How Long Do AC Capacitors Last

How Long Do AC Capacitors Last?

AC capacitors play a crucial role in the functioning of air conditioning (AC) systems by storing and releasing electrical energy. But how long do they last? Let’s delve into the intricacies of AC capacitors to understand their lifespan and the factors affecting them.

Introduction to AC Capacitors

What are AC Capacitors?

AC or run capacitors are electrical components found in AC units. They store and release energy to help start and run the compressor and fan motors.

Importance of Capacitors in AC Units

Capacitors are essential for the smooth operation of AC systems. They provide the necessary jolt of electricity to start the motor and keep it running efficiently.

Functionality of AC Capacitors

AC capacitors work by storing and releasing electrical energy. There are two main types: start capacitors and run capacitors. Start capacitors provide the initial boost to start the motor, while run capacitors ensure the motor continues to run smoothly.

Factors Affecting the Lifespan of AC Capacitors

Several factors influence how long AC capacitors last:

Temperature Fluctuations

Extreme temperatures can affect the performance and lifespan of capacitors. High temperatures can cause them to degrade faster.

Electrical Stress

Frequent power surges or voltage fluctuations can stress capacitors, leading to premature failure.

Age of the Capacitor

As with any electronic component, the age of the capacitor can impact its performance and longevity.

Quality of Manufacturing

The quality of the capacitor and its components can significantly affect how long it lasts. Cheaply-made capacitors may fail sooner than higher-quality ones.

Average Lifespan of AC Capacitors

On average, AC capacitors can last anywhere from 10 to 15 years. However, this lifespan can vary depending on several factors, including usage, environmental conditions, and maintenance.

Signs of a Failing AC Capacitor

It’s essential to be aware of the signs indicating a failing capacitor:

  • Weak or no airflow: If you notice reduced airflow from your AC vents, it could be due to a failing capacitor.
  • Trouble starting: Difficulty starting the AC unit or frequent cycling on and off may indicate capacitor issues.
  • Strange noises: Unusual sounds from the AC unit, such as buzzing or humming, can signal capacitor problems.

Preventive Maintenance for Prolonging Capacitor Lifespan

Regular maintenance is critical to prolonging the lifespan of AC capacitors:

  • Keep the unit clean: Regularly remove debris from the AC unit to prevent overheating.
  • Schedule professional inspections: Regular maintenance by a qualified technician can help identify and address potential issues before they escalate.

Replacing AC Capacitors

When it’s time to replace a faulty capacitor, it’s essential to do so promptly and correctly:

  • DIY vs. Professional Replacement: While some homeowners may attempt to replace capacitors themselves, hiring a professional is generally recommended to ensure proper installation and safety.
  • Cost Considerations: The cost of replacing a capacitor can vary depending on factors such as the type of capacitor and labour costs.
  • Use Compatible Capacitors: When replacing a capacitor, it’s crucial to use one compatible with your AC unit to ensure optimal performance and longevity.


AC capacitors are vital components of air conditioning systems, crucial in starting and running the compressor and fan motors. Understanding the factors that affect their lifespan and knowing the signs of a failing capacitor can help homeowners maintain their AC units and ensure efficient operation for years.

FAQs (Frequently Asked Questions)

  1. How do I know if my AC capacitor could be better?
  • Look for signs such as weak airflow, trouble starting the unit, and unusual noises from the AC system.
  1. Can I replace the capacitor myself?
  • While some may attempt DIY replacement, hiring a professional for safety and proper installation is generally recommended.
  1. How often should AC capacitors be replaced?
  • AC capacitors typically last around 10 to 15 years, but regular maintenance can help prolong their lifespan.
  1. What happens if a capacitor fails?
  • A failed capacitor can cause the AC unit to struggle to start, reduce cooling efficiency, and potentially lead to other system malfunctions.
  1. Is regular maintenance necessary for AC capacitors?
  • Yes, regular maintenance, including cleaning and professional inspections, is crucial for ensuring AC capacitors’ optimal performance and longevity.