Temperatures are expected to reach as high as 35 degrees celsius during the upcoming heatwave

A rising "heat tax" is hitting millions of households as the UK braces for its fourth heatwave this summer, with the warm weather showing no signs of easing.

Families are pouring increasing amounts of money into adapting their homes and daily lives to cope with hotter summers, new research from The Harris Poll UK, a Stagwell company, has found.

The study reveals that two-thirds of the public, 66 per cent, are worried about the growing frequency of heatwaves, with a similar proportion, 67 per cent, saying they now give more thought to preparation than in previous years.

Confidence in the home as a refuge from extreme heat has fallen sharply: only 35 per cent of people feel their property is adequately equipped to stay cool, a significant drop from the 50 per cent who said the same when surveyed during last summer's heatwave.

The effects are already being felt across the country, with 93 per cent of people reporting that recent heatwaves have had some impact on their lives.

Some eight in 10 say their daily routines have been disrupted, and for 38 per cent that disruption has been substantial. Sleep is the most commonly cited problem, with 65 per cent finding it hard to get proper rest in hot weather.

Staying cool personally is a challenge for 62 per cent, while 61 per cent report difficulty maintaining a comfortable temperature at home.

Nearly one in five, 18 per cent, say heatwaves have taken a toll on their mental health. This is a figure that climbs to 28 per cent among those aged 25 to 34, suggesting younger working-age adults are disproportionately affected.

More than half of consumers, 57 per cent, have already spent money on products to beat the heat this summer, with a further 10 per cent expecting to make similar purchases before autumn arrives.

Yet over half of households, 52 per cent, say they simply cannot afford upgrades that would make a meaningful difference to their home's ability to cope with high temperatures.

The broader cost of living crisis is compounding the problem, with 64 per cent saying it has made preparing for warmer summers harder.

Energy prices represent another barrier: 73 per cent would run cooling appliances more frequently if bills were lower, and 60% would fit air conditioning if installation costs were more accessible.

Sarah Beams, the managing director at The Harris Poll UK, said: "Our research indicates we're reaching a tipping point in how consumers think about hotter summers.

"What was once seen as an occasional inconvenience is increasingly becoming a part of the cost of living. Households are adapting out of their own pocket because they see no other choice.

"They're buying cooling products, using more energy and changing their routines, but most don't believe they should be carrying the burden alone. In fact, almost three-quarters say they would use cooling appliances more if energy costs were lower.

"That's what we describe as the UK's heat tax. It's the financial cost of hotter summers and the growing expectation that households will absorb the cost of adapting, even though consumers believe responsibility should be shared much more broadly across government, public services and businesses."