Is It Time To Replace The Air Conditioner Capacitor?

When it comes to indoor comfort and energy costs, the air conditioner capacitor plays an important role. The compressor in your air conditioner uses considerable energy, especially when starting up, but a capacitor makes the unit start quickly.  If your indoor temperature has risen in the spring and summer months, you may need to check your air conditioning capacitor. Your air conditioner might need a new capacitor if it’s not working as efficiently as it used to. 

Why You Should Replace Your AC Capacitor


When your thermostat signals that it’s time to cool off, it signals the air conditioner, which turns on the capacitor. The capacitor sends a jolt of electricity to start the cooling cycle. It then maintains a steady stream of energy to run the unit until it reaches the target temperature.  If the capacitor fails, it can cause your air conditioner to not turn on or operate at full capacity. A capacitor is attached to your air conditioner via several cables, so replacing it is more difficult than just opening and replacing it.

How an HVAC Technician Tests a Capacitor

Like any major appliance or HVAC unit, it’s important to stay on top of your air conditioning service. If you receive regular inspections, you can identify capacitor issues before they result in catastrophic failure. During an inspection, we can quickly inspect your unit and identify any problems that may exist. We can then replace any problematic parts before they become a larger issue.  To prevent trouble, they use a multimeter to determine the current, resistance, and voltage of the capacitor. A multimeter lets them see if the capacitor can store the charge required to start and finish the cooling system. If the readings are poor or don’t register at all, it’s time to replace the capacitor. 

Signs You Should Replace Your Capacitor

If your air conditioner is not working, the most common cause is a bad capacitor. When you see any of these signs that your capacitor has failed, contact us to set up an appointment.

Heat Damage

Long-term exposure to heat can break down capacitors. Thus, in order to stop the capacitor from deteriorating, shade your air conditioner unit as much as possible to make it spend fewer hours in the sun.


Capacitors last between 10 and 20 years, but a variety of factors can shorten their lifespans, such as heat exposure, under-sizing, or even the use of incorrect components. We can check and replace your capacitor for you if it is past its lifespan. 

Incorrect Voltage Rating

There is a specific voltage rating for each A/C capacitor, and some homeowners don’t always get the one designed for their unit when they replace it themselves. During this process, the capacitor might short or overwork, reducing its lifespan. Incorrect capacitors may cause parts to fail, leading to system failure. Although the replacement of a capacitor may appear simple, it’s best to leave it to the HVAC experts. 

Delayed in Beginning a Cooling Cycle

As a capacitor ages, it becomes less effective at storing energy, so it will take longer for the system to begin a cooling cycle. Additionally, it may stop cooling altogether. There is a good chance that you will need to replace your capacitor if your home is much warmer than normal.

Rattling or Clanking Noise

When capacitors go bad, they can sometimes make clanking or rattling noises when they release their stored energy. This may cause other problems with your air conditioner as well, such as flickering lights or buzzing noises from fans or motors.

Burning Smells from Your Unit

This can be a sign that your capacitor is failing and needs to be replaced immediately. If this happens, do not attempt to fix the issue on your own. Call us immediately so we can diagnose the problem and repair or replace it quickly.

Increased Energy Costs

A high energy bill is another indicator of a faulty capacitor. If your capacitor isn’t functioning properly, your air conditioner will use more energy than usual to chill your home. As soon as you notice a spike in your energy costs, you should contact us to check your capacitor. 

Remember to Schedule Your Inspection

A poor capacitor can cause an array of issues, including an inefficient air conditioner and potential damage to your electrical system. Regular air conditioner maintenance every spring and fall ensures that you avoid an unexpected and unwelcome repair bill.  Schedule a service call with us to see if your capacitor is on its way out and remember to ask how often you should service your unit‌. If your air conditioning capacitor is failing, you’ll be glad you scheduled your HVAC checkup early enough to replace it.