Insulation, Radiant and Vapor Barriers - Whole house fan same as venting bathroom fan into attic?
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VoltageHz
01-01-09, 08:14 PM
Most Whole House Fans seem to just pull the air from your home into the attic, they rely on attic ventilation to finally get that air outside.
Isn't that the same as venting your bathroom exhaunst fan into the attic? Won't the same ill effects (mold, etc.) of venting humid heated air into the cold attic occur?
Isn't that the same as venting your bathroom exhaunst fan into the attic? Won't the same ill effects (mold, etc.) of venting humid heated air into the cold attic occur?
goldstar
01-01-09, 08:27 PM
First, the whole house fan is blowing air into the attic which is probably 15 - 30 % in the winter. The large volume is diffused over a large area.
A bathroom fan, when showering, is blowing very warm, humid air 50-80 % out of a small opening in a fixed direction. Vent the bath fan out the roof, a side wall, or the eaves.
A bathroom fan, when showering, is blowing very warm, humid air 50-80 % out of a small opening in a fixed direction. Vent the bath fan out the roof, a side wall, or the eaves.
airman.1994
01-01-09, 08:28 PM
?? OOOH! Bath and kitchen exhaust will be humid. Hole house fans are only recommended in non green grass areas because they will bring in all the humidity to the living space. They should not be used in humid areas. So if you yous one in a green grass area the attic because of the heat will be less likely to grow mold than the living area.
Michael Thomas
01-01-09, 08:37 PM
Generally, whole house fans are not running when the outside temperatures are low enough to cause significant condensation within the attic, and on summer day high internal air and material temperatures tend to dry things out pretty quickly. (Even in a cold climate like mine in Chicago, it's very common to see condensation on the North side of the roof on a cold winter's day, but not on the South side).
Also, a whole house fan is generally moving unconditioned air at the ambient exterior temperature and relative humidity in from windows on the living spaces below and out through the attic - you can contrast this with the situation where a power vent roof or gable fan is extracting conditioned air from the living spaces below.
Also, a whole house fan is generally moving unconditioned air at the ambient exterior temperature and relative humidity in from windows on the living spaces below and out through the attic - you can contrast this with the situation where a power vent roof or gable fan is extracting conditioned air from the living spaces below.
VoltageHz
01-02-09, 06:51 PM
I see, what you say makes a lot of sense.
I still just don't like the idea of putting that air into the attic. I'd rather install some type of mushroom fan on the roof and run a duct straight down to the living space, maybe terminate it into a typical air conditioning return vent in the ceiling.
I still just don't like the idea of putting that air into the attic. I'd rather install some type of mushroom fan on the roof and run a duct straight down to the living space, maybe terminate it into a typical air conditioning return vent in the ceiling.