What Is an AC System Capacitor?

Residential AC systems contain a variety of different parts. Some of these parts use a mechanical method of operation, whereas others are electrical. Capacitors fall under the latter type. Regardless of your AC system’s size, it probably has at least one capacitor. What is a capacitor exactly, and how does it affect your AC system?

The Basics of AC System Capacitors

Capacitors are electrical devices that are designed to store electricity. They are relatively small and tube-shaped. In AC systems, capacitors provide the initial jolt of electricity that’s needed to start the cooling cycle, and in some cases, continue the cooling cycle.

How Capacitors Work in AC Systems

Your AC system won’t work without a functional capacitor. Capacitors aren’t much different than rechargeable batteries. When running your AC system, one or more capacitors will store electricity. And the next time you run your AC system, the capacitor or capacitors will use this stored electricity to begin the cooling cycle.

There are two primary types of capacitors used in AC systems: start and run. Start capacitors live up to their namesake by providing the electricity needed to start your AC system. Run capacitors, on the other hand, provide the electricity needed to keep your AC system running.

With that said, both types of capacitors can be bundled into a single unit, which is why some AC systems only have a single capacitor. Other AC systems have a separate run capacitor and a separate start capacitor.

Signs of a Bad Capacitor

With a bad capacitor, you may not be able to turn on your AC system. Alternatively, your AC system may take longer than usual to begin its cooling cycle. These symptoms are the result of a lack of electricity. Your AC system won’t receive a sufficient amount of electricity if it has a bad capacitor.

Depending on the type of damage or failure sustained, a bad capacitor can lead to higher cooling costs. It can force your AC system to draw more power from your home, resulting in higher cooling costs. For greater efficiency, you’ll need to replace the bad capacitor.

Because it’s an electrical component, you shouldn’t attempt to replace a bad capacitor yourself. Rather, you should contact a heating, ventilation and cooling (HVAC) technician for assistance. HVAC technicians know how to properly replace bad capacitors safely and properly.