Generally speaking, a unit that is either on or off is less expensive than one that keeps cycling on and off repeatedly. Every time your system starts up, it will use a lot of electricity and not produce much cooling. That’s why a smaller system is often more economical to operate, even though it runs nonstop and may deliver less comfort, it will usually consume less power than a larger system that cycles on or off. Of course, it’s best to have your system sized to match the requirements of your home.
There is no exact answer for how long your system should run during each cycle. The average air conditioner is sized to remove the heat from your home as fast as it comes in, on a 110 degree day. Therefore, ideally on a 110 degree day the system should be able to keep up with the incoming heat, but not gain on it and be able to turn off. The cooler it is below 110 degree, the more the system will cycle on and off.
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