Estimate how much heat a van loses on a cold night through windows, insulated surfaces, and air exchange.
Camper Van Heat Loss & Heater Sizing Calculator
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How it works
For each surface, divide area by the whole assembly’s U.S. R-value. Multiply the total by the indoor-to-outdoor temperature difference. Add a sensible air loss estimate of 1.08 × airflow in CFM × temperature difference, then apply your margin.
Reference: U.S. Department of Energy guide to insulation and R-value.
What to check before you use the result
This is a steady-state estimate. Use effective assembly R-values that account for metal framing and gaps. Check minimum output, altitude derating, and installation requirements for the heater you are considering.
