Turn up/down the air conditioner?

[peppy_man]

'It's very hot. Let's set the air conditioner at a lower temperature'.

If we replace 'set the airconditioner at a lower temperature' with 'turn up OR turn down the air conditioner',
which is correct, 'turn up' or 'turn down'? :roll:

 

[Casiopea]

Try,

"Turn the temperature down" (to make the room cooler)
"Turn the temperature up" (to make the room less cool)

"Turn up the air conditioner" tends to refer to the speed of the fan. The faster the fan, the more cool air it'll produce. The slower the fan the less cool air it will produce. For example,

"Turn down the air conditioner. It's way too cold in here."
"Turn up the air conditioner. It's way too hot in here."

 

[David L.]

Turn up the air conditioning.

Turn down the air conditioning

This is done with a thermostat dial, either on a small machine, or on the wall of the room.
Altering the speed of the fan is done with separate buttons on small single units.