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 some 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: Do this outdoors or with something below the filter so you don’t end up with a mess): Position the filter horizontally, then using common table salt, pour 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 know that the filter will let dust pass through as well. You should probably 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 dimensions, or just measure it yourself. Typically home air filters are 1” thick, but there are a numerous 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 tells the user, under the least efficient conditions, how well the filter is designed to contain contaminants.
As a basic example, these are some common MERV ratings and how they connect to efficiencies. This is only a guide, so make sure you 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 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 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 prevents ALL contaminants and all the air from getting into your Livermore home. That's all-out 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 based upon the advice of your Service Experts Heating & Air Conditioning technician to verify your system has the capability of moving the suitable amount 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 deals with allergies or respiratory problems and the situation necessitates a high MERV rated air filter, consider a whole-home air filtration solution that will meet your energy and filter efficiency needs.
Filtration has changed significantly over the past several years. In the beginning, 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. Livermore 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!