Not all roof top a/c units need their own separate steel support framing (which is called dunnage, btw). We have two "package" units on the roof of our rowhouse. We were dubious about not needing dunnage too, but after triple-checking with architect, structural engineer, mechanical engineer, expediter, ac contractor, and the city, everything went through. Building inspector came, saw, and approved, and the units have their own DoB permits to show for it. This was all wrapped up last year. It may have to do with weight/size of units. Each one cools half the house (ca. 1500 sq feet each).

Posted by: rfr at June 6, 2008 12:13 AM in response to A/C Compressor in basement

Can you sit those things on a parlor floor deck? Are they just too loud/hot to live with them there?

Posted by: guest at June 6, 2008 11:32 AM in response to A/C Compressor in basement

Last year, we installed a split unit air conditioner to cool our parlor floor. The compressor sits on the side of the garden apartment's terrace. It's very, very quiet with no noticeable breeze. Our tenant has never complained and entertains on the terrace. And the unit cools our 1000 square feet easily. Best investment I ever made.

Posted by: walester at June 7, 2008 12:17 PM in response to A/C Compressor in basement

rfr -- if you didn't build a steel platform -- then what are the units sitting on? I'm in the process of trying to site our 3 units (200 lbs each) and the dunnage prices (and rigging to get it onto the roof) are exhorbitant. Any more specific suggestions for options for a roof platform would be greatly appreciate.

Posted by: guest at July 28, 2008 11:12 AM in response to A/C Compressor in basement