By Chen Ly.
There are windows in a house.
Alamy images/Botastock.
A smart window that keeps heat in during the winter and lets it out in the summer could be a cost-effective way to save energy.
Windows are the least efficient part of the building, accounting for as much as 60 per cent of their energy loss.
In hot weather, windows warm up from the outside and the thermal energy is transferred into buildings. When it's cold outside, windows warm up from the inside and heat the outside environment. radiative cooling is a process.
It means that windows aren't very effective at keeping buildings cool. In the US, heating and cooling through windows accounts for 4% of energy usage.
Yi Long and her colleagues at Nanyang Technological University in Singapore have developed a window that can turn on or off the radiative cooling effect on its own.
