I have property where I am boon-docking an airstream. I've been looking into a passive solar hot water heater design, For the holding tank I was looking at using an old hot water heater, I found a used gas hot water heater online, and it made me think, is it possible to use propane with a gas hot water heater? Perhaps I could still do the passive solar setup, but also have the ability to heat the hot water with propane.

3 Answers 3


I have done the conversion many times, in fact if you have the paperwork your water heater came with the orifice to change it over may be in there. On the water heaters, furnaces and ovens/ stove tops I have done all that was needed was a small brass orifice . The orifice is a brass disk with a tiny hole and usually a number or letter stamped on it. The orifice is on the output side of the regulator and changes the amount of gas the pressure was the same with both propane and natural gas. If your’s did not come with the orifice your local plumbing and electric specialty store may have them that’s where I got them several times. I would check with the manufacturer to make sure your water heater can be run on propane but all it has taken in the dozens I have done was the larger orifice.

  • AO Smith 30 gallon gas water heater was the uses one I was looking at. Looks like they allow conversions from Propane to LP but not the over way around for some reason .... according to this hotwater.com/lit/partslists/PSD3598a.pdf
    – user379468
    Commented Aug 23, 2019 at 20:15
  • To tell you the truth I thought propane and LPG were the same.
    – Ed Beal
    Commented Aug 23, 2019 at 20:43
  • Sorry that was a typo you are right Ed Beal, I meant Natural Gas to LP
    – user379468
    Commented Aug 23, 2019 at 20:44
  • Oh I wonder if the newer efficiency requirements are why. I haven’t done a conversion for a while and I know the only difference was the orifice I want to say propane orifice was larger than natural gas but it has been many years since the last one I did.
    – Ed Beal
    Commented Aug 23, 2019 at 20:51

Sometimes, it is possible. Some manufacturers have conversion kits available that can allow you to convert the water heater. I think the items that need to be converted are the regulator, valve/thermostat, burner and the orifice for both the main flame and pilot light. It would be advisable to only do this if there is an official conversion kit available for the exact model you have, and you know what you're doing. This could obviously be very dangerous if done wrong, since safety-related components need to be switched out.


Yes. The "propane tank in the backyard" market is huge, however not huge enough to justify a totally separate line of water heaters, dryers, ranges and furnaces just for it.

Therefore most manufacturers offer jetting kits to convert the appliance from one fuel to the other.

Check with the manufacturer, or read the installation manual online. But I would bet "yes".

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