What's in your air and what can
you do about it
Unfortunately, in today’s world, pollution is everywhere. And with the type of cleaning products,
manmade goods, and activities undertaken within homes and buildings, indoor environments can become very uncomfortable. Even
“fresh,” outdoor air has as many as 30 million dust or pollutant particles per cubic foot.
There are, however,
measures you can take to lessen the effects of these particles in your home. Since the home is essentially an enclosed system,
heating, ventilation, air conditioning, and refrigeration (HVACR) contractors are able to tackle pollution head-on by moving
the air through a high-efficiency air cleaner.
What does an air cleaner do?
At its most basic level, an air cleaner filters out the
particles that cause irritation, such as pollen, spores, dust, and other contaminates. In order for any air cleaner to work
correctly, the particles need to pass through it. Hence, if the particles are not in the air stream (for example, they’re
dust on furniture), an air cleaner won’t remove them. However, a good air cleaner will:
- Remove allergy-causing particles that pass through it.
- Perform
well consistently.
- Be economical to maintain.
- Handle
a large volume of air efficiently.
How can an air cleaner help with allergies?
A good air cleaner reduces or removes the irritants that cause allergic symptoms. You may choose a portable air cleaner
for smaller spaces or a whole-house air cleaner that works in conjunction with your forced-air system to provide cleaner air
throughout your home.
What
kinds of residential air cleaners are out there?
There are basically two: furnace-mounted, whole-house units
and portable single-room units. Both types of cleaners have different models with varying methods of cleaning the air and
capacities for doing so. Your dwelling may help determine the right unit for your needs. A room air cleaner may be best in
an apartment, for example, while a whole-house unit might work better with a furnace and air conditioning system. It’s
important to note that both room and system air cleaners come in a variety of models, and that not all models use the same
technology to clean the air.
Each kind of air cleaner has its pros and cons, which may differ depending on your air-cleaning
requirements. Take a look at what your needs are based on your dwelling and allergies and talk to your professional HVACR
contractor about the best kind for you.
What are the most effective air cleaners?
Media Air Cleaners
These units use high-efficiency
pleated filters, or “media,” to remove about 99% of larger particles, including many allergens. With irritants
in the spore and pollen range, they are as effective as HEPA filters but not as effective in filtering out the super-small
particulates such as bacteria, viruses, and respirable dust. Media air cleaners are cost effective compared to HEPA filters
because the filters are usually less expensive and generally need to be replaced only every one or two years.
HEPA Air Cleaners
HEPA (High Efficiency
Particulate Air) cleaners also use high efficiency pleated media to remove particles. To be designated HEPA, an air cleaner
must remove 99.97% of all particles 0.3 microns in size (such as dust and mold spores). Due to high cost, operational complications,
and other problems, HEPA units are usually seen in residential applications as one-room, portable units. When media in these
units need to be replaced, it’s often relatively expensive to do so. Some require charcoal filters that need to be cleaned
frequently. Warranties for HEPA cleaners are normally one to three years.
Electrostatic Air Filters
Electrostatic air filters are not recognized
as true high-efficiency air cleaners. However, they are generally recognized as being more effective than the standard one-inch
throw-away filters. Electrostatic air filters depend on the movement of the air through the filter to give particles a weak
electronic charge. Usually, these models are less than 20% efficient, with some models having efficiencies below 5%. They
need to be cleaned often, sometimes weekly, to maintain air flow. Electrostatic air filters have warranties ranging from one
year to lifetime.
Electronic
Air Cleaners
There are two types of electronic air cleaners. Both electrically charge particles and attract them
to a collection material. The standard electronic air cleaner will collect charged particles on a specially designed “plate.”
Most electronic cleaners can obtain 95% efficiency or higher on various particles when the collection plates and ionizing
wires are clean, but they can lose some efficiency as they collect dirt.
A newer technology in electronic air cleaners is called “electronically enhanced
media” combining elements of both electronic and media air cleaners. Particles are electrically charged and then collected
by the massive air cleaning media of a traditional high-efficiency cleaner. Because the replacement of the media is simple
and there are no plates to clean, efficiency is maintained throughout the media’s life. Electronically enhanced media
air cleaners are 99% effective in the removal of numerous particle categories. Electronic air cleaners generally have warranties
of one to five years.
© Air Conditioning Contractors of America Association, Inc., www.acca.org. Reprinted with permission.
