The Question Every Long Island Homeowner Asks in July

It's the middle of summer, you're heading out for the day, and you're standing at the thermostat wondering: do I leave the AC running, or turn it off to save money?

It's a surprisingly common debate — and the answer isn't as simple as "always leave it on" or "always turn it off." The right choice depends on your home, your schedule, and how your system is set up. Here's what you actually need to know.

The Case for Leaving It On

The argument for leaving your AC running all day goes like this: it takes more energy to cool a hot house back down than it does to maintain a steady temperature. If you turn it off and your home heats up to 90°F while you're gone, the system has to work overtime when you get back.

There's some truth to this — but it's often overstated. Modern air conditioners are designed to handle recovery cycles efficiently. The energy used to cool a hot house back down is almost always less than the energy used to run the system continuously for 8–10 hours while you're not home.

Exception: If you have pets, plants, or humidity-sensitive items (musical instruments, wood furniture, electronics), maintaining a consistent temperature matters more than energy savings. In those cases, leaving the AC on — but at a higher setpoint — makes sense.

The Case for Turning It Off (or Up)

For most Long Island homeowners without special circumstances, raising the thermostat or turning the AC off while you're away will save money. The Department of Energy estimates you can save up to 10% per year on cooling costs by raising your thermostat 7–10°F for 8 hours a day.

The key word is "raising," not "turning off." Setting the thermostat to 78–80°F while you're out — rather than 72°F — keeps the house from getting dangerously hot while still reducing runtime significantly.

The Smart Middle Ground: A Programmable or Smart Thermostat

The best answer to this question isn't a binary choice — it's a smart thermostat. With a programmable or Wi-Fi thermostat, you can:

• Automatically raise the temperature when you leave in the morning
• Start cooling back down 30 minutes before you get home
• Set different schedules for weekdays, weekends, and vacations
• Control everything remotely from your phone

This gives you the savings of not running the AC all day, without coming home to a sweltering house. Most homeowners who switch to a smart thermostat see noticeable reductions in their summer electric bills within the first month.

What Temperature Should You Set It To?

Here are general guidelines for Long Island summers:

• When home and active: 72–76°F (comfort range for most people)
• When sleeping: 68–72°F (slightly cooler aids sleep quality)
• When away: 78–80°F (reduces runtime without letting the house overheat)
• On vacation: 82–85°F (protects the home without running the system constantly)

Every degree you raise the setpoint while away saves roughly 3% on cooling costs. Over a full Long Island summer, that adds up.

Signs Your AC Is Working Harder Than It Should

If your system is running all day and your home still isn't comfortable — or your electric bill is unusually high — the problem may not be your thermostat settings. Common culprits include:

• A dirty air filter restricting airflow
• Low refrigerant from a slow leak
• Dirty condenser coils reducing efficiency
• Ductwork leaks losing conditioned air before it reaches your rooms
• An aging system that's lost efficiency over the years

A system that's struggling to keep up in July will only get worse as temperatures climb into August. If your AC is running constantly but not cooling effectively, that's a sign it needs attention — not just a thermostat adjustment.

The Impact of Long Island's Humidity

Temperature is only part of the comfort equation on Long Island. Humidity plays a huge role in how hot your home feels. When relative humidity climbs above 60%, even a 74°F home can feel sticky and uncomfortable.

Your air conditioner removes moisture from the air as it cools — but only when it's running. If you turn the system off completely for long periods, indoor humidity can rise significantly, especially in older homes. This is another reason why raising the setpoint (rather than turning the system off entirely) is usually the better strategy.

If humidity is a persistent issue in your home, a whole-home dehumidifier can work alongside your AC to maintain comfort at higher temperature setpoints — which means less runtime and lower bills.

Bottom Line

Don't leave your AC running at full blast all day while you're out — but don't turn it off completely either. The sweet spot is raising the thermostat to 78–80°F when you leave and letting a smart thermostat handle the rest. If your system is running constantly and still struggling to keep up, it's time for a tune-up or inspection.

Schedule a Summer AC Tune-Up with A1

If your air conditioner is working overtime this July and your energy bills are climbing, our team can help. A1 Heating & Air Conditioning serves homeowners throughout Suffolk County — Smithtown, Hauppauge, Commack, Babylon, Patchogue, and beyond.

We'll inspect your system, clean the coils, check refrigerant levels, and make sure everything is running as efficiently as possible for the rest of the summer.

Call 631-331-2102 or contact us online to schedule your appointment today.