gonjah wrote:

Should I still be using my attic fan during still periods? I thought
they were not cost effective. I have a 1500 sf house. How many sf
should I have in

soffit vents?


According to my corrected calculations, you need one sq ft of soffit vents
per 150 sq ft of floor space, or 10 sq ft.

This is ten UNRESTRICTED sq ft. Some of the screening on soffit vents take
up a considerable amount of space, so figure on 20-50% more actual venting.
Looking at the commercially available vent covers, I decided to make my own.

Here's what I did.

1. I got a roll of gutter screening. Plastic, 6"wide. Actually, several
rolls.
2. Using 1/2 x 2 furring strips, I constructed a number of 4' long frames to
hold the screening. A pneumatic staple gun is a great labor-saver here.
3. After trying all manner of saws, I ended up using a pruning chain saw(!)
to cut the 5" by 4' sections out of my 1/4" plywood soffits.
4. I installed the aforementioned frames with sheet metal screws. The soffit
screens were painted before installation*.
5. I installed a LOT of these home-made soffit screens. The perimeter of my
house is about 200'. At least 100' of that contains soffit vents. That works
out to 2.5 times the recommended minimum.

Of course I live in a hot, humid, town (Houston), so my needs may greatly
exceed yours.

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* Before painting my house the last time, I investigated the available
colors of spray paint available at the box store. I found one that was
acceptable ("Camouflage") and bought several cans. I then painted the tip of
a wood paint stir-stick with the spray paint and asked the paint department
to match the color with several gallons of exterior paint. Now, when a bit
of the house needs a touch-up, I spray it.

Anyway, the spray cans came in handy when painting the soffit screens...