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.

Estimated Energy Savings from Turning AC Off at Night It probably won't surprise you to learn that a central AC system uses far more energy during the day than at night. In hotter, more humid climates, somewhere around two-thirds of the system's total energy consumption occurs between the hours of noon and midnight.

For three kinds of cooling system – central air conditioning, air source heat pump and minisplit – it was most efficient to turn cooling off during the eight-hour workday and then on again at the end of the day.

The lowest outside temperature at which to run your AC is typically around 60-65 degrees Fahrenheit. At temperatures below this range, your air conditioner might not operate efficiently, causing increased energy consumption and potential strain on the system.