I am planning to install central A/C in attic for the house addition and three existing rooms on the second story. There will be no forced air furnace, just central split system A/C.
I cannot find any good resources and particularly a diagram of installing just central A/C in attic. Any advice or links would be appreciated.
I understand the unit is installed in horizontal position. Should it be installed on ceiling joists or hung from roof rafters? The unit will be directly over the bedroom so I worry much about the noise. Is anything I can do to make it run quite and reduce vibrations?
How does the air filter get changed when the unit is in the attic? I obviously do not want to climb to the attic every three week to clean the filter.
The unit will have two zones and will supply air to 7 rooms of different sizes. I will hire a pro to do a design and load and heat loss calculations but I still want to understand it myself. Should I have just one main return or return from every room or both main return and return from every room?
I understand that ducts in attic must be well insulated. But should I also insulate entire unit? I guess it does not need combustion or any other air and I can build a box around it from Styrofoam sheets.