RV Propane Usage Calculator
Estimate propane consumption for your RV's furnace, water heater, fridge, and stove. Find out how long a 20/30/40 lb tank will last.
How much propane your RV actually uses
Propane stores about 91,500 BTU per gallon, or roughly 21,600 BTU per pound. Every appliance in your RV that runs on LP has a BTU/hr rating — multiply by the hours it actually burns and you get a real consumption figure.
The biggest LP users in most rigs:
- Furnace — 30,000 BTU/hr typical, often the dominant load in cold weather.
- Refrigerator on LP — 1,500 BTU/hr continuous (so 36,000 BTU/day even sitting still).
- Water heater — 10,000-12,000 BTU/hr, but only when actively heating (cycles on/off).
- Stove and oven — 7,000-15,000 BTU/hr per burner, but typically used for less than an hour total.
Real-world consumption rules of thumb
| Conditions | Approx. propane use |
|---|---|
| Summer, fridge on LP, modest cooking, water heater 1hr/day | 0.5-1 gal/day (one 30 lb tank lasts a week) |
| Cool fall, furnace 2-4 hours/night, fridge on LP | 1-2 gal/day (one 30 lb tank lasts 4-6 days) |
| Cold winter, furnace cycling all night, all appliances | 3-5 gal/day (a 30 lb tank lasts 1.5-2 days) |
Conservation tactics
- Switch the fridge to electric when on shore power. 1500 BTU/hr × 24h = 36,000 BTU/day saved — about 0.4 gal of propane.
- Use a small electric heater on shore power instead of the propane furnace. The furnace also uses your battery (its blower fan is the second-biggest 12V load in winter).
- Insulate. A reflective windshield cover and bedroom door curtain can cut furnace runtime by 30%.
- Drop bedroom temp at night. 60°F instead of 68°F can roughly halve overnight burn time.
Frequently Asked Questions
How long does a 30 lb propane tank last?
For an average summer trip (fridge on LP, modest cooking, water heater 1hr/day), about 7 days. In cold weather with the furnace running 4-8 hours/night, the same tank lasts 2-4 days. The calculator above gives a precise estimate for your usage pattern.
Can I refill my own propane tanks?
If you have a transfer adapter and a larger tank, yes. The catch: 20/30/40 lb DOT tanks legally require a recertification stamp every 12 years (the date is on the tank collar). Most U-Haul, Tractor Supply, and propane dealers will refill for $3-4/gallon, much cheaper than the swap exchanges (which only fill to ~15 lb in a 20 lb tank).
Should I use the fridge on propane or electric?
On shore power, electric is essentially free and saves the propane. Off-grid, it depends on your battery bank. Absorption fridges on 12V draw 25-30 amps continuously — they will drain a 100Ah lead-acid battery in 4 hours. Off-grid, propane is almost always the right answer for an absorption fridge.
How can I tell how much propane is left?
External tanks: weigh the tank (full minus tare weight printed on the collar). Onboard ASME tanks: most RVs have a level gauge but they're often inaccurate — an ultrasonic level sensor stuck on the side gives a much more reliable reading. There are several Bluetooth-equipped gauges that pair with phone apps.
Related Calculators
About our math & sources
Every default and formula in this calculator is grounded in published manufacturer specs, industry standards, or peer-reviewed measurement. Where we make assumptions, we tell you what they are so you can adjust.
- BTU per gallon/pound. Propane: 91,500 BTU/gallon and 21,594 BTU/lb (Propane Education & Research Council, NIST). One gallon weighs 4.24 lb at 60°F.
- Furnace BTU ratings. Atwood/Suburban RV furnace ratings: 16,000–40,000 BTU/hr typical. Spec sheet figures are nameplate input — actual draw cycles on/off based on thermostat.
- Absorption fridge consumption. Dometic and Norcold 3-way absorption fridges: ~1,500 BTU/hr continuous when running on LP. 24-hour operation = ~36,000 BTU/day.
- Water heater BTU. Atwood/Suburban 6-gallon water heater: 8,800–12,000 BTU/hr. Cycles on as needed; typical real-world burn is 30–90 minutes/day for two people.
Disclaimer. This calculator provides estimates only. Real-world results depend on equipment efficiency, environmental conditions, and installation quality. Always verify against your equipment's spec sheets and consult a licensed installer for safety-critical decisions.