wrote in message
ups.com...
A 30 degree diff between the living area and the attic on a hot day is
excellent. It's not unusual for attics to reach 110+ on a hot day,
even with excellent venting. That's well within the capability of the
insulation to handle. Would you be concerned if during the winter the
outside temp was 30 deg below the inside temp? Attic ventilation is
important to keep humidity down and to prevent really high temps, like
140, which are possible with poor ventilation.

So, I wouldn't do a thing. Plus, installing a powered fan raises the
possibility of a considerable amount of air just being pulled in via
the ridge vent and blown out by the fan, effectively short circuiting
what is already there. Also not clear that adding a few more box vents
is going to do much either.

I think the latter is the key point -- a powered fan may not be be much help
because of cross currents with the ridge vents. Many years ago I installed
a powered vent at my house in Ohio and immediately noticed a significant
decrease in my need for air conditioning. For that house, the powered vent
was worth it.

Since then, insulation has gotten much thicker and electricity more
expensive. Reportedly, tests now show that a powered vent will use about as
much electricity as it will save in a/c costs and that the cost-effective
way (for houses with soffit and ridge vents) is to add more insulation.
Nevertheless, I did put in a powered vent (I have soffit vents but no ridge
vents here in hurricane country). I can't quantify a savings in my electric
bill, but now if I have to get something from the attic the temperatures are
bearable, even here in Central Florida. Regards --