Heating Calculator

Calculate heat loss for each room of your house.

Our heating calculator / BTU calculator can help work out the appropriate heat output for each room of your home. We'll show you a list of radiators that will generate enough heat to keep your room at an efficient yet comfortable temperature.

Once you have your list of suitable radiators, simply add them to your basket and checkout when you are ready.

Please note - Calculations based on Delta-T 50°C (Δ-T50°C).

What room would you like to work out the heat-loss calculations for?

You can calculate more rooms later.

Please enter the dimensions of your room (metres), including the area of all windows (metres2) if applicable.

Tape Measure

Squared area = times the total height by the total width. Enter "0" if there are no windows in this room.

What type of windows are there?

How many external walls are there?

What type of walls are there?

If your house was built after the 1920s it is likely to have cavity walls. Older houses are more likely to have solid walls.

Look to the brickwork on the outside of the house. If the brickwork has an alternating pattern it is likely to be brick cavity. If the brickwork has been covered, you can also tell by measuring the width of the wall. Look to a window or door on one of your external walls. If a brick wall is more than 260mm thick then it will likely have a cavity; a narrower wall is likely solid. Stone walls can be thicker still but are usually solid.

What is below this room?

What is above this room?

BTU Calculator

Heat Loss Calculations For Your Home

Choosing the right radiator can help reduce your energy bills. For example, too large a radiator will increase bills unnecessarily, and too small a radiator won't provide enough heat and will be constantly running at maximum. By using our BTU calculator you can establish your Watt / BTU outputs required for a particular room to ensure that your room(s) will be heated comfortably and efficiently.