I have a Spanish-style home located in Southern California, featuring a mostly flat roof surrounded by parapet walls. The roof does have a slight slope that faces toward the north, away from the ideal sun exposure. The main roof area measures 25 feet wide by 35 feet long, with decorative angled tile roofs at the front and one side. I'm considering building a rack to mount solar panels flat on the roof. This would keep them mostly hidden, but I'm weighing my options. If I go flat, I can fit around 22 panels, but if I angle them at 15 degrees, I can only fit about 18, and at the optimal 28 degrees, only around 15 panels. I also have a detached garage with a flat roof where I could potentially install more panels. Given that flat would be visually less intrusive and might save on installation costs, should I prioritize maximizing the number of panels over aesthetics?
3 Answers
I hear you on the utility costs—our last electric bill was sky-high too! If you're still using your original windows from 1927, upgrading them might help a lot with insulation. Old windows can really add up in energy loss.
A great move would be to use the NREL's PVWatts tool to compare the energy yields for each setup. It can help you see how much energy you'd get with flat panels versus angled. The estimates showed that flat could yield about 19,900 kWh annually, while at 15 degrees you'd get around 18,250 kWh, and only 16,575 kWh at 28 degrees.
Honestly, with how cheap panels are getting nowadays, going for the flat installation seems like the best bet. Especially considering space for the A/C. You’ll get more panels on the roof, which means more energy production overall. While aesthetics matter, maximizing output might be more beneficial in the long run.