How to Clean AC Coils

While most air conditioner repairs are best left to a professional, there are several things you can do to boost your system’s performance and lower your utility bill. From changing your filters and cleaning your coils to being a little more mindful when landscaping, you can make a big difference with minimal effort. When you search “how to clean AC coils” online, you’ll likely be overwhelmed with the options and industry terms thrown around in the countless tutorials. This is because air conditioning systems are fairly complex machines, with most having both an inside and outside unit that harmoniously work together to cool your home. Both units have coils, so it is important to start by identifying what you will actually be cleaning.

Prep and Clean the Coils

Before we get started, it's important to cut the power to your unit to avoid electric shock to you or damage to the unit. We’re going to focus on your outside unit’s coils. More specifically, we’re going to clean the fins, which run along the outside of the unit. Oftentimes, these fins get dented from years of wear and tear, making it hard for air to pass through them. If you notice that your unit’s fins are dented and bent, buy an AC fin tool at the hardware store and use it to straighten the fins (Image 1). Once you’ve straightened the fins, use a vacuum to remove any debris (Image 2). Now that the surface is clean and any debris within the fins has been cleared, you can use a foaming AC coil cleaner to coat the entire surface of the fins (Image 3). This cleaner will soak into the coil and begin to break free any remaining debris. Our cleaner featured a scrubber on its cap, but you could also use a stiff brush to further clean between the fins (Image 4). Though most of these foaming cleaners are self-rinsing, using a hose to rinse the area will help to wash away dirt and other buildup.

Clean Around Outside Unit

Over time, dirt, mulch and leaves can gather around the base of the outside unit and cake along the sides. Once a year, it's wise to rake back any buildup and clean along the bottom of the unit to keep the fins clean and free of buildup.

Change Your Filter

To keep your air conditioner running efficiently, it’s imperative that air can flow through the system. Many times, units begin to run poorly and suffer due to insufficient airflow caused by clogged return filters (Image 1). Returns get their name because they are where the system removes the hot air from the space and returns the cooler air for recirculation. It would be horribly inefficient to constantly cool down the hotter outside air, so the system recycles the already-cooled air in the home, cooling it and passing it through once more. All return covers are different, but they typically have two latches that you pull back by hand, releasing the door (Image 2). To replace the filter, simply measure the return size or reference the old filter’s listed size, buy a new filter and set in place, being sure to follow the air-flow-direction arrow printed on the filter (Image 3). Regularly changing filters according to the manufacturer’s guidance will save you money and keep you cool all summer long.