On Wed, 4 Aug 2010 06:13:54 -0700 (PDT), Yong Huang
wrote:

On Aug 4, 8:00 am, jamesgangnc wrote:

Increase the hvac service to the room by adding another run and duct
or by increasing the size of the existing runs, ie change the 6" flex
to 8". Improve the insulation in the ceiling.

Thanks. More than half the time at night, the AC is not running. I
hope the room is not too warm during that time. I'll try to put more
insulation in the ceiling above this room.
You REALLY need to insulate the floor of this room to keep the
radiated heat from the driveway out. I'd put a reflective barrier over
the insulation (actually under - on the driveway side) to help cut
down the absorption as well.