system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 What takes more energy, to maintain the house at a temperature while I'm gone for a few hours or to turn off the ac and turn it back on when I come back?
gpt
It takes more energy to maintain the temperature.

From a thermodynamic perspective, your AC pumps heat from the inside of the building to the outside. How much the AC needs to run (and how much power it uses) is determined by how much heat 'leaks' from the outside to the inside. And that depends on the temperature difference between the two. The bigger the temperature difference, the more the AC needs to run.

If you turn off the AC for a while and allow the temperature inside the house to rise, that will reduce the heat transfer between the two sides.

In other words, the power required to cool the house back down is less than to maintain the temperature, because if you maintain the temperature, more heat gets into the house (that the AC has to remove).

This becomes very obvious when you look at longer time frames, like say a week.