You’ve probably experienced the feeling of confusion when trying to select the correct home air filter for your needs. What does my system require? Should you just get the cheapest? These are just two of many of the questions that make selecting home air filters so 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 old 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 standard table salt, pour the salt through the filter to 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 particles of similar size pass through. You really should upgrade your filter to something more efficient.
Home air filter selection depends primarily on three factors: Size, material and MERV rating.
1) Filter Size
Unless you have the proper size home air filter, you will never enjoy the full effectiveness your system and filter can provide. Simply look at the label of your existing filter to see the height by width and thickness, or just measure it yourself. Most 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
The efficiencies of filters are rated on a scale of 16, known as MERV ratings. MERV stands for Minimum Efficiency Reporting Value. This number informs the user, under the least efficient conditions, how well the filter is designed to trap contaminants.
To explain MERV ratings more impactfully, these are some usual MERV ratings and how they correspond to efficiencies. This is only a guide, so don’t forget 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 ensure better filtration efficiency, it is extremely important to understand that too high a MERV filter may also cost you 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 goal is 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 stops ALL contaminants and all the air from entering your Girard home. That's definitely the “best” air filtration, but would also be the least comfortable way to go.
The default choice for most systems would be a MERV 6-8. A higher MERV filter should be used on the advice of your Service Experts Heating & Air Conditioning representative to ensure your system has the capability of moving the correct quantity of air through higher efficiency filters. You normally do not want to give up energy-efficiency for filter efficiency; you want a balance of the two. However, if your family deals with 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 considerably over the past ten years. Originally, 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. Girard area homeowners expect their air filter to save kids from a wide variety of harmful pollutants, dust mites, and even prevent the need for dusting. Dare to dream!