A customer in Milford, NH recently called with a question about his home’s air filter. Trying to be a responsible homeowner, he was changing his filter every three months. However each time he went to check it the air filter was still clean, looking as good as new. After about a year of this he knew that there must be something else going on.
How Your Home’s Air Filter Works
To heat or cool a home your system will pull air from a room over coils that will heat or cool the air, then releasing it back into the home through the vents. Dirt and dust that gets sucked in through the air is trapped by the air filter, preventing the dirt from reaching the coils. Clogged, dirty coils cannot efficiently heat or cool the air as it passes over them, making an air filter’s job particularly important. But not all air filters are created equal.
Knowing Your Air Filter’s MERV Rating
The MERV (Minimum Efficiency Reporting Value) rating is a measure of the percentage of particles, based on their size, which the filter will remove from the air that passes through. Inexpensive 1” thick disposable air filters have a low MERV rating, generally between 1 and 4. The particle catching efficiency is lower on these air filters, allowing much of the smaller dust and debris to travel through. Pleated air filters made of fiberglass or natural fiber strands can capture more particles than a flat surface, with a MERV rating of 8 or higher.
With our suggestion, this Milford homeowner made the switch to a pleated air filter. With regular changes every three months he can now see that the new air filter is doing its job, capturing the dirt and dust before it can pass through to the unit’s coils.