Capacitor Basics
The tiny but critical part that starts your AC compressor and fan motors. Here’s exactly what it does and why it fails so often in North Texas.
The tiny but critical part that starts your AC compressor and fan motors. Here’s exactly what it does and why it fails so often in North Texas.
A bad capacitor is one of the most common reasons your AC or furnace suddenly stops working.
A capacitor is a small cylindrical component that stores and releases electrical energy to give your compressor and fan motors the powerful “kick start” they need. Without it, the motor hums but never starts — or runs weakly.
There are two main types in HVAC systems:
Motor tries to start but can’t.
Overheating due to weak start.
Capacitor struggling to engage.
Capacitor overheating or leaking.
Motor works harder without proper boost.
Visible physical failure.
Capacitors store high voltage even when power is off. Never attempt to replace one yourself — it can cause serious injury or damage your system. Legend Air technicians replace capacitors safely in 15–30 minutes on the truck.
Most capacitor failures are caused by extreme Texas heat, power surges, and lack of maintenance. Our Seasonal Maintenance Plan includes capacitor testing and early replacement — before they fail.
Typically 5–10 years. In North Texas heat they often fail closer to 5 years.
No — high voltage danger and risk of damaging the motor. Always use a licensed technician.
Usually $150–$350 including labor.
Yes — if left running, it forces the compressor to work harder and can cause permanent damage.
It’s likely your capacitor. Our Arlington team is ready 24/7.