To overcome the lack of real estate, Emerson offers 4-inch media air cleaners that are available in four different cabinet sizes. (Courtesy of Emerson.)

Air filters have come a long way over the years. Not that long ago, homeowners had few options when it came to selecting mechanical air filters for their central heating and cooling systems: The only choice was usually an inexpensive fiberglass filter that some contractors have noted was little more than a rock catcher.

Now there are a wide variety of filters available that are better able to capture airborne particles such as dust, pollen, dust mite allergens, some molds, and animal dander. Flat or panel air filters with a MERV of 1 to 4 are still commonly used in residential furnaces and air conditioners, however, homeowners often seek out pleated or extended surface filters with MERV ratings between 7 and 13. As the Environmental Protection Agency notes, these medium-efficiency filters are reasonably efficient at removing small-to-large airborne particles, and the airflow resistance of these filters does not necessarily increase as the MERV increases.

Higher-efficiency filters with a MERV of 14 to 16, sometimes misidentified as HEPA filters, have a higher average resistance to airflow than medium-efficiency filters, which is why some contractors are leery about recommending them. Fortunately, manufacturers offer numerous higher-efficiency filters - usually between 4 and 6 inches deep - that can offset the increase in resistance to airflow due to their increased depth.


Most homes in the United States still utilize 1-inch fiberglass filters, which are only 2 to 5 percent efficient and cannot remove particles smaller than 10 microns, such as household dust and animal dander, noted Ken Perkins, director of contractor support team, Emerson Climate Technologies, St. Louis.

“Virtually all untreated indoor environments have a much lower quality of air than the outside air, but in most cases, people simply aren’t aware that the air in their homes is unhealthy. A MERV 8 rated media air cleaner is up to 55 percent efficient at removing allergens such as plant spores, pollen, animal dander, and dust. Upgrading to a MERV 11 filter brings up to 70 percent efficiency and filtration of particles as small as 1 micron - or 1/100th the diameter of a human hair.”

The good news is that homeowners are gradually becoming more educated about the need for better filtration, said Ron Cox, category manager filtration products, Kimberly-Clark, Roswell, Ga. “If you look at the mix of products that are being sold, I think the recent trend is that people are buying a better class of filter than they used to. People are becoming more concerned about IAQ.”

One reason why homeowners are more interested in better filtration may be due to the fact that their contractors are educating them about improved air quality through the use of upgraded filters. Contractors, in turn, are being educated by the OEMs, most of whom now offer high-efficiency filter products.

“Most of the OEMs now offer 4-inch filters, which are so much more effective than the standard 1-inch filters,” said Cox. “Unfortunately, there’s often not enough real estate in a mechanical room to install a 4-inch filter housing. But if a contractor can make it work, it’s so much better for the customer. The larger depth dramatically reduces the airflow resistance, which means the system doesn’t have to run as hard to keep a home clean.”

To overcome the lack of real estate, Emerson offers 4-inch media air cleaners that are available in four different cabinet sizes, which cover 600- to 2,200-cfm applications. Each cabinet comes with a pleated MERV 8 filter, and premium MERV 11 replacement filters are also available to upgrade these installations. “Emerson media air cleaners have a slim profile, which makes them easy to install in tighter locations,” said Perkins.


With a plethora of upgraded filter products available, homeowners will look to their contractors to help them make sense of their options. “It’s kind of like buying a car,” said Cox. “When you go into a dealership, someone asks you what you are looking for: Are you hauling around kids? Or do you want a little sports car? A lot of times contractors just say, ‘You need a 3-ton unit, here’s the price.’ But if they talked to the homeowners, they’d find out their daughter has asthma, and filtration might be a bigger deal than just the best price on the 3-ton unit.”

Better filtration will not only lead to happier customers, it will help the bottom line. As Perkins noted, “Most contractors know that a clogged filter can cause problems and decrease system efficiency. This is why the contractor should make it easy for the homeowner to get regular filter replacements. Filters can provide a steady revenue source for the contractor, all while providing the homeowner an efficient system and purified air that can assist in maintaining good health for their customer base.”

Replacing 4-inch filters provides a special opportunity for contractors because those are primarily manufactured by the OEMs, so they need to be purchased from the dealer. “Some contractors see this as a low-dollar service, but if the technician is out there anyway, he can bring in the new filter and take care of it before he leaves. It’s easy money.”

Sidebar: Pink Filters Fight Cancer

Koch Filter Corp. ( has teamed up with the Susan G. Komen Foundation ( to help fight breast cancer. The company recently introduced its Pink Multi-Pleat XL8™ filters, which are available in 20 different products sized at 24 by 24 by 2 inches. Features include MERV 8 and MERV-A 8 performance ratings, low resistance to airflow, high dust holding capacity, and a sturdy double-wall frame design. From August 2 to November 30, 2010, Koch Filter Corp. will donate at least $30,000 to the Susan G. Komen for the Cure® in connection with the Pink Filtration Products Crafted with Pride campaign for North America.

Sidebar: New Filter Attracts Spores

A newly introduced air filter promises to attract pollen like a magnet, due to its dual-panel multilayer technology. Paul Honnen, president, PollenTec, Phoenix, noted that the air filters are made from PollenTec material, which has been tested and certified in a hospital setting and can effectively capture up to 100 percent of airborne pollen spores. “The material is made from very specific, tightly spun, high-grade, 100 percent polyester followed by a patented coating process that attracts pollen.”

The filters are constructed utilizing four cross-directional layers. The filter’s first two layers capture all airborne pollens and the majority of other microscopic particles, and the second two layers ensure that remaining particles are trapped. The MERV 8 PollenTec filter captures allergen-size particles as small as 0.3 microns and can be washed and reused.

“The PollenTec filter is a 1-inch filter that is available in any size,” said Honnen. “The unique design of the filter allows for quick and easy cleaning, which in turn provides outstanding airflow and performance.”

The company states that PollenTec filters can last for up to five years. For more information, visit

Publication date:05/31/2010