I have a 200 sq ft second story vaulted ceiling room. The ceiling is
the roof. I think there's R19 fiberglass insulation above the drywall
ceiling. The walls are 6" with maybe R29 insulation. There are 3 large
windows that make up about 2/3 the wall volume on walls facing East,
South-East, and South. The windows have a low E film, and wood blinds.

I have excellent AC going to the room with the use of zoning. However,
the room still requires a great deal of AC to keep it at 78 degrees
during the day. Even at night when the temperature drops to the mid to
high 60s, the morning temp of this room will be 77 degrees (no AC).
The other upstairs rooms in the house will be around 75 degrees in the
early morning. If there wasn't enough insulation in the walls and
ceiling, wouldn't this room be much colder in the morning?

I think I've done everything imaginable to improve the cooling in the
room. My next step might be to investigate the insulation in the walls
and ceiling. Would a laser infrared thermometer be a good tool to
determine hot spots caused by poor insulation in the ceiling or walls?
Or is this just a waste of money? What ceiling or wall temp would be
considered excessive? I've checked around the light fixture boxes and
there is insulation. Maybe the whole problem is the large volume of
double pane glass windows relative to the size of the room.

I'm just out of ideas as to what else can be done to improve this
room. I've had several HVAC contractor look at it too, and that
resulted in zoning which works great. Thanks for any suggestions.