What Size Air Conditioning Do I Need?
Enter your room dimensions below to get an estimated cooling capacity in kilowatts (kW). Adjust the factors to better reflect your room's specific characteristics.
Guide only. This calculator provides an estimate based on standard assumptions. A professional survey is always required to confirm the correct unit size for your home. Factors such as conservatories, large roof glazing, south-facing glass walls, unusual ceiling heights, and adjacent heat sources can significantly affect the result.
1Room Dimensions
2Room Characteristics(select the best match)
Room Type
Glazing
Room Orientation
Insulation / Property Age
Why kW, not BTU?
In the UK, air conditioning capacity is measured in kilowatts (kW). You may see BTU used on some websites — 1 kW is approximately 3,412 BTU. We use kW as it matches the specifications on all UK-sold units.
When should I get a survey?
Always. This calculator is a useful starting point, but a free survey by one of our F-Gas certified engineers is the only way to confirm the correct unit size, the best position for the indoor unit, the pipe run route, and the electrical supply requirements.
What about conservatories?
Conservatories are one of the most challenging rooms to cool due to high solar gain through the roof and walls. A standard calculation will significantly underestimate the required capacity. Always select 'Conservatory' as the room type and request a survey.
Can I cool multiple rooms?
Yes — a multi-split system uses one outdoor unit connected to multiple indoor units. This is ideal for cooling two or three rooms without multiple outdoor units. Our engineers can advise on the best configuration during your free survey.