During your search for the right filter for your home you could spend a lot of time in the filter aisle reading labels and trying to make sense of all the information listed. What you’ll find is various ratings listed to explain efficiency and lists of what each filter will capture. What you won’t see is the amount of airflow restriction a filter will have. Increasing airflow restriction is not good for your heating and cooling system. Hopefully this article can help you identify what is best for you and your home.
MERV (Minimum Efficiency Reporting Values) is the most common rating used to compare the efficiency of a filter. The epa.gov website has more information including a table breaking down what each MERV rating technically stands for, but simply put the higher the MERV value the more the filter will capture. This sounds great right?! All you have to determine is how much or what type of contaminates you want to filter and go. Sure the price will be more for greater filtration, but what you have to also think about is how much more is that more expensive filter making your HVAC system work? No matter what if you swap out the same dimension filter for one of a greater MERV value it will restrict the airflow more.
The thickness of a filter is important, but might not affect filtration like you expect. A thicker filter should restrict more air because it blocks more space in your duct, right? Actually, no. A thicker filter has a large surface area and surface area is incredibly important for filters. I might be easier to think of it this way, take a 1 inch 10 MERV filter and a 4 inch MERV 10 filter. Both essentially will have the same amount of filter material however the 1 inch filter jams that same amount into a smaller area making the it more restrictive. A filter like the Aprilaire 213 is the filter we really like because it is not only 4 inches thick, but the filter fits tight into the track not allowing air to bypass the filter like some others might.
If you have a 1 inch filter track we suggest you don’t go crazy with your filter. A filter around a MERV 8 should provide good filtration, without having a negative impact on your furnace and air conditioner. If you have a 2 inch filter anything between an 8 and 11 MERV would be a good choice. With a 4 inch filter MERV values of 13 and 16 are definitely feasible and will capture most indoor contaminants. If your filter track is only 1 inch wide you obviously can make a wider filter fit, but some feasible duct changes can make a larger filter track a reality providing you will greater filtration options. Another perk not mentioned above is often the thicker filters also have a longer service life, some filters lasting up to a year long.
If you are interested in improving your home’s filtration contact Bryant Air Conditioning, Heating, Electrical & Plumbing. One of our specialist can take a close look at your home’s system and see if a new filter track can be installed and your home air improved.