Guides built from the UK housing record and the primary sources, not brochures: what works in a heatwave, what it costs, what the rules say and who the grant pays.
Data
Days above 30°C, warm nights and cooling demand for UK areas now and at 2°C, 2.5°C and 4°C of global warming, from the Met Office UKCP18 local projections.
Keeping cool
A room-by-room plan for a UK heatwave: stop the sun before it hits the glass, ventilate at the right hour, and know when passive cooling will not be enough.
Planning and rules
Since May 2025 the answer turns on one thing: whether the unit also heats. The permitted-development rules for England, flats, conservation areas and noise.
Grants
Not for cooling alone. The Boiler Upgrade Scheme pays £2,500 towards an air-to-air heat pump in one situation: who it pays, who it does not, and when.
Systems and costs
How to size air conditioning for a UK room in kW and BTU, why sun, glass and a roof above you change the answer, and which standard unit sizes to shortlist.
Systems and costs
What split, multi-split, ducted, portable and air-to-air systems cost an hour and a summer to run at the Ofgem price cap, and what changes your bill.
Data
We ran the checker's overheating model across the real EPC mix of four home types in 133 areas. The homes and places that run hottest, and why.
Planning and rules
How the MCS 020 a) sound calculation works, why the limit is now 37 dB(A), and the placement choices that decide whether an outdoor unit passes.
Keeping cool
Top-floor flats score highest for overheating of any common UK home type. The physics behind it, what the data shows, and the fixes in order of impact.
Planning and rules
Leases, freeholder consent, planning permission and where the outdoor unit can go: what it takes to cool a UK flat, and the options when you cannot fit one.
Systems and costs
Portable units cost less to buy and nothing to fit. Split units cost far less to run, are quieter and cool properly. The honest comparison for UK homes.
Systems and costs
Typical installed prices for air-to-air heat pumps by number of rooms, what the £2,500 grant does to the bill, running costs, and what changes a quote.
Keeping cool
Why bedrooms are hottest at bedtime, the 26°C line overheating tests use, and a bedtime routine that keeps a room cooler, with and without air conditioning.
Keeping cool
Loft rooms sit right under the roof with big windows and little thermal mass. Why a loft conversion overheats, and the fixes, from blinds to cooling.
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