An air conditioner is a single machine that de-humidifies and cools the air. Air conditioning applies to a system as a whole that does the same thing. An air conditioning can consist of one air conditioner or many. A hotel, for instance, would have several individual large air conditioners to provide cooler air.

air conditioner is a machine- which condition the air according you and air conditioning- is the situation which air conditioner presents, or by another technique

air conditioning = 空調 air conditioner = 空調機 (?) Q: Does your house have air conditioning (in general) ? A: Yes, we have air conditioning! There is an air conditioner in each room - 3 air conditioners total.