Just go to any home improvement store and the choice of home air filters can be dizzying. What does my system require? Is the more expensive products worth the investment? These are just two of many of the questions that make selecting home air filters so mind-boggling. Let Eveready Service Experts try to help you de-mystify the air filter dilemma.
Here’s a tried and true way to determine how efficient your existing filter is (NOTE: Do this outdoors or with something below the filter so you don’t end up with a mess): Hold the filter horizontally, then using 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 imagine that the filter will let dust that same size flow through. You might want to upgrade your filter to an air filter that’s more efficient.
Size, MERV rating and material – these are the three primary factors used to pick the proper air filter for your home.
1) Filter Size
Size is the easiest factor to ascertain. Simply look at the label of your existing filter to see the dimensions, or just measure it yourself. Typically home air filters are 1” thick, but there are a number 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 hold contaminants.
As a basic example, these are some usual MERV ratings and how they relate to efficiencies. This is only a guide, so be sure 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 offer better filtration efficiency, it is extremely important to understand that too high a MERV filter may also require more to operate your furnace and AC 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 objective should be to get the right balance between air flow, air filtration level and energy efficiency.
Consider it this way, the most efficient ‘filter’ would actually be a piece of plywood that would just trap ALL contaminants and all the air from getting into your Richmond 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 Eveready Service Experts 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 a high MERV rated filter is required, consider a whole-home air filtration solution that will meet your energy and filter efficiency needs.
Filtration has changed greatly over the past ten years. Early on, home air filters were used in the furnace or air handler only to shelter the comfort equipment itself. But (in the words of Bob Dylan) the times they are a changing. Richmond area homeowners expect their air filter to save kids from a a growing list of harmful pollutants, dust mites, and even prevent the need for dusting. Dare to dream!