What Are Air Conditioner Capacitors and Why Are They Important?

As the weather gets warmer, you may be thinking about firing up your air conditioner for the first time…
Man serving the air conditioner

As the weather gets warmer, you may be thinking about firing up your air conditioner for the first time in months. But before you do, you should check your air conditioner’s capacitor. An air conditioner capacitor is an electrical component that helps start and run the compressor. An AC capacitor provides the initial jolt of electricity your air conditioner’s motors need to run successfully. It also helps regulate the flow of electricity to the compressor. The capacitor stores energy and releases it in short bursts, which helps the compressor start and run smoothly.

If the capacitor for AC unit fails, the compressor will not start or may not run correctly. In general, your capacitor is likely to go bad before other parts of your AC unit and will need to be replaced at some point. Capacitors are made to last around 20 years, but many factors can contribute to premature failure. If your AC over cycles, experiences extremes in temperature or surges, or if the capacitor has a defective part, it won’t last that long. Let’s take a closer look at air conditioner capacitors.

How do you know if your AC capacitor is bad?


As discussed, AC capacitors are used to start the compressor and fan motors. They also stabilize the voltage supplied to the motors. If an air conditioner capacitor is bad, it will not be able to start the compressor or fan motor. The compressor may hum but will not start. This is the primary sign that your capacitor has gone out. Before it completely fails, however, you might notice some other symptoms. If you notice that your AC system takes some time to start a cooling cycle or that it shuts off at random intervals, you may have a capacitor problem. Additionally, you might also experience higher than normal energy bills or smell a burning odor from air conditioning components.

You can test an air conditioner capacitor with a multimeter tester. Set the meter to ohms and touch each lead to each terminal on the capacitor. The meter should read zero resistance if the capacitor is good. If there is resistance, the capacitor is bad and needs to be replaced. An HVAC professional will be able to help you check your capacitor.

Why do capacitors go bad?

Problems with your AC capacitor will prevent your system from performing as it should. A faulty capacitor can occur at any time and leave you with uncomfortable indoor temperatures. If your system overheats and the system circuitry is impacted, your capacitor could fail. In addition, power surges, a lightning strike, and extremely high outdoor temperatures could also cause the capacitor to fail prematurely. Your capacitor might also go bad as part of normal equipment wear and tear.

What are the potential problems with AC capacitors?


There are a few potential problems that can occur with your AC capacitor. One is that they can overheat and cause a fire. Another is that they can leak, which can damage other parts of the air conditioning unit. Additionally, a failing capacitor could trigger a tripped breaker in your home. This could also impact other electrical devices in your home.

Finally, they can fail completely, which will prevent the air conditioning unit from working properly. It is important to pay attention to the signs that your capacitor is going bad to prevent problems with your AC unit and uncomfortable temperatures in your home. Regular HVAC maintenance is essential for getting your system checked out annually to ensure that components like your capacitor are in good shape.

Altogether, capacitors are important components of air conditioners because they help regulate the flow of current and ensure that the AC unit operates smoothly. If you have a bad capacitor, your air conditioner will not be able to function properly, which could result in decreased cooling performance and possible damage to the unit.