AC quit on a hot day? Get it cooling again.

Some no-cooling calls end with a switch or a filter. These checks need no tools and no opening of panels. If none of them fixes it, call the number on this page or send the form.

1. The thermostat. Set to cool, set below the room temperature, fan on auto, and fresh batteries if it uses them.
2. The breaker. Look for a tripped breaker for the air conditioner or the furnace in the electrical panel. If it trips again after you reset it, leave it off and call.
3. The air filter. A clogged filter starves the system of air. ENERGY STAR says to inspect, clean or change the filter once a month, and that a dirty filter can raise energy costs and damage equipment.
4. The condensate drain. Water in the drain pan or around the indoor unit points to a plugged drain line.
5. The outdoor unit. Clear leaves, boxes and plants away so air can move through it, and keep the area around it open.

More detail, and what each check tells you, is in AC not cooling? What to check first.

A repair visit starts with questions: what the system is doing, when it started, and what you have already checked. Then the contractor tests the equipment. ENERGY STAR’s checklist for an air conditioner check-up gives a good picture of what a contractor looks at, and the same parts come up when something has failed:

Once the cause is found, ask for the repair in writing: what is wrong, what will be done, and the price. If the fix involves replacing a major piece of equipment, ask whether it needs a permit, because the City of San Diego’s mechanical permit covers air conditioning systems that are installed, altered, replaced or repaired.

A few public rules protect you on any AC job in San Diego. They apply whoever does the work, so they are worth knowing before anyone starts.

• The license. California’s Contractors State License Board (CSLB) license class for heating and air conditioning is C-20, Warm-Air Heating, Ventilating and Air-Conditioning. You can look up any license number on cslb.ca.gov.
• The $1,000 limit. Since January 1, 2025, an unlicensed person may do a small job under $1,000, counting all costs, and only if no workers are hired and no building permit is needed. A job that needs workers or a permit needs a licensed contractor in the right class.
• The permit. The City of San Diego’s Development Services Department says heating, ventilating, air conditioning and refrigeration systems may not be installed, altered, replaced or repaired unless a mechanical permit has been obtained. Other cities in the county run their own building departments.
• The money. CSLB cautions that a down payment should not exceed 10 percent of the contract price, and later payments should not run ahead of the work completed or the materials delivered.

The HVAC contractor guide goes through each of these step by step, with a checklist you can use before you sign.

San Diego has had record heat waves, and an AC that quits in one is more than an inconvenience. While you wait for the repair, it helps to know where you can go to cool off.

During a heat wave, San Diego County lists air-conditioned Cool Zones, such as libraries and community centers, that anyone can use. Check the County’s Cool Zones page for the nearest one. If someone shows signs of heat stroke, call 911.

The San Diego heat wave guide covers how to keep a working AC running through the hottest days and what to do if it stops.

This site is about home air conditioning. For a car’s AC, an auto repair shop is the place to ask. Here the subject is the system that cools your house: the outdoor condenser, the indoor coil and blower, the ducts or the ductless heads on the wall, and the thermostat.

Air Conditioning Repair San Diego is an independent referral service, not an air conditioning or HVAC company. Calls and form requests are passed to an independent local AC and HVAC contractor, who can contact you about your system; that contractor gives any quote and does any work.