There are two methods of keeping your home free from pollutants and allergens, an air purifier or opening windows.
Air purifiers are great for those who suffer from allergies, asthma, or other respiratory problems.
Air purifiers filter out small particles to keep the air clean. They also kill mold spores that can trigger allergic reactions in people with mold sensitivity.
For some people, however, opening their windows is all they need to feel better. It keeps them connected with nature and provides fresh, oxygen-rich air through natural breezes.
In this article, I compared the differences between an air purifier and vs. open window.
Let’s get started…

Should You Open A Window With An Air Purifier?
There is no problem using both an air purifier and open windows to keep the air clean in your home.
The choice between these two options is a personal preference.
What suits you best depends on which one will provide better relief for your respiratory problems.
You can even open the doors as well so that the air can flow more freely through your home.
What Factors Should You Consider Before Opening Your Window
Before deciding to open your windows for fresh air, you should consider a few factors.
Do You Live In A Cold Climate?
If so, opening your windows will not provide the relief that an air purifier would.
Are There Any Allergens or Pollutants In The Area?
Air purifiers are more helpful if this is the case. They filter out small particles to keep indoor air clean and free of allergens.
Will It Have Negative Consequences On Plants Or Pets?
This might apply more to gardeners who’ll need regular access to their plants while airing them out with fresh oxygen-rich air through natural breezes now and then during hot summer months.
Pets may also enjoy having some time outside, but when leaving them outdoors, they have a safe place to be.
Are You Going to Want the Window Open For Long Periods?
If so, it might not be worth the energy cost as air purifiers are more affordable in maintenance costs and last longer than an open window unit.
Do You Need Ventilation Or Temperature Control From Your Cold-Air Solution?
Air purifier units typically provide this. Some even offer additional features such as humidification or changing room temperatures.
They do this by cooling down your home’s interior space without using artificial heating/cooling systems that negatively affect your monthly bills.
If There Is Any Mold Present Within 250 Feet Of Where You Live?
Some people with asthma and other respiratory problems can experience adverse reactions when exposed to high levels of mold spores.
Since window units don’t filter out these spores, they may not be the best choice in this case, and an air purifier might be more helpful.
Other factors include allergies inside your home (i.e., to pets, carpeting, dust mites), smoke from cigarettes, or other sources in the vicinity of your home that may affect your indoor air quality and health.
When Should You Only Use An Air Purifier And Not Open A Window?
There are instances when it is advisable only to use your air purifier and keep windows closed.
If the air outside is heavily polluted with smog (i.e., if you live in a big city).
An open window might not help as much.
In this case, it would be best to stay indoors until the air pollution clears up and use your purifier when the windows are closed for better relief from indoor pollutants that may worsen allergies or asthma symptoms.
Air purifiers can also work great at night while all doors and windows remain shut during sleep hours.
So there’s no need to keep them open just because of discomfort caused by stuffy rooms due to pollen coming in through cracks around doorframes or windowsills.
An air filter will effectively clean the surrounding area without leaving any allergens inside.
This will improve sleeping conditions and comfort levels.
You should also keep windows closed if other allergens close by, such as smoke from cigarettes or other sources in the vicinity of where you live, affect your indoor air quality and health.
How To Keep The Air Fresh With An Air Purifier Running And Windows Closed
There are various ways you can keep the air fresh with an air purifier running and windows closed.
Turn your HVAC on “auto” mode to adjust to the outside temperature changes during colder months.
Do this also when there’s a big difference in indoor and outdoor temperatures that may result in uncomfortable drafts coming into your home from open windows.
Related Post: How To Ventilate A Bathroom Without Windows
This will keep you comfortable without any need for constant adjusting of window positions throughout the day.
It will also save energy by not having to run both simultaneously, which could affect monthly bills negatively depending on how much is used simultaneously via each appliance separately.
Purchase dehumidifiers if necessary, too, for those times when humidity levels are high inside due to heat waves or rainstorms that lead to increased mold and mildew growth levels.
You also want to ensure your air purifier is well maintained with the proper filters and vacuum cleaners to keep it running efficiently without clogging or breaking down.
Can You Put An Air Purifier In Front Of A Window?
It would be best to put your air purifier in front of a window if you live near an area with high pollution levels.
This will filter the outside pollutants without letting any inside, which could worsen allergies or asthma symptoms.
Putting your air purifier in front of a window will also help keep your home’s living conditions and comfort levels more comfortable.
Note, however, that your air purifier may have to work harder since it will now work in two directions.
When Is The Best Time to Use An Air Purifier?
The best time to use an air purifier depends on various factors.
For instance, if you live in an area with poor air quality (i.e., a big city), it’s best to use your purifier while keeping windows closed unless there are times when the pollution levels outside have gone down.
You also want to turn your air purifier on when your house is more crowded with people due to holidays and gatherings, so the air ventilation system can handle all that’s coming in.
Also, if it’s a season when there are a lot of allergens, such as pollen, it’s best to use your purifier while keeping windows closed, as mentioned before.
It should relieve indoor pollutants that may worsen allergies or asthma symptoms and help keep living conditions and comfort levels in your home more comfortable.
Air Purifier vs. Open Window Comparison
Here are a few pros and cons of each method of keeping the air clean in your home.
Air Purifiers | Open Window |
Pros: | Pros: |
Filter out small particles to keep the air clean – Kill mold spores that can trigger allergic reactions in people with mold sensitivity – Increase quality of life for those who are asthma and allergy sufferers – Reliable and consistent – Some units can humidify the air, and some even control the temperature as well. – Higher initial cost than opening windows but less expensive long-term in maintenance costs. | – It keeps you connected with nature and provides fresh, oxygen-rich air through natural breezes. – Increases quality of life for those who want to have an open space in their home free from the sound of a purifier running. – A natural way of getting fresh oxygen-rich air through natural breezes – It decreases energy bills by up to 25% since you don’t need an artificial system to pump it around the house constantly. – Great if you live in a hot climate |
Cons: | Cons: |
– It may not be enough for people with allergies, asthma, or other respiratory problems. – It may not provide adequate relief in winter when temperatures are frigid. Air | Not always reliable and consistent – It does not kill mold spores that can trigger allergic reactions in people with mold sensitivity. – Allows pollutants and allergens inside |
Summary – Can you run an air purifier with the window open?
As discussed earlier, running your air purifier with the window open is totally okay, but there are a few things to keep in mind.
However, your air purifier may have to work harder since it will now work in two directions.
It will be filtering pollutants coming from outside and those inside the house.
In summary, you need to know when to open and close the window to get the desired results with your air purifier running.
However, it’s best to use your air purifier while keeping the windows closed with high pollution levels outside and allergens that are present during certain seasons.
Looking For Air Purifier Guides?
If you’re looking for more air purifier resources, consider checking out our other posts on air purifiers.
- 5 Top Air Purifiers For Air Purifier for Chemical Sensitivity
- 5 Top Air Purifiers For Eczema
- 5 Top Air Purifiers For Windowless Rooms
- 5 Top Air Purifiers For Paint Fumes
- 5 Top Air Purifiers For Radon Gas
Resources
- Air Pollution Study
- Indoor particles in the homes of children study with air purifiers
- Pollen Air purifier study

(Author)
<p>Irene Batres is eager to help others create an indoor allergen-free home. She has years of experience testing out air purifiers, dehumidifiers, and other products designed to help with indoor air quality. Learn more about me.