New Orleans Heat Wave AC Survival Guide: What's Normal, What's Not, and When to Call

When the forecast says 97° and the heat index is pushing 110°, our phones light up. Plenty of those calls are real breakdowns. But a good share come from folks whose air conditioner is doing exactly what it was built to do — it's just being asked to do more than it was designed for.

This guide will help you tell the difference, take some load off your system, and recognize the signs that mean you need help now, not next week.

What your AC is actually designed to do

Home AC systems are sized using a load calculation — Manual J is the industry standard — built around a local design temperature. For New Orleans, that's somewhere around 93–95°F, paired with an indoor target of about 75°F. In plain English: on a typical hot summer day, a properly sized system should hold your house near 75° and still cycle off now and then.

When it's 97° or 98° outside, with the sun beating on the roof and the attic at 130–150°F, the system is working beyond those conditions. On those days, here's what's normal:

• Running nonstop through the afternoon and early evening
• The house drifting a few degrees above your setpoint in the late afternoon, then catching back up after sunset
• Upstairs rooms, camelback additions, and rooms with big west-facing windows running warmer than the rest
• A bigger Entergy bill than in May

That's different from a system that's failing. A healthy AC on a brutal day still blows noticeably cold air and recovers overnight. A failing one blows lukewarm air, falls further behind each day, or never catches up — even at 2 a.m.

The 10-minute health check: measure your temperature split

The most useful thing you can do before calling anyone is measure the temperature split — the difference between the air going into your system and the air coming out. All you need is a basic digital thermometer; a kitchen probe thermometer works fine.

1. 1Let the AC run for at least 15 minutes.
2. 2Hold the thermometer at the return grille — the large vent where the filter often lives — for a minute and note the reading.
3. 3Hold it in the supply vent closest to the indoor unit for a minute or two and note that reading.
4. 4Subtract the supply temperature from the return temperature.

A healthy system usually shows a split of about 15–20°F. On very humid days it may read a little lower, because more of the system's effort is going into pulling moisture out of the air.

Don't crank it down to 65

When the house hits 80°, it's tempting to slam the thermostat down to 65. It won't help. Your AC isn't a gas pedal — most home systems run at one speed or two, and the air comes out at the same temperature whether you set 76 or 65. A lower setting just keeps it running longer, chasing a number it can't reach today.

It can also make things worse. A system running nonstop against a very low setpoint — especially with a dirty filter — can drop the indoor coil below freezing. Ice builds on the coil, airflow chokes off, and cooling drops even further. When that ice melts, it can overflow the drain pan. (More on that in our clogged drain line guide.)

Thermostat settings that actually work

• 78°F when you're home. That's the U.S. Department of Energy's recommendation for summer comfort and savings. A ceiling fan makes 78 feel several degrees cooler.
• Small setbacks, not shutdowns. In a humid climate, shutting the AC off all day lets heat and moisture soak into your walls, furniture, and floors. The system then has to run for hours to pull it back out — and on a hot afternoon, it may never catch up. Raise the setpoint a few degrees when you leave instead.
• Fan on AUTO. With the fan on ON, moisture on the coil gets blown back into the house.
• Get ahead of the afternoon. Let the house cool a little extra in the morning, when the system is working less hard, then let it ride up slightly through the hottest hours.

A programmable or smart thermostat handles all of this automatically. If yours is older than your kids, it may be time for a thermostat upgrade.

Lighten the load on your house

Every bit of heat you keep out is heat your AC doesn't have to remove.

• Close blinds and curtains on east-facing windows in the morning and south- and west-facing windows in the afternoon. Those long west walls on shotgun houses take a beating.
• Set ceiling fans to spin counterclockwise (looking up at them) so they push air down. Fans cool people, not rooms, so turn them off when you leave.
• Cook outside or go small. The grill, microwave, slow cooker, or air fryer add far less heat than an oven at 4 p.m.
• Run the dishwasher, dryer, and laundry at night.
• Don't close vents in unused rooms. It can raise pressure in the ductwork and reduce airflow across the coil.
• Seal obvious gaps — weatherstripping on exterior doors makes a real difference in older homes.

Three maintenance jobs you can safely do yourself

1. Change the filter monthly in peak summer

When your system runs nonstop, filters load up fast — even faster with pets, nearby construction, or spring pollen. A clogged filter cuts airflow, lowers cooling capacity, and is the most common cause of frozen coils. Check it monthly from June through September, and change it when it looks gray.

2. Rinse the outdoor coil

1. 1With the power off, clear leaves, grass clippings, and cottonwood fluff from around the base.
2. 2Using a garden hose at normal pressure, spray the coil fins from the outside, working from the top down. Don't use a pressure washer — it bends the fins.
3. 3Let it drip-dry for a few minutes, restore power, and turn the system back on.

If you live near the lake, salt air is tough on outdoor coils, so a gentle rinse every few weeks in summer is worth the effort.

3. Keep 2 feet of clearance

Your condenser pulls air in through its sides and blows hot air out the top. Shrubs, fences, trash cans, or stacked lumber within about 2 feet make it re-breathe its own hot exhaust. Never put a cover, board, or shade structure directly on top.

A professional tune-up covers what you can't safely do yourself: checking refrigerant charge, testing capacitors and contactors, and cleaning the indoor coil.

Warning signs that mean call now

If you see ice, turn the cooling off (you can leave the fan running to help it thaw) and call. Running a frozen system can damage the compressor. For anything on this list, our emergency AC repair line is open 24/7, and for less urgent issues you can schedule AC repair during regular hours.

If the AC quits: protecting people and pets

A dead AC in July isn't just uncomfortable — it's a health risk, especially for older adults, babies and young children, people with heart conditions or on certain medications, and pets.

• Move to the coolest room — usually the lowest floor on the north or east side — and close the blinds.
• Drink water regularly, before you feel thirsty. Go easy on alcohol and caffeine.
• Take cool showers, and put damp cloths on the neck and wrists.
• Check on elderly neighbors and relatives at least twice a day.
• If the house is getting dangerously hot, go somewhere air-conditioned: a relative's house, a library, or a cooling center. The City of New Orleans posts cooling center locations through NOLA Ready during heat advisories.
• For pets: bring them into the coolest room, keep fresh water down, and walk dogs early in the morning. Test the pavement with the back of your hand — if it's too hot for you, it's too hot for paws. Short-nosed breeds struggle most.