Air Purifiers Buying Guide
Americans spend more than $350 million each year on room and whole-house air purifiers-also known as air cleaners-mostly in
the hope that they'll ease the symptoms of asthma and allergies. But there's little medical evidence that any air cleaner
alone can do that effectively.
- Getting started
- Types
- Features
- Brands
Types
There are two basic types of air purifiers. Room models, which are most heavily promoted, can be moved from room to room. Whole-house models are built into the ductwork of a forced-air heating or cooling system and, as their name implies, filter the air in the entire house.
Room air purifiers
These are the only option for a home that doesn’t have forced-air heating or cooling. Room air purifiers cost much less than whole-house models. Most room air purifiers weigh from 10 to 20 pounds, have a handle, and stand on the floor or on a table, while heavier models might have wheels. Some room models use a high-efficiency particulate air (HEPA) filter, which can capture ultrafine particles. Most HEPA filters need to be replaced annually, an expense that might approach the cost of the air cleaner (A few air cleaners are now available with cleanable HEPA filters.) Room models that use either electronic precipitator or ionizer technology produce some ozone, a lung irritant. And they might soil the walls by depositing some pollutant particles on them.
Dedicated ozone generators
These are a subcategory of room models. Unlike electrostatic precipitators, which tend to emit small amounts of ozone as a byproduct, these niche products produce large amounts of ozone by design. According to manufacturers, that is to reduce allergens such as dust, smoke, pollen, germs, and mold. Ozone is a serious health concern. We judged the two ozone generators we tested Not Acceptable as air purifiers.
Whole-house air cleaners
This type is a reasonable choice if your home has forced-air heating. But built-ins can be expensive to buy, and they must be installed professionally in the ductwork of your heating system and most need to be wired into your home’s electrical system. Most of the built-in air cleaners we tested did an excellent job of removing dust and smoke particles from the air. Some use a high-efficiency filter. Those that use an electronic precipitator produce some ozone, and they might soil the walls by depositing pollutant particles on them.
Whole-house air filters
These inexpensive alternatives to a whole-house built-in unit replace the existing furnace filter in your forced-air heating or cooling system. You simply slip out the old filter and slide in the replacement. But those we tested worked much less effectively than the built-in whole-house models, especially in clearing smoke. Some are conventional fiberglass filters; others are charged and pleated models. The latter are not electrically powered, even when they have names like Electroclean, so they don’t produce ozone. The filter must be replaced every one to three months.
Read more about electrostatic air purifiers.
