like the top burners on a gas stove).

(The same, is also true, of gravity circulation hot water systems).

That advantage, is that if it uses a millivolt type gas valve, powered by a 750 mv, powerpile type generator, operated by a pilot light, it is then totally immune, to all electric power outages, so long as the gas stays on.

Although a furnace contractor. would think it to be a rather strange order, if, it currently uses a 24 volt AC valve, it could be changed out for a millivolt type.

If you want to learn more about them, (assuming yours is a hot air furnace, and not a boiler), I suggest, that you find a copy, of one or both of the following old books:

Gravity Warm Air Heating, by James Hoffman, U of IL, 1935

Warm Air Furnace Heating, A. M. Daniels, various editions thru about 1930

Both, give very detailed explanations, of how they work.

They could also help you change the piping around properly, if say you wanted to heat an addition you added, or had a room that was not warm enough.

You might be lucky, but from from my experience, almost all modern heating contractors, (even the very best ones), don't have the faintest idea, of how to properly install, gravity hot air furnaces.

Also, it is possible, to add a blower, to a powerpile operated, gravity hot air furnace, in a way, that the system would still work, even if the power to operate the blower, went off.

It is more complicated, than simply putting a blower into the cold air return, but it can be done, and at a fairly minimal cost.

Obviously, I do suggest, that you take appropriate precautions, against any loose asbestos, and check for any cracks in the heat exchanger, firebox etc.

True, gravity furnaces are not as efficient as a modern ones, but all thing considered, I think that is a small price to pay for peace of mind, particularly, if one lives in a very cold state.

I don't know what state you live in, but I live in Montana.

Why go to all the expense and mess, (and have the fire insurance company drastically raise your rates), to install a wood stove for back up heat, when your regular furnace can do it?

If you were out of town, and the power was out for 2 days, because of an ice storm, you would not have to worry about coming home, to find frozen and broken pipes, and 3 feet of water in the basement.

A wood stove is not going to do you any good, if nobody is there to fire it up.

Far from being afraid of it, if I was buying a house, given 2 otherwise equal houses, I would be willing to pay more, for the one with the old "octopus" in the basement.

If you have any more questions, hopefully I can answer them.