As a general rule of thumb, your home’s occupancy determines how often you should change the air filters inside your home. If anyone in your house suffers from asthma or allergies, or if you have young children or pets in the house, it’s important to help keep the air you breathe as clean and healthy as you can. Photo by Mikael Blomkvist/Pexels.
Most modern homes have central air, a forced air system that delivers temperature controlled air through the air ducts and vents inside your house, that is used for both heating and cooling your home. Air filters keep the air clean by trapping particles of pollen, mold and other contaminants, and keep dust out of the ductwork. Maintaining clean air filters is important to help keep the air you breathe at its optimal quality, and helps ensure your HVAC unit is operating efficiently.
So, one of the best things you can do yourself to care for the HVAC system is to clean or change the air filters. A clogged filter will restrict the air flow inside your home, and will not only degrade the quality of the air your family breathes, it will also increase the load on your central air system, making it work harder and thereby shortening its lifespan. Dirty, clogged up air filters will also raise your home’s electricity bill.
Where is the air filter, and how do I change it?
Your air filter is located in the return air grill, a large vented grill that recirculates the air in your house. It’s usually located in a hallway or on the ceiling. Each return air grill in your house should have an air filter, and they should be replaced regularly.
To replace the air filter inside the return air grill, first turn off your HVAC system, then simply remove the grill panel and slide out the dirty air filter and replace it with a new one of the correct size and thickness. When reinstalling the filter be sure to install it in the right direction, there will be an arrow on the sides of the new filter that shows the direction of the air to flow. Install the new filter so the arrow is pointing into the opening. Then, replace the grill and turn the system back on. A lot of dust can also build up inside the vented grill panel, so you should also clean both sides of the return grill with a soft bristle brush before reinstalling it.
You should see a difference between the colors of the old and new air filters – the old one will look gray and dirty, and the new filter will be bright white.
There are two types of air return grills, one type has a simple latch that can be opened very easily, or it might have screws that need to be removed to open it. A simple Philips head screwdriver will do the job, and then you can easily pop out the old filter.
It’s important to replace the dirty filter with the recommended filter type for your system. The filter dimensions are printed on the side of the old filter’s frame, usually there is a ‘nominal’ size in big print along with actual size in smaller print. You can also measure the frame of your old filter with a tape measure to get the actual filter size.
There are also two main types of air filters, fiberglass or pleated air. Fiberglass air filters are more affordable but they are less efficient and should be changed every month. Pleated air filters cost more but are more efficient, and should be changed about every 90 days. Whatever air filter you buy, check the manufacturer’s recommendations for its optimal replacement schedule.
How often should I change the air filter?
If you live alone and in an area where there is good air quality, the filter manufacturer’s recommendations should be sufficient. But other factors will also help you determine how often you should replace your air filters: If you live in an area where there is heavy smog, or if you have pets that release dander into the air regularly, have very young children, or have family members living at home with allergies or asthma, you should consider using pleated filters and change them more often, preferably every 3-6 weeks, depending on your circumstances.
Here are some rough estimates on how often you should change the air filters in your home:
• Single person or vacation home / no pets or allergies: 6-12 months
• Average family / no allergies or respiratory conditions: 90 days
• Family with young children: 60 days
• Average family with one pet* / no allergies: 60 days
• Multiple pets* / people with allergies or respiratory conditions: 20-45 days
Changing your air filters regularly is a very important part in helping to maintain the efficiency of your central air system and the indoor air quality of your home, but it’s not a replacement for having your HVAC system maintained regularly by a licensed HVAC technician. Most HVAC system manufacturers recommend that you have each of the heating and air conditioning portions of your system serviced at two separate times of the year, service the air conditioning system in the spring and the heating system in the fall.
*If you have one or more pets check your air filter every 30 days and replace if dirty. In any case, always follow the manufacturer’s guidelines for your filter’s recommended replacement schedule.