How to Perform End-Of-Season Maintenance For Your AC?

Learn how to perform maintenance for a season's AC unit. Discover tips for maintaining the home AC evaporator coil and ensure residential HVAC maintenance with Sandium.

Updated on Oct 23, 2023
5 min read
How to Perform End-Of-Season Maintenance For Your AC?

With the onset of autumn and changing seasons, it is officially time to get your home ready to brace the cold winter months.

While many homeowners are more concerned about their yard and taking the right steps to prep it for the coldest months of the year, winterizing your air conditioning unit is just as important. Most homeowners do not use their AC units during the winter months and any issues that are left unattended can potentially result in damage.

This guide will walk you through all the necessary steps required for end-of-the-year AC maintenance.


It is always a good practice to check and clean filters in an AC. However, energy professionals at the US Department of Energy consider this step to be the most important. This is because your air conditioning will stop working if the filters are damaged or clogged.

It is recommended that you check the filters one last time before turning off the unit for the season. This cleaning becomes particularly important if you live in an area that gathers dust or have pets.


It is recommended by the Department of Energy to check evaporator coils at least once annually. This can be done before or after the cooling season. However, it is considered a best practice to check and clean AC coils both before and after the cooling season. It can never hurt to check whether AC coils are clean even if you did so during spring.

You should also pay special attention to your unit’s condenser coil. It should be clean, undamaged, and free from any sort of debris before you can turn off your unit for the winters. Make sure you take precautionary steps to protect your unit. Removing dirt and leaves from around the unit would prevent debris from entering it. You should also consider trimming back foliage and bushes near the unit.

Coil Fins

Coil fins on an AC can become damaged or distorted over a period of time. It is recommended that you use a fin comb on both the evaporator and condenser portion of your unit to straighten the coil fins. You can easily acquire a fin comb online or from a local home improvement store.

Make sure you are careful while straightening the fins and don’t cause any undue damage. In case you find a fin that is severely bent or broken, call your HVAC contractor to take care of the problem before you forget about it.

Final Step

The last step to effectively winterize your AC for the coldest months of the year is to turn off the unit at the mains (doing this in the summer time is necessary too for most people but at least in the winter it’s cool so you won’t sweat while doing this). Remove or cover any of the smaller window boxes and consider covering the large exterior units.

However, use your best judgment here since many experts are of the opinion that mold and mildew can grow if there is no air circulation around the coils. Make sure you check up on the exterior parts regularly to prevent the potential buildup of snow (probably not going to happen in the Bay Area) and ice that could damage the unit.

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