Greenhouse Heating Cost Calculator
Greenhouse Heating Cost Calculator
Find out how much heat your greenhouse needs on the coldest night, what size heater to buy, and roughly what winter heating will cost each month.
Compare heating conditions
Typical winter heating
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Based on the entered average winter temperature.Extreme cold protection
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Based on the entered coldest-night temperature.These are two design scenarios, not heaters you must run continuously. Actual operation depends on sun, wind, air leaks and heater controls. USDA zone temperatures are rough presets; use site-specific outdoor temperatures for better results.
Recommended heating setup
Cost by fuel (whole season)
| Fuel | Per month | Per season |
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Your greenhouse at a glance
Ways to cut your heating bill
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How this is calculated
The typical-winter capacity uses the 24-hour winter-average outdoor temperature. The extreme-cold capacity uses the entered coldest-night outdoor temperature. Heater counts are calculated separately using the selected heater's estimated delivered output. USDA plant hardiness zones are not heating-design temperatures; preset outdoor values are rough estimates only.
Heat loss = covered surface area × U-value × temperature difference, plus air leakage. The U-values used (BTU/hr·ft²·°F) are 0.69 for 4 mm twin-wall and 0.63 for 6 mm, reduced 30% with bubble wrap. The calculation assumes about 1.5 air changes per hour of leakage (1.0 with bubble wrap). Surface area comes from each model's nominal width, length, and height. Heater choices are generic planning sizes; electric efficiency assumes resistance heating and vented fuel heaters assume 80% delivered efficiency. Monthly cost uses your average winter temperature for 730 hours a month and ignores solar gain, so sunny climates will usually pay 10–30% less than shown. Propane is figured at 91,500 BTU/gal and natural gas at 100,000 BTU/therm, both at 80% efficiency for a vented heater. These are planning estimates, not guarantees. Your site, wind exposure, and habits change real-world results.