"If you really want to save money install two systems...one for
the night time sleeping areas, and for the day time living
areas... install set back thermostats on each system so the
HVAC gets set high in bedrooms during the day, and the living
areas get set low at night (these settings can be easily
overridden when needed) "

How exactly does this save him money? I would think the initial outlay
for two seperate systems in a house that typically would have only one
would be impossible to recover in reduced operating costs. Where is
this savings supposed to come from? And in my house here in NJ, if I
set the temp to 50 at night, the house would never get there, because a
house with decent insulation won't cool off that fast.