I'm in the process of installing a whole house fan and will need to install
some additional venting on the roof to accommodate the air flow needs. I need in the area of about 7-8 additional square feet of venting.
My home has concrete S tiles on the roof- exactly the same as the last photo here: http://www.ohaginvent.com/products_concrete.asp
-and I'm debating between installing O'hagen vents or dormer vents. It appears that the o'hagen's give about .75 sq ft of venting per vent whereas the dormer will give about double that per vent at 1.5 sq ft. The o'hagens seem fairly straight forward to install.
I'm undecided as I'm not so sure that I want to install 10 o'hagens compared to only 5 dormers. The only issue is that I can't seem to be able to find anywhere on the net instructions on how to install the dormers so am basically at square one as to how many tiles will need to be removed to be installed, and just how to go about it.
Anyone with experience or insight that could comment or point me in the right direction would be much appreciated.
thanks in advance