Ventilation

Posted in: Ventilation
Whole House Fan in Cathedral Ceiling
By Martin Smith
Aug 26, 2008 - 3:57:10 PM

Question: Where we live is just perfect for installation of a whole house fan. The evenings are cool and dry. But the confounding problem is getting one installed in our home which has a ranch style structure. It has walkout finished basement. The room on the upper floor is ideal for cathedral ceiling. As we do not have an attic we do not know where the whole house fan could be installed or how to install one.

One location where it can be installed is on the exterior wall but this will be ugly besides it being exposed to the natural elements. We do not know whether this will be a suitable place or not. Another possible location could be the inner wall near the garage attic which is a separate laundry room. It does have a high ceiling but the doorway could come in the way of free airflow. Attic horizontal mounts constitute the majority of the house fans that I have come across. But we need a vertically mounted fan.

When the remodeling of our home was being done, we had asked them to install one. But then they kept on stalling and evading. They side stepped to avoid addressing our need. Besides they did not also want to enter the garage in the summer heat.

Answer:  I have installed all sorts of whole house fans in all kinds of homes. Of course, the height here is something like 750 feet above mean sea level. From the experience, there are some things that come to my mind.

You need only two things to make sure that the fan work fine.

· An interior ceiling surface that is flat
· Adequate roof exhaust ventilation ports that fulfill the free net area specified in the installation instructions for the fan.

The first is a bit hard in your instance.

You need to forgo the effect of sloped ceiling in that part of the house where you want to install the fan. A flat ceiling space has to be created for installation of the fan. May be a flat ceiling can be created in a smaller room.

The required roof vents have to be installed above this space. The space should be as specified as required for the free net area. This is to enable the whole house fan to move the air outdoors from the house.
I have done a similar work some years ago. In this case, eight traditional pot vents had to be joined together into one adjacent to the peak of a roof. The vents did what they are supposed to do despite the fact that it looked a bit odd.


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