Timberline Blog

HVAC Condenser and Evaporator Coils: Keeping Them Clean Is Critical

April 25, 2022 by Timberline

HVAC systems have two types of coils: the evaporator coil and the condenser coil. They are where an air conditioner does the work needed to manage the air temperature in your home or business.

HVAC technician checking coil

You’ve got a company to run and a life to live, so you probably don’t want to become an expert in the physics of climate control. But having a basic understanding of how the coils function and how you or an HVAC technician must care for them helps ensure that the system can meet your cooling needs for many years.

This article describes how the evaporator and condenser coils work together to cool your indoor spaces. It also explains how best to keep those coils clean and operating at peak efficiency.

Understanding HVAC Evaporator Coils

People often think of air conditioners as generating cool air. That’s not entirely incorrect. It’s more accurate to say that they cool warm air. Specifically, they extract heat from warm air and move that heat outside of your home or business. They do this by using a refrigerant (also called coolant) to absorb heat and then circulating it in a way that enables it to release that heat to the outside environment.

What does the evaporator coil do? Also called the evaporator core, the evaporator coil is made of copper, aluminum or steel tubing in repeating “U” shapes set within a panel. The evaporator also has what are called fins. They bring as much air as possible into contact with the tubing, where the removal of heat (i.e., the heat transfer) takes place.

The evaporator coil utilizes refrigerant in approximately a 75% to 25% mix of liquid and gaseous states respectively to capture the heat and cause a phase change to a 100% gaseous state. Just like it takes heat to change water to steam, this heat transfer and phase change is why the air feels cold on the supply side.

Understanding HVAC Condenser Coils

A condenser coil works in tandem with an evaporator coil to maintain the desired temperature in your indoor environment. The condenser coil is housed in what people commonly refer to as an air conditioning unit (or the condensing unit)—the big “box” outside your home or business.

After the evaporator coil does its work, coolant carrying the heat it absorbed from your indoor spaces travels to the condenser unit outside. There, a compressor pressurizes it before sending it into the condenser coil.

That is when a second phase change occurs. At the condenser, the system pulls air over coils, removing the heat from the refrigerant as it changes from a gas to a liquid/gas mixture. This mixture is then sent back to the expansion valve and evaporator coil, completing the cycle.

By using these two-phase changes and the associated heat absorption/expulsion, the system removes heat from inside and disperses it outside. The cycle continues until the indoor temperature control (thermostat) is satisfied. At that time, the system cycles off until the temperature rises and exceeds the set point again.

How Dirty Coils Impact HVAC System Functioning

As you can see from the description above, the process your HVAC system uses to remove heat from indoor air relies on multiple physical factors. The most important of them is the degree of contact between moving air and the system’s evaporator and condenser coils. To keep your system operating efficiently and effectively, you must ensure the coils are clean.

If you fail to keep your evaporator coil clean, you will experience problems like:

  • Reduced heat absorption and cooling capacity
  • Higher energy use and associated costs
  • Lower pressures and temperatures that can damage system components
  • Unwanted frost/ice accumulation due to reduced airflow across the coil

The last problem on this list occurs when the coil temperature is below freezing. Because the coil is below the air’s dew point it “sweats,” resulting in ice build-up.

And it doesn’t take much to cause the issues above. Even a thin layer of dust acts as an insulator and reduces the efficiency of the heat transfer process and, as a result, the system’s cooling capacity. That means that the system has to run longer to achieve and maintain your desired indoor temperature and that you have higher energy bills as a result.

For the outdoor condenser coil, the enemy tends to be an accumulation of things like “cotton” from cottonwood trees, grass, leaves, pet hair and other debris on the air conditioner’s fins. This buildup makes it harder for the condenser to release heat.

As with the evaporator coil, if you fail to keep your condenser coil clean, the first issue is decreased performance. However, mechanical stress and resulting damage to system components are not far behind.

Keeping Your Coils Operating Efficiently

There are steps you can take to keep your coils clean and your system operating efficiently. They include carefully wiping down the evaporator coil and using a utility vacuum cleaner to remove debris from around the condenser coil or cleaning it with water.

However, it’s easy to damage fins and other system components on cooling systems. And this work should always be performed on de-energized equipment. If you’re not sure how to de-energize the unit, you shouldn’t proceed. A better approach for preventing damage or injury is to contact Timberline Mechanical and have a trained technician service the inside and outside components of your system.

Not only can they clean the coils, but they can also inspect all of the other components to look for small leaks and other minor problems that can turn into significant expenses if not addressed properly.

How often should you have a technician clean your evaporator and condenser coils? That depends on several factors, including how much you use the system, the indoor and outdoor environments at your business or home and others. But a good rule of thumb is to have Timberline inspect your cooling system at least once a year and ensure your filters are changed on a regular basis.

Our skilled and experienced technicians can complete their work quickly and efficiently, with minimal disruption to your regular routine. This can help prevent major problems and system failures, which can be costly and leave your family members or employees uncomfortably warm until repairs can be made. It also helps increase the lifespan of your equipment.

Our goal in an annual cooling inspection is to share our findings with you and develop the best solutions for any challenges we encounter.

Trust the Pros To Maintain Your HVAC System Properly

To ensure your HVAC coils are clean and protect your system, all you have to do is get in touch with Timberline Mechanical. We can perform a one-time service or provide regular system maintenance. Contact us at your convenience to learn more.

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