patriotnutrients
if you get a "package" unit then you could put the whole thing on your roof.. the system you are referring to is a "split" system..

norman7774
UNFORTUNATELY Yes... that is the transfer unit that goes(generally )in the attic. There is no way around that.... I just had one put into my house.. what a job.. and for my condo, I am going to have one put in there also when it gets a little cooler

barrbou214
the "part" that goes inside is referred to as a air handler. it can be placed in the attic or in the crawlspace if interior space(living space) is limited.

uplantin2lips
the answer is no you don't ,unless you don't have any crawl space under your house .Then your stuck with a split- system. If you can't have a unit in side try putting the air - handler in the attic.

William E
Norman is wrong, you can get a package unit which contains both the evaporator and condensor outside in one nifty package. Norman got a split system, and he probably got lied to by the hvac company which sold it to him. The only issue I see would be duct work, and an air return. Flexible duct can be used for each room through the attic or crawl space and probably an air return in the wall or ceiling closest to where the system is installed. The entire "package system" is always exterior, not in a crawl space or attic (that is a split system) and can sit on a small concrete slab outside of your home. It is possible for it to go on your roof, if you have a flat roof and it is sturdy enough, but is much easier and more common to put in on the ground.