This page will be about evaporative air-conditioning coils. This is the heart of the inside unit. This is the part of the system that does the work on the inside. This piece of equipment allows Freon gas to absorb heat from and dehumidify the return air system. The by product of this piece of equipment is cooler less humid air. Most coils have their lives shortened by improper maintenance. What damages a evaporator coil is the lack of maintenance, low airflow or low Freon levels


Lack of maintenance, when you fail to change your air-conditioning filters you allow an excessive amount of dirt to be pulled through the filter by the blower suction power. This dirt is then lodged on to the air-conditioning coils. A small amount of dirt can be generally washed away by the natural process of the evaporator coil removing humidity from the air in the form of condensation drain water. Large amounts of dirt tend to lodge on the coil and accumulate to a point where it blocks the amount of air flow that can pass through the coil. This causes two problems, less ability to transfer heat to the Freon. An excessive amount of dirt in a very small three-quarter inch drain line.


Low airflow, generally caused by a dirty filter or dirty coil. Sometimes caused by a blower motor or wheel malfunction. Also buy anything obstructing the return air system. This can cause even a clean evaporator coil to freeze up.

Low Freon level, a low Freon charge or a restricted Freon line can also cause the evaporator coil to freeze up.

A frozen evaporator coil causes a lot of damage. As ice builds on the evaporator coil it forms a block of ice. This large piece of ice can do a tremendous amount of damage. As you know ice expands, when this ice expands on and through the coil it has a tendency to cause freon leaks. A good example of this would be to look at any road that you drive on. You’ll see where the city maintenance people have placed tar in the large cracks in the road.

This is done to keep the winter water from going into the road cracks. That water in a road crack that freezes makes the crack even worse. This is the same thing that happens to the evaporator coil that freezes up. So when people ask me whose equipment is the very best?. I really want to honestly say this; all equipment is only as good as the installer and maintenance program the homeowner or business owner has in place. Even the top of the line highest price equipment on the market can not defeat these problems.

I have placed several pictures above so that you can have first hand knowledge of poor maintenance. I’m not going to come out and try to twist your arm into buying a maintenance agreement. You will pay for poor maintenance one way or the other. I believe you will come out on top by having a maintenance program.

Not only can a freeze up situation damage your evaporator coil, but the same situation can have disastrous effects on the compressor in your outdoor unit. If you would like us to further explain this feel free to have one of my men to teach you what happened to a compressor when you have an excessively dirty or frozen coil. We can generally tell this by taking the outside readings on an air-conditioning unit.

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