It depends. Possibly, depending on your system, your schedule, and the outside temperature. Maintaining a temperature gradient takes energy, so the larger the

It depends. Possibly, depending on your system, your schedule, and the outside temperature. Maintaining a temperature gradient takes energy, so the larger the difference between the interior temperature and the exterior temperature, the faster heat will enter the house, and thus the more energy that is required to remove it. Turn off your a/c for an entire day and see how much the temperature inside increases. The bigger the difference between your a/c set temperature and the equilibrium temperature reached with the a/c off, the more significant this will be. For most people, it is not very significant -- often the equilibrium temperature is only 5-8F above set point, in which case the difference is really minimal. On the other hand, your a/c performance and efficiency is not constant. On the one hand, there is energy lost to starting the compressor up to begin cooling, making really short cycles very inefficient. On the other hand, the system will become less efficient as the components heat up, so really long runs will be less efficient than shorter-but-not-too-short runs. Separately, if you have a variable speed or multi-stage cooling, it will not be equally efficient at all speeds/stages. Of these three effects, this one is largest (in multi-stage systems) and will tend to dominate. In the end, generally, turning off the a/c will tend to use a little bit less power if you stay gone for a long time, but not always and not that much. Usually the more effective thing to do is to focus on running the a/c as much as possible during hours when the grid is mostly renewables or is otherwise underutilized, and "storing up the cold" is that you don't need to run it at peak times. You will use slightly more power (probably), but it will probably be cheaper and less stressful to the overall grid, and will make better use of the otherwise-wasted renewable power. (During peak daylight, overproduced solar power is often spent at low efficiencies to do things like pump water up hill (for energy storage), so if you can put that energy to productive use rather than using the energy released by the "water battery" during peak hours, your effective usage is lower, and this probably dwarfs the difference between "a/c all day" and "off while away"