Keep a Spare AC Capacitor on Hand Before Yours Fails on the Hottest Day of the Year

The Problem

A run capacitor is one of the most common points of failure in a central AC unit, and it tends to fail under exactly the load that a 95-degree day puts on the system. The part itself is cheap — usually $10 to $40 — but an HVAC company's emergency call during peak summer can run several hundred dollars, on top of a wait during their busiest week of the year.

The Technique

1. Find your outdoor AC unit's condenser fan/compressor capacitor — it's mounted inside the access panel on the unit.
2. Read the µF (microfarad) rating and voltage rating printed on the capacitor itself, or check your unit's model documentation for the specified capacitor.
3. Order a matching replacement capacitor with the same µF rating and voltage.
4. Keep it on a shelf in the garage or wherever you store spare parts, so it's on hand the moment you need it instead of something you have to order and wait days for.

Having the exact part already in hand turns a capacitor failure from a multi-day wait — or an emergency service call at premium pricing — into something that can be swapped as soon as a qualified technician (or you, if you know how) is available.