I need better ventilation in my bedroom. Here is the setup.Typical 12x18 bedroom with a master bath.Hot water heat. AC is a wall AC.When I built this addition to my house I insulated all the walls even interior and ceiling.This room is on main floor with a 2nd story above.Bathroom insulated the same.There is only 1 crank out egress type window in the room. The bathroom has no window only a vent which we always use.Here is the problem in the morning the room is always very stuffy.Even with the window open.There is a ceiling fan always running plus another fan.I cut a couple small vents one in the bathroom one in the bedroom to maybe get some airflow from the adjacent room but it didn't help much.The only thing that helps is leaving the door open a little,but that is really not desirable. No ductwork at all in the house. There is a crawlspace under this room.The humidity is usually running 65% or higher in this room. Ive got the bath vent fan on a timer so I can run it extended times.Any easy fixes?
Is there a small vent fan I could install in the wall to circulate the air to the adjacent room?
As Jim correctly points out, if there is no ground vapor barrier in the crawl space it can become a significant source of humidity in very-tight construction, and is usually retrofittable with a ground vapor barrier, provided it's deep enough to work in. (6 mil polyethylene min, 10mil is better. Overlap any seams between sheets by about a foot, and seal the seams with duct-mastic. If the foundation walls aren't insulated, it's cost effective to put 2-3" of spray polyurethane sealing the edge of the vapor barrier to the concrete, all the way up & over the foundation sill & band joist.)
To ventilate a single room efficiently,
Panasonic's FV-04VE1 room-ERV set to run continously at it's lower CFM delivers good air flow at a very low heating/cooling efficiency penalty.
The exhaust-only scheme in the bathroom may work when the outdoor humidity is low (which most of the time, in ND), but as Jim points out it WILL of-necessity pull in outdoor air somewhere else in the house in an uncontrolled fashion. ERVs are designed with balanced flow, and have both a dedicated air-source vent as well as an exhaust vent. Unlike an HRV, the ERV does a partial humidity transfer between the incoming & outgoing air streams, which lowers the latent cooling load when outdoor humidity is high, but when the outdoor dew points are lower than the indoor dew point, it will still dry the indoor air (the moisture transfer is nowhere near 100%- more like 40-50% on average.)
It may be useful to download & read
the manuals, including the
installation manual before committing, but it's a good solution.
ND is cold enough that the ERV will have frost-up issues running in winter, but your winter air is dry enough that you can (and probably should) just turn it off when it gets cold in November, then back on when it warms up in March.
Note: The manual doesn't recommend using it as a total ventilation solution in much of ND, but if the stuffiness is primarily summertime issue, it's safe to run it whenever average daily temps are above 40F.