It might be easy to forget about changing your air conditioning system’s air filter, but it’s important to understand how this simple fix can help save your system.  In order to keep air conditioning and heating systems running smoothly, it’s best to change the system’s air filter regularly – at least at the beginning of every season, or every three months.  Although most thermostats offer a filter display alert, a tip is to set a reminder “task” within your smartphone or computer calendar.  This way you are alerted every 90 days to make a decision on buying a new replacement filter. I would also recommend placing the filter size (16×25?) within that task’s notice, so you are reminded what size to buy.

Whether you have a true pleated (collapsible) filter like I do, or a self-contained cardboard framed filter, changing it will help extend the life of the heating and air conditioning system, increase efficiency, and improve comfort in your home.

Indoor air pollution is among the top five environmental health risks, according to the United States Environmental Protection Agency. Air filters help mitigate this risk by decreasing or eliminating indoor air pollutants, such as dust, smoke, pollen, animal dander, and even particles and gas generated from cooking stoves, pesticides and cleaning products.

As we approach a seasonal change, there are a few things homeowners should consider when switching out air filters:

• Dirty or Clean? This is probably a question you more often ask about your dishwasher, but even if the air filter looks clean upon initial inspection, dirt and dust particles might be lodged inside. If you believe it does not need to be changed, take a moment to compare the dirty filter with a clean, new filter before making a decision.  Leaving a filter in too long can cause harm to the system and decrease efficiency.
• 20 Minutes or Less: Changing a home air filter is simple and quick—it usually takes less than 20 minutes.  To make the process smoother, follow the instructions that came with the HVAC system or the replacement filter.  If the task becomes too complicated, call a contractor to assist or answer any questions.
• Good Performance: A clean air filter can remove a lot of dirt and dust from the air conditioned space and from other components within the system.  Keeping the blower motors and other components clean helps the air move through the heat exchangers, and is critical to maintain good performance and extend the life of the system.
• When to Call a Professional: If you change the filter regularly and it appears to be extremely dirty, cleaner than expected, or has insects or mold visible, call a contractor to inspect the system.  We also recommend calling a contractor if particles are being visibly released from the indoor registers.

I recently changed my pleated air filter. Here’s a look at the simple steps I took:

First, you’ll need to locate your filter (mine was inside a utility closet, but many are at the base of the main unit). Be sure to turn off the system to make sure that it does not run while you are changing the filter. 

After removing the cover, I simply followed the instructions on the box to replace the filter cassette. 

Here you can see the view of the filter as the air would be passing through it. 

In these photos you can see color difference between the dirty filter and the clean filter. 

I removed the old filter and put the new one in the cassette.