AIR CLEANERS

Should I buy an air cleaner?

The answer is �it depends.� Mostly it depends on the area you are in � does it have high amounts of dust, pollen or other particulates in the air? Do you generate a lot of indoor air pollutants from hobbies, new furniture or other sources and/or do you have especially sensitive individuals in your home. Do remember, air is something we cannot do without, it only makes sense to breath clean air � especially for those of us who live in major metropolitan areas!

What about my air filter?

Central forced air systems in homes usually have a rectangular, one-inch thick fiberglass filter that slides underneath the furnace fan, or into a wall or ceiling register where the air returns to the furnace. These filters remove less than 10% of the particles, ten microns or less in size, that reach the filter. They are disposable and typically cost $4 to $6.

Often, merely upgrading this filter to a medium- or high-efficiency filter will help improve the air quality in your home. Medium-efficiency filters are typically pleated, woven material and are rated at 20-50% efficiency for removing particles of 0.3 to 10 microns (a micron is one millionth of a meter). They cost about $8 to $25, and both disposable and washable models are available. Some medium-efficiency filters use static electricity created by air flow, but their effectiveness may decline as the static charge decreases over time.

High-efficiency filters (sometimes mistakenly called �HEPA� filters) are rated at 60-95% efficiency. They cost about $30-$170, depending on whether they are disposable or washable. Do not confuse these with true HEPA (high efficiency particle arrestance) filters, which are 99.97% efficient, require very powerful fans, and are usually sold separately as an addition to the forced air systems of homes.

How do I mantain my filter?

Proper installation, operation, and maintenance are critical for effective operation of air filters:

	To maintain filter efficiency, make sure that the filter fits tightly in its seat to prevent air from bypassing the filter.
	Check the filter for dust and debris buildup at least every month during heavy use. Replace or clean the filter as necessary, based on usage or your service technician�s recommendations.
	To accurately show when a high-efficiency filter needs changing, you may want to have an inexpensive  pressure gauge installed; the filter maximum pressure drops for each filter model. Some filters or air cleaners come with a sensor that indicates when filter replacement is necessary.
	To prolong the useful life of a high-efficiency filter, you may want to install a low-efficiency pre-filter upstream in order to prevent rapid overloading of the filter.

Source material from California Air Resources Board, price estimates in document converted to Canadian dollars.

Which is right for me?

Even if you have taken actions to remove pollutant sources in and near your home, provided ventilation, and upgraded your central air filters, you may still have a problem with excess dust or odors. If so, you may benefit from an air cleaner. The information below will help you determine what type and size of air cleaner you need, and how to use it properly.
Air cleaners are available in different configurations we are focused on Central air cleaners, here. They can cost on the order of $1300 to $4000, depending on the size and efficiency of the device.

Most air cleaners remove particles, a few remove gases (and odors), and some do both. If you feel you have pollutants other than particles and dust that require removal contact an experienced indoor air quality consultant. If you spend much time outdoors when levels of dust or allergens are high, you should consider wearing a properly fitting dust mask designed for particles; contact the mask manufacturer for fitting instructions.

PARTICLE REMOVAL. Some types of air cleaners can effectively remove particles such as dust and allergens from the air: mechanical or physical-barrier air cleaners, and electronic air cleaners.

Mechanical air cleaners. These devices draw air through a fibrous or metal filter with different sized pores that trap particles. These devices should use high- or medium-efficiency filters (see above). The filter will need to be sealed tightly in its seat, and replaced regularly, although some units have filters that can be cleaned and re-used. These filters may be flat, round, or pleated.

Electronic air cleaners. There are three types of electronic air cleaners: electrostatic precipitators (ESPs), ionizers, and mechanical-electronic hybrids. ESPs use a small electrical charge to collect particles from air pulled through the device. Ionizers, or negative ion generators, cause particles to stick to materials near the ionizer (such as the carpet and walls). Also available are hybrid air cleaners that have both mechanical and electronic devices for pollutant removal.

Both ESPs and ionizers produce ozone as a by-product. To minimize ozone emissions, these devices need to be cleaned and maintained regularly and operated only according to the manufacturer�s instructions. High levels of ozone may create unhealthful air quality and a pungent odor.

GAS REMOVAL. Residential air cleaning devices that remove gases and odors are relatively costly, both to purchase and maintain. Gaseous pollutants are typically trapped or destroyed as the air is drawn through materials such as activated charcoal or alumina coated with potassium permanganate. However, the filter material can become quickly overloaded and may need to be replaced often.

These filters (usually charcoal) are offered as an option with some residential particle air cleaners. If you have very sensitive individuals in your home or odors that are difficult to remove, especially in just one area of the home, you may want to consider this option.

Source material from California Air Resources Board, price estimates in document converted to Canadian dollars.