How to Clean Air Conditioning CoilsCleaning air conditioning coils is one of the easiest and most effective ways to maintain your AC system. It not only lowers operating costs; it also extends the systems’ lifespan while ensuring a steady supply of cool air. Cleaning your air conditioner is a simple procedure that should be carried out at least once a year. This short guide will walk you through the process step-by-step, to help keep your air conditioner in good working condition.

Types of Air Conditioning Coils

Your AC controls temperatures by circulating air through two sets of coils that work in tandem to transfer heat from inside to outside your home.

Evaporator Coils

Evaporator coils remove heat and humidity. Part of your indoor AC system, they vaporize refrigerant, converting it from a liquid to a gas as it enters through the expansion valve. The sudden change lowers its temperature, allowing it to cool the air passing through your system.

Condenser Coils

Located in a large metal container outside your home, condenser coils dissipate heat by converting vaporized refrigerant back into liquid, raising its temperature in the process. The hot liquid is then pumped through a series of tubes and aluminum fins that disperse the heat absorbed inside your house, with the help of a large fan at the top of the unit.

Importance of Cleaning Air Conditioning Coils

When dirt or debris builds up along the coil surface, it creates a barrier that insulates the coils, slowing the absorption and dissipation of heat, which can have a significant effect on your air conditioner. By annually cleaning coils, you:

  • Increase Efficiency. Central air conditioners have grills and filters that trap dirt and dust particles. Unfortunately, no filter is 100 percent effective, so some debris does pass through. This gradual buildup results in less heat being absorbed and expelled, reducing the supply of cool air in your home.
  • Lower Costs. Dirty coils increase the length and frequency of run times, which leads to more energy consumption and higher utility bills.
  • Reduce Wear and Tear. Decreased efficiency forces the compressor to cycle more often. By slowing the dispersal of heat, dirty coils also raise the compressor’s internal temperature and strain the fan, shortening the life of the entire system.

How to Clean Air Conditioning Coils

Air conditioning coils are not particularly robust. The tubing is thin and the condenser fins are made from soft aluminum, so a gentle approach works best. Before you begin, you’ll need to gather the necessary supplies, including:

  • Coil cleaner
  • Mold remover
  • Compressed air
  • Shop vac
  • Nylon brush
  • Spray bottle
  • Garden hose
  • Screwdriver
  • Towels or rags
  • Plastic bags (to store loose screws)

Though it’s possible to clean coils with soap and water, coil cleaner is far more effective. An alkaline solution made from potassium or sodium hydroxide, it’s specially formulated to remove greasy contamination from copper and aluminum piping. Though it’s nontoxic, it can irritate your eyes and skin, so you’ll need some basic safety equipment: gloves, goggles, and a mask, to protect you from fumes in a confined space. Once you’ve assembled all your material, cleaning air conditioning coils is fairly straightforward.

How to Clean Condenser Coils

For your safety, don’t power down the unit from your thermostat. Cut power from the breaker box instead, to prevent electrical shocks. After the system has been disconnected:

  1. Unscrew the top cover and protective grill around the sides, placing the screws in separate bags for safekeeping.
  2. Remove the condenser fan by turning out the screws that hold the fan assembly in place. In some cases, you may be able to unsnap the wiring harness from the fan. If not, simply set the fan on a stepstool next to the unit and pull the wires off to the side.
  3. Inspect the unit for damage, such as corrosion, frayed wiring, and bent or cracked piping. If you find any, stop and call a professional.
  4. Remove large debris ‒ dirt, bark, mulch, pebbles, etc. ‒ that may have gotten trapped inside the unit or protective grill. Then vacuum out the bottom of the condenser.
  5. Dust the condenser coils with compressed air. Make sure to blow the coils from the inside out, the opposite direction that air flows through the unit ‒ to drive debris from the clean side out through the dirty side. Be sure to blow the air out straight, not at an angle, to prevent damaging the fins.
  6. Spray the coils with coil cleaner from the inside, same as you did with the compressed air. If you notice any mold or mildew, spray it with mold remover first, then apply the cleaner.
  7. Wait 5-10 minutes, then rinse the coils with a garden hose on a low-pressure setting. Start from the top and work down, spraying from the inside, then from the outside.
  8. Let the unit air dry, then screw the fan, top cover, and protective grill back into place.

How to Clean Evaporator Coils

The condenser is generally installed on the side of your house, which makes it easy to access. By contrast, the evaporator assembly is located inside your furnace or air handler, normally located in the attic or basement, which may make it harder to get to. Once you’ve identified the unit:

  1. Shut off the power from the breaker box.
  2. Unscrew the access door, generally located near the blower fan. (Call a professional if you can’t locate it.)
  3. Inspect the coils for damage. Call a professional if you notice any.
  4. Brush the coils lengthwise with the nylon brush. Once the coils are clean, vacuum up any debris that may have fallen to the bottom of the unit.
  5. Spray the coils with coil cleaner. Be sure to reach around and spray the sides of the unit, not just the front.
  6. Wait 5-10 minutes and then rinse the coils off with water from a spray bottle. You may have to repeat this step several times in order to wash the cleaner off entirely.
  7. Don’t wipe down the unit. Let it air dry, but use a towel to soak up any water that may have collected at the bottom of the evaporator assembly or dribbled onto the floor.
  8. Once the coils are completely dry, reattach the access door and screw it into place.

Cleaning AC coils isn’t overly difficult, but it is delicate work. To save time, you can always ask an HVAC technician to clean them as part of your annual maintenance check. Besides removing dirt and grime, regular service calls allow you to fix potential problems before they cause a serious malfunction.

Save on Home Repairs with Agway EnergyGuardTM

Cleaning air conditioning coils reduces wear and tear, but doesn’t eliminate it. Motors, coils, and fans all break eventually and can cost hundreds of dollars to replace. Home insurance doesn’t cover this type of damage, but Agway EnergyGuardTM does.

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