Ceiling Assembly (Ceiling unit, airbox, adb, plenums, diffusers, ducts)

 

  DID YOU KNOW
Air conditioners work by 'sucking up' hot air, removing the heat out of that same air, and pushing it right back out. 
They don't really cool a room by 'blowing' anything.  They move the heat out of the room... but recycle the air AFTER

they moved the heat outside, so it'e nice and cool inside.

Air Conditioners and heat pumps require some way to separate the returning hot air from the outflowing chilled air.
That's a BIG part of what your ceiling unit does.
A clear unobstructed return air flow is REQUIRED for ANY air conditioner to work well.
You'll cool the same area more efficiently  when you have a good flow of return air.