Free tools for a hotter summer

Quick, honest answers to the questions people ask before they call an installer. Built on the same engine, rules and data as the Home Cooling Checker. No sign-up, and nothing you enter is stored.

AC size calculator

The right kW and BTU for each room

Work out the cooling capacity a UK room needs in kW and BTU/h, from its size, orientation, glazing, floor and occupants. Free, no sign-up.

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Running cost calculator

What an hour of cooling really costs

Compare the running cost of split AC, air-to-air heat pumps, portable units and fans at the current Ofgem price cap or your own tariff.

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Grant eligibility checker

An honest yes or no on the air-to-air grant

Answer five questions and see honestly whether the Boiler Upgrade Scheme air-to-air grant could apply to your home, or why it would not.

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Planning permission checker

Is your outdoor unit permitted development?

Check an outdoor AC or heat pump unit against the permitted-development limits for England, including conservation areas and listed buildings.

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Outdoor unit noise checker

Will your unit pass the 37 dB test?

Estimate the noise an outdoor AC or heat pump unit makes at your neighbour’s window using the MCS 020 method, and see what changes the result.

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Keep cool without AC

A free, room-by-room heatwave plan

Build a heatwave plan for your home: shading, night ventilation and room swaps ranked by how much they cool, before you spend on a system.

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Real property data

Compare two homes

Which one will be hotter in summer?

Buying or renting? Compare two UK addresses side by side on overheating risk, EPC fabric, cooling options and planning, from public property data.

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Future summers

How hot your area is set to get

See how many hot days and warm nights your council area has now, and at 2°C, 2.5°C and 4°C of global warming, from the Met Office UKCP18 projections.

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