Air purifiers hopefully improve their indoor air quality, but in some cases, it might not be as effective as you thought. What should you look for in an air purifier—and should you buy one at all?
Air Purifiers: The Basics
- Air filters use a paper, fiber, or mesh filter to capture particles, such as dust and dander. The filters need to be cleaned or replaced regularly. High-efficiency particulate air (HEPA) filters are included in this category.
- Electrostatic air filters use an electrically charged panel or screen to capture particles. A similar type, called an ionizer or ion-generating air cleaner, attaches electrically charged ions to dust and other pollutants, making the particles heavier and causing them to drop from the air.
- Activated carbon filters remove gases and odors with activated carbon or a similar product. They're not typically used in home air purifiers, they may not remove certain gases (such as carbon monoxide), and they often have a short lifespan.
- UV light is supposed to destroy biological impurities, such as mold and bacteria, with ultraviolet light, but there's no guarantee it will make your home completely germ-free. The light won't remove particles, such as dust and dander, so it should be used in conjunction with a filtering device.
- Ozone generators use either UV light or an electrical discharge to create ozone, a gas that can cause or aggravate serious health problems, including lung damage and asthma. Although ozone is effective at killing mold, mildew, and other air contaminants, these purifiers should only be used by professionals in special cases where other options won't do the job.
Most home air purifiers have a fan that sucks air through a filter (or combination of filtering options) to clean it. Look for an air purifier with a clean-air delivery rate (the measurement of its cleaning speed) of at least 300. Any air purifier with a rate below 100 is really just an overpriced fan.
The Benefits and Drawbacks
Consumer Reports testing found some purifiers are decent at cleansing the air of particles, such as dust, pollen, and smoke. But no unit can remove all the gaseous pollutants from indoor air, including volatile organic compounds (VOCs). A quality unit might help a person with allergies or other respiratory issues, though there isn't sufficient medical evidence to link air purifiers with better health.
In addition to what the air purifier is intended to filter, it's imperative to pay attention to room size guidelines. The more affordable units typically can only clean one room at a time—sometimes just a small bedroom. The bright side is these units can easily be moved from room to room to purify different areas of your home. But if you want to filter the air in a more open area, you'll likely have to look at the larger, more expensive units or a household-wide system.
Filters have to be cleaned or replaced regularly, or the unit's purifying power will be greatly diminished. If your model doesn't come with a washable filter, factor in the added expense of replacements over the life of your unit—some of which can cost $100 or more per filter.
Moreover, some units might only be effective at the highest fan speed, which is also the noisiest setting that uses the most energy. Consumer Reports recommends getting a larger unit and running it at a lower speed to minimize noise without sacrificing efficiency. Finding one that's Energy-Star certified can help with the cost.
More Ways to Clean Your Air
An air purifier might be a useful tool to clean some aspects of your indoor air, but you can't rely on it alone. According to the EPA, the most effective way to improve indoor air quality is to minimize pollutants and ventilate your home with outdoor air.
To maintain clean air inside your home:
- Use a vacuum with a HEPA filter to clean your home frequently and thoroughly.
- Maintain your HVAC system and change or clean filters regularly.
- Keep pets well-groomed to minimize shedding and dander.
- Don't smoke indoors, and limit the use of wood-burning fireplaces and candles.
- Use exhaust fans in the kitchen and bathroom.
- Take off your shoes at the door to avoid tracking in pollen and other pollutants.
- Avoid household items with VOCs—certain cleaners, paints, furniture, etc.—as much as possible.
Before you spend money on an air purifier, you first might want to try some of these more economical ways to improve indoor air quality.