Seasonal Checklists

Summer HVAC Checklist

Quick answer

Summer HVAC care is about protecting a system running at its limit: check filters monthly, keep the condenser clear and shaded if possible, raise the thermostat rather than pushing during extreme heat, watch the condensate line, and treat weak cooling as an early warning instead of waiting for total failure.

Mid season habits that prevent breakdowns

Cooling systems fail during heat waves because that is when marginal components meet maximum load. These habits keep margin in the system.

Check the filter every 30 days; summer runtime loads filters twice as fast as shoulder seasons
Glance weekly at the condensate drain termination for steady dripping during humid weather, the sign the drain is clear
Keep grass clippings, mulch, and cottonwood fluff off the condenser, and rinse the coil mid season if it looks gray
Listen for longer cycles and diminishing coldness, the classic prelude to a capacitor or refrigerant failure
Keep supply vents open; closing rooms raises duct pressure and hurts efficiency rather than helping it

Heat wave protocol

Above 95 degrees, a correctly sized system may run continuously and only hold 18 to 22 degrees below outdoor temperature. That is design behavior, not failure. Fighting it by cranking the setpoint lower achieves nothing except hiding real problems.

During extreme heat: set the thermostat a few degrees higher than usual and hold it steady, close blinds on sun facing windows, run ceiling fans to raise the comfortable setpoint, avoid oven use in the afternoon, and pre cool the house overnight and in the morning. If cooling declines noticeably during a heat wave, call promptly; response queues during heat emergencies run days long, and early callers get served first.

Watch the two summer failure points

Two components cause most summer emergencies. The run capacitor weakens with heat and age, then fails on a 100 degree afternoon, announced beforehand by the outdoor fan starting sluggishly or the unit humming before starting. The condensate system clogs with summer algae growth, then floods a ceiling; a float switch, a $15 part, converts that flood into a harmless shutdown. Ask for both to be checked at any summer service visit.

Frequently asked questions

Why cannot my AC keep up on the hottest days?

Systems are sized to hold about 20 degrees below outdoor temperature at your area's design condition, which the hottest few days each year exceed. Running continuously while holding 78 inside during 100 degree heat is normal. Losing ground it previously held, however, signals a dirty coil, weak capacitor, or low charge.

What temperature should I set my AC in summer?

78 degrees while home is the standard efficiency recommendation, with 7 to 10 degrees higher while away paying roughly 1 to 3 percent savings per degree over 8 hours. Comfort rules over rules of thumb, but every degree lower costs about 3 to 5 percent more energy.

Should I shade my outdoor AC unit?

Natural shade from trees or structures helps marginally, a few percent, but never enclose the unit or restrict airflow, which costs far more than shade gains. Two feet of side clearance and open discharge above matter more than shade.