The calculation method

For each appliance:

  1. Find the input BTU rating (nameplate label or manual)
  2. Estimate operating hours per year
  3. Multiply BTU/hr by hours = total BTU/year
  4. Divide by 91,500 = gallons/year

Sum across all appliances for your annual usage estimate.

Typical annual hours by appliance

  • Furnace (whole-home heating, moderate climate): 1,200–1,800 hrs/year at full load equivalent
  • Water heater (tank type, 50 gal): 1,200–1,800 hrs/year
  • Range (cooking): 200–400 hrs/year per household
  • Clothes dryer: 200–300 hrs/year per household
  • Standby generator: 0–100 hrs/year depending on grid reliability
  • Pool heater: 300–800 hrs/year if used seasonally

Worked example

A typical 2,000 sq ft US home with full propane appliances in a moderate-cold climate:

  • Furnace (80,000 BTU/hr × 1,500 hrs) = 120 million BTU = 1,311 gallons
  • Water heater (40,000 BTU/hr × 1,500 hrs) = 60 million BTU = 656 gallons
  • Range (65,000 BTU/hr × 300 hrs) = 19.5 million BTU = 213 gallons
  • Dryer (22,000 BTU/hr × 250 hrs) = 5.5 million BTU = 60 gallons
  • Total estimated usage: ~2,240 gallons/year

Real households typically consume 70–90% of this theoretical maximum because most appliances run below full nameplate capacity. Adjust accordingly — actual usage is usually 1,500–2,000 gallons/year for this household profile.

Tank sizing from usage

Standard recommendation: pick a tank holding at least 6 months of winter usage at 80% fill. For a 1,500-gal-annual household with most consumption in winter (October–March), 6 months ≈ 1,000 gallons, suggesting a 1,000-gallon tank. For lighter households (500–1,000 gal/yr), a 500-gallon aboveground is the default. See tank sizes.

FAQ

How accurate is this estimate?

Usually within ±20% of actual usage. Real factors that shift the number: climate severity that year, household behavior (thermostat setpoint, hot water use), appliance efficiency (AFUE), and changes in occupancy.

Where can I find historical usage data?

Your dealer invoices show gallons delivered per year. Most US propane customers can request a 12-month delivery history from their dealer — the most accurate basis for forecasting future usage.

Going further