Roof power vents and whole house fans
I own a two story house that was built in 1940. The house was built with no soffits. There was an old house fan in the attic floor that never worked since we bought the house 2 years ago. Just had a new power roof vent installed along with a new roof. My question is this. If I leave the hole open in the ceiling where the house fan was (it has a decorative grate), would the power vent be adequate of should a house fan be installed. I guess I will probably have to find out for myself but the reason I am asking is the electrician is coming to connect the power vent and while he is there I thought he could connect both. Are whole house fans hard wired or could a plug be installed for a receptacle. Thanks for any replies.
Replies
Negative pressure in the attic from a power vent can cause other problems, depending. They also tend to be power hogs. If you leave that grate open to attic, you will not be able to close it if you use A/C, or get a cold night. You can also expect insulation and other dust to come down.
How about the whole house fan instead of the power vent?
It will clear the hot air from the attic AND cool the house.
I really like my Tamarack HV-1000. Automatic motorized foam doors seal tight when off, relatively quiet, low power consumption, easy install. I use a lot less A/C now that I have this.
It is designed to be hard-wired, but I wired mine to an outlet easily enough. I operate mine with an X10 remote control instead of a hard switch. The unit does come with a nice hard switch, I just chose not to use it. Can easily be setup to work off a thermostat, if you like. If you really wanted the wiring done in advance for this particular unit, you would want 2 outlets installed, one 'always on', and one controlled by a wall switch. Best of luck.
http://www.tamtech.com/hv1000.htm
Edited 10/10/2003 4:52:13 PM ET by csnow
csnow:
Your "whole house fan", does it suck air from the house through the ceiling into the attic and thus force hot attic air out the roof vents? Is that how they work?
If so, any worry that the cross sectional area all roof and gable vents are less than the power of the fan? (cubic feet of air/second)
That is exactly how it works. I have a thermometer up there for reference, and it works very well.
The HV1000 only requires 1.5 sq. feet of roof ventilation. Even an 'unvented' attic probably has that!
Hogan, I am confused. Do you have gable vents? If not, and no soffits, what is the source of air for the power roof vent other than hot of the house (conditioned air)
It is most helpful to change the attic air often during the a/c season, but counter productive to a/c with opening to attic to sky.
What is your geography?
Also, be very careful when exhausting livable space. It is easy to reverse flue fumes. Paul
Practical Energy Cost Reduction for the Home