Thanks, guys, for taking an interest in my problem.

I live in Houston, TX, and my cooling bill is about 30% higher than
neighbors with similar sized homes, despite the fact that I have solar
screens and they don't. I have soffit vents and one powered fan vent
near the ridge.

I spoke to one neighbor and he says he can see the white styrofoam
channels in his attic. Another neighbor, with almost the exact same
floor plan and vent system as mine, can see light around the edges of
his attic. I see neither in mine.

If there are other things I can check to explain my high electric
bills, I'm game. Are there people I can hire to analyze my house and
figure it out?