As someone with seasonal allergies, I rely on my air purifier to help me through the spring. I mean experts recommend these devices have HEPA filters to capture pollutants, allergens, even bacteria and other viruseswhich helps prevent illness.
But there is one mistake you can make that will cause your air purifier to have the opposite effect, releasing pollutants and allergens back into your home’s air where they can affect your health.
“If the filter is not changed regularly, accumulated dirt can build up and clog the filter. This leaves more dirt in the air, and a dirty filter can release dirt back into your home, making the air more polluted than not using an air purifier at all,” said Dr. Karyi Coyle, a pulmonologist and assistant professor of medicine at New York College.
I consulted a health expert to learn more about the consequences of not changing your air purifier filter and how often it should be changed.
Your air purifier and your health
The purpose of an air purifier is to trap pollutants, preventing them from circulating in the air and entering your body. As Coyle said, these contaminants build up over time and can clog your filter, reducing airflow and filtering efficiency. Not only will this leave more pollutants in the air, but the filter can even release particles it previously collected in the air, further reducing your air quality.
“This may have consequences for respiratory, cardiovascular or allergic health,” said Dr. Lyndsey Darrow, an epidemiologist and professor of public health at the University of Nevada, Reno.
A dirty air purifier filter is also susceptible to mold growth, Coyle says, and the air purifier can then circulate those mold spores around your home. “This can cause serious illnesses such as severe allergies, asthma symptoms and other respiratory problems,” he explained. “A dirty filter can create worse indoor air quality than it would without a filter at all.”
In other words, by not changing your air purifier filter, you are creating the opposite effect. Everything allergensbacteria, bacteriaThe pollen and mold spores that you want your air purifier to trap are not blown back into your air, where you can breathe them in and get sick.
Not changing your air purifier filter can set off your allergies and make you sick.
It can also hurt your wallet
Aside from the health-related consequences of not regularly changing your air purifier filter, Darrow explains that a clogged filter will require more energy to push air, thus increasing energy use and costs. Over time, this can shorten the life of the air purifier by wearing out the motor or fan, requiring you to buy a new device and spend more money.
“Continued stress on the engine can result in the need for repair or replacement of the unit, which is more expensive than changing filters regularly,” says Coyle.
The best type of air purifier filter
The gold standard filter recommended by many pulmonary and allergy specialists is the HEPA filter. “This is because it can remove most of the air pollutants down to the microscopic level,” Coyle said. “This includes the removal of dust, pollen, mold, mites, pet dander and other allergens, as well as many bacteria and viruses.”
Note that a HEPA-type or HEPA-like filter is not the same as a true HEPA filter.
The US Environmental Protection Agency states that HEPA filters typically remove at least 99.97% of airborne particles measuring 0.3 microns (µm) in size. This is very beneficial because, according to pediatrician and immunologist Dr. Zachary Rubin, who was contacted exclusively by CNET Labs the best air purifiers for cold and flu seasonviruses such as influenza and coronavirus are carried by respiratory aerosols that are usually less than 5 μm in size, and most are less than 1 μm.
Activated carbon and pre-filters
Although HEPA filters remove many particles, chemical fumes, cigarette smoke and odors are not among them. That’s why Coyle recommends buying a HEPA filter with an activated carbon filter, which will capture these pollutants. To remove volatile organic compounds, gases emitted by products such as paint, cleaning products and furniture, the EPA advises the use of an activated carbon filter.
There’s also a front filter, which Coyle describes as another layer of breathability. It removes large particles, such as lint, hair and dust particles, keeping them out of your HEPA filter and extending its life.
“If you’re concerned about allergens, mold or wildfire smoke particles, having a HEPA filter is essential,” says Darrow. “If you’re more concerned about gases (including volatile organic compounds) or odors, an activated carbon filter should work better for that purpose.”
There are air purifiers without filters known as ionizers that work by charging airborne particles, causing them to fall into the air or stick to other surfaces. However, Darrow says these machines can produce ozone, an air pollutant that is well established as a respiratory irritant. This is why HEPA and activated carbon filters are safer.
Before purchasing an air purifier filter, make sure it is the one recommended by the manufacturer, as you will want the right product for your specific model and room size.
If you’re not sure when it was the last time you changed your air purifier filter, it’s probably time.
How often to change the air cleaner filter
Since there is no universally accepted recommendation for when to change your air purifier filter, you should refer to the manufacturer’s guide for your specific device. However, Darrow says it depends on how dirty your air is and how often you use your air purifier.
“For example, if the manufacturer’s recommended frequency of changing the HEPA filter is every 6 months, it may need to be changed more often if it is used during wildfire events or in homes with additional allergens such as mold or a pet,” says Darrow.
In general, it is recommended to change your air purifier filter every three to six months, depending on the filter type, usage and air quality. Coyle offers the following guide:
- Main HEPA filters: Every 6 to 12 months
- Carbon filters: Every 3 to 6 months, or when the odor returns
- Pre-filters: Every 1 to 3 months
But again, factors like use, smoke, high pollution, animal allergies or pets may require you to change your air purifier filter more often. That’s why you’ll want to look for signs — such as reduced air flow, increased allergies, more dust in your home or a strong odor — that your filter may need to be replaced.
If you have pets, you may need to change your air purifier filter more often.
Can you wash the air cleaner filter instead?
Most HEPA and carbon filters are disposable, and if you wash them, they can become damaged and ineffective — especially at trapping airborne particles like bacteria and allergens. If they are not completely dry before being reinstalled, the filter may become a breeding ground for mold.
“It’s important to always check your manufacturer’s manual to see if your particular filter is washable, as cleaning non-washable types can damage the unit’s performance and air quality,” Coyle emphasizes.
An important point
Before you turn on your air purifier, consult the manufacturer’s instructions to ensure that your filter is changed correctly and on time. Also note that if you have pets, live in a heavily polluted area or experience wildfires, you will likely need to change the filter more often. Finally, keep an eye out for reduced performance of your air purifier, which could indicate that the filter needs to be replaced.
Your job as an air purifier is to clean the air you breathe in the name of your health. Not changing your filter can have the opposite effect. So, even though a new air purifier filter every few months may be an expense you don’t want to spend, clean air and clean health money are very important.