On Wed, 4 Aug 2010 05:54:14 -0700 (PDT), Yong Huang
wrote:

I have 4 rooms all upstairs. Below 3 are all indoors like living room,
etc. They're cool. One is above outdoor driveway. It's noticeably
warmer. I can't think of any explanation. One day I used a thermometer
to measure floor temperature. It was between 1 and 2 degrees higher
than the floors of the other 3 rooms. I think that explains it. But I
don't think there's anything I can do.


...." 1 and 2 degrees higher..."

And you are worried about that?! What you describe is what I would
call a "carport". Open on two sides with an entrance door to the home.

Does the driveway face east or west?! What kind of siding? Window
treatments inside / outside (solar screen, awning, etc.)? Is there a
ceiling fan in the room?

Have the floor joist filled with blown insulation. No different than
filling wall cavities, IME.


..."what about those many
rooms above a garage? Are they warmer too? What do you do to remedy
it? Thanks."

Insulate the garage door, especially if facing east of west: with
temps from 90° - 117° (morning/afternoon respectively).