The Air Filter: Your HVAC System's Greatest Defender

Your HVAC system cycles the air in your home, cooling and heating it as needed. It cools it by blowing the air across a coil that’s filled with refrigerant. The refrigerant pulls the heat out of the air, then your vents let the cool air back into the home.

Your air filter protects that system from any dirt or grit in the air. It acts as a barrier, catching debris that would damage your system and letting air pass through. The higher the quality of the filter, the smaller particles it can catch.

If your air filter gets too dirty or can't catch enough debris, that dirt or dust can blow into your HVAC system. Beyond making it hard to breathe, the dirt can get caught on the coils inside. That makes it harder for the coil to cool the air and the refrigerant stays warm. Then the air conditioner can’t get the home as cool as it should.

Water in the air condenses on that coil as well, so the dirt can mix with the water and drip into the drain pan below. Once it does that, it can block the drain pipe and send water back into the air conditioner. From there it can flood into the home, leading to extensive water damage. That can mean tearing out and rebuilding entire rooms.

Now that you know why a clean air filter is important, here are some tips on replacing it. The first one is to change it on time! Pick a specific day each month you’re going to replace it. It could be when you pay your electricity bill, on the first day of the month, or any day that works for you. Once you have a day set aside, it can be helpful to set a reminder on your phone for the day you picked.

Next, if you don’t know where your home’s air filter is, start by checking near your thermostat. If it’s not there, you can check your furnace next. The air filter is there to protect your HVAC system, so it has to be close to it. Finally, stick to the mid-range when buying a new air filter. The cheap options don't catch enough dirt, and the expensive ones can make your system work too hard.

We’ve been talking about your air filter’s job being to protect your HVAC system. But it makes sense to take advantage of the system that moves the air around your home if you want to breathe better. Even so, it’s still often better to avoid the most expensive filters. The restricted airflow can cause your system to fail sooner than it should.

The best option is to find an air purification system that works in line with the rest of your HVAC system. That can clean the air you breathe and let your air filter do the job of protecting your system.