Greenhouse Heating Cost Calculator

About this calculator

Heat loss from a greenhouse follows Q = U × A × ΔT, where U is the structure's U-value (heat transfer coefficient, reflecting glazing material — single-layer poly film loses heat far faster than double-wall polycarbonate), A is the surface area losing heat, and ΔT is the temperature difference between inside and the outside design temperature. This calculator converts that heat-loss rate into energy consumed over a heating season and multiplies by your electricity price to estimate the seasonal heating bill.

Because U-value differences between glazing types can be dramatic — double-wall polycarbonate typically has roughly half the U-value (and heat loss) of single-layer film — the choice of covering material often has as much impact on heating cost as the heater's efficiency itself. Commercial growers, hobby gardeners planning a greenhouse build, and horticultural consultants use this calculation to compare glazing options and size a heating system correctly before committing to a structure.