trader_4 wrote, on Sun, 31 Aug 2014 04:29:33 -0700:

Lowering the attic temp will help. The question is how much you can
reasonable lower it via the possible methods and how much actual benefit
that will have in the living space.

That's why I had asked. I'm just curious if it's a good idea or not,
given that it would be work to do it. Luckily, there is electricity
in the attics, as each have a light bulb at least.

The attic is insulated and that is
the primary means of preventing heat transfer. I notice you have blown-in
insulation about equal to the joists. In some spots, it's a lot less.
Adding more insulation would probably have a bigger impact year round
than adding a fan.

The blown in stuff is all that I see. There are boards on some of the
attics, but usually only in the center where we can store some stuff.