How to de-mystify the Air Filter Dilemma Published on February 06, 2015 Trying to select the right air filter for your Kitchener home can be a daunting experience. What’s the best one? Is the more expensive products worth the investment? These are just some of the questions that make purchasing air filters for your home mind-boggling. Let Hammond Plumbing & Heating try to help you de-mystify the air filter dilemma. Here’s a tried and true way to tell how efficient your current filter is (NOTE: Do this outdoors or with something below the filter so you don’t end up with a mess): Hold the filter horizontally, then taking common table salt, 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 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 height by width and thickness, or just measure it yourself. Typically home air filters are 1” thick, but there are a variety 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 identifies for the user, under the least efficient conditions, how well the filter is designed to hold contaminants. To help explain the scale of this system, these are some usual MERV ratings and how they correspond to efficiencies. This is only a guide, so be sure to read the filter manufacturers’ information when shopping for 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% Extended pleated MERV 13-16 >98% Electronic Be Careful About High MERV Ratings While a higher MERV number may provide better filtration efficiency, it is extremely important to understand that too high a MERV filter may also require more to operate your furnace and AC system. The higher the MERV, the less 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 equivalent to a piece of plywood that stops ALL contaminants and all the air from getting into your Kitchener home. That's all-out air filtration, but would also be the least comfortable way to go. Your best bet for most systems would be a MERV 6-8. A higher MERV filter should be used based upon the advice of your Hammond Plumbing & Heating service advisor to verify your system has the capability of moving the correct 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 has allergies or respiratory problems and the situation necessitates a high MERV rated air filter, consider a whole-home air filtration solution that will satisfy your energy and filter efficiency needs. Filtration has changed significantly over the past several years. Initially, home air filters were used in the furnace or air handler only to protect the comfort equipment itself. The story is different today. Kitchener 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!