UK air conditioning, made simple
What size air conditioner do I need?
Free, accurate UK calculators to size a unit, estimate running costs and compare efficiency — backed by buying guides and honest top picks. No sign-up, no jargon.
- ✓ Based on current Ofgem rates
- ✓ Built for UK homes
- ✓ Completely free
Free calculators
Three tools to choose with confidence
Everything you need to pick the right air conditioner and understand exactly what it will cost to run.
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BTU calculator
Enter your room dimensions and heat sources to get a recommended BTU output.
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Running cost calculator
Estimate annual and hourly running costs based on unit size and usage hours.
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Efficiency calculator
Compare SCOP and EER ratings to find the most efficient unit for your budget.
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Buying guides
Plain-English advice for UK homes
Long-form guides covering sizing, running costs and what to check before you buy — no fluff, no hard sell.
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How much does an air conditioner cost to run in the UK?
How to estimate air conditioning running costs using your unit's wattage and the current electricity unit rate, with a worked example for a UK home.
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Portable vs split air conditioning — which should I choose?
How portable and fixed split air conditioners differ on installation, cost, performance and the rules that may apply, so you can pick the right type for your home.
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Air conditioner buying checklist
A practical pre-purchase checklist for UK buyers, covering BTU sizing, single vs dual hose, noise, energy rating, drainage, window fit and useful extra modes.
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Top picks
Best portable air conditioners UK (2026)
Ranked by BTU output, room coverage, efficiency and noise — with buying tips and links to our free size and running-cost calculators.
Preview — we're still finalising our real picks. The guide covers what to look for so you can assess any unit yourself in the meantime. Check back soon for live recommendations.
Browse all top picks →Common questions
Quick answers before you buy
- How many BTU do I need for a typical UK bedroom?
- Most UK bedrooms (around 10–15 m²) need 5,000–8,000 BTU. South-facing rooms or rooms with large windows may need more. Use the BTU calculator for a personalised figure.
- How much does it cost to run an air conditioner in the UK?
- A typical 9,000 BTU portable unit running for 8 hours a day in summer costs roughly £1–£1.50 per day at current UK electricity rates. Try the running cost calculator for your own figures.