An experiment on BBC Morning Live has demonstrated two low-cost methods that can make rooms feel 'noticeably cooler' during the UK's third heatwave of the year. The tests, conducted by presenter Nick Knowles and Polly Turton of Shade The UK, showed that placing ice-cold water bottles in front of a fan and applying tin foil to windows can reduce indoor temperatures by several degrees.
Bottle and fan method drops room temperature by nearly 2°C
In the first experiment, Knowles and Turton placed ice-cold water bottles in front of a fan set to maximum speed. The room initially measured 27.1°C. After one hour, the temperature had dropped to 25.4°C. Knowles described the room as 'noticeably cooler,' and Turton explained that moving air across a cold object can effectively cool a room.
Turton emphasised the health benefits of even a small temperature reduction: 'For a young child in a hot bedroom, or an elderly adult suffering from heat, that's going to make a big difference to their health and wellbeing.' She also noted that the electricity used for the fan is minimal compared to an air conditioning unit.
Tin foil on windows reduces surface temperature by 2-3°C
The second method involved sticking tin foil on windows to reflect sunlight and prevent heat build-up. After one hour, the surface temperature of the glass pane dropped from about 32°C to around 28°C, a reduction of two to three degrees. Knowles called the method 'cost-effective,' noting that a roll of tin foil typically costs around £1.50.
Turton added: 'It is an effective solution if you don't have any other options available to you.'
Heatwave continues across the UK
The experiments come as the UK faces its third heatwave of the year, with temperatures in some areas reaching the mid-30s. The Met Office reported that Friday is likely to be the peak of the heatwave, with Deputy Chief Forecaster Tom Crabtree stating: 'While temperatures are expected to ease across southeast England through the weekend and into next week, it won't be a straightforward end to the warm weather.'
The UK Health Security Agency has issued amber and yellow heat health alerts, warning of considerable effects on health and social care services. Overnight conditions remain muggy and humid, making it difficult for many to sleep comfortably.
Cost comparison: fan vs air conditioning
The Energy Saving Trust estimates that running air conditioning for 24 hours can cost up to £6, while a free-standing fan for the same period typically costs between 15p and 31p. The bottle-and-fan method offers a low-energy alternative to air conditioning, with minimal electricity use.
As the heatwave persists, these simple hacks provide affordable ways for households to stay cool without relying on expensive air conditioning units.
