How this calculator works
How we calculate propane use
We add up the heat each appliance uses in a day, in BTU, and divide by about 91,500 BTU per gallon of propane. Cylinders are rated by the propane they hold (a 20 lb cylinder holds about 4.7 gallons and a 30 lb about 7.1, according to cylinder maker Worthington), while built-in motorhome tanks are rated by water capacity and are filled to 80%.
- Furnace: 20,000 to 40,000 BTU an hour, based on Suburban's RV furnace range; enter how many hours it actually runs.
- Water heater: 12,000 BTU an hour, typical of a 6-gallon RV water heater.
- Refrigerator: 1,500 BTU an hour on propane, assumed to run about half the time (an estimate).
- Stove and oven: about 7,500 BTU an hour per burner on average, and 7,100 for the oven.
Your real use depends on the weather, your RV's insulation, the thermostat setting, and how often you cook, so treat the answer as a planning estimate.
Cold-weather camping
Propane in cold weather
- Keep tanks fuller: Below about 20°F, a small cylinder may not keep up with a large furnace even with propane left in it. An emptier tank supplies even less.
- Turn the thermostat down at night: Every degree lower shortens how long the furnace runs.
- Bring a spare: On a cold-weather trip, carry a spare full cylinder, and know where the nearest propane refill is.
Safety first
Propane safety in your RV
- Test your alarms: RVs are built with propane and carbon monoxide alarms; test them before every trip and replace them as their manuals say.
- Never heat with the stove: Never use stove burners or the oven to heat your RV.
- Know the smell: If you smell propane, turn off the supply at the tank, put out any flames, get everyone out, and don't use switches or phones inside.
Helpful gear
Gear that makes propane easier
- Propane tank gauge: See how much is left before you run out on a cold night.
- Propane and CO alarm: Replace an old alarm with a combination propane and carbon monoxide detector made for RVs.
- Automatic changeover regulator: Switches to your second tank automatically when the first runs dry.
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Common questions
Frequently asked questions
How long does a 20 lb propane tank last in an RV? +
A 20 lb cylinder holds about 4.7 gallons, or roughly 430,000 BTU. A 30,000 BTU furnace burns that in about 14 hours of actual running time, so in cold weather a single 20 lb tank may last only a day or two. With only the fridge and some cooking, it can last a week or more. Use the calculator above for your own setup.
How much propane does an RV furnace use? +
A 30,000 BTU furnace uses about a third of a gallon an hour while it's running (30,000 BTU divided by about 91,500 BTU per gallon). How many hours it runs depends on the outside temperature, your insulation, and your thermostat.
How much propane does an RV refrigerator use? +
An absorption fridge on propane is rated at about 1,200 to 1,500 BTU an hour, but its burner cycles on and off. We assume it runs about half the time, roughly a pound of propane a day; check your own fridge's manual for its rating.
Why does my propane stop working in very cold weather? +
Propane has to turn from liquid into gas, and that slows down in the cold. Below about 20°F, a small cylinder may not be able to supply a big furnace even when there's still propane in it. Keep your tanks fuller in cold weather.
Is it safe to heat an RV with the stove or oven? +
No. Never use stove burners or the oven for heat. Use the furnace, keep your propane and carbon monoxide alarms working, and test them before every trip.
How do I calculate propane usage? +
Multiply each appliance's BTU rating by the hours it runs in a day, add them up, and divide by about 91,500, the BTU in a gallon of propane. For example, a 30,000 BTU furnace running 8 hours a day uses 240,000 BTU, or about 2.6 gallons. A 30 lb cylinder holds about 7.1 gallons, so it would last a little under 3 days for the furnace alone. Our propane usage calculator adds up your whole setup.
How long does a 30 lb propane tank last in an RV? +
A 30 lb cylinder holds about 7.1 gallons, or roughly 650,000 BTU, about half as much again as a 20 lb tank. In cold weather with the furnace running about 8 hours a day, expect two to three days. With only the fridge and some cooking, it can last well over a week.