Just go to any home improvement store and the choice of home air filters can be dizzying. What does my system require? Is the more expensive products worth the investment? These are just a couple of the questions that make the selection mind-boggling. Let Aramendia Plumbing, Heating and Air, A Service Experts Company 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): Set the filter horizontally, then taking common table salt, begin to 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 assume that the filter will let dust particles of similar size pass through. You should probably upgrade your filter to something 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 proper measurements, or just measure it yourself. Most 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 identifies for 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 make sure you 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 ensure better filtration efficiency, it is extremely 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 difficult 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 would just trap ALL contaminants and all the air from coming inside your San Antonio home. That's maximum air filtration, but would also be like living in a box.
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 Aramendia Plumbing, Heating and Air, A Service Experts Company representative to ensure your system has the capability of moving the correct volume of air through higher efficiency filters. You probably do not want to sacrifice energy-efficiency for filter efficiency; you want a balance of the two. However, if your family has allergies or respiratory problems and a high MERV rated filter is required, consider a whole-home air filtration solution that will satisfy 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. The story is different today. San Antonio 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!