Wattage Calculation Guide

We've prepared the following guide to calculating the wattage requirements for your home.

Please note, this is an approximate guide. Heat loss can be affected by many different factors.

Our team can provide you with an accurate, professional heat loss calculation for your home and help you decide on the exact panels for your needs.

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Step 1 - Measure your Room and Calculate the Total Volume

To calculate the wattage requirement for your room, you'll first need to calculate the volume of your room.

To do this, you'll need to multiply Room Area x Room Height.

• If you have a rectangular or square room, multiply the Room Width x Room Length x Room Height to calculate the room volume in cubic metres.
• If your room is an odd shape, you'll need to work out the total floor area of the space, then multiply Room Area x Room Height to calculate the room volume.

Example

• Jim has a room that's 4 metres long, 5 metres wide and 2.4 metres high.
• Therefore 4 metres x 5 metres x 2.4 metres = 48 cubic metres.

Step 2 - Calculate the Wattage Requirement of Your Room

Next, you'll need to consult the table below to find the appropriate watts/cubic metre figure for your room, so that you can calculate the total wattage requirement.

1. Find the column with the house efficiency description that best matches your home.
2. Find the row with the room description that best matches your room.
3. Multiply Room Volume x Watts/Cubic Metre to calculate the wattage requirement for your room.
4. Select the radiator or combination of radiators that meets the wattage requirement of the room. Remember that it's always better to specify more heating than less. It won't cost more to run (because the radiators will only use the energy needed to keep the room at a stable temperature), but it will ensure the room stays warm and the heaters aren't working harder than they should.

Example

• Jim worked out in Step 1 that the volume of his room is 48 cubic metres.
• He has a Good Modern Home that's at least 7 star efficiency.
• The room he's trying to heat has large windows and more than 50% of the walls are external facing, so it best matches the Living Space Poor row. Therefore, he needs 25 Watts/Cubic Metre.
• Jim multiples the room volume x watts/cubic metre to calculate the wattage requirement for the room. 48 x 25 = 1200 Watts
• Jim chooses a 1250W radiator as this is the closest match to his requirements