A propane sauna heater is the option people reach for when there is no circuit to the cabin and no appetite for tending a fire. It works, it heats quickly and it is genuinely the right answer in some situations, but it is a combustion appliance in a small sealed room and that is where the requirements come from.
Where gas wins
Off grid cabins, remote yards where a trenched electrical run costs more than the sauna, and anywhere the panel has no spare capacity for a large heater. Propane also heats fast and holds temperature well, and you can run it wet on stones like any traditional heater. If you already keep propane for other things, the supply is solved.
Venting is not optional
This burns fuel and produces combustion gases, so it needs a sealed combustion chamber, a flue to outside, and combustion air. Carbon monoxide in a small closed timber room is the risk, and it is why every gas sauna heater is specified with a particular flue system that you fit as designed rather than approximate.
Why they are uncommon
Fewer models, higher hardware prices, a professional gas installation, and permitting in most jurisdictions. Against an electric heater that a licensed electrician can wire in a morning, the whole package usually costs more unless the electrical run is genuinely difficult. That arithmetic is what makes propane a specific answer rather than a general one.
Running cost
Propane against electricity depends entirely on local prices for both, and the gap moves by state and by season. Price your own numbers rather than accepting a rule of thumb: the energy per session is comparable, so the comparison is really the local price of a therm against the local price of a kilowatt hour, plus the delivery you have to arrange.
Questions people ask about propane sauna heater
Can a propane heater be used indoors?
Only with the manufacturer's flue and combustion air arrangement, professionally installed. Never with an unvented burner in a closed room.
Can you pour water on the stones?
Yes, on a traditional gas heater with a stone load, exactly as on a wood or electric one.
Is propane cheaper than electric?
It depends on your local prices for both, which vary widely. Work it out with your own rates rather than trusting a general claim.