You’ve probably experienced the feeling of confusion when trying to select the correct home air filter for your needs. What’s the best one? Should you just get the cheapest? These are just a few of the questions that make the selection mind-boggling. Let Donelson Air Service Experts crack the code of home air filters for you, so you can feel comfortable with your purchase.
Here’s a tried and true way to tell how efficient your old filter is (NOTE: To avoid a big mess, we highly recommend conducting this test outside or over a protected surface): Set the filter horizontally, then with common table salt, start pouring the salt through the filter and see the amount comes out the other side. If some or all the salt falls through the filter, then you can imagine that the filter will let dust particles of similar size pass through. You should probably upgrade your filter to higher quality filter that is more efficient.
Home air filter selection depends primarily on three factors: 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. Typically 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
Filter efficiencies are given a number from 1-16 called the MERV rating. MERV stands for Minimum Efficiency Reporting Value. This number identifies for the user, under the least efficient conditions, how well the filter is designed to capture contaminants.
To help explain the scale of this system, these are some common MERV ratings and how they connect to efficiencies. This is only a guide, so be sure to read the filter manufacturers’ information when shopping for 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 offer better filtration efficiency, it is extremely important to understand that too high a MERV filter may also take more to operate your heating and air conditioning 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 goal is to get the right balance between air flow, air filtration level and energy efficiency.
Think about it this way, the most efficient ‘filter’ would probably be a piece of plywood that stops ALL contaminants and all the air from getting into your Nashville home. That's maximum air filtration, but would also be the least comfortable way to go.
Your best bet for most systems would be a MERV 6-8. A higher MERV filter should be used on the advice of your Donelson Air Service Experts service advisor to confirm your system has the capability of moving the suitable quantity of air through higher efficiency filters. You normally do not want to lose energy-efficiency for filter efficiency; you want a balance of the two. However, if your family suffers from allergies or respiratory problems and needs a high MERV air filter, consider a whole-home air filtration solution that will satisfy your energy and filter efficiency needs.
Filtration has changed considerably over the past several years. In the beginning, home air filters were used in the furnace or air handler only to protect the comfort equipment itself. But (in the words of Bob Dylan) the times they are a changing. Nashville area homeowners expect their air filter to save loved ones from a whole host of harmful pollutants, dust mites, and even prevent the need for dusting. Dare to dream!