Size a greenhouse heater so your seedlings survive a cold night without overspending on wattage. Enter the length, width and average height of the greenhouse in feet to get its exposed surface area, then set the temperature you want to hold inside and the coldest outside temperature you expect. The calculator uses the heat loss formula, surface area times the temperature difference times a covering U factor, to estimate the BTU per hour the heater must supply. Single layer glass or film loses heat fast, while double wall polycarbonate holds it far better, so pick the U value that matches your covering. It converts the result to watts for electric heaters too. Everything is calculated instantly in your browser with no signup.
Size a greenhouse heater so your seedlings survive a cold night without overspending on wattage. Enter the length, width and average height of the greenhouse in feet to get its exposed surface area, then set the temperature you want to hold inside and the coldest outside temperature you expect.
Yes. Greenhouse Heater Size Calculator is completely free, with no sign-up and no usage limits.
Yes. Greenhouse Heater Size Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Greenhouse Heater Size Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.