Danny D. wrote:
Here is one of my five attics:
https://c2.staticflickr.com/4/3895/1...670115cf_b.jpg

Would an attic fan, of some sort, be feasible in this location?
https://c2.staticflickr.com/6/5582/1...59e28b99_b.jpg

The house has AC, and three floors, and it's insulated with the
loose stuff, at least anywhere where I can 'see' the rafters.

It's California. Northern. So, it's a pretty mild climate, but,
it's as hot as blazes in these attics, so, I was just wondering
if it's better to run the home heating system fans, or, put an
attic fan in to cool the house down, without running the A/C?



You are going to receive differing opinions about the value of an attic
fan. Some maintain that the cost of running the attic fan is offset by
the cost savings of running an air conditioner less and therefore a
wash. They see it as useless to keep the attic cool if you spend the
same amount on electricity.

I live in a southern state where the outside temperature often reaches
100 degrees in the summer months. My furnaces are in the attic, and the
evaporator coils for the AC are of course inside those furnaces. If the
outside temperature reaches 100, you can imagine what the temperature in
the attic reaches. I have a gable roof like you do, with vents in the
eaves. I have two gable fans that are set to turn on at about 95
degrees so that when the AC is running the temperature around the
furnaces is as low as it can be. My theory is, that not doing so would
be like having the evaporator coils in an oven.

The bottom line is that although I do consume electricity to run the
fans, my electricity bill is much lower than my neighbors. I also have
programmable thermostats, so that also helps. I will finish with the
fact that I placed a thermometer in the attic once to see how high the
temperature would go without the fans on, and it exceeded 120 degrees.
That was as high as my thermometer would read.