A filterless purifier works by giving the incoming air an electrostatic charge. This charge also charges particles in the air. The air is then moved past an oppositely charged collection grid. The impurities in the air are attracted to the grid, like a magnet. The grid must be removed periodically and cleaned of the impurities. This is easily done with a damp cloth. Once the grid is completely dry, replace it and turn the machine back on. These systems can be installed on a forced air heating system to treat the whole house, or can be purchased in portable units.

This process creates ozone in the air. If you have been outside after a thunderstorm, you have smelled natural ozone in the air. These systems clean the air the way nature cleans the outdoor air.

However, some feel the ozone that is created can be a health hazard, particularly if it is highly concentrated. If you are using a portable air cleaner, be sure it isn't too big for the room in which it is being used. The square footage is listed on the box and in the owner's manual. Another option is to run it for a while and then turn it off before using the room.

There are no filters to change with this type of purification system. Replacement filters can be expensive and not having one saves money in the long run.

They use a collection grid to collect impurities, rather than a filter. The impurities stick to the grid and are wiped off with a damp cloth. Once the grid is clean and dry, place it back in the machine and turn it on.

The filtration process leaves a fresh smsell in the air that many people find vitalizing. You won't need to use air fresheners with these systems.

They are nearly silent when running. This is great for night time use. Some air purification systems can be very noisy and may need to be turned off at night.

Drawbacks of Filterless Air Purifiers

The safety of these filtration systems was called into question a few years ago when Consumer Reports gave the Ionic Breeze a bad review and called it hazardous. The reason is the ozone that is a by product of the purification process. Ozone is a pollutant and can be irritating to people with asthma or other respiratory disorders. Sharper Image responded by adding a component called “Ozone Guard” which is said to convert most of the ozone into oxygen. On a later review, Consumer Reports still gave the machine low marks, but said the ozone output is now in acceptable levels.

These systems are more expensive than other air purifiers. However, when you add in the cost of replacement filters, this price difference diminishes over time.

The collection grid must be cleaned frequently. If it isn't clean, it won't work. The frequency depends on the number of impurities in the air. Homes with pets, smokers, a lot of dust, etc, will need more frequent cleaning.