Just go to any home improvement store and the choice of home air filters can be dizzying. What does my system require? Should you just get the cheapest? These are just a couple of the questions that make selecting home air filters so mind-boggling. Let Neal Harris Service Experts Heating, Air Conditioning & Plumbing attempt to resolve your home air filter questions and allow you to continue enjoying the comfort of your home without concern.
Here’s a tried and true way to figure out how efficient your existing filter is (NOTE: Spare yourself a huge mess by conducting this experiment outside or with something below the filter to help keep things clear): Position the filter horizontally, then taking everyday 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 particles of similar size pass through. You might want to upgrade your filter to higher quality filter that is 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 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
Filter efficiencies are given a number from 1-16 called the MERV rating. 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 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 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 provide better filtration efficiency, it is critical 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 difficult 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 actually be a piece of plywood that prevents ALL contaminants and all the air from entering your Kansas City home. That's maximum air filtration, but would also be a terrible way to live.
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 Neal Harris Service Experts Heating, Air Conditioning & Plumbing technician to ensure your system has the capability of moving the proper amount of air through higher efficiency filters. You probably 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 achieve your energy and filter efficiency needs.
Filtration has changed significantly over the past ten years. In the beginning, home air filters were used in the furnace or air handler only to shelter the comfort equipment itself. The story is different today. Kansas City 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!