Recommendations are selected independently by Reviewed editors. Purchases made through the links below generate commissions for us and our publisher partners.
An air purifier is the best way to maintain high indoor air quality. Depending on the filter type, they can remove airborne particles like smoke or pollen or remove problematic chemicals like formaldehyde.
Purifier filters require regular replacement or cleaning to function properly, but filter replacements can be expensive. That’s why when we test air purifiers, we include the cost of a replacement filter in our estimate.
The more efficient the filter, the more expensive it can be. We checked to see if there are ways to cut these costs and keep indoor air clean, odor-free and soothing to allergies.
Autumn is here, let’s get comfortable. We are handing out a Solo Stove fire with a stand. Participate in the draw until November 18, 2022.
We tested filters with controlled amounts of smoke, dust particles, and volatile organic compounds (a type of chemical that includes formaldehyde and paint fumes) and measured how quickly the air cleared.
In all our tests, we used the Winix 5500-2 air purifier. Winix is one of the best air purifiers we’ve tested, with filters for particulate matter and chemical contaminants.
In addition to our usual dirt removal tests, we also measured air pressure changes across the filter. The amount of pressure change indicates the filter’s resistance to airflow. A high resistance indicates that the filter is too clogged to work effectively, while a low resistance indicates that the filter is not doing its job of capturing the smallest particles.
Our data helps us answer important questions such as whether old filters really need to be replaced, whether cheap filters can save costs, and whether old filters can be cleaned instead of replacing them.
For them, we focused on the most expensive type of filter, the HEPA (High Efficiency Particulate Filter) filter.
Most of the air purifiers we’ve tested in Reviewed have HEPA filters, which is an increasingly common feature among the most popular air purifiers. They are tested against known standards, and the best HEPA filters are judged based on their ability to block particles as small as 0.3 microns.
Compared to this tiny size, pollen grains are large, ranging from 15 to 200 microns. HEPA filters easily block larger particles and also remove tiny smoke particles from cooking or wildfires.
The best HEPA filters are expensive to manufacture because they require very fine meshes. Considering how expensive they are, is there anything you can do to lower the cost of HEPA air purification?
In most cases, air purifier filter change intervals are 3 to 12 months. Our first set of tests used real 12 month old HEPA filters from a well used Winix 5500-2 air purifier.
The HEPA filter being used looks dirty. While you may be skeptical about dirt, it’s actually a good thing because it means the air purifier is working properly. But does dirt limit its performance?
A new filter, recommended by the manufacturer, captures particles 5% better than a used filter. Similarly, the resistance of the old filter was almost 50% higher than the resistance of the new filter.
While a 5% drop in performance sounds good, a high resistance indicates a clogged old filter. In large spaces, such as your living room, the air purifier will struggle to get enough air through the old filter to remove air particles. Essentially, this will lower the purifier’s CADR rating, which is a measure of an air purifier’s effectiveness.
HEPA filter traps particles. If you remove these particles, you can restore and reuse the filter. We decided to try.
At first we used a handheld vacuum cleaner. This did not have a noticeable effect on the visible level of dirt, so we switched to a more powerful cordless vacuum cleaner, but again no progress.
Vacuuming reduces filtration efficiency by 5%. After cleaning, the filter resistance did not change.
Based on this data, we concluded that you should not vacuum the HEPA filter, as you can damage it in the process. As soon as it becomes clogged and dirty, it must be replaced.
If the vacuum isn’t working, can you do something more drastic to clean that filter? We tried replacing the HEPA air purifier filter.
HEPA filters have a thin, paper-like structure based on many fine fibres. The sad end result was a soft pile, apparently still full of stuck dirt.
Cleaning can render standard HEPA filters unusable, so do not clean filters unless recommended by the manufacturer!
Some types of filters are washable. For example, both the activated carbon filter and the pre-filter in our Winix can be rinsed with water to remove dust and chemicals. We don’t know of a real HEPA filter that can be cleaned in this way.
All air purifier manufacturers recommend their own brand of replacement filters. For almost all filters, other suppliers can provide inexpensive alternatives. Can you get similar performance from an inexpensive filter on a budget?
Compared to the manufacturer’s recommended option, the inexpensive filter is approximately 10% less effective at retaining particles and has 22% lower resistance than the recommended filter.
This low resistance indicates that the cheaper filter design is thinner than the recommended brand. At least for Winix, lower costs mean lower filtering performance.
If you want to get the best performance out of your air purifier, it’s hard to avoid the schedules and costs of filter replacements.
Luckily, there are a few things you can do to keep your air purifier running at its best.
Dirty filters perform worse than clean filters. Unfortunately, if a standard HEPA filter becomes dirty, it cannot be cleaned, so there is no need to replace the filter.
If the manufacturer recommends a 12-month replacement plan based on assumptions about how often you use the purifier and how polluted the air is. The filter will not self-destruct after 12 months!
So rely on your own judgment, if the filter looks clogged with dirt, replace it, if it still looks clean, wait a while and save some money.
The cheaper version of the HEPA filter we tested performed worse than the more expensive products recommended by the manufacturer.
This isn’t to say that inexpensive HEPA filters should be avoided, but your decision to go with the cheaper option depends on the type of particle pollution you’re most concerned about.
Pollen grains are relatively large, so if you have seasonal allergies, a cheaper filter might work for you.
Smaller particles such as pet dander, smoke and aerosols containing viruses require more efficient filters. If you’re allergic to pets, worried about wildfires, cigarette smoke, or airborne viruses, a high-end HEPA filter is well worth the extra cost.
Reviewed’s product experts can cater to all your shopping needs. Follow Reviewed on Facebook, Twitter, Instagram, TikTok or Flipboard for the latest deals, product reviews and more.
© 2022 Reviewed, a division of Gannett Satellite Information Network LLC. All rights reserved. This site is protected by reCAPTCHA. The Google Privacy Policy and Terms of Service apply. Recommendations are selected independently by Reviewed editors. Purchases made through the links below generate commissions for us and our publisher partners.
Post time: Nov-05-2022