"mm" wrote in message
...
On Sat, 28 May 2011 07:14:36 -0700 (PDT), ls02
wrote:

I am looking for whole house fan with insulated cover.Anyone has one
of thse installed in house and can recommend?

We had one of those when I was in JHS and HS. It seems to me it is
only useful after the outside has cooled off, and that can be pretty
late 8 PM to 1AM on a hot day, depending on how hot the day was and
other things.. Otherwise, when you turn the fan on it draws hot air
from the outside through the open windows making the house warm or
hot, maybe hotter than it was.

If you ran the AC during the day, it sucks all the cool air out of
your house, replacing it with hot outside air.

It probably does cool off the attic, but you dont' care aobut that, do
you?

I have a roof fan (though a gable fan would do the same thing). It
goes on maybe between 10 and noon, and blows the hot air out of the
attic, replacing it with outdoor air, which won't be as hot usually.
It turns off betweem 5 and 8 Pm, or 4 and 9, when the attic cools off
to some preset but adjustable temp.

It keeps the attic as cool as possible which lowers the amount of heat
ing the atttic which can go through the insulation in the floor of
the attic to the occupied floor below. Maybe it's possible to have
enough insulation that no heat makes it from the attic to the floor
below, but i'm not there yet.

I guess the ideal would be to have both or an either/or option. Could be
done with dampers. Cooling the attic space helps with keeping the heat down
so the AC runs less.

On days you don't need AC, but want to cool the attic and suck the heat from
the oven out of the kitchen, or otherwise change the house air quickly, a
whole house fan is ideal. Fans don't remove humidity either.