
When your AC starts to act up, there are a number of culprits that could be the cause. However, certain signs point to the system’s powerhouse, the capacitor. The capacitor supplies electricity to your system to ensure the motors can function. When your AC capacitor is faulty, it can wreak havoc on the entire system. Keep reading to discover how the capacitor works, signs it’s failing, and when to call a technician for replacement.
What is an AC Capacitor?
Due to the amount of power your AC system uses, it requires a jolt of electricity to kickstart the motors. The AC capacitor, which functions similarly to a battery, is connected to your AC wiring and stores electricity to send to the motors in strong bursts when turned on. Once the system is running, the capacitor continues to supply power to the motors at a lower voltage until the cycle is complete.
Signs Your AC Capacitor is Failing

Supplying large bursts of electricity is a strenuous job that puts a significant amount of wear and tear on the capacitor. Because of this, it’s not uncommon for the capacitor to fail or break down over time. Knowing the signs that your capacitor is failing can help you get ahead of the issue before your unit stops functioning completely.
Keep an eye out for any of the following signs that your capacitor is on its last legs:
- Your AC is blowing warm air: If your system is blowing lukewarm or hot air through the vents, this can indicate a bad AC capacitor, which can cause short circuits or other electrical damage.
- Increased energy bills: When your capacitor begins to break down, it uses significantly more energy for your AC to function. If your energy bills suddenly increase, it may be time to schedule service.
- Humming noises: A failing AC capacitor can cause your unit to create a buzzing or humming sound within the access panel.
- Burning smells: If the capacitor fails, you may notice burning smells from the motors. Contact a technician as soon as possible if this occurs.
- Your system turns off without warning: If your AC is turning off on its own, this is a clear sign that the capacitor is faulty.
Troubleshooting a Faulty Capacitor
If your AC system shows any signs of being faulty, it’s best to contact a licensed technician. Working with electricity presents serious dangers and should only be done by those with the proper training and experience. They’ll know how to diagnose the issue and safely fix the faulty AC capacitor.
If you’d like to troubleshoot the capacitor yourself, follow these troubleshooting steps to test the power of the capacitor:
- Turn off the power on your unit at the breaker panel.
- Put on safety equipment and use a voltage tester to confirm the power is off.
- Conduct a visible inspection to look for loose connections, cracks, leaks, or burn marks.
- Use an insulated screwdriver to touch both terminals of the capacitor at the same time to discharge stored electricity.
- Remove the capacitor from the AC unit and disconnect the wires from the terminals.
- Grab a multimeter and set it to capacitance measurement mode.
- Connect the multimeter to the capacitor terminals and read the value displayed.
- Check the capacitor’s rated capacitance value, listed on the body, and compare it to the reading on the multimeter.
- The capacitor is likely working properly if the reading value is within 10% of the rated value. If it’s outside of this range, the capacitor is faulty.
AC Capacitor Replacement
If your AC system shows signs of capacitor failure or a multimeter test shows a value outside of the normal range, contact a certified technician for replacement. Capacitors can hold a large electrical charge, and replacing them yourself can pose a serious threat of electric shock.
When a technician visits your home, they’ll confirm that the capacitor is faulty, remove the old one, and install a new one. They will then test your system to ensure everything is working correctly and answer any questions you may have.
It’s important never to ignore signs of a bad AC capacitor. Failing to replace it can result in further damage to your system, costly repair bills, and a fire hazard. If you’re looking for a capacitor replacement in North Carolina, contact the team at Jay’s.
Preventing Future AC Capacitor Problems
The best way to prevent future capacitor issues is to schedule annual AC maintenance. AC maintenance enhances the lifespan of your system, ensures everything is working correctly, and helps you stay ahead of repairs.
During the service, a technician will inspect, clean, and tune up your system. They’ll also identify and complete any necessary AC repairs before they become more significant.
Call Jay’s for AC Services in North Carolina
If your AC capacitor is showing signs of failure, contact our team at Jay’s Heating, Air, and Plumbing. Our family-owned business proudly serves residents in Mount Airy and surrounding areas. With four generations of experience, you can trust that we’ll get the job done right.
We offer a flat-rate pricing system, so you’ll always know how much you pay before the bill arrives. If you’re unhappy with the service for any reason, you can rest easy knowing you’re protected by our 100% satisfaction guarantee. We also offer flexible financing options, so you never have to worry about a service breaking the bank. Call us or book online to schedule your service today!
Frequently Asked Questions
When should I replace my AC capacitor?
Capacitors can last up to 20 years. If yours is nearing the end of its lifespan or is displaying signs of failure, it’s best to have an HVAC technician replace it. Installing a new capacitor will help your system function better, reduce energy bills, and prevent further damage to your AC.
My AC fan isn’t spinning. Could the capacitor be the cause?
If your AC fan isn’t spinning, a faulty capacitor could be the cause. A broken capacitor is one of the most common causes of malfunctioning or burnt-out fans. Contact our team today if you notice a broken fan or any other signs of AC malfunction. Our technicians will quickly diagnose the issue and get your AC back in working order.