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Greenhouse Heater Calculator

If you need to purchase a greenhouse heater, this calculator will help you decide on the size of heater needed for your greenhouse, based upon your climate, desired minimum greenhouse temperature, and the greenhouse covering used.

If you need Surface area in square feet, Please select this link for Greenhouse Surface Area Calculators

MaterialLoss Value (approx)
4-mil polyethylene1.20
6-mil polyethylene1.15
6-mil polyethylene - double layer, inflated0.70
Glass - Single Layer1.13
Glass - Double Layer0.50
Acrylic Double Wall0.54
Corrugated Polycarbonate1.00
4mm Twinwall0.70
6mm Twinwall0.63
8mm Twinwall0.60
10mm Twinwall0.56
10mm Triplewall0.54
16mm Triplewall0.40
16mm Five-wall0.33
25mm Triplewall0.28
25mm Five-wall0.25

Note: U-Factor (BTU/hr. - ft2 F) or (1/R-value) 1 divided by the U-value equals the R-value.