UK households are being urged to put tin foil on their windows before Sunday to combat the upcoming heatwave, according to Cambridge professor and BBC regular Hannah Fry. The advice comes as the UK braces for its third heatwave of the year, with temperatures expected to reach up to 30°C from Monday, July 6.
Why houses feel 'insanely hot'
Hannah Fry explained to her 2.2 million followers on Instagram that the greenhouse effect is responsible for the unbearable heat in many UK homes. Light from the sun passes through glass window panes easily, but once inside, the light waves change to shorter wavelengths and become trapped. This creates a one-way filter that lets energy in but prevents it from escaping, causing rooms to heat up rapidly.
The tin foil trick
While many people close curtains during hot weather, Fry suggests this is only partially effective. She recommends hanging a sheet or, better yet, attaching tin foil to the outside of windows. Aluminium foil reflects up to 90% of radiant heat from the sun, acting like a mirror for invisible heat rays and bouncing the sun's energy back outside before it can enter the room.
Fry said: "If you really want to minimise the amount of extra energy that is coming in when it's absolutely boiling outside, you should get some tinfoil and basically copy what they do in space. Get some tinfoil and then attach it to the outside of your window."
Important safety precautions
It is crucial to place the foil on the outside of the glass. If foil is placed on the inside, the heat still goes through the glass and gets trapped between the glass and the foil. This extra heat can make the window too hot, potentially causing it to crack or shatter.
Upcoming heatwave details
The Met Office has named 30 areas facing heavy rain on Friday, but the heatwave is expected to follow. UK weather maps have pinpointed the exact date a 37°C scorcher will hit, with 12 areas seeing temperatures above 32°C. The heatwave is set to last seven days in July, with temperatures soaring to 40°C in some regions.
