The Jews are strictly forbidden to use the air conditioning on Saturday. However, like any other appliances during the Sabbath. More precisely, it is forbidden to turn it on or change settings.
Bypassing this trick, most families just don't turn off any HVAC equipment on Friday. The same thing they have to do with any electrical equipment.
For example, the light on Friday they either do not turn it off, or install photosensitive switches responsive to movement of the person.