Whole House Fan in Cathedral Ceiling

DEAR TIM: We are in a perfect area for installing a whole house fan, central Colorado, with cool dry evenings, but trying to get one installed in an existing structure is proving to be almost impossible. We have a ranch style home with a walkout finished basement and the upper floor has a great room concept with all cathedral ceilings. With no attic to speak of we are unsure where or how to have a whole house fan installed. The only feasible mounting location is either on an exterior wall (very unsightly) and the fan would actually be exposed to the elements (not sure if this is even possible) or one inner wall that is adjacent to the garage attic but is also a separate room (laundry), still has the high ceiling but air flow would be restricted by the doorway. Also, most whole house fans I have seen are for attic horizontal mounts. We would have to have a fan mounted vertically and I haven't seen any at the local home improvement stores. We had some remodeling done on the interior and tried repeatedly to get them to do the installation and I never saw so much stalling and side stepping. Needless to say they avoided the issue entirely. No one wanted to go into the garage attic in the summer either. Wayne, Black Forest, CO

DEAR WAYNE: Perhaps the altitude is affecting all of those builders and remodelers. One option open to you immediately popped into my mind, but in all fairness, I am only at about 750 feet above sea level here and have put whole house fans in all sorts of homes.

To make the fan work well, you really only need two things:

• a flat interior ceiling surface
• sufficient roof exhaust ventilation ports to satisfy the free net area called for in the fan installation instructions.

The second item is the tough one in your case.

To create the flat interior ceiling space, all you need to do is locate the fan in a portion of the house where you are willing to give up the sloped ceiling effect. Perhaps, there is a smaller room you can transform into a flat ceiling.

Then above this space, you need to install the needed roof vents that collectively will satisfy the free net area, so the whole house fan can push the air from the house outdoors.

I did this once in a job several years ago, where we had to join together eight traditional pot vents next to one another near the peak of a roof. It looked a little odd, but the vents did their job.

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