Calculate Your Air Conditioning Requirement

So you need to install an air conditioning unit? But you have no idea what size you need? Would you like to find out the easy way, on the internet rather than having to have an engineer come out? Well, we have an air conditioning calculator which can estimate the size of unit you need depending on certain factors about the room you would like to install it in to.

The Simply AC Air Conditioning Calculator

The air conditioning calculator measures the capacity of unit required in “BTUs” (British Thermal Units) per hour. Use it to estimate the ideal cooling capacity of air conditioner for your room. It is important to note that most air conditioning units have the capacity to heat as well as cool.

Using the air conditioning calculator is easy: Select your room size, level of insulation, sun exposure and room type. Once selected click ‘calculate’ and our air conditioning calculator will recommend the required size of air con unit in BTUs.

Simply AC Air Conditioner Calculator
Room Size (sq ft)	99 to 149149 to 249249 to 349349 to 399399 to 449499 to 549549 to 699699 to 999
Level of Insulation of Area	ExcellentVery GoodAveragePoorNone
Exposed to Sun?	Yes No
Kitchen or Other?	Kitchen Other
The estimated air conditioning unit size in BTUs is:	BTUs per Hour

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How does the Air Conditioning Calculator work?

• We take in to account the level of insulation of the room to measure how quickly it is likely to lose its core temperature.
• Sun exposure plays a big role in the heating of an area and can add over 10 degrees in temperature to a space, so we need to know whether your room is exposed to the sun or not to help gauge a more accurate calculation .
• Kitchens naturally use more hot appliances than any other room so we also need to factor in whether this room is a kitchen or not.

When you have calculated the size of air conditioning unit required please do contact us at Simply Air Conditioning London where we can use the estimate to give you a free quote for an installation. We also offer a free site survey to give you further confidence.

© Simply Air Conditioning London Air Conditioning Calculator.

Planning an air conditioning installation in London? See our 2026 AC installation cost guide for a full breakdown by property type — or if you’re fitting AC in a flat, read our complete guide to AC in London flats.