Air conditioning systems, which have become ubiquitous over time, rely on several crucial components to keep them functioning. AC capacitors are one of these parts, and when they stop working, fixing them quickly is essential. Here’s what you need to know about AC capacitors and how to replace them, if necessary.

What Is an AC capacitor?

An AC capacitor is a part of an air conditioning system. It’s one of the essential components to fix if the compressor is not kicking on. The capacitor stores a charge, which is then transferred to the ground when the compressor starts. Without this part, the condenser or compressor isn’t likely to start up. If the compressor can’t turn on, it must be replaced.

A capacitor is a type of electrical storage device, which stores electric charge in an electrostatic field. The capacitance of a capacitor is measured in farads, or units denoted by the letter F.

What Does an AC Capacitor Do?

The capacitor charges up when the compressor kicks on, but it discharges back to the ground once it’s done charging. This process of charging and discharging allows the compressor to operate.

The capacitor is constructed with several electrodes spaced apart to create an electric field across the plate structure. The more charge that is stored in the capacitor, the stronger this electric field will be, increasing its ability to store electric charge while preventing current from flowing freely between the electrodes.

Signs of a Bad AC Capacitor

If your air conditioner is having trouble starting or the compressor isn’t starting, this may be due to a bad capacitor. If you hear the compressor start up but then shut down after just a few moments, this could also be a sign of a bad capacitor.

Your air conditioning unit produces humming or buzzing sounds during operation, which may also indicate a bad capacitor. If your AC produces high-pitched sounds, or if the compressor starts with a pop, this could also be a sign that a bad capacitor is to blame.


A bad capacitor can cause your energy bills to be high, which is often the first thing that alerts you that your air conditioner may have a problem. After all, if your AC unit isn’t working correctly, energy is not used efficiently. The AC unit uses a lot of electricity to keep your home at a specific temperature, so when it’s not working properly, you may pay higher energy bills.

You should also check for a bad capacitor if your system randomly shuts off. This is because the compressor may be shutting down. After all, the capacitor is not transferring enough charge to the system.

You detect a burning smell from your air conditioning unit, often resulting from a lousy system part. If you notice this smell, you should contact a professional AC technician as soon as possible.

How Much Does It Cost to Fix a Bad Capacitor?

The cost of replacing a capacitor depends on factors such as the type of system you have and if you want a professional to replace it. A good rule of thumb is to check with a service provider or call the manufacturer and ask for a quote. Some older units may require more than one capacitor to be replaced.

Many brands use proprietary parts, so it is difficult to say what an individual replacement will cost. You may need to consult with a repairperson before knowing your system’s brand or type.

Can I Replace a Bad AC Capacitor?

Replacing a bad capacitor is not difficult. However, you’ll want to be sure that you are working with the correct type of capacitor, and this can be tricky because the only way to know for sure is to look at the part number on your air conditioner. This may require you to disassemble your air conditioning unit, which should only be done if necessary or by an experienced technician.

Find a local certified technician to fix your AC capacitor. A good technician has good knowledge of air conditioners and is capable of fixing your system.


Regular maintenance of your air conditioner will ensure that it lasts for a more extended period. We at Ultimate Homes & Cooling can inspect your system and fix issues. We are located in Cape Coral, FL.

In conclusion, AC capacitors work to start your air conditioning unit by storing electricity and then releasing it to the ground. They provide a charge that allows the compressor to start, and when the capacitor stops working, the whole unit may stop functioning. Therefore, it’s important to get them checked yearly. We offer cooling, heating, and indoor air quality services. Contact Ultimate Homes & Cooling today for more information.

Contact an AC technician today!

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