Originally Posted by UAVirgin
You HVAC installer should be able to get and install dampners under the HVAC unit. Basically rubber pads that sit between the unit and the floor. It is important that the bolts that attach the unit and duct work to the floor/walls/ceiling are isolated as well.
One of our offices is above a nightclub and we noticed that there was a big bass beat (thump thump thump) coming up from the club at night. We don't want massive external noise in certain key areas and had people from the club up to join us when their bass was 'kicking'. They agreed that it was way too loud, and were amazed it could be heard on the second storey of our building. When our engineers investigated the club, they found to their utter amazement that the giant newly installed bass speaker, was bolted onto the wall (with no damping or isolation at all) and the noise was just being transmitted up the wall.
This has since been rectifed
.