Definition
A small component that stores and releases the jolt of electricity needed to start and run motors. A failed capacitor is one of the most common (and inexpensive) AC repairs.
Why this matters for your home
Capacitors come in two roles: a start capacitor gives a motor the surge it needs to begin turning, and a run capacitor keeps it spinning smoothly. Heat is their enemy, so they tend to fail during the hottest stretch of summer — exactly when you need the AC most.
The upside is that a failed capacitor is usually a quick, low-cost fix once it's correctly diagnosed. The symptom — a humming outdoor unit with a fan that won't spin — can mimic bigger problems, so we test the part rather than guess before recommending a replacement.