More than 18 million UK homes, or 64 per cent of households, are struggling with condensation, damp and mould this winter, according to survey research published by Uswitch on 23 February 2026. The comparison service said the cost of heating has led households to keep windows shut and turn down the thermostat, and that one in three households (36 per cent) report the problem has been worse this year1.
The research was conducted online by OnePoll between 26 January and 2 February 2026 among 3,000 UK residents, weighted to be nationally representative. Uswitch calculated the 18 million figure from 64 per cent of 28.4 million UK homes. Half of homes (49 per cent) reported damp or mould in bedrooms and three-fifths (58 per cent) in bathrooms. Other affected areas included windowsills (41 per cent), ceilings (27 per cent) and behind furniture (26 per cent). Four-fifths of people (81 per cent) said they had used at least one cleaning product or tool to tackle mould1.
Over a third of households (36 per cent) said mould had become more of a problem because the heating had been on less, and more than half (53 per cent) believed mould issues would likely be reduced if their home was heated adequately. Two-fifths (39 per cent) said they had been drying clothes naturally around the home more frequently this winter because of increased energy costs, and 44 per cent said they were more likely to keep doors between rooms closed to retain heat1.
Actions households reported taking this winter because of the cost of energy:
| Habit | % |
|---|---|
| Slept with the heating turned off overnight | 43% |
| Kept all windows shut | 39% |
| Used the heating for fewer hours a day | 37% |
| Turned the heating on only when it felt absolutely necessary | 37% |
| Dried clothes in the house (not in the tumble dryer) | 37% |
| Turned down the thermostat | 32% |
| Reduced heating in bedrooms | 23% |
| Turned heating off for the day | 22% |
| Avoided opening windows even when there was condensation | 14% |
| Used portable heaters instead of central heating | 13% |
| Heated only one room and left the rest of the home unheated | 13% |
| Left condensation on windows rather than wiping it away | 7% |
| Avoided using a dehumidifier due to electricity costs | 7% |
| Avoided using extractor fans in the kitchen or bathroom | 7% |
| Avoided turning on heating to dry out damp rooms | 7% |
Source: Uswitch.com1
By location, Southampton had the highest share reporting at least one of condensation, damp or mould at 76 per cent, followed by Liverpool at 74 per cent and Cardiff, Sheffield and Leicester at 70 per cent each. Oxford had the lowest rate at 52 per cent1.
Ben Gallizzi, energy expert at Uswitch, said:
"Millions of households are suffering problems with damp, mould and condensation this winter, with the high cost of heating preventing them from improving the situation."
Why it matters for households
Condensation, damp and mould are shaped by how a home is heated, ventilated and insulated, and the survey points to a tension between cutting bills and keeping a home dry. Reducing heating, keeping windows shut and drying clothes indoors all lower energy use but add moisture to indoor air, which is the mechanism Uswitch describes behind the reported rise in problems1. For a household's energy independence, the findings suggest that lower consumption achieved by turning heating down or off can carry a fabric and air-quality cost that is not captured in the bill alone. Long-term fixes named by Uswitch include improving insulation, fixing leaks and upgrading ventilation systems1. Households in the private rented sector have separate duties and deadlines covering damp and mould in rented homes, and landlord duties on energy, heating and home safety set out what a tenant can expect. Uswitch also notes that condensation, damp and mould can follow insulation work where ventilation is not addressed.
What happens next
No dated next steps were reported. Uswitch said it is urging households to air their homes frequently, turn on extractor fans where possible and consider using a dehumidifier1.