I have a small studio - around 650 sq feet. I try to ask about energy
economy using my central air. There are two conflicting theories

1 Theory that most people follow : keep the ac all the time - when you
leave, just increase the temperature
2. Theory that I follow : when I leave I switch it off completely

Please tell me who is right ?
Explanation for my (#2) theory : I understand that the central unit
runs at the steady pace (?). It does not matter whether it is 95
degrees or 80 degrees in apartment ...once I set the temp to 75 degrees
(when I come back from work) the ac will be blowing air at the same
speed, consuming energy at the same rate. True it will take it longer
to knock down temp from 95 to 75 (40 minutes ) than from 85 to required
75 (20 minutes). But ..assuming that you leave the apartment and set
the tempt to 85 the ac will switch on/off multiple times during the
9-10 hrs period you are away from home which will in effect be longer
(more energy consumed) than 40 minutes. Please provide me with some
good information - am I rite on this ?

The reasoning might get qualified if

A) somebody had large, good insulated house and it would take him
horribly long to knock down temp from 95 to 75. So I guess in this case
it be better to just allow ac unit to switch off/on for short periods
of time during 9-10 hrs you are away from home.

B) The ac unit runs at different speeds ..consuming more energy with
higher spread between present temp in the apartment and requested temp.