How To Clean AC Coils

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Cleaning the AC coils in your HVAC system or window unit is a preventive home maintenance task that can save you money and lead to a healthier indoor environment. Arista notes that cleaning your AC coils is like an "insurance policy" that extends the life of your system. Although you don't see the coils, they work whenever your AC runs. The evaporator coils inside the indoor unit extract heat and humidity from the indoor air. Located in your home's exterior unit, the condenser coils release the heat and moisture to the outdoor atmosphere. 

When dirt builds up on the coils, it blocks this transfer process. Interior evaporator coils collect dust, pollen, pet dander, and allergens from the indoor air. Exterior condenser coils may become even dirtier as they are exposed to organic debris from trees and shrubbery, as well as dirt, pollen, and multiple pollutants in the outdoor air. According to Bradbury Brothers Cooling, Heating, Plumbing & Electrical, the job of cleaning AC coils must be approached with care. DIYers should take the time to learn proper methods for cleaning their units. Otherwise, the homeowner may inadvertently damage the coils, causing further problems. With knowledge and caution, you can keep your AC unit in premium condition by cleaning the coils correctly and regularly. Here's how.

You should clean both the evaporator and condenser coils in your HVAC system at least once a year. Big Mountain Air notes that more frequent cleaning may be necessary under certain conditions. For example, the coils in older HVAC systems need to be cleaned more often than those in new units. Additionally, coils become dirtier with heavy usage. Therefore, if climate conditions in your area cause your AC to run almost continuously, the coils will need to be cleaned as much as twice a year or quarterly. The location of your outdoor HVAC system is an additional factor that affects the frequency of cleaning. For example, a unit located close to a busy street will be exposed to air pollution, and a unit situated under trees and shrubbery will collect pollen and organic debris.

You should also give them an extra cleaning if you notice certain conditions in your home. Robert B. Payne, Inc. explains that if your electricity bill is increasing or your house feels warmer than usual, you might suspect that dirty coils are preventing your AC from operating at top efficiency. But don't wait until problems start to occur before cleaning the unit. It's a good idea to inspect the AC coils every couple of months. 

Before you can clean your AC coils, you'll need to access them within your indoor and outdoor HVAC units. Evapco explains the safety precautions that apply to this procedure. First, turn off your HVAC system at the thermostat. Then, turn off the electrical current that flows to the HVAC system. In most cases, this is accomplished by flipping a switch at the circuit breaker panel. Once you've cut the electrical current, you can safely work on cleaning your AC coils.

Your indoor HVAC unit is typically found in a closet, attic, or basement. You'll need to remove the screws, covering, or panel to access the evaporator coils. Inside the unit, the refrigerant-filled evaporator AC coils are configured like a large, capital letter A. Similarly, you'll need to access the condenser coils in your outdoor HVAC unit by removing screws and panels. It's important to exercise caution when cleaning because the soft-metal coils and fins may be easily damaged.

You can use a brush with moderately stiff nylon bristles to clean your AC coils. This will only work if they don't have caked-on grime. If you're simply dealing with dust and dry debris, a brush may be the only tool you need. Do not use a metal or wire brush, as it can damage the coils and fins, as per Day & Night Air Conditioning, Furnace, & Plumbing. If you haven't serviced your coils in a while and need to clean them with a solution, you should use a scrubbing brush with soft nylon bristles.

Top 10 Best recommends commercially available tool sets designed for cleaning AC coils. Along with fin combs, these sets provide brushes that resemble small whisk brooms. The manufacturers of the AC coil-cleaning tool sets include Boao, Chengdu, Fiada, Midwest Hearth, Pimoys, and Shuian. The tool sets with brushes are available from Amazon.

When it's time to clean the AC condenser coils in your outdoor HVAC unit, hosing them down with water is an ideal cleaning method. If you've already switched off the electrical current to the HVAC system, it's safe to spray water from a garden hose onto the condenser coils. However, Provincial Heating & Cooling Inc. warns that you should affix plastic wrap securely around the motor and electrical wires to avoid water damage. Although moderate pressure from a garden hose is recommended, the intense water pressure from a power washer may damage the condenser coils and fins. These parts are typically made from copper and aluminum, and those soft metals can bend easily. 

After spraying your condenser coils with water, you'll want to use a commercial or homemade cleaner to continue the job. After applying a foam or a detergent mixture, the garden hose comes into play again for rinsing away the residue from the cleaners. After the final rinse, allow all parts of the outdoor HVAC unit to air dry for at least 60 minutes before reattaching the covering panels and restarting the system.

It's not necessary to purchase a commercial cleaner for your AC coils. You can make your own cleaning solution following these suggestions. Action Air recommends diluting white vinegar with water in a spray bottle and spraying the mixture onto dirty AC coils. White vinegar is an effective natural cleaner due to its acidity level. For greasy or sticky residue on the coils, you may want to add 1 tablespoon of baking soda to the diluted vinegar solution. Alternatively, you can achieve good results by mixing a mild dish detergent with water in a spray bottle and spritzing the coils. Of course, rinsing is recommended.

According to Breathe Better Air, you can mix white vinegar with rubbing alcohol in a 1:1 ratio and then add a small amount of baking soda to create an effective cleaner for mold and mildew in your AC coils. Alternatively, a mixture of water, dish soap, and baking soda makes a slightly abrasive cleaner that removes stubborn, stuck-on dirt from coils. If mold and mildew are a significant problem, you can spray a solution of 1 part bleach and 3 parts water onto the coils. This method should be used with caution, as the smell of bleach might disperse throughout your house via the ventilation system. After using cleaners on your AC coils, follow up by rinsing with clear water.