How to Use the Boiler Run Time Calculator
Even at the same outdoor temperature, strong wind increases heat loss from your home, meaning your boiler needs to run longer to hold the target indoor temperature. This calculator takes outdoor temperature, wind speed, and target room temperature to estimate the recommended daily boiler run time and heating intensity based on the windchill-adjusted outdoor temperature.
Windchill is applied using the standard formula when the temperature is 50°F or below and wind is strong enough to matter; a larger gap between the target and windchill temperature increases the recommended run time. Results are capped between 1-20 hours: under 4 hours is light heating, 4-8 is moderate, 8-14 is heavy, and 14+ is maximum output. Actual needs vary by insulation, room size, and boiler efficiency, so treat this as a reference estimate.
Frequently Asked Questions
Strong wind increases heat loss from your home, raising the actual heating load, so the calculation uses windchill as the baseline.
Actual needs vary by insulation, room size, and boiler efficiency, so treat this as a reference estimate.
Enter 0 for wind speed and the calculation uses the raw outdoor temperature without a windchill adjustment.