Sometimes I wonder if these companies ever install their own products in real houses.
That’s the part that gets me too. The install guides always assume you’ve got a textbook roof and modern wiring—never mind the 80-year-old attic with mystery insulation and rafters at weird angles. I had to jerry-rig a bracket just to get my panel facing close to south, and even then it’s not perfect. Curious if you noticed any drop in fan performance on cloudy days or when the sun’s at a low angle? Mine seems to slow way down unless it’s high noon, which is kind of annoying considering the price.
I get what you’re saying about the performance drop, but I’ve actually had a bit of a different experience. My setup’s on a low-slope roof with older rafters too, and yeah, getting the panel aimed right was a pain—ended up using some scrap aluminum to make my own mount. But even with that, I haven’t noticed as much slowdown on cloudy days as you described. Maybe it’s the panel size? Mine’s a 30W model, and it seems to keep the fan spinning decently unless it’s really overcast.
One thing I did notice: if there’s any shade from nearby trees or even the chimney, the output tanks fast. I wonder if that’s part of what you’re seeing—sometimes it’s not just clouds but random shadows during the day. Also, wiring length can matter more than they let on in the manual. I kept mine short after reading about voltage drop issues.
Not saying these things are perfect (they’re definitely not), but maybe there are a few tweaks that could help with your setup. Still, for what they cost, you’d think they’d be more forgiving of less-than-ideal conditions...