I want to know if I can use a 40 lb propane tank for my central heating.

I have not tried anything. I don't want to put natural gas in, just want the propane gas. If someone can answer that, I want to know if is dangerous to connect my 40 lb propane gas tank just for my central heating.

  • You can use any size tank. Whether it's safe or not is based on how well the connections are made and if they are to code.
    – DA01
    Nov 27, 2013 at 17:23

2 Answers 2


You're question is vague and has a couple sub-questions, so let me offer a little Q&A:

Q: Are there any central heating furnaces that use propane?
A: Yes

Q: Can I convert an existing natural gas furnace to use propane?
A: Perhaps, but only with a manufactorer-approved adapter. Propane has more energy than natural gas does, so you must not just swap out the connection without checking.

Q: Can I use a high-pressure 40lb BBQ tank with central heating?
A: Most large-scale propane appliances will expect low-pressure propane, not the high-pressure that comes out of a BBQ-style tank. You may be able to get a regulator to step down the pressure.

Q: Will a 40-lb tank last a meaningful amount of time running heating for an entire house?
A: Probably not. A full 40lb tank of propane will have around 850kBTU, or around 8.5 therms. How much you use is going to vary based on all kinds of factors but the "average US home" (whatever that means) uses about 2 therms per day.

  • 1
    Plus in cold weather, you want the big tank. LPG evaporation frosts the tank and for the quantity used in central heating can lower the temps enough that a 40LB tank will quit producing any appreciable gas despite being 3/4 full. Surface area is your friend here, that's one reason why the large tanks lay on their side. Nov 28, 2013 at 1:58
  • @FiascoLabs your last sentence doesn't make sense.
    – Dale
    Dec 31, 2015 at 1:39

Certainly you do that and it will work to some measure. However, if the heating equipment is designed for natural gas, it will require some adaptation to work successfully with propane. In many appliances a refit kit is available which alters the gas orifice.

However, the practical reason this is not commonly done is that a 40 pound propane tank will provide only a few days worth of heating. If the heating system is large, it could overwhelm the ability of the tank to provide fuel quickly enough. You'll probably notice ice forming on the tank.

Also, propane is several times the expense of natural gas for the same amount of heat. I did a comparative pricing about five years ago and propane worked out to three times the expense of natural gas, though a small part of that was delivery costs. Since then, natural gas prices have gone down 40% in our region (U.S. Pacific Northwest) while propane has held approximately steady.

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