It's a 2-story, Cape-Cod style house, 2 bedrooms and a bathroom. Bathroom is a big dormer on backside of house, and a dormer in each bedroom to the front. There is no attic, so to speak. The slope of the roof starts partway up the wall by the dormers up front, so ceiling follows that to a point, then flattens out and stays flat to the far wall. Behind wall, there is a crawl space opened up from the closet... same level as rest of room otherwise and roof slopes in there, as the oppposite end in bedroom. AC ductwork comes up through this space. Additionally... upstairs ceiling height is barely 7 feet. Currently, there is a ceiling fan in each bedroom. I installed a new one that has maximum possible clearance from ceiling without hitting my head. AC vents are one-per-room, in wall at floor level in bedrooms. If need be... I can take photos and post somewhere to help visualize this layout.
Now here's the deal... rooms are simply too uncomfortable during the day at this time of the year... quite muggy despite AC on and fans on. The AC system seems adequate enough... no problems downstairs. I suspect the upstairs is problematic in part because there is no attic to act as a buffer of sorts. I also suspect that the ceiling fans are nearly useless since they are possibly just circulating warm air off a warm ceiling. Cool air does come out of the vents, but being near floor, I suspect it just isn't getting circulated well enough.
Here's my thoughts...
a: I need to move AC vents from floor level up near ceiling. This will allow ceiling fan to circulate that air. OR... use floor fans instead if those will be more effective than a "hugger" ceiling fan to begin with. Getting rid of ceiling fans will let me have ceiling lights anyways. Moving ducts up, however, will let me have greater flexibility in furniture placement.
b: In the crawl space behind wall, get roof vents to exhaust stale, hot air. Passive vents, active vents, thermostat-controlled vents... any thoughts? Since ducts come up through this space, and space is hot, perhaps it's warming up the air in the ducts before it exhausts into bedrooms?
c: On the "front" side of the bedroom, where roof slopes and forms part of ceiling... I'm wondering if I should have vents there too? Sun is beating down directly on that and, with no attic as a barrier, is contributing to the heat in the room.
That's all I can think of for the moment. Thanks for any and all feedback.