Patio Heater Cost Per Hour Calculator

See exactly what your propane or electric patio heater costs to run per hour, per day, and across a full outdoor heating season. Enter your heater output, current fuel price, and usage schedule to get a precise monthly bill — and find out whether switching heater types would save you money.

BTU/hr or W
$ / gal or kWh
hrs
days

What This Calculator Measures and Why It Matters

A standard 40,000 BTU propane patio heater looks inexpensive at purchase — $150 to $300 — but the running costs over a season can easily exceed $300 to $600 depending on how many hours you use it and what propane costs in your area. Electric infrared heaters often carry a higher sticker price but lower monthly bills. This calculator gives you the honest per-hour and per-month figures for both fuel types so you can make an informed decision before buying or plan your outdoor heating budget accurately.

The cost math differs meaningfully by heater type. Propane is measured in BTUs and priced per gallon; natural gas patio heaters are priced per therm; electric models are measured in watts and priced per kilowatt-hour. The calculator handles all three, converting your heater output to fuel consumption automatically.

The Core Formula

Cost Per Hour = (BTU Output ÷ BTU per Unit of Fuel) × Fuel Price × Number of Heaters

For propane, one gallon contains approximately 91,500 BTU. A 40,000 BTU/hr heater consumes about 0.44 gallons per hour. At $3.50 per gallon that is $1.54 per hour. For electric heaters, divide watts by 1,000 to get kWh, then multiply by your electricity rate — a 1,500W infrared heater at $0.16/kWh costs $0.24 per hour.

Typical Patio Heater Outputs and Real Costs

Knowing the common output range for each heater type helps you benchmark your numbers:

  • Standard freestanding propane tower (40,000 BTU): $1.35–$1.75/hr at typical propane prices of $3.10–$4.00/gal
  • Table-top propane heater (10,000–12,000 BTU): $0.34–$0.52/hr — much cheaper to run, but less heat output
  • Electric infrared wall/ceiling heater (1,500–3,000W): $0.22–$0.48/hr at $0.15/kWh
  • Natural gas patio heater (40,000–60,000 BTU): $0.45–$0.90/hr at $1.10–$1.50/therm — significantly cheaper than propane for equivalent heat
  • Commercial mushroom propane heater (50,000 BTU): $1.75–$2.20/hr — expensive but heats a large area

Propane vs Electric: Which Costs Less to Run?

The answer depends almost entirely on local fuel prices. In areas where propane is $2.50/gallon and electricity is $0.18/kWh, electric infrared heaters usually win on operating cost. When propane dips below $2.00/gallon — common in rural areas with bulk tank delivery — propane heaters can match or beat electric. The key comparison point is heat output per dollar spent, not the sticker price on fuel. A propane heater running at 40,000 BTU is putting out roughly 2.7x the heat of a 1,500W electric unit, so raw cost-per-hour comparisons need to account for the heat being delivered.

Common Mistakes When Estimating Running Costs

  • Using the maximum BTU rating continuously: Most patio heaters have a variable flame or thermostat. Actual consumption at a moderate setting is 60–80% of the maximum rated output.
  • Ignoring tank rental fees for propane: If you rent a large LP tank from a supplier, the monthly rental adds $10–$25 to your effective fuel cost.
  • Forgetting that electricity rates vary by time-of-day: If you use a time-of-use electric plan, evening patio heater use may cost 50–100% more than daytime rates.
  • Not accounting for wind: On windy evenings a propane heater can lose 30–50% of its effective heat output, making you run it longer and at higher output to feel the same warmth.

Frequently Asked Questions

How much propane does a patio heater use per hour?
A standard 40,000 BTU freestanding propane patio heater burns approximately 0.44 gallons of propane per hour at full output. A 1-pound disposable propane cylinder holds about 0.24 gallons and would last roughly 30 minutes at full blast. A 20-pound tank (the standard BBQ grill size) contains about 4.7 gallons and gives roughly 10–11 hours of runtime at full output on a 40,000 BTU heater.
Are electric patio heaters cheaper to run than propane?
Often yes, but it depends on your local rates. A 1,500W electric infrared heater costs about $0.22–$0.30/hr at typical US electricity rates ($0.15–$0.20/kWh). A comparable propane heater (40,000 BTU) costs $1.35–$1.75/hr at $3.10–$4.00/gal propane. However, the electric heater puts out far less heat — about one-third the BTU output — so you need to compare cost per BTU delivered, not raw hourly cost. For close-range directional warmth, electric infrared wins on efficiency and cost. For heating a large open area, propane is hard to beat.
How much does it cost to run a patio heater for a whole season?
For a 40,000 BTU propane heater used 3 hours per evening, 4 evenings per week across a 5-month outdoor season (roughly 240 hours total), expect to burn about 105 gallons of propane. At $3.50/gallon that is approximately $370 for the season. A 1,500W electric heater on the same schedule uses about 360 kWh — at $0.16/kWh that is $57.60 for the season, but it provides much less heat coverage. Most households with large outdoor spaces find a 40,000 BTU propane heater and budget $250–$500 per season realistic.
Does a patio heater use more gas on a cold or windy night?
Yes on both counts. On very cold nights you will likely run the heater at higher output and for longer — effective consumption can increase by 20–40% compared to mild evenings. Wind is the bigger factor: even a 10 mph breeze disperses radiant and convective heat rapidly, forcing you to crank the heater higher or move closer. Windbreak screens, pergola walls, or a sheltered patio layout can cut effective fuel use by 30–50% on breezy nights and dramatically improve comfort at lower heat settings.

Practical Guide for Patio Heater Cost Per Hour Calculator

The single biggest variable in patio heater running cost is how often you actually use it. Most buyers estimate generously — four evenings a week — but end up averaging two, especially once autumn temperatures drop and the heater struggles against wind. Run your calculation at your honest average, not your optimistic maximum, and the monthly figure will be far more accurate. If you are buying a heater and comparing propane vs electric, model both at the same number of hours and your real local fuel prices before deciding.

Propane prices are volatile and highly regional. In summer, propane often sits around $2.50–$3.00/gallon at hardware stores, but in colder months it climbs to $4.00 or higher in many markets. If you use a dedicated 100-pound or 500-gallon bulk tank with annual delivery, your effective price per gallon drops significantly — sometimes below $2.00. Factor in your actual purchase method, not just the price on a single tank at Home Depot, to get an accurate season cost.

Electric infrared heaters deserve more consideration than they typically get. A 1,500W directional infrared panel mounted on a wall or overhead warms the people in its beam very effectively, uses roughly one-seventh the energy of a 40,000 BTU propane unit, and has no fuel to buy or tank to refill. For covered patios, pergolas, or screened porches where the heated area is defined and enclosed, electric infrared often provides better cost-per-degree-of-comfort than an open-flame propane tower heater fighting an unenclosed outdoor space.

Review Checklist

  • Use your realistic weekly hours, not your ideal ones, when running the monthly cost estimate.
  • Compare your local propane price to the national average ($3.10–$4.00/gal) and your electricity rate to the US average ($0.16/kWh) to see if you are above or below typical costs.
  • If you use propane, check whether a bulk tank rental from a local LP supplier would lower your effective per-gallon price enough to change the comparison.
  • Re-run the calculation mid-season once you have a real fuel receipt to validate your estimate against actual consumption.