HeyBub wrote:

Big Jim wrote:

If you want ventilation get a fan. More insulation is always good




The problem with a fan is that it must exhaust massive amounts of air to be
effective. Assuming an 1800 sq ft house with a 6' attic at the peak, we're
talking (roughly) 6 x 1800 x 0.5 = 5,400 cu ft. An attic exhaust fan should
change the air every 2 minutes,

Where does that come from? It sounds pretty aggressive to me. I think
an attic fan can make a big difference even if it's only capable of
changing the air a couple of times an hour.

IMHO, an attic fan isn't a panacea, but it can be useful in the mix.
I know mine has relieved some of the stress on my (much more expensive
to replace) A/C unit.

I'm also a big fan (no pun intended) of radiant barriers.

so you'll need a fan that moves 2,700 cu ft
of air per minute. That's a good sized fan.

"For well-insulated ceilings (i.e. insulation levels of R-19 or above) it is
doubtful that a power ventilation can be justified economically. "

http://factsfacts.com/MyHomeRepair/ventilation.htm