How Do I Change the Air Filter on My AC Unit?

September 14, 2022
How Do I Change the Air Filter on My AC Unit?


One of the shocking things about living in Tampa — air conditioning units can be something a lot of homeowners take for granted.  Many systems operate on a set-it and forget-it schedule that keeps you comfortable day and night. When it’s working well, we hardly know it’s there. Other than the “ahhh” sound we make when walking inside from the sweltering heat, we might not give our AC unit much thought.


But these workhorses need our attention every now and then to continue operating optimally. One easy maintenance step you should be doing every one to three months is changing your system’s air filter (if you have pets & kids, you want to do it more frequently – if you don’t, you can go towards every three months). It’s an easy step you can take to prolong the life of your HVAC system, improve your energy efficiency and ensure the best air quality in your home. Here’s how to do it.


How to Change Your Air Conditioner Filter


  • Find your filter’s location and size – Step one is to identify where your air filter (or filters) is located. The main filter for your unit will likely be within or near your air handler cabinet, but the best place to look is wherever the air enters into your HVAC. There may also be several filters throughout your house. In some rooms they may be on the ceiling at the outlet of the ducting. Check your vents to see which ones have a filter for return air.

Once you find them, pull out the existing filter to check its size. If it doesn’t have the size labeled on the filter, measure its length, width and thickness to find the appropriate replacement size.

  • Replace the air filter – Turn off the AC unit and remove the filter cover panel. If dirty, give the panel a wipe-down or clean with a brush attachment on your vacuum. Remove the old filter and insert the new one with the airflow arrows pointing in the correct filter direction. The directional arrows will be on the new filter indicating which way to insert it (hint: they should point toward the unit).

For filters on the ceiling, the  intuition might be to have the arrow point down into the room, but given they are for return air they should point into the duct, which in turn goes back to the AC unit. The other way to check which are supply vs. return vents would be to feel the direction of the airflow when the unit is running.

  • Replace the cover panel – Lastly, replace the filter cover, dispose of the old filter and turn on your AC unit. The whole process should take you less than 10 minutes.


Here in Hudson and across Tampa, it’s important to change your air filter on a regular basis – doing so monthly is a good idea in the summer. Keeping your filter clean will improve your indoor air quality, help your AC system run much more efficiently, and increase the lifespan of your AC.

Cleaner air plus lower energy bills is a double-win in our book. For help with your AC unit or to schedule a tune-up or inspection, give our team at Mario’s Air Conditioning & Heating a call at 727-843-9598.


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