In the dead of winter, opening your windows might seem like the opposite of a wellbeing hack. But in Germany, it’s a standard practice called lüften: airing out one’s home every day, even in the bitter cold.
Lüften, which translates to “airing out” in German, is common practice because the country’s homes are very well-insulated, and opening windows is thought to reduce mold, humidity, pollutants, and odors. In the wintertime, some Germans even practice stoss lüften, which translates to “shock ventilation,” and involves opening all of a house’s windows completely for five or 10 minutes. The German tradition is becoming trendy in the U.S.—at least on social media—with TikTokers partaking in the practice and nicknaming it “burping” their home.
But does lüften actually benefit your health? Experts overwhelmingly say yes.
People are often more concerned about outdoor air quality than indoor air quality, says Ian Cull, founder and chief science officer at Indoor Science, an indoor air quality consulting and training company. But, he says, “in general, the air quality is worse inside homes than you would find in the outdoor air.” Everything from air fresheners, candles, and scented wax melts to gas stoves, dust, new furniture, and cleaning products can contaminate indoor air.
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Sometimes people are the sources of contamination. When humans are indoors, they are always shedding microscopic particles, says Mark Hernandez, a professor of biomedical engineering and director of the aerobiology and disinfection lab at the University of Colorado Boulder. “We have our own little microbiome,” he says. “We continually shed our skin, we shed our hair. It doesn’t bother most of us most of the time, unless you have something like asthma or severe allergies. When we open the windows, essentially that dilutes and removes whatever we shed.”
Some people are more sensitive to chemicals and allergens in the air than others. “Sometimes it’s hard to really grasp the impact of indoor air quality because people can experience it so differently,” he says. But the COVID pandemic highlighted the importance of indoor air quality. “Air quality is an important piece of a healthy lifestyle,” Cull says. “It’s not just about exercising, eating right, and getting good sleep. Now more than ever, indoor air quality is part of that conversation.”
Here are some of the benefits of airing out your home.
Better sleep
Research suggests that sleeping with the windows open helps people fall asleep more quickly and sleep more soundly, Cull says. “Sleeping with your windows open has been shown to have a beneficial effect.”
But this is only a worthwhile practice if you live somewhere relatively quiet. One 2021 study published in Science and Technology for the Built Environment found that people snored and woke up significantly less when they slept with the windows open. However, some people reported sleeping worse because they were awoken by outdoor noises.
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Lynelle Schneeberg, a sleep psychologist at Yale University, believes practicing lüften right before bed could help people get more restful slumber at night. “You know that feeling when you’ve washed your sheets and they’re so clean and fresh?” she says. With lüften, “it’s almost like you’re giving yourself that feeling on a daily basis. So I think it’s really a great idea.”
Improved mental health
There’s ample research being done right now on indoor air quality in educational settings, Hernandez says. One 2025 study, for example, found that classrooms with higher concentrations of carbon dioxide (due to more students and less ventilation) were linked to lower cognitive test scores.
“In terms of wellness, cognition, and worker performance, there’s an emerging literature that says we need fresh air to be OK and to be fully functioning in our respective indoor environments,” Hernandez says. Lüften also has potential mood benefits. One 2025 study published in BMC Geriatrics found that older adults who lived somewhere with better indoor air ventilation were less likely to be depressed compared to older adults with less indoor air ventilation.
Laurence Chan, assistant professor of medical psychology in the psychiatry department at Columbia University Irving Medical Center, believes lüften offers a unique opportunity for mindfulness, especially for people who are sedentary, spend a lot of time indoors, or are prone to mood disorders or anxiety.
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“It’s an opportunity for us to take a break from whatever activity we’ve been focusing on and directing our attention to,” he says. “When we feel that fresh air, maybe that rush of cold, we become more attuned to our five senses. How are we feeling? What are we thinking? I think what fresh air offers us is a moment to be present and take a break.”
A handful of exceptions
“It’s great to ventilate homes,” Cull says, but there are a few exceptions. For example, if the outdoor air quality is worse than the indoor air quality, “having your windows open could have a negative effect.” This can happen during a wildfire, a dust storm, a high pollen day, a high mold spore day, in an area with industrial pollution, or in an urban area during rush hour. “You have to be very mindful about when you’re opening windows and in what situation,” he says.
Hernandez says his windows are open as much as possible, weather permitting. Even when it’s cold outside, his family opens them first thing in the morning, when they get home from work, and before they go to bed. They don’t just do this because he studies aerobiology, but also because his wife grew up with a Romanian proverb reminiscent of the lüften practice: “If you don’t open the windows, the doctor will come through the door.”
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