Air Conditioning Size Calculator

Air Conditioning Size Calculator

Find the right size air conditioner for your room in under 30 seconds.

Step 1 – Room dimensions

Room length (m)

Room width (m)

Ceiling height (m)

Step 2 – Room type

Bedroom

Living room

Kitchen

Conservatory

Office

Step 3 – Sunlight

Low

Medium

High

Step 4 – Number of people usually in the room

1

2

3

4+

Your recommended unit size

Room Volume

Typical Cooling Capacity

Up to 40 m³

2.0–2.5 kW

40–70 m³

2.5–3.5 kW

70–110 m³

3.5–5.0 kW

110–160 m³

5.0–7.1 kW

Over 160 m³

Site survey recommended

Please note: This is an estimate. Factors such as insulation, glazing, orientation, and heat-generating appliances can affect the size required.

Ready for an accurate recommendation?

Book a free, no-obligation survey with 21Degree Heating. We'll assess your property and recommend the most efficient system for your home or business.

To make it even more useful, the calculator could automatically adjust the recommended size:

Kitchen: add around 0.5–1.0 kW because of cooking appliances.

Conservatory: increase the recommendation by 20–30% due to solar gain.

South-facing room: increase by around 10–15%.

Poor insulation: increase by around 10%.