About Greenhouse Heater Calculator
To keep plants alive in winter, you need to offset the heat loss through the plastic/glass coverage.
Formula
Area × Delta T × U-Value = BTUs
- Delta T: Diff between Outside Low and Target Inside Temp.
- U-Value: Heat conductivity (Inverse of R-value). Single poly ≈ 1.15. Double poly ≈ 0.7.
How to Use
Enter Surface Area, Temperatures, and Glazing Type. The tool outputs minimum heater BTU rating.