Electric Air Cleaner

How can electricity clear the air of contaminants? There are two general methods by which an electric air cleaner can use electricity to do this. The simplest way is by providing power for a fan that drives air through a filter. In this arrangement, the actual air purification is done by a filter, and the electricity is simply providing power to the fan. Electricity can also be used to power a number of other technologies that can purify the air. Alternatively, the specific properties of electric charges can be used to cause contaminants to fall out of the air. The term “electric air cleaner” can be used to refer to any of these methods.¹

Many methods of air purification can use electricity in their operations. In theory, an air filtration system that uses a fan to push air through a filter could use any source of power for the fan, but for residential air purifiers the source of power is always electricity.

Using UV Light

Ultraviolet germicidal irradiation (UVGI) air cleaners use UV light to damage or kill airborne pathogens, rendering them harmless. A high-intensity UV lamp irradiates air that passes through the electric air cleaner, which keeps the potentially harmful UV light away from any occupants of the space. One drawback of UVGI air cleaners is that they do not remove particulate matter or volatile organic compounds from the air.

Photocatalytic oxidation (PCO) combines UV light and a catalyst like titanium dioxide to oxidize gaseous contaminants into harmless components. Electricity powers the fan and the UV light. PCO air purifiers are only designed to reduce the amount of volatile organic compounds in the air. PCO electric air cleaners are not effective at removing airborne particulate matter, such as pollen and pet dander.

Each method has a different level of efficacy for different air pollutants. UVGI electric air cleaners make for effective air purifiers for bacteria control, but are ineffective at reducing the amount of airborne particulate matter. PCO, or photocatalytic oxidation, can reduce the amount of volatile organic compounds in the air to be an effective air purifier for chemicals, but doesn’t remove airborne particulate. A HEPA or ULPA fiber filter, when combined with an activated carbon filter, can be an effective air purifier for dust, bacteria, mold, and chemicals.

Using Electric Charges

Some electric air cleaner designs use electric charges to remove contaminants from the air. Electrostatic precipitators and ionizers add a charge to particles in the air so that they will be attracted to surfaces with the opposite charge. Electrostatic precipitators include an oppositely-charged metal surface within the air purifier itself, sometimes integrated into a filter medium for increased efficacy. Ionizers release the charged particles into the surrounding area with the assumption that they will quickly become attracted to nearby surfaces. Both are effective at removing particulates from the air.

Power Usage

An electric air cleaner uses enough energy that this usage should be taken into account when purchasing an air purifier for home use. In fact, an air purifier can use as much energy as a refrigerator.² When choosing an air purifier, make sure to get the correct size. Too small, and the purifier won’t be able to clear enough air to make a difference. Too large, and you will end up paying higher energy bills for a device that could be used in a larger space.