One of the simplest yet most important aspects of maintaining the heating and cooling equipment in your south Texas home is tending to the air filter. This includes choosing the filter that’s rated for your specific needs, checking it regularly and cleaning or replacing it when it’s dirty.
The MERV Scale
An important factor to consider when you’re choosing an air filter is its minimum efficiency reporting value. MERV is an industry standard used to rate an air filter’s ability to trap airborne contaminates. The rating scale runs from 1 to 20, with higher numbers denoting higher efficiency. Filters for use on most home heating and cooling systems generally fall in the 1 to 16 range. Filters rated 17 to 20, which are high-efficiency particulate air filters, can be found in many air cleaners but are not suitable for most standard furnaces and air conditioners, as they are too dense.
Good, Better, Best
Some HVAC units come equipped with an air filter at the lower end of the the MERV scale. These can keep relatively large particulates–such as carpet fibers, pollen, dust mites and sanding dust–out of your system, but they don’t do much for the air quality in your home. This is because many contaminates are much smaller. Air filters rated MERV 5 to 8 are better at trapping particulates such as mold spores, hair spray and household cleaning products.
For superior residential air filtration, most experts recommend MERV filters in the 9 to 12 range. These filters are able to remove contaminates including Legionella, lead and humidifier dust, welding fumes and automobile emissions. But there’s a rub. Many 1-inch filters in this range–the kind available at most home-improvement stores–are too dense for many HVAC systems. They can block airflow and make your furnace work too hard. Talk with your HVAC-system contractor and follow his recommendations. He may advise getting a 4- or 5-inch filter, which can be just as effective but won’t restrict airflow in your system.
Contact Mathews CCAC Air Conditioning & Heating, Corpus Christi’s premier indoor air-quality expert, for more guidance on selecting and maintaining your home’s air filters. We’re here to help.
Our goal is to help educate our customers in Corpus Christi, Texas about energy and home comfort issues (specific to HVAC systems). For more information about air filters and other HVAC topics, download our free Home Comfort Resource guide.
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