Are sheets at the window a real alternative to shutters and blinds?

Do curtains and sheets help prevent the warm sunlight from entering the apartment on hot days? It's better than nothing, say experts. Photo: Jens Kalaene/dpa-Zentralbild/dpa

What's the best way to keep the heat out on a hot day? According to experts, it's roller shutters. But unfortunately not every building has them, and installing them can be expensive.

Is putting up a sheet in the window or the balcony door a real alternative for renters?

Generally speaking, roller shutters, awnings and Venetian blinds that are attached to the outside of the window are the best protection, as they prevent large parts of the sun's heat from entering the house in the first place, says German consumer expert Lorenz Buecklein.

Bright colours absorb less sunlight

Putting up sheets, however, can be a good alternative for those who don't have roller shutters. Make sure to choose light colours or white sheets, however.

"This already achieves a certain cooling effect – the light colours prevent the air directly outside the window from heating up too much by absorbing less sunlight. At the same time, it remains bright enough inside," explains Buecklein.

Another solution for buildings without shutters, awnings and blinds: Sun protection films, which are applied to the window pane and reflect the sunlight.

High-quality films can even reduce the use of air conditioners and other climate-control devices, says Germany's Stiftung Warentest consumer test group. However, they tend to absorb a lot of light. – dpa