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There are numerous issues that can cause your home’s air conditioning system to stop working properly. One such issue is if the evaporator coil is leaking. When this happens, the system won’t have enough refrigerant to work properly, making it far more difficult for the AC to fully cool the home. Evaporator coil leaks are a fairly common issue, especially in older systems, and here is everything you need to know to spot the potential signs of a leak and what can be done to fix it.


The evaporator coil is located within the air handler unit inside the home. The condenser unit outside the home provides a steady supply of cold refrigerant to the evaporator coil. As warm air from inside the building is drawn into the system, it passes over the evaporator coil. The cold refrigerant then absorbs heat from the air so that the air circulated out of the system is cooled. The evaporator coil also works to remove excess humidity from the air. As warm air passes over the coil, water vapor condenses on the coil and then drains out through the condensate drain system.

If you suspect that your evaporator coil is leaking, have the system inspected immediately. When the coil is leaking, it will lead to reduced home comfort and can greatly increase your energy costs. If left unchecked, it can also seriously damage your AC system or potentially ruin it altogether. It’s important to note that refrigerant leaking out of the system can be dangerous for your health and seriously damaging to the environment. In fact, hydrofluorocarbon (HFC) refrigerant is one of the most dangerous greenhouse gases and is over 1,000 times more damaging to the environment than carbon dioxide.


One of the most common signs that your evaporator coil is leaking is when your AC is blowing out hot air instead of cold air. You may also notice that the air coming out of the vents constantly fluctuates in temperature or that certain areas of your home are much warmer or cooler than others.

Alternatively, you may notice that your system suddenly takes much longer to fully cool your home. In this case, you will also notice that your home is more humid than usual. An evaporator coil leak can also cause the AC to not respond when you turn on your thermostat or not turn on at all. Many newer condenser units have a fail-safe that will prevent the unit from turning on if it is low on refrigerant in order to prevent the motor from possibly burning out or damaged in some other way.

You may also notice a strange, sweet smell coming from the air handler or being pumped out of your vents whenever the air conditioning is running. In this case, what you’re smelling is the refrigerant itself, and this is a very obvious sign that you need to immediately contact a professional HVAC technician.

One final sign that can indicate a leak is if the condensate drain pan starts to overflow or you see visible water around the air handler. If the system doesn’t have enough refrigerant, it can cause the condensation to freeze on the evaporator coil. This will typically result in hot air blowing out of the vents until the coil fully thaws out. As the coil begins to thaw, the additional water can overwhelm the condensate drain system and cause it to leak or overflow.

This problem could also be simply a result of the condensate drain line being clogged. However, if it is caused by a frozen evaporator coil, attempting to run your AC before it fully thaws out could burn out the condenser unit. At this point the entire unit will need to be replaced. This is why it is imperative that you have a professional HVAC technician inspect your system as soon as you notice the issue.


Several different issues can cause the evaporator coil to start leaking. One common issue is that the vibrations inside the unit cause the aluminum fins on the coil to rub against the copper tubing and eventually wear a hole in the copper. This is especially common if the air handler and evaporator coil are more than 15 years old.

The coil may also begin to leak due to corrosion. Known as formicary corrosion, the issue occurs due to a chemical reaction between oxygen, moisture and volatile organic compounds (VOCs) in the air. Over time, this reaction can eat away at the copper tubing and create small pinholes in the coil. Newer AC systems use R-410A refrigerant instead of the R-22 (Freon) found in older units. Although R-410A is far less harmful to the environment and less toxic to humans, it makes the evaporator coil more susceptible to corrosion because it operates at a much higher pressure.

Mold and mildew growing on the evaporator coil can also slowly damage the copper tubing and lead to leaks. This is why it is important to make sure you have your evaporator coil cleaned as part of your yearly HVAC maintenance.


If your evaporator coil is leaking, the only truly effective option is to have it replaced. While there are sealant products that can help patch small leaks, this method is generally not very effective and may cause your energy bills to rise even if it does seal the leak. In fact, in less than 50% of cases where the sealant works, it is still only a temporary fix. In most cases, the sealant will eventually wear away over time. Although replacing the evaporator coil isn’t necessarily a cheap option, it is really the only way to make sure that the leak is taken care of and the system works properly.


If you suspect that your air conditioner’s evaporator coil is leaking, the expert technicians at 3D Air Services, LLC are always ready to help. Our team can quickly inspect your system and measure the level of refrigerant to ensure everything is working properly. If we determine that the evaporator coil is leaking or there is a leak anywhere else in the refrigerant lines, we can also repair the issue in a practical, cost-effective way.

We work on all brands and types of heating and air conditioning systems, all of our technicians are NATE-certified, and undergo regular training in the latest technologies. When you choose 3D Air Services, LLC, you can rest assured that you’re getting a good deal thanks to our honest pricing and 100% satisfaction guarantee. Our services include heating and cooling installation, repairs, and maintenance as well as generators and water heaters. We can even improve your indoor air quality with duct cleaning and air filtration solutions.

Visit our website for more information on specials and financing or take a look at our reviews. We have been serving customers in Alabaster and the surrounding areas since 2005, so give us a call today to schedule an appointment or if you have any questions.

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