8 Most Common Reasons For AC Failure

ac failure

Are you wondering what the most common reasons for AC failure are? Knowing the main reasons that can create problems with the air conditioning system can help prevent unwanted and sudden interruptions in operations, especially during the hottest days.

This article goes over the main reasons your AC can stop working, but if you still need help from a professional, don’t hesitate to contact Hurliman Heating.

What are common problems with air conditioners?

In most cases, you can figure out a problem with your AC by yourself even before the situation gets too complicated and your system experiences a major breakdown. Sometimes, you understand you have to take action by a sound or a slight change in how your AC performs.

Here are the common problems you can expect from air conditioners:

1. Low refrigerant

Every AC unit uses refrigerant to remove heat and humidity from the air. Generally, the refrigerant level diminishes due to internal licks.

It is not always easy to spot refrigerant leaks because they are not visible. Still, if you detect that the AC unit has lower efficiency, consumes too much, or has uneven cooling, you can suspect that the refrigerant level is low.

Often the problem cannot be resolved by replacing the refrigerant, but a professional needs to intervene and locate the leaks and repair them.

2. Frozen evaporator coil

The evaporator coil needs warm air to continue to work correctly. If something impedes airflow into the system, and if the coil cannot get warm air, it will freeze and stop working. Therefore, a constant airflow into the system is necessary for the AC to perform well.

The things that can impede the airflow are blocked ducts and vents, damaged fans, and dirty filters. In most cases, it is only necessary to regularly change the filters and make sure to clean the ducts to prevent a frozen evaporator coil.

You can spot that the coil is frozen by the warm air coming out from your AC unit and by inspecting the state of the filters.

3. Drain problem

Another common problem is a clogged drain line. After a while, dust, dirt, mold, and fungus develop and accumulate in the drain line blocking it. If this happens, the water collected from the moisture has no way to go down the drain and leak.

Water leaks can damage the walls, the AC system, and furniture. In addition, the accumulation of bad things into the drain line can result in gasses and foul odors getting into your house. The solution to this problem is the cleaning of the drain line.

4. Dirty condenser coils

Every AC unit has a condenser coil situated outside the house to remove the heat in your home and expel hot air outside. However, it can get dirty due to regular usage or outside pollution. If the condenser coil becomes too dirty, it will become challenging for the unit to do its job.

It can result in higher energy consumption, increased wear, and even breakage of the AC system. The solution is to clean the condenser soil routinely to prevent dirt buildup.

5. Thermostat problems

Sometimes the thermostat is not working correctly because of a problem with the batteries or a malfunctioning part. If the thermostat has a problem, the AC unit may not work to produce the result you want.

It can create a problem with your temperature, which will be too hot or too cold, and higher utility bills. The issue can be resolved by changing the batteries or replacing a broken thermostat.

6. Fan problems

In general, an AC unit has a fan responsible for bringing hot air to the evaporator coil to make the air cooler, and there is another fan liable to blow air to the outside unit and expel hot air. Both fans need to work appropriately for the air conditioning system to perform at its best.

The fan can experience a problem due to a malfunctioning motor, low lubrication, damaged belt, and accumulation of dirt and debris. The result is terrible airflow and lousy air conditioning. In addition, if the situation is not resolved in time, it can result in a breakage of the entire AC unit.

7. Leaking ducts

Leaking ducts will reduce the efficiency of your AC unit. Holes through the ducts are responsible for dispersing the cool air produced by the air conditioning system. This means the unit has to work much more to make your house cool and reach the thermostat temperature.

Not only will it be harder to make the environment cool, but you will experience a higher utility bill. The solution is to have your ducts inspected for holes, and once they are found, seal them. In addition, it is also possible that ductwork is poorly fit, and air will manage to escape through the holes.

When the ducts are old, they are more susceptible to getting holes, if this is the case, routine inspections should be done, and in some instances, one should consider replacing them.

8. Damaged air conditioner compressor

The compressor is a vital part of an air conditioning unit. It has to compress the refrigerant to flow into the system and remove the heat. If you experience a weak airflow, hear a banging noise, and a high electricity bill, you could suspect that there is something wrong with the compressor.

With a weak airflow or a flow of unwanted warm air, you can suspect that your compressor is not functioning anymore. A professional should come to inspect the system and advise you on repairing or replacing the compressor.

How can you prevent AC system failures?

To prevent AC system failures, you can start with simple actions that you can do yourself and ask for a technician to do routine maintenance and the work you can’t do yourself. For example, you can make sure to replace dirty air filters routinely.

You can also have your ducts inspected every one or two years, and in case of any hole found have them sealed. Then, the ducts can be cleaned of dirt and dust with the same inspection.

The thermostat should be inspected regularly to find any discrepancy between the house temperature and the one shown on display. You should also check the batteries to make sure they are charged.

Finally, regular cleaning should be done through the drain line and the condenser coil.


There are many reasons for AC failures. You can often maintain good operational standards by cleaning the ducts, the condenser coil, the drain line, and the vent and regularly replacing the filters. But, it may not be enough.

If you have problems with your AC unit that you can’t resolve yourself of the yearly maintenance, contact us.

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