Heat waves are when AC systems fail most often — and when getting a repair technician is hardest.

When outdoor temperatures hit 95°F+ for multiple days in a row, your air conditioner runs nearly continuously, pushing every component to its limits. Systems that have been limping along with small problems often fail completely during a heat wave. A little preparation before extreme heat arrives can make the difference between staying comfortable and waiting days for an emergency repair.

1. Replace the Air Filter

A clean filter is the single most important thing you can do for your AC's performance. Before a heat wave, check your filter and replace it if it has been more than 4 weeks since the last change. A clogged filter restricts airflow, reduces cooling capacity, and can cause the evaporator coil to freeze — the last thing you want when it is 98°F outside.

2. Clear the Outdoor Condenser Unit

Walk outside and inspect your condenser unit. Remove any leaves, grass clippings, or debris that have accumulated against the sides. Trim back any vegetation that has grown within two feet of the unit. The condenser needs to reject heat efficiently — anything blocking airflow reduces its ability to do so.

3. Check the Condensate Drain

In high humidity, your AC removes a significant amount of moisture from the air — up to several gallons per day. All of that water drains through the condensate line. Pour a cup of water into the drain pan and watch that it drains freely. If it backs up, clear the line before the heat wave hits.

4. Test Your Thermostat

Set your thermostat to a temperature well below the current room temperature and confirm the system starts and runs. If you have a smart thermostat, check that it is connected and the schedule is set correctly. Replace thermostat batteries if it is battery-powered.

5. Check All Vents Are Open and Unobstructed

Walk through your home and make sure all supply and return vents are open and not blocked by furniture, rugs, or curtains. Closed or blocked vents increase static pressure in the duct system and reduce airflow throughout the house.

6. Pre-Cool Your Home Before the Heat Peaks

On the day before or the morning of a heat wave, run your AC to bring your home to a lower temperature than your normal set point — say 72°F instead of 76°F. Your home's thermal mass (walls, floors, furniture) stores that coolness and helps maintain comfort even as outdoor temperatures climb. This is especially effective in homes with good insulation.

7. Have Your System Inspected if It Has Not Been Serviced This Year

If your AC has not had a professional tune-up this season, consider scheduling one before the heat wave rather than after. A technician can check refrigerant levels, test the capacitor and contactor (the components most likely to fail in extreme heat), and identify any issues before they become emergencies.

What to Do If Your AC Fails During a Heat Wave

If your system fails during extreme heat, call A1 immediately. We provide emergency AC repair throughout Long Island 24 hours a day, 7 days a week. While you wait:

• Close blinds and curtains to block solar heat gain
• Move to the lowest floor of your home (heat rises)
• Use fans to create airflow
• Stay hydrated and watch for signs of heat exhaustion

Call 631-331-2102 for emergency AC service or request service online.