Thanks for the suggestions. I live in PA. I think they are coming in for warmth mostly. It still gets cool here at night. I plan to put screens over the cracks in the soffet. I don't think the cracks in the soffet between the upper and lower levels are designed vents since they bump right up against the bricks, but I will not seal them just in case. The soffet between the upper level and the attic contain vents.