Greenhouse Heating Cost Calculator
Find out what it costs to heat your greenhouse for a whole winter. Enter your greenhouse, how cold your winters get and your energy prices, and compare electric, propane and natural gas side by side.
How it works
How we estimate greenhouse heating costs
First we work out how fast your greenhouse loses heat for every degree of difference between inside and outside. That depends on the area of the walls and roof, what they are glazed with, and how drafty the site is.
Heat per winter = Heat loss rate × (Inside temp − Average night temp) × 14 night hours × Days of heating
We assume the sun does most of the heating during the day and add 10% for cloudy days. Then we convert the heat to fuel: 3,412 BTU per kWh of electricity, 91,500 BTU per gallon of propane, and 100,000 BTU per therm of natural gas burned in an 80% efficient vented heater.
Your real bill depends on the weather each winter, so treat this as a planning estimate. To size the heater itself, use the heater size calculator.
Save money
The biggest ways to lower your heating bill
| Change | Typical saving |
|---|---|
| Line single glass with bubble insulation for winter | 30 to 40% |
| Keep the greenhouse 5°F cooler at night | 10 to 20% |
| Seal gaps around doors, vents and the base | 10 to 25% |
| Choose twin-wall or triple-wall polycarbonate over single glass | 45 to 60% |
| Use a thermostat with a remote sensor at plant height | 5 to 15% |
Questions
Heating cost FAQ
How much does it cost to heat a greenhouse in winter?
It depends on size, glazing and climate. A 10 x 12 ft twin-wall polycarbonate greenhouse kept at 45°F in a mild zone 7 winter often costs about $100 to $300 a season with propane, and more with electric. Glass greenhouses and colder zones cost more.
Is propane or electric cheaper for heating a greenhouse?
Per unit of heat, natural gas is usually cheapest, then propane, then electric at typical US prices. Electric heaters cost less to buy and add no moisture or fumes, so they often make sense for small greenhouses.
How can I heat a greenhouse cheaply?
Insulate glass with bubble wrap, seal drafts, keep the night temperature as low as your plants allow, add thermal mass such as water barrels, and use a thermostat so the heater only runs when needed.
What temperature should I keep my greenhouse at night?
40 to 45°F keeps most overwintering plants safe. Seedlings and cool-season vegetables do well at 50 to 55°F. Tropical plants and orchids usually need 60 to 65°F.
More tools
Other greenhouse calculators
- Heater Size CalculatorHow many BTUs it takes to keep your greenhouse warm on the coldest night.
- Fan and Ventilation CalculatorThe exhaust fan CFM and vent openings that keep summer heat down.
- Snow Load CalculatorHow much the snow on your roof weighs and when to brush it off.
- Foundation CalculatorConcrete, gravel, pavers and lumber for your greenhouse base.
- Greenhouse Size CalculatorHow big a greenhouse you need for the plants you want to grow.
- Shade Cloth CalculatorThe right shade percentage and cloth size for your greenhouse.
- Grow Light CalculatorHow many grow lights it takes to give your plants enough light in winter.
- Rainwater CalculatorHow much water your greenhouse roof can collect for your plants.
Want a second opinion?
Tell us about your greenhouse and where you live, and we will help you get it right.
Call 678-408-8222Send us a message