Why Sutton homes get so hot
Sutton, Cheam and Carshalton are dominated by interwar semis — the classic 1930s three-bed with a bay window, a garden and, increasingly, a loft conversion. These houses were built long before anyone worried about overheating. Insulated lofts and filled cavity walls keep warmth in through winter, which means they also trap it during a hot spell. Loft rooms and south-facing rear bedrooms tend to suffer worst, and sitting inside Greater London means the borough runs warmer than the open Surrey countryside just beyond it.
The same housing stock is what makes installs simple here. A semi with side access and a garden gives an installer an easy spot for the outdoor unit and a short pipe run up to the bedrooms. What you pay depends mostly on how many rooms you want to cool and how far the pipework has to travel — our cost guide sets out typical ranges and what moves the price, so you can sanity-check any quote you're given.
Worth knowing: a modern split system is a reversible air-to-air heat pump, so the same unit that cools in summer heats efficiently in winter — genuinely useful in a draughty semi, though grant schemes for heat pumps generally don't cover air-to-air systems, so budget without one.
Things to check before you book anyone
- Conservation areas. Parts of Cheam Village and Carshalton's older village centre fall within conservation areas. If you're in one, check with Sutton Council before fixing an external unit to a wall. It's a quick call and saves grief later.
- Electrics. Plenty of interwar homes are still running on older consumer units, and some need electrical work before a split system goes in. Our guide on whether your home electrics can handle air conditioning covers what an electrician will look for.
- Flats and maisonettes. Around Sutton town centre especially, leasehold flats almost always need the freeholder's written consent for an outdoor unit. Get that in writing before paying anyone a deposit.
Where Coolhouse is up to in Sutton — honestly
Straight answer: our vetted installers currently work in Hertfordshire, on the other side of London. We don't yet have a local crew we can send to SM or CR postcodes, and we won't pretend otherwise or promise a survey we can't deliver. What we can do is take your details when you request an estimate, tell you plainly where you stand, and get in touch the moment we've vetted installers covering the borough. Registering interest costs nothing and genuinely helps — it shows good local installers there's demand worth turning up for.