Can the wrong air filter damage my furnace or AC system?

Owned by Isabel White (Unlicensed)
Last updated: Oct 31, 2019 by Ben Reed (Unlicensed)
2 min read

Choosing the correct air filter solution for your home can be difficult. When trying to choose a new filter, you'll find that filters have different rating systems (MPR vs MERV vs FPR) and are made from different materials (fiberglass, polyester, cotton). Which one is right for your home? Well, it depends.

For general information about central air systems and filters, see Central Air Systems & Filters

Firstly, an air filter's primary purpose is to protect the equipment in your central air system. Basic filters will trap larger particles from building up on the fan or heating/cooling elements. This central equipment was (hopefully) designed with the size of your home in mind, which means it should provide the adequate ventilation needed for your home if maintained properly. One critical element of this system's performance is the air pressure.

Let's equate air moving through your duct-like water flowing through a river: anything in the path of the flow removes energy from the water. To keep the same speed, you either need to add more energy or reduce the number of obstructions.

Static pressure is produced by the fan pushing / pulling air through the central air; without this pressure, air will not move. The filter, heat exchanger, and (cooling) coils all create a pressure loss or "drop" that decreases the static pressure of the system. The state of the registers in your home can also cause pressure problems - if they are closed or blocked, it may be causing your fan to work harder than necessary.

If the wrong filter is used, or the existing filter is too dirty, the fan will not be able to overcome the additional resistance and can overheat or malfunction. If you have cooling coils in your system, they are designed to have a minimum amount of airflow moving over them. Without adequate airflow, they will condensate and freeze up.

Luckily, when you get HAVEN installed, we send a professional to investigate this for you. Check out our article on What Happens During the Professional Installation?