About the Heating Calculators
Heating calculators help HVAC engineers determine equipment capacity, fuel input requirements, and discharge air temperatures for heating systems. This collection includes tools for calculating gas heater output, airflow, or discharge temperature and converting between input and output BTU ratings using combustion efficiency, evaluating heat pump capacity and supply air temperature rise, finding the air leaving a reheat coil, and correcting the sensible heat factor for altitude and humidity. These calculators apply the standard air heating formula and efficiency factors used throughout the industry so results align with manufacturer specifications and code requirements. Use them during equipment selection to verify a heater can deliver the required thermal output, during plan review to confirm nameplate ratings match design loads, or during commissioning to validate measured temperature rise against the original design.