Your air conditioning questions, answered
Air conditioning used to be something we only thought about on holiday. Not any more. After a run of properly hot British summers, more homeowners than ever are wondering whether AC is worth it, and asking us the same handful of questions.
We’ve pulled together the ones we get asked most. If yours isn’t here, give us a call on 0330 383 0000. We’re always happy to talk it through.
How much does air conditioning cost to run?
Less than most people expect.
A modern wall-mounted unit isn’t the energy-guzzler people imagine. Once a room reaches the temperature you’ve set, an inverter system throttles right down and only sips the power needed to hold it there. As a rough guide, a typical bedroom unit costs around 10–20p an hour once the room is cool, and a larger living-room unit a bit more. (Based on the Ofgem price cap of roughly 26p per kWh, summer 2026.)
Three things make the biggest difference to your bill. First, the unit itself: a fixed inverter split is far more efficient than a portable. Second, your insulation: a well-sealed home makes the system work less. Third, the right size for the room: a properly matched system reaches your set temperature quickly and then ticks over gently, rather than straining to keep up.
How much does it cost to install?
For most homeowners the starting point is a single-room “split” system, one neat indoor unit paired with an outdoor condenser. In 2026, a fully fitted single-room install typically lands around £2,000-£3,000, depending on the unit and how straightforward the pipe run is.
Cooling more of the house costs more. A multi-split covering three or four rooms is usually £5,000 to £8,000, and fully ducted whole-home systems higher again.
Can I spread the cost?
Yes. Through our partnership with Novuna Consumer Finance and Worcester Bosch, you can pay for your air conditioning monthly, with a £0 deposit and payments spread over a term that suits you, subject to application and eligibility. It’s a simple way to get comfortable now and spread the cost over time. You’ll find the full details and can apply at customheat.co.uk/pay-monthly.
Is air conditioning noisy?
Far quieter than the reputation suggests. A modern wall-mounted unit, like the Worcester Bosch Climate range we fit, runs from as low as 19 to 22 decibels on its quietest setting. That’s below a whisper, and quieter than a still bedroom at night (roughly 30dB). For most of the time, that’s all you’ll hear: once the room reaches temperature, the fan throttles right back.
The outdoor unit is a little louder, roughly 48 to 55dB when it’s working hard, but it lives outside and rarely runs flat out. The noisy machines people remember are portable units. A fixed split is in a different league.
Do I need planning permission?
Usually not. For most homes, a domestic air conditioning unit falls under “permitted development”, so no application is needed, as long as it meets a few conditions on size and where the outdoor unit sits (kept modest, off the roofline, and set back from your boundary).
There are exceptions. Listed buildings and homes in conservation areas often do need permission, so it’s worth a quick check with your local council before booking anything in. If you’re a Custom Heat & Cool customer, we’ll flag this as part of your survey.
Can air conditioning heat my home too?
Yes, and this surprises a lot of people. A modern air conditioner is an air-to-air heat pump, so it works in reverse to warm a room in winter as effectively as it cools it in summer.
Better still, it does it efficiently. For every unit of electricity it uses, it can deliver three to five units of heat. That makes it a genuinely cheap way to take the chill off a home office, your bedroom or lounge in spring and autumn without firing up the whole central heating system for one room. So it’s not just a summer purchase. It earns its keep all year round.
Portable or fixed, which is better?
Portable units are cheaper up front and need no installation, which makes them tempting for renters. But there’s a trade-off. A portable has no inverter, so it runs near full power the whole time, costs more per hour, and vents warm air through a hose you have to route out of a window.
A fixed split system costs more to install but is quieter, far more efficient, and much better at actually cooling a room. Plus, as above, it heats too. For a room you’ll want comfortable year after year, fixed almost always wins.
How long does installation take?
For a single-room split, usually half a day to a day. A multi-room system takes longer, typically one to three days, depending on how many rooms and how the pipework runs. It’s a tidy job. A good installer protects your floors, clears up after themselves, and walks you through how everything works before they leave.
Can I install it myself to save money?
No, and not just because it’s fiddly. Air conditioning systems contain refrigerant gases that are tightly regulated in the UK. By law, anyone installing or servicing them must hold the correct F-Gas qualifications. Doing it yourself risks your warranty, your safety, and the environment. Always use a properly accredited installer.
Is it actually worth it in a UK home?
For a growing number of homeowners, yes. British homes are built to hold heat in, which is wonderful in January and miserable in a July heatwave, particularly upstairs, in a home office, or for anyone elderly or unwell, where a stiflingly hot room is more than just uncomfortable.
Factor in that a modern system cools in summer and heats efficiently the rest of the year, and it stops looking like a luxury and starts looking like a sensible, year-round investment in a comfortable home.
Thinking about air conditioning for your home?
We’ve been keeping homes comfortable since 1980, and we’re Gas Safe, MCS and REFCOM accredited, so you’re in safe, properly qualified hands from survey to switch-on.
For a chat about the right system for your home, give us a call on 0330 383 0000 or visit customheat.co.uk.
Comfort you can feel, care you can trust.
