Phil Spencer: How you can heatwave-proof your home – and what it will cost you

Even for the most dedicated sun-lover, the novelty of Britain’s series of heatwaves wore off long ago. Weeks of baking temperatures with no rain have caused wildfires and left gardeners facing hosepipe bans and farmers reporting poor harvests. For most of us, the extreme heat has been uncomfortable at best, dangerous at worst. British homes tend to be designed to keep heat in rather than out, and many people have endured weeks of sweltering temperatures both inside and outside. This summer’s record-breaking temperatures are no one-off. Met Office data published last week shows 2025 was the hottest year on record, and that the hottest day of the year in the south of England is now typically 4.5C warmer than it was in the three decades to 1990. Shorts Weather that was once considered extreme is becoming normal, and as Met Office climate information scientist Mike Kendon put it, the “climate of the 20th century has now gone”. Unfortunately, the vast majority of UK homes were built in that century. The Home Builders Federation estimates that we have some of the oldest housing stock in Europe; 78 per cent of our homes were built before 1980 and four out of 10 were built before 1946. While some new builds include features to keep out summer heat, most British homes require modification to make them heatwave-proof. Fortunately, the tech needed has become much more affordable in recent years. There are three main upgrades to consider. Air conditioning This is a reliable and effective way to keep your home cool even when it’s scorching outside. Air condition (AC) systems absorb heat from indoor air and push it outside, leaving you with cool, dehumidified air inside. They’re a familiar sight in American homes and southern Europe, but are less common here. The cost of installing AC in a single room – a bedroom or home office for example – is around £2,000, while adding AC to every room requires ducting from a central system and could cost five times as much. Modern AC is much more efficient than the aircon of yore, but it is still fairly power-hungry so your electricity bills will increase during the weeks that you use it. Heat pumps There has been lots of buzz around these as an alternative to conventional gas boilers. But despite their name and unlike a boiler, most heat pumps can be used to cool your home as well as heat it. In cooling mode they work much like an air conditioner, shoving hot air out of your home and circulating cool air inside. Many are very efficient and cheap to run; look for ones with a high SEER2 (Seasonal Energy Efficiency Ratio) rating for the best cooling performance. However, they’re not cheap to install and may require your heating pipework to be upgraded. Depending on the type you choose and the size of your home, a heat pump system could set you back anything from £8,000 to £30,000. The Government’s Boiler Upgrade Scheme currently offers grants of £7,500 towards the cost, which brings the price you pay right down. Another big plus is that you can use a heat pump all year round; in winter you just switch it to heat mode. Provided your home is well insulated, the Energy Savings Trust says you could save hundreds of pounds a year on your fuel bills by replacing a conventional boiler with a heat pump. Solar panels These won’t cool your home on their own, but they are the perfect partner for either aircon or a heat pump. They generate free, green electricity even in cloudy weather, but are most efficient in bright sunshine. This means they really come into their own during a heatwave, and can produce enough energy for you to run an AC or heat pump system for free during daylight hours. However, solar panels aren’t suitable for every home; they may be difficult or impossible to install on flats, they need loft space if you put them on a roof, and they can look unsightly. If your home doesn’t need all the electricity generated by your panels, you can automatically ‘sell’ the surplus to the National Grid. Better still, modern panels have batteries that store excess electricity for you to use at night or when the weather is poor, although these take up space and are an additional cost. Installation costs vary dramatically but there are plenty of good online calculators you can use. I fed in details for a four bedroom house and was told the price and installation cost would be £9,000, with a predicted energy saving of £880 per year. How to decide what’s right for your home Weeks of sweaty discomfort and the realisation that extreme heat is the new normal for the British summer have got many people thinking seriously about making their home heatwave-proof. Retrofitting cooling tech requires a big upfront investment, but get it right and it will save you money off your energy bills and may add value to your home when you come to sell. There’s no one-size-fits-all solution, so it’s worth talking to a renewable energy expert to get a fix on what the costs and returns might be for your home. For a few ideas on more questions to ask, check out my podcast on Which home energy upgrades are worth it? Phil Spencer is a property expert and co-presenter of Channel 4 show ‘Location, Location, Location’. He is also the founder of Move iQ