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Where Is the Evaporator Coil?

an outdoor AC unit

Homeowners depend heavily on their air conditioners for comfort, especially when it is hot outside. But despite their reliance on this appliance, few are familiar with an AC’s inner workings and how to maintain it.

While you don’t have to understand how the entire AC system works, it can be beneficial to know the basics. That includes locating the evaporator coil and caring for it. Here’s everything you need to know about this essential part of your AC unit.

Remember that you can always contact AC specialists for problems you encounter with your unit. They have the necessary tools and expertise to have it running smoothly again.

What Is the Evaporator Coil, and How Do You Locate It?

Air conditioners don’t produce cold air like a furnace makes heat. AC units have refrigerant flowing inside them, and the refrigerant absorbs the heat and humidity so the air that flows into the home feels cold. The evaporator coil plays an essential role in the cooling process.

So where is the evaporator coil? You can find it near or inside the air handler, which houses the blower fan. It’s usually made from aluminum, steel or copper because these metals are excellent heat conductors. It has fins all around it for protection and to assist in heat dissipation. When you turn on the AC, the compressor will push the refrigerant through an expansion valve. This valve will reduce pressure from the refrigerant and instantly cool it.

The cold refrigerant will then flow through the evaporator coil. As it’s doing so, the blower fan will push hot air from your home over the evaporator coil. The refrigerant will absorb the heat from the air, which will cause it to warm up and evaporate. At the same time, the water vapor in the hot air will condense into a liquid and drain outside. Without the evaporator coil, you can’t enjoy cool air at home.

However, the evaporator coil can’t do the job alone and needs the help of the condenser coil. These two parts may look similar, but they have very different roles. While the evaporator coil absorbs the heat from the indoor air, the condenser coil releases the heat outside.

Why Is It Important To Maintain Your AC’s Evaporator Coil?

Homeowners must check their AC’s evaporator coil because it can become dirty over time. Surface moisture and debris can build up in the tight spaces between the coil fins, hampering the AC’s ability to remove heat from the air. In severe cases, a dirty evaporator coil can restrict airflow, the most vital element in the cooling process. Here are a few things that can happen when you don’t maintain the evaporator coil.

Reduced Efficiency

Even a thin layer of dust can significantly lower the evaporator coil’s efficiency. Because dust is an insulator, it will prevent the heat from reaching the evaporator coil and the refrigerant inside. Since the evaporator coil can’t absorb as much heat as when it’s clean, the AC will have to run longer than usual to reach your desired room temperature. It will consume more energy and lead to higher electricity bills.

Shorter AC Life Span

Dirt and debris buildup on the evaporator coil can strain the entire AC system. The fans and compressor must work much harder to achieve the target temperature. The compressor will also have to operate under a higher load, which can cause it to wear down. That’s the last thing you want to happen because the compressor is an expensive part of an AC unit. By cleaning the evaporator coil, you’re protecting the compressor.

Freezing Over

A dirty evaporator coil is unable to absorb enough heat. That means the refrigerant running through it can’t warm up properly. Instead of turning the water vapor into liquid, the cold refrigerant will freeze it. If you let the AC run, the evaporator coil will eventually freeze over. It can take an entire day to thaw a frozen AC.

How To Maintain Your AC’s Evaporator Coil

Given the essential role of the evaporator coil, homeowners must give it the proper care it deserves. It can function more efficiently if you clean it at least once a year. Here are some DIY methods you can try that don’t require the removal of the evaporator coil.

Compressed Air

Compressed air can be a quick and effective way to clean a dirty evaporator coil. It can loosen and push away surface dust and debris. However, compressed air is forceful enough to bend the fragile coil fins. Leave at least two to three inches between the nozzle and the evaporator coil. If you’re dealing with stubborn buildup, contact an AC professional who can address the issue.


You’ll find many commercial coil-cleaning solutions on the market, but detergent will do just fine. Mix it with warm water and put it in a low-pressure spray container. Spray the mixture on the evaporator coil and use a brush with soft bristles to wipe the grime away. Let the evaporator coil dry thoroughly before turning the AC on.

Given the fragile nature of evaporator coils and their fins, it’s better to let an experienced AC specialist do the cleaning. When you go the DIY route, you risk damaging AC parts and spending more to repair them. But you don’t have to worry about that when your AC is in the hands of a trained professional.

An AC unit

How To Check the AC Compressor

If you think your AC’s compressor is malfunctioning, you can confirm your suspicions by testing it. You can do so through the following steps:

  • Go to your fuse box and switch off the AC’s power supply. You should also turn off the breakers, so there is no electricity flow.
  • Remove the access panel to reveal the electronic parts.
  • Inspect the wires, capacitor and compressor for damages. Specifically, check if the compressor’s terminals have burn marks.

The best way to prolong a compressor’s life is by scheduling regular tune-ups with an AC professional.

Signs of a Malfunctioning AC Compressor

Your AC relies heavily on the compressor to function. That’s why it’s easy to notice when your AC compressor is not working or malfunctioning. Here are some signs of a failing AC compressor.

Your AC Makes Noises

If you notice your AC making noise, like rattling or clunking sounds, it can be a sign that the compressor is going through an electrical failure. Another indication of compressor issues is if the condenser coil is vibrating. Don’t let your AC keep running, hoping the sounds will disappear eventually. That will only damage your unit further.

Your AC Blows Warm Air

Your AC has one job, and that’s to cool down a room. If your unit is failing to do that and is instead blowing warm air, there might be something wrong with the compressor. Double-check that the air filter and condenser coil are clean and the refrigerant isn’t leaking. If there’s nothing wrong with these components, the compressor could be to blame for the lack of cold air.

You Can’t Get Your AC To Start

If you’re having trouble getting your AC to start, check the breaker and fuse box before assuming it is a compressor problem. But if both are in perfect working condition, you might have a faulty compressor on your hands.

a breaker box

How Do I Stop My AC From Tripping the Breaker?

It can be frustrating when you want relief from the heat, but your AC keeps tripping the breaker. There are many possible reasons for this issue.

Clogged Air Filter

A clogged air filter can restrict the airflow inside your AC, causing the indoor unit to overheat and trip the breaker. It can also make it harder for your AC to function efficiently, unable to cool down your home like it used to. You can prevent this by replacing the air filter every three months.

Dirty Condenser Coils

Condenser coils are responsible for dispersing the heat in your home to the outside. But they can’t do their job well if they’re dirty. Your AC will have to work much harder to push heat out, which can cause the unit to overheat and the breaker to trip.

Broken Coil Fan

Coil fans aid in the cooling process, helping to release the heat inside the AC. They run on motors, but these mechanisms can wear out over time. When that happens, it can cause the energy usage to soar and the breaker to trip.

If your AC keeps tripping the breaker, there’s an underlying issue you shouldn’t ignore. Call an AC technician as soon as possible to prevent more expensive problems. Have a professional perform regular air conditioning preventative maintenance checks so your unit can keep running at its best.

The Bottom Line

Where is the evaporator coil? How do I stop my AC from tripping the breaker? These are questions homeowners might struggle with. AC units are complicated, but there is no issue professional AC specialists can’t address. They will assess the situation and provide the best solution so you can feel comfortable in your home again.

ABC Can Keep Your AC Working Efficiently

Dealing with AC issues requires lots of technical know-how. Instead of trying to figure it out yourself, contact ABC Home & Commercial Services. Our professionals can efficiently diagnose and repair your AC problem.

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