Just go to any home improvement store and the choice of home air filters can be dizzying. What’s the best one? Does the price reflect the quality? These are just some of the questions that make purchasing air filters for your home mind-boggling. Let Service Experts Heating & Air Conditioning try to help you de-mystify the air filter dilemma.
Here’s a tried and true way to determine how efficient your current filter is (NOTE: To avoid a big mess, we highly recommend conducting this test outside or over a protected surface): Position the filter horizontally, then with common table salt, pour the salt through the filter then see the amount comes out the other side. If some or all the salt falls through the filter, then you can assume that the filter will let dust that same size flow through. You should probably upgrade your filter to an air filter that’s more efficient.
There are 3 primary considerations when choosing a household air filter; Size, Material and MERV rating.
1) Filter Size
Size is the easiest factor to ascertain. Simply look at the label of your existing filter to see the proper measurements, or just measure it yourself. The majority of home air filters are 1” thick, but there are a variety of standard width and height dimensions, and some systems have thicker filters.
2) Material & MERV Rating
The efficiencies of filters are rated on a scale of 16, known as MERV ratings. MERV stands for Minimum Efficiency Reporting Value. This number tells the user, under the least efficient conditions, how well the filter is designed to hold contaminants.
To explain MERV ratings more impactfully, these are some usual MERV ratings and how they relate to efficiencies. This is only a guide, so don’t forget to read the filter manufacturers’ information when buying specific filters.
Rating Average Filtration Efficiency
MERV 1-4 60-80%
Fiberglass, Disposable Panel, Washable metal/synthetic, self-charging (Passive)
MERV 5-8 80-95%
Pleated, Media panel, Cube
MERV 9-12 >95%
MERV 13-16 >98%
Be Careful About High MERV Ratings
While a higher MERV number may provide better filtration efficiency, it is very important to understand that too high a MERV filter may also cost you more to operate your HVAC system. The higher the MERV, the more restricted the air may flow through the system, and the harder the system may need to work. Your aim is to get the right balance between air flow, air filtration level and energy efficiency.
Look at it this way, the most efficient ‘filter’ would probably be a piece of plywood that stops ALL contaminants and all the air from entering your Houston home. That's all-out air filtration, but would also be like living in a box.
A safe bet for most systems would be a MERV 6-8. A higher MERV filter should be used based upon the advice of your Service Experts Heating & Air Conditioning representative to confirm your system has the capability of moving the proper volume of air through higher efficiency filters. You normally do not want to sacrifice energy-efficiency for filter efficiency; you want a balance of the two. However, if your family has allergies or respiratory problems and needs a high MERV air filter, consider a whole-home air filtration solution that will meet your energy and filter efficiency needs.
Filtration has changed considerably over the past ten years. Initially, home air filters were used in the furnace or air handler only to safeguard the comfort equipment itself. The story is different today. Houston area homeowners expect their air filter to save loved ones from a a growing list of harmful pollutants, dust mites, and even prevent the need for dusting. Dare to dream!