As part of a commercial heat pump retrofit, we had to comply with the residential noise ordinance. Our solution was to combine two quieter 7.5 ton units for a single 15 ton unit that could not meet the decibels levels of the ordinance.
Out with the old inefficient AC unit with electric resistance heat. This was replaced by two smaller high efficiency heat pumps.
New high efficient heat pumps replacing old AC units with electric resisitance heat. Seattle City Light stepped up with a substantial energy conservation grant.