When choosing from the array of HVAC air filters on the market the one that’s right for your home, you should ask what it is you want that filter to do. Is cleaner air in your home a priority, or do you just want a basic, inexpensive filter to keep debris out of your HVAC system so it doesn’t malfunction?
HVAC air filters run the gamut, from the kind of cheap fiberglass filter that will keep larger particles out of your system, to the expensive and high-functioning HEPA (high efficiency particulate air) filters used in industrial or clinical settings. It’s important to know the difference, and what is available in between the two extremes.
Any discussion of HVAC air filters should begin with MERV, or the minimum efficiency reporting value. The MERV scale was developed by the HVAC industry to provide a rating system for filter efficiency. Some big box retailers have developed their own rating systems for their own filter brands, but MERV is the benchmark.
MERV runs from 1 to 20, and the higher on the scale the filter is listed, the smaller the particles it can trap. Filters are tested for their ability to trap dust, dust mites, pollen, cigarette smoke, carpet and textile fibers, bacteria, pet dander, mold spores and other particles.
Cheap filters, usually rated from 1 to 4, do an adequate job of keeping debris out of your HVAC system. Most experts recommend using a filter rated 7 to 12 for the typical residence. Filters rated higher are generally for commercial or hospital settings, and can actually slow your airflow if the system is not designed to accommodate them.
The better quality filters recommended for most homes are made of polyester or cotton fiber pleated material. They should be able to trap such particles as those listed above, as well as cockroach debris, sanding dust, fabric protector, flour and spray paint dust.
If someone in your household has severe allergies or respiratory problems and you think it might be worthwhile to explore what an even higher quality air filter can do, be aware that filters rated MERV 13-16 can trap bacteria, smoke and insecticide dust. But you will need to do significant modifications on your HVAC system so that it can accommodate this type of filter.
Air Filter Options
Some of the other types of filters on the market that might provide better indoor air quality:
Electrostatic: Made of self-charging cotton or paper, these attract particles to the filter material by means of static electricity. They come in disposable and permanent types, and the latter, which are expensive, can be washed and reused.
Electronic: These filters use a method similar to that of the electrostatic filter, but rather than trapping particles by means of surface static electricity, a transformer delivers a high-voltage charge that traps particles as the air passes through the filter. A separate source powers the transformer. The particles are gathered on a collection plate or other grounded surface. The collection plates must be cleaned periodically to maintain the effectiveness of the filters.
High-efficiency pleated: This type of filter is generally used in hospital settings and is rated MERV 14-16. They are made of 4-5-inch pleated cotton and contained by a rigid metal frame and grid. They are very expensive and need a special housing for installation.
Indoor Air Quality
Bear in mind that your HVAC system isn’t in use all year long, so if better indoor air quality is important to you, you can’t rely on the system alone to provide it for your household. What’s more, some of the smaller particles from the pollutants in your home are hovering in the air, and are not necessarily going to be drawn into your HVAC system so that they can be trapped. You may want to consider other types of air cleaning or purifying technology, depending on the problem you’re dealing with. Your HVAC consultant can advise you.
Ultimately, the best means for controlling dust and other irritants in your home is to keep a clean house. Vacuum frequently with a HEPA filter and use damp mops and electrostatically charged cloths to clean surfaces. Seal all cracks and gaps around windows and doors with weatherstripping and caulk. Take shoes off when entering the home.
Above all, change your HVAC air filters frequently. For more information on HVAC air filters, contact us at Conditioned Air TX. We’ve been serving Bellaire, Sugarland and River Oaks since 1957.