When Is the Best Time to Turn On the AC?
Your new morning checklist: Make coffee, read the newspaper, turn on the air conditioner
Highlights
The best time to turn on the AC is when temperatures outside start hitting 75 degrees Fahrenheit.
The best time of day to turn on the AC to save money is in the morning.
The interior temperature of your home, personal cooling preferences, window efficiency, and insulation may alter the best time to turn on the AC in your home.
Many HVAC experts say that when the outdoor temperature hits 75 degrees Fahrenheit, it’s time to turn on the air conditioner. While the mid-70s would normally indicate late spring or early summer weather, the climate in your region might have a mind of its own. That’s why it’s important to consider a variety of factors, including personal preference, when deciding when to turn on your AC.
When Is It Time to Turn On the Air Conditioner?
Weather can be fickle, which is why it’s hard to pinpoint a good time to turn on the AC. Summer may arrive early in your region, so you could have the cool air already cranking by mid to late May. On the flip side, you might have to keep it on well into September, even though leaves are turning color to herald the arrival of spring.
It’s always a good idea to turn your AC on at some point prior to the hot weather simply to test it out. If cool air isn’t blowing as it should, then you’ve given yourself plenty of time to hire a local AC installer or HVAC pro to fix it before you really need it.
Aside from that initial test run, here are three factors to consider when determining an appropriate time to turn on the AC:
Interior Temperature
While it’s best to go by the outdoor temperature—again, 75 degrees is a good starting point—rather than the calendar, it also depends on how you’re feeling indoors. Sometimes, temperatures swing wildly, so if it’s in the 70s during the day but dropping down to the 50s at night, your home’s internal temperature may be just fine without the AC on.
Personal Preference
Even if the outdoor temperature has been steadily in the mid-70s, you might find that turning on a ceiling fan or opening a few windows for some cross-ventilation is enough to keep things comfortable. Remember: It’s your house, your rules, and, ultimately, your utility bill.
Windows and Insulation
If you’ve got energy-efficient windows and good insulation, your home might stay cooler for longer, even as outdoor temperatures rise. This is also important for keeping your home warm in the winter. If you’ve got poor insulation or drafty windows, it’s worth it to repair or replace them to conserve energy and lower your monthly utility costs.
When Is the Best Time to Turn on the AC During Summer?
Even during the dog days of summer, the outside temperature will drop overnight for one very simple reason: The hot sun has set.
Whether you have central air, a mini-split unit with a programmable thermostat, or you simply press a button on a window AC unit, do so in the mornings during the summer. The internal temperature will be lowest then, so turning on the AC early in the day will ensure that it has time to cool off the space.
Wait any longer and the temperature will continue to rise, making your AC work even harder than it usually does. This is bad news for the longevity of your appliance and the size of your utility bills.
Frequently Asked Questions
This is a bit of a trick question. Even though the seasons arrive at the same time every year, the weather doesn’t always behave according to the calendar. So, while it’s fair to say that you can expect to turn on your AC starting in late May or early June, it all depends on the outside temperature and how cool you like to keep your home.
On a summer day, expect your AC to run between 12 and 16 hours. However, this time frame depends on just how hot it is outside and the comfortable temperature you’re hoping to maintain indoors. Assuming the size of your AC is appropriate for the space you’re trying to cool, it shouldn’t be a problem for it to work this many hours.