Is it Good to Leave Your Windows Open?

Is it Good to Leave Your Windows Open?

A World Health Organisation report released in 2016 revealed that 92% of the world’s population is breathing sub-standard air (source). It’s not surprising, then, that people are questioning whether it’s a good idea to leave your windows open.

Is it good to leave your windows open? Yes, it is good to leave your windows open, according to both the WHO and CDC, to let in fresh air and sunlight. Proper ventilation is critical to removing stale air and toxins in the home, and sunlight can help kill harmful bacteria. At the same time, there are a number of factors that you need to consider first, including pollution.

In this article, we’ll guide you through those factors so you can decide when to leave your windows open.

When to Open a Window and Why

For some of us, there’s nothing better than throwing open a window, letting a fresh breeze blow in through the curtains but, for others, an open window can be far less desirable.

While you might be one of those individuals who don’t like the idea of keeping windows open throughout the day, there are numerous benefits to allowing fresh air and sunlight into a room.

Conditions that Warrant an Open Window 

If you live in an area with poor air quality, then you’ll know just how much it can seriously impact both your health and your lifestyle.

As we have become increasingly aware of the dangers of outdoor air pollution, individuals have responded by changing the way they do things. Responses include limiting our outdoor exercise and not allowing our children to play outdoors.

What many people don’t consider, however, is how the air inside your home or office space can be equally as harmful as the air outdoors. Factoring in this indoor air pollution, we can see why it may be entirely necessary to open a window (source).

Indoor Air Pollution

Several factors can cause indoor pollution, such as allergens, pet dander, and dust. However, it can also result from the carbon released by your appliances, such as your fridge, TV, and smart devices.

Keep this in mind when purchasing appliances and try to ensure that they are as eco-friendly as possible. 

Another concern is radon, which is a naturally occurring gas that can be very dangerous in high quantities. It can build up in the basements of houses and can adversely affect your health. 

While we are on the topic of potentially harmful and invisible pollutants in your home, houses built in the pre-1980s may also contain toxic building materials such as lead-based paints and asbestos.

To help remove these harmful chemicals, you must make sure to open windows in your house for proper ventilation.

Outdoor Pollution vs Indoor Pollution

Now you might be sitting there thinking, “Well, there’s pollution outdoors and pollution indoors, so where do I go from here?”

Well, it comes down to weighing up outdoor pollution versus indoor pollution. If you live in a city with high pollution rates, then the air quality outdoors may be worse than the indoor air quality. 

You could say the same if you live near a motorway or factories. You may experience outdoor air pollution that is more severe, and this may outweigh the pollution you have indoors. 

People who reside in cities are much more likely to suffer from low outdoor air quality than those people who live in the countryside.

Although, factors such as insecticides and pesticides used to spray crops may influence the quality of the air in the countryside as well (source).

If you do live in an area that suffers from low outdoor air quality, then perhaps you can compromise.

You might decide to open the windows in your home for a while every day to ventilate the rooms. Then you might avoid doing things such as exercising or other activities where you have to spend extended periods outdoors.

Fresh Air and Combating Indoor Air Pollution

Letting in the air from outside is the easiest way that you can help ventilate your house and get rid of dangerous air inside. However, there are several additional measures you can take.

As mentioned before, you can also try to purchase eco-friendly appliances.

Furthermore, it would also be a good idea to make sure that you have properly-installed appliances and fixtures so that you don’t have any dangerous materials or gases escaping into the room.

If you are looking for additional measures to help filter pollutants and allergens in your home, then you can invest in an artificial air purifier or a dehumidifier. 

You may have heard that you can use certain types of plants indoors to filter the air, but there is still a lot of debate surrounding this notion. NASA did a study which suggests that some indoor plants might be useful in filtering the air.

While the extent of their effectiveness is disputable, what we do know is that plants produce oxygen from exhaled carbon dioxide, creating more oxygen and thus improving air quality in the home.

The American Lung Association suggests several ways in which you can limit the air pollution inside of your home. These suggestions include not smoking indoors and getting your home checked for harmful gases such as radon (source).

They also suggest trying to find alternative cleaning products that are not harmful or toxic and reducing humidity, which can cause mold and mildew.

The Health Benefits

There is no shortage of sources that will tell you how good it is for you to have an open window in your home. The introduction of fresh air and sunshine has some key benefits for your health.

The Removal of Pathogens

During the COVID-19 crisis, the WHO and the CDC warned about the dangers of poor ventilation and the way it can help spread disease. They even suggest opening windows as a way to rid your space of harmful pathogens (source). 

While air conditioners help circulate the air, both health organizations discourage the use of air conditioners instead of fresh air as they help encourage the spread of harmful pathogens. 

The spread of disease-causing microorganisms through air conditioners is usually due to a lack of machine maintenance or insufficient air exchanges.

Additionally, air conditioners provide the ideal breeding ground for molds and other bacteria, which is why WHO advocates for natural ventilation systems.

Relying solely on natural ventilation can be trickier in areas with higher humidity where an open window does not help to cool a room down but can even worsen the situation. 

Benefits to Sleep Patterns

There have been several studies conducted on how fresh air can be beneficial to our sleep patterns.

A paper written by A.M. van Ruitenbeek of the Eindhoven University of Technology showed the relationship between the level of CO2 in the bedroom during sleep and its effect on sleep quality.

The report revealed that having a window open helps to reduce the levels of CO2 in the air, creating a better balance and resulting in a better night’s sleep (source).

Additionally, opening a window in the summertime can help to cool a room down and lower your body temperature, making you more comfortable and able to sleep easier. Improved sleep patterns will also have a positive impact on your mental health.

Let the Sunshine In

Sunshine is a great reason to open a window because our bodies love a bit of vitamin D. This wonderful vitamin can protect us against a host of illnesses, including cancer and depression (source). 

Vitamin D also helps our bodies to absorb calcium, which is essential for maintaining bone health. Sunlight can also help against ailments such as eczema and jaundice. Additionally, UV rays can act as a disinfectant (source).

Sunshine in the home can be especially important in countries where seasonal depression comes into play (source). 

Sunlight helps our bodies to release more serotonin, which is a hormone that can act as a mood elevator. Imagine, just a little bit of fresh air and sunlight can chase the blues away (source).

If you are interested in learning more about how long you should leave your window open, you can read more here.

Concerns about Open Windows

When someone in your household asks, “Should we open a window?” pollution, fear of creepy crawlies, colds, and security are just some of the reasons people may respond with a resounding “No!”

While none of these reasons are without merit, there are some precautions that you can take to ease your mind so you can allow fresh air to circulate in your home.

For those who live in areas with high crime rates, where security is a significant concern, you can reinforce your windows with iron bars or guards.

Similarly, you can fit your windows with screens to prevent insects and other animals from coming in.

For those concerned that leaving a window open can make you sick, having fresh air circulating in your home means that you are even less likely to catch a virus unless there’s an abrupt change in temperature (source).

However, whether leaving a window open at night will negatively affect you largely depends on the quality of the air.

If the air is very dry, then you may wake up with a sore throat and, if there is a high percentage of allergens in the outside air, you might wake up sneezing (source).

If you also worry about allowing dirt and dust through your window and into your home, as both of these can negatively impact your health, then you might be interested to learn how to stop your windows from getting dusty.

How Much Fresh Air Do You Need?

In this case, you can’t get too much of a good thing, but here’s what you need to know about such variables as the season and time of day.

You may be one of those people who have their window open day or night, rain or shine. Whatever the case, there are better times to open a window than others.

Consider the Season

Summer may seem like the obvious time to leave a window open because the flow of air can cool down the room. However, you need to monitor outdoor air pollution and try to make sure you are only opening windows when the levels are lower. 

There are mainly two groups of air pollutants: ozone and particulate pollutants.

Particulate pollutants are the teeny tiny particles that we can inhale, and that comes from a host of sources, such as emissions from cars, coal burning in factories, and even naturally occurring events like wildfires.

When the sunlight makes contact with some type of pollutant like vehicle exhaust, it creates ozone. Ozone levels can rise throughout the day, and the heat of summer exacerbates the levels of ozone (source).

Thus, on sweltering summer days, air pollution can be quite severe due to high ozone levels combining with particulate pollutants. However, while some people may believe that air pollution is worse during summer, this is not altogether true.

Individuals tend to create a lot more air pollution during the winter as they burn fuels like wood or coal to keep warm. This pollution gets trapped near the ground and can be more severe than summer air pollution (source). 

The World’s Air Pollution: Real-time Air Quality Index is an excellent resource to help you check the air quality of each city. It is user-friendly and color-coded by severity.

People may also hesitate to leave windows open during winter because of fear of the cold. However, we may be doing ourselves a disservice by leaving out windows closed in winter (source). 

Our bodies require fresh air for us to breathe properly, and this is compromised during the winter when we hold up in stuffy houses and offices.

Those who argue that leaving a window open during the colder months is a waste of money as it lets out all the warmth that has been created by artificial heating systems aren’t wrong.

However, the costs can be small when compared to the health benefits of periodically opening a  window. 

Another factor to consider when discussing the seasons is allergies. If you suffer from bad seasonal allergies, you may need to be careful not to leave a window open for too long as you might invite in pollen and other sneeze-inducing visitors.

However, remember to consider indoor allergens too. If you have pets, dust, or any kind of mold indoors, you need to make sure you ventilate correctly (source).

Considering Others

When deciding to open a window, it is essential to consider carefully which window to open and who could be affected by it.

Windows in the bathroom or the kitchen are useful to open because they are in areas of the home where there are higher concentrations of pollutants.

Additionally, due to heat or moisture, they require more ventilation and are also not as frequently occupied.

As mentioned earlier, factors such as security, insects, and outdoor pollution are also factors when deciding which window to open. 

You need to be careful when opening windows in rooms with children, the elderly, or pets as they may be more susceptible to temperature changes and the factors mentioned above.


SIDS, or Sudden Infant Death Syndrome, is the leading cause of infant death in babies under the age of one in the USA. Scientists continue to research the reasons for SIDS, but they have not yet found definitive answers.

One possible cause is high temperatures, and a paper published in the PMC journal entitled “Ambient Temperature and Sudden Infant Death Syndrome in the United States” linked elevated temperatures with an increased risk of SIDS (source).

Based on that knowledge, you must maintain a comfortable climate in the room (source). 

In addition, you need to be aware of how far your child or baby is from the open window. Curtains and blinds can be dangerous if they are too near a baby’s crib. Smaller children may also be tempted to climb out of an open window (source).

The Elderly

Open windows can also be a concern for the elderly who are unable to get up to open or close them on their own. Sudden rises or drops in temperature may wreak havoc with their ability to maintain body heat and get a good night’s sleep.


A final consideration is pets who need to use an open window to go into the garden. If you do have an indoor/outdoor pet and are concerned about leaving a window open at all times, you can look into alternative entrances such as a cat or doggy door. 

Alternatively, you can leave a window open in a room with a closed door at night and let your pet sleep in that room.

Final Thoughts 

Despite the presence of air pollution, major players such as the American Lung Association, the WHO, and the CDC still recommend that people open their windows to ventilate their homes.

Allowing fresh air and sunlight into your home can have a range of health benefits on the body and the mind. Opening windows, and creating better ventilation can also help to reduce allergies and can limit the spread of pathogens.

Take the time to ventilate your home and experience the benefits of fresh air and sunlight.


I'm a Pharmacist and a passionate researcher into clean air and pure water for the home. I believe these 2 elements play a significant role in our health and overall wellbeing.

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