In the Phoenix area, your air conditioner isn’t a luxury — it’s essential. The best time to make sure it’s ready for triple-digit days is before they arrive. Here’s a simple checklist to prepare your AC for extreme heat, plus tips to keep it running efficiently all summer.

Quick answer

Before summer, schedule a professional tune-up, replace your air filter, clear the area around the outdoor unit, test your thermostat and listen for unusual noises. During heat waves, keep the thermostat steady, close blinds on sun-facing windows and avoid running heat-producing appliances in the afternoon.

Your pre-summer AC checklist

1. Schedule a professional tune-up

A technician can check refrigerant levels, test capacitors and contactors, and inspect coils before small issues turn into summer breakdowns. Spring appointments are also easier to get. See what’s included in our tune-up.

2. Replace the air filter

Start the season with a fresh filter and check it monthly. A clean filter keeps air moving and helps prevent frozen coils.

3. Clear around the outdoor unit

Remove weeds, leaves and stored items, and trim plants so the unit has open space to breathe. Never cover the unit while it’s in use.

4. Test the thermostat

Switch to Cool, lower the set temperature and confirm the system starts. Replace batteries if needed. A smart or programmable thermostat can help manage cooling costs.

5. Check vents and returns

Make sure furniture and rugs aren’t blocking supply vents or return grilles, and keep vents open so the system stays balanced.

6. Look and listen

Watch for water around the indoor unit, ice on the lines, or new noises like grinding, buzzing or squealing. Any of these deserve a call before the heat peaks.

Tips for getting through a heat wave

• Keep the thermostat steady. Large swings make the system work harder to catch up.
• Block the sun. Close blinds and curtains on east- and west-facing windows during the day.
• Shift heat-producing chores. Run the oven, dryer and dishwasher in the morning or evening.
• Use ceiling fans to help rooms feel cooler — and turn them off in empty rooms.
• Don’t close too many vents. It can reduce airflow and strain the system.

Know when to call

If your AC can’t keep up, cools unevenly or shows any of the warning signs above, don’t wait for a full breakdown during a heat wave. Read about common summer HVAC problems or schedule AC repair.