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 some of the questions that make the selection mind-boggling. Let Knochelmann 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 determine how efficient your existing 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 with everyday table salt, begin to pour the salt through the filter and see the quantity that comes out the other side. If some or all the salt falls through the filter, then you know that the filter will let dust that same size flow through. You really should upgrade your filter to higher quality filter that is more efficient.
Home air filter selection depends primarily on three factors: Size, material and MERV rating.
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. The majority of 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 tells 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 common MERV ratings and how they connect to efficiencies. This is only a guide, so don’t forget 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 cost you more to operate your HVAC 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 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 Sharonville home. That's definitely the “best” 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 Knochelmann Service Experts Heating & Air Conditioning technician to confirm your system has the capability of moving the suitable 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 suffers from 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 considerably over the past several 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. Sharonville area homeowners expect their air filter to save children from a whole host of harmful pollutants, dust mites, and even prevent the need for dusting. Dare to dream!