Heating & HVAC Calculators
Our heating and HVAC calculators help you size a heating or ventilation system correctly. Work out the heat loss from a room and the radiator or boiler output it needs, and size round or rectangular ductwork from the required airflow.
Each tool gives results in both metric and imperial units — BTU and kW for heating, and m³/h, litres per second and CFM for airflow — so you can plan radiators, boilers and ducting whether you work to UK or US conventions.
Heating & HVAC Calculators(4)
Radiator BTU Calculator
The quick “what size radiator do I need” tool – get the BTU and kW output to warm any room.
Room BTU Requirement Calculator
Work out the BTU/hr needed to heat a room from its size, type, insulation and external walls, with an optional radiator cost estimate.
Heat Loss Calculator
Estimate the heat loss and radiator or boiler size needed for a room from its dimensions, insulation level and target temperature.
Duct Size Calculator
Size round and rectangular ductwork from the required airflow and target air velocity for heating, cooling and ventilation systems.