Air conditioning unit

An air conditioning unit comprises a hollow body 6 arranged within a space above the ceiling B of a chamber to be air conditioned, a discharge blower 8 within the body to draw air from the chamber through a suction opening formed in the ceiling and discharge it to the outdoors, and a circulation blower 9 within the body to draw in outdoor air and to draw air from the chamber through the suction opening; after mixing the air drawn from the two sources, the circulation blower discharges the air into the chamber through an air discharge opening 14 formed in the ceiling. A heat exchanger 7 in the unit body exchanges heat between the in-drawn outdoor air and air drawn from the chamber by the discharge blower, and a filter 10 in the unit body filters the mixture of in-drawn outdoor air and the air drawn from the chamber by the circulation blower 9.