How high is the central air conditioning ceiling - What is the size of the central air conditioning ceiling

The concept of reserving the size of the ceiling is inaccurate and the procedure is wrong. Should first install the central air conditioning internal machine, and then the ceiling to pack and hide the internal machine. Currently on the market within the thickness of the machine home installed machine damage ceiling, ceiling height needs to be 280MM, the general home can be done 300MM. ceiling width, need to be based on the width of the body and the way to go tube, ceiling width in the indoor area of the proportion of the relationship to be determined, both the need for beautiful, but also the need to be practical.