Ideally, how long should my AC be on in a cooling cycle?

If you have the right AC unit size, your unit should run about 15 minutes at a time, and it may run two or three times per hour, even on the hottest days of the year. If your AC unit is running more often than that, you may have an issue that is affecting the efficiency of your cooling system. If your AC unit is running less than that, yet your home still isn’t getting enough cool air, then it’s likely that you have a problem with your thermostat.