KW Calculator

This kilowatt calculator will give you an estimated guide to the heat output in KW needed for any given room in your home to achieve a comfortable temperature of approximately 21-22 Celsius (based on 0 degrees outside temperature). As a general rule, 1KW of heat is required for every 14 cubic meters (494 cubic feet) of room space if the room has average insulation values.

For solid fuel, gas and oil stoves, you should aim to purchase a stove which has an output of 2 - 3 KW higher (on average)  than the room size requires as a non-electric stove does not run at its maximum output continuously compared to an electric heater.

To use the calculator, enter the rooms dimensions in the box below, use meters or feet.

Any stove over 5KW will require additional room ventilation. PLEASE NOTE THAT THIS CALCULATOR SHOULD NOT BE USED AS A SCIENTIFIC INSTRUMENT. Calculations are very approximate and a simple calculator like this cannot take into account all of the diverse thermal conditions affecting the relevant area to be heated and a qualified surveyor should be consulted.

For customers purchasing stoves for DIY installation, our calculator gives a reasonable guide to the heat output required. For customers utilizing our installation service, our surveyors will always measure your room and take into account the degree of insulation, the age of the property, number and size of windows/doors etc. to give you a more precise kW requirement.