Should the heating remain on when ventilating or should it be switched off? Opinions on this vary greatly. But consumer protection, BUND and WWF agree.
Regular ventilation is important. But you should always pay attention to the heating. (Source: hrabar/depositphotos.com)
- Should I turn off the heating when ventilating?
- Why shouldn’t I heat with the window open?
Pay attention to the recommended minimum temperature
Heating properly with smart helpers
You would actually think that there are no two opinions about what needs to happen to the heating when the windows are open. And yet you always read different recommendations on the Internet. Some say that the heating must always be turned down when ventilating. Others say that the heater should continue to work during brief bursts of ventilation.
The latter may seem strange at first. Leave the heater on with the window open? You’re heating up unnecessarily to combat the cold air outside. The other side argues that less energy is consumed in this way than if you had to switch the heating on again after the shock ventilation and heat it up. But how do you heat properly?
In principle, you should of course not leave the heating running when the window is permanently open. Both sides would probably agree. But what is right about shock ventilation? Leave the heating on or turn it off?
Should I turn off the heating when ventilating?
Since this question is discussed controversially, we consulted three reputable sources to answer this question: the German Federal Environment Agency, Stiftung Warentest and the North Rhine-Westphalia Consumer Center. And all three have the same opinion.
Ventilating with the window fully open prevents mold from forming on the edges of the window. (Source: Ladanifer/depositphotos.com)
They all recommend always turning the heating down completely when you ventilate. It doesn’t matter whether you leave the windows open for just a few minutes or for several hours. The season doesn’t play a decisive role either. All three also emphasize that regular ventilation is also important when heating. The WWF also agrees with this opinion.
Forced ventilation with the windows completely open is always preferable to longer ventilation with the windows tilted, because less heat is lost through the open windows. Around five minutes is enough. Ideally, you should open all windows completely to ventilate to ensure adequate draft in the apartment.
Why shouldn’t I heat with the window open?
But why is it so important that you ventilate? Can’t you just keep the windows closed all day and minimize heat loss? That’s not a good idea. Moisture accumulates in every home every day, for example when showering or cooking. Even human breath results in more humid air.
This humid air not only promotes the formation of mold in the house, it also worsens the air quality. As a tenant, you are then obliged, for example, to repair the damage or pay compensation. But as a homeowner, you will of course also have to clean up at your own expense.
When you ventilate, the moist air escapes through the open windows and dry air flows in from outside. The following applies: the cooler it is in the apartment, the faster moisture collects in the air and the more often it needs to be ventilated.
It goes without saying: You can keep your energy costs as low as possible by only turning on the heating when the windows are closed. (Source: depositphotos.com / belchonock)
Pay attention to the recommended minimum temperature
Therefore, the temperature in the apartment should always be at least 20 degrees Celsius during the day, especially during the recommended heating period. If you only ventilate on tilt, you run the risk of more mold forming on the edge areas of the window because the moist air cannot flow directly through.
During shock ventilation, only a small amount of heat is lost because the dry air heats up more quickly after ventilation than moist air. A short time after the shock ventilation, your apartment will be at the optimal temperature again as soon as you turn up the thermostat again.
Apart from the heating energy and heat used, there is another advantage if you ventilate regularly. Fresh air contains more oxygen than stale room air that contains carbon dioxide. That’s why fresh air has a positive effect on our body and brain.
Heating properly with smart helpers
We summarize: Regular ventilation is mandatory in the apartment. You should always turn down the heating to keep energy and heat consumption to a minimum. It is important that you open the windows completely and not just tilt them. Last but not least, you should ventilate regularly, but definitely after showering or cooking. After all, the air is particularly humid then.
The modern smart home now offers you good options for optimal heating and keeping your energy consumption as low as possible. The most important tool here are the smart radiator thermostats, which independently adjust the room temperature and can be conveniently controlled using a smartphone app.
Smart radiator thermostats tested in 2022: These devices help save heating costs
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The thermostats are particularly practical in combination with window contacts. If you pair the smart devices with each other, the thermostat automatically turns the temperature down when the window opens and turns it up again as soon as it is closed.
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