Homeowner Articles Suspect an AC Evaporator Coil Leak

An evaporator coil is an essential part of your HVAC system. It is a vital component that helps reduce the temperature of your home.

If there is any problem with the evaporator coil (also called an Evap Coil), then your cooling system will not function properly. One of the most common problems that can occur is an evaporator coil leak.

So when you see symptoms that your evap coil has leaks, you need to fix it immediately.

In This Blog:

What Is An Evaporator Coil?

A naked evaporator coil

An evaporator coil is one of the two coils in your cooling system. The other one is the condenser coil. These two coils are responsible for providing comfort to your home by reducing the temperature through the transportation of heat between the two systems.

The evap coil is located within the air handler inside and looks just like the picture above. The condenser is located outside in the outdoor unit. Your cooling system works really well until you have a refrigerant leak….

Related Reading: Why is My Heat Pump Not Cooling?

How An Evaporator Coil Works

How an Evaporator coil works

Evap coils do not work alone inside the A/C. It works in conjunction with the condenser. The purpose of the evap coil is to cool down your home through heat absorption.

How it works is pretty simple. It is done through refrigerant gas inside a closed system. This refrigerant gas has a heat-absorbing trait. So when it comes into contact with the warm air passing over the evap coil, it absorbs the heat, allowing the warm air inside to cool down.

The refrigerant gas is then transported to the condenser, where the refrigerant releases the heat into the outdoor environment. The cool air passing through the evaporator coil is moved through the air handler via a fan, blown into your ducting system to cool your home.

How An Evap Coil Leak Occurs

Dirty AC evaporator coil

There are a few reasons why a refrigerant leak may occur. It also depends on the age and model of the unit you are using.

Here are the most common causes of why you might experience a leak.

1. Vibrations

This is most often seen in older Air Conditioning units. The vibrations caused by older A/C units cause the aluminum fins to rub on the copper tubing creating pinhole leaks in the tubing.

Since the evap coil is made up of a ton of fins mated to the copper tubing, it’s almost impossible to repair if the leaks are internal. In this case, the component must be replaced with a new coil.

2. Corrosion

Since newer A/C models don’t vibrate like the older ones, the next problem you may have is caused by corrosion. Newer systems generally use a type of refrigerant gas knows as R-410A.

Depending on the manufacturer of the coil, your unit may suffer from what’s known as “formicary corrosion“. This is caused by a combination of residual organic compounds, water, and oxygen.

These compounds create pinholes when combined with uncoated copper within the coil and will also occur if the coil is not aluminum.

3. High Humidity

High humidity also contributes to corrosion. A humid climate means the presence of moisture in the air is prevalent. If water molecules come in contact with refrigerant, a chemical reaction occurs creating formic acid. This formic acid can then damage the copper tubes, causing your evap coil to leak.

4. Volatile Organic Compounds

This is similar to water particles. Volatile Organic Compounds (or VOCs) are chemicals that when combined with moisture in the air produce acids leading to corrosion. Examples of VOCs are benzene, ethylene glycol, formaldehyde, and toluene.

VOCs can be found in many products, such as coil cleaning foams, aerosol air fresheners, chemicals left in your garage near the air handler. The presence of these chemicals can corrode copper tubes.

What are the signs that your AC may have a leak?

So how do you know if your AC has a leak? The first thing is your AC will take a long time to cool the air in your home. Even if you run your AC at 71 degrees Fahrenheit (or 22° Celsius for everyone else), you feel that the air is still warm.

Since your HVAC equipment has to work harder to cool down your house, you will also experience higher utility bills.

The other key symptom is that you will frequently need to refill your refrigerant gas. The refrigerant gas inside the air conditioner is in a closed system and is continuously recycled.

Which means that you should never have to refill it that often. If you need to refill your refrigerant gas more frequently than usual, that means these gasses are escaping through a leak.

How To Prevent and Fix Evaporator Coil Leaks

Proper cleaning of an evaporator coil

Evaporator coils are prone to leaks, but there are a few things you can do as a homeowner to prevent them. If your AC is already leaking, here’s what you can do to fix it.

1. Watch out for VOCs

Understand everything you use in your home could contain VOCs. Everything from paints, cleaning products, and aerosol air fresheners can make their way into your indoor airflow and into your air handler.

Even something as simple as storing chemicals near your air handler can cause corrosion. So be aware of what chemicals you use in your home that can affect your indoor air quality.

2. Reduce Humidity.

If you live in an area with high humidity, you may consider installing a whole-house dehumidifier. That way your AC doesn’t have to work as hard in removing moisture from the air and reducing the amount that reaches the evap coil.

3. Replace the Coil

If your evap unit has a ton of refrigerant leaks which is usually the case, then, unfortunately, there is no chance to repair them all. So repairing, in this case, would be very difficult, time-consuming, and very costly.

The best solution would be to replace the damaged coil with a new one. The cost to replace may be cheaper than a repair.

If you have an older HVAC system, it might also be time to spring for a completely new air conditioner. New models are much more efficient so it won’t be long before you are actually saving money.

4. When to Call In A Professional?

Evaporator Coils are delicate objects, and replacing them takes skill. So if you want to replace your damaged coil, please do not attempt to replace it yourself. This is not a DIY project.

They are installed deep inside the air conditioning system so any wrong move might damage other parts of the system. So if it’s the coil, hire an HVAC technician to replace it.

Final Thoughts

Evap coil leaks are one of the most common problems that occur in an HVAC system. Most are unaware of how they occur, how they can help prevent them, and what they need to do to fix them.

Hopefully, you found our article educational and helps you in identifying issues quickly saving you some pain and money.

If you’re in need of an air conditioning or heat pump repair and live in the Spartanburg County area, reach out to our team at Upstate Home Maintenance Services.

We provide free estimates on all AC repairs and replacements. Our HVAC technicians can provide quick and honest repair and replacement services. We want to be your preferred HVAC company!

This article was written by Morgan Loch

Owner of Upstate Home Maintenance Services LLC and Local HVAC Guru

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