Annual HVAC maintenance is recommended to preserve the performance and boost the energy efficiency of your heating and cooling equipment. Air conditioning systems should be inspected prior to the cooling season and vice versa for the heating system. We tend to forget about the vital components that keep our indoor temperatures comfortable when the weather turns hot outdoors. One of the hardest working parts is the AC evaporator coils and when they become dirty the system can lose a lot of performance and efficiency and it’s more prone to a breakdown. In this article, we will take a closer look at evaporator coils and show you how to clean them yourself.

Why are Evaporator Coils Important?

Before we begin, it’s a good idea to get a basic understanding of how the AC system works and why the evaporator coils are an essential component. The primary function of the evaporator coils is to capture heat that’s gathered from the indoor air and release it outdoors. An AC system doesn’t cool the home, it makes the home cooler by removing the heat. This may seem like a petty distinction, but it’s an important concept that many people misunderstand. The evaporator coils are made from copper usually and they are encased in aluminum fins that facilitate the heat transfer.

The evaporator coils are located in the home, they are a critical part of the indoor air handling unit and they work under the hottest temperatures. The secondary function of the evaporator coils is to condense water from hot air that lands on the fins. This is then removed from the home via the condensate drain pan and drain line. This is how the air conditioner acts as a basic dehumidification system to keep your home comfortable.

What Happens When the Evaporator Coils are Dirty?

The ability to disperse heat and dehumidify your home are both impaired when the evaporator coils become dirty. As you might imagine, the evaporator coils are usually wet as a side effect of the dehumidification process. This is a key factor when airborne particulates, such as dust, dirt, pollen, and other materials stick on the coil surfaces when the air passes over them. This risk is mitigated when an air filter is in place, but if the air filter is missing or dirty the problem is much worse. When sufficient quantities of dirt and dust are on the evaporator coils they cannot perform efficiently. This can lead to five key problems. They are:

  1. The capacity for cooling is lowered.
  2. The heat transfer process is compromised.
  3. Ice will build up on the coil and this can cause damage.
  4. The wear and tear can lead to frequent repairs and lasting damage.
  5. The energy consumption will increase leading to higher energy bills.

5 Techniques to Clean the AC Evaporator Coils

Before you can attempt these cleaning techniques, you will need access to the evaporator coils. They are located in the indoor air handling unit and you will need to remove the access panel. Turn off the power to the AC system at the thermostat and as an extra safety measure, shut off the circuit breaker too. Remove the fasteners or screws to loosen the access panel and set the fixing aside to keep them safe. Then use one of the following five techniques to clean the evaporator coils. They are:

1.   Compressed Air

This is a good cleaning method if there is only a light buildup of dust and dirt on the coils. Simply use a can of compressed air to blow the debris away, but take care to direct the air in the opposite direction of the normal air flow. Wear eye protection to keep your eyes safe and a shop vac is the best way to clean away the dirt and debris.

2.   A Soft Brush

If there is a light accumulation of dirt and dust, it can be removed with a soft brush. When compared to the compressor air technique this gives you more control over the areas you clean and the pressure applied to them. Some light scrubbing may be needed for those dirtier areas and a soft brush is needed to avoid damage to the fins.

3.   Commercial Cleaning Products

There are a number of cleaning products specifically designed for evaporator coils. Whichever brand you choose, make sure to follow the cleaning instructions carefully to avoid damage to the evaporator coils. Most cleaners are sprayed onto the coils, they then foam, and the debris simply drains away. These products can be applied multiple times as needed until the coils are completely clean.

4.   Mild Detergent and Water

If you don’t want to use a commercial cleaning product, you can use a mild detergent and water to clean the evaporator coils. Simply mix the two together in a spray bottle and apply the solution to the coils. Allow the mix to soak into and loosen the debris, then wipe away the material with a clean cloth or soft brush.

5.   Heavy-Duty Cleaning

When the evaporator coils are very dirty, you may want to consider a steam cleaner, pressure washer, or heavy-duty chemical cleaning products. This will require you to remove the coil and refrigerant lines which may be beyond many people. Taking the equipment apart and then putting it back together is a job for a professional HVAC contractor.

In Conclusion

Experts estimate that dirty evaporator coils can consume up to 40% more energy than comparable units with clean coils. The cooling function may drop by at least 30% and the system will lose a lot of performance and efficiency. This is why it’s important to check the coils regularly and during the cooling season, they should be checked every three months. Inspecting and cleaning the evaporator coils is part of a comprehensive annual maintenance visit which is recommended for all HVAC systems. Regular filter changes can reduce the buildup of dust, dirt, and debris but sooner or later some cleaning will be needed.

If you want to schedule some essential maintenance and cleaning for your AC system, contact your local heating and cooling specialist today.