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? Is the more expensive products worth the investment? These are just a few of the questions that make the selection mind-boggling. Let Service Experts Heating & Air Conditioning 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 figure out how efficient your old filter is (NOTE: To avoid a big mess, we highly recommend conducting this test outside or over a protected surface): Hold the filter horizontally, then using everyday table salt, pour the salt through the filter and see how much 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 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
Purchasing a properly sized air filter for your Raleigh home is important. 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
The efficiencies of filters are rated on a scale of 16, known as MERV ratings. 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 contain contaminants.
To help explain the scale of this system, these are some common MERV ratings and how they correspond to efficiencies. This is only a guide, so be sure to read the filter manufacturers’ information when purchasing 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 very 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.
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 Raleigh home. That's all-out air filtration, but would also be the least comfortable way to go.
A safe bet for most systems would be a MERV 6-8. A higher MERV filter should be used subject to the advice of your Service Experts Heating & Air Conditioning representative to verify your system has the capability of moving the proper volume 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 achieve 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. Raleigh 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!