Steve - The answer I think is "both". I think it comes down to a couple of factors, neither of which have anything to do with efficiency. The customer that does not have a convenient way to house the GARN and does not want to build a shed will opt for the solution that "fits" their physical parameters. The other issue is that for some, the PERCEPTION that a more "technically sophisticated" solution will provide better results rules the day, irrespective of data. I am also a follower of Occam's Razor, so I always look for the simplest solution first. However, a smaller unit that can fit within the desired space, plumbed with divorced storage, with cost and complexity equal to or greater than a GARN, is still a better solution than an old smoke dragon in the backyard or a hungry oil burner in the basement. I also lost a sale of a GARN due to nothing more than the physical constraints of the customer's situation. The customer WANTED the GARN, but the consequential costs of accomodating its size put it out of his budget. For those of us lucky enough to have the room to install one, well we just have to count our blessings . . .