How does panel efficiency change with temperature, especially with the extreme summer heat in Phoenix?
Heat negatively effects panels, but it is more than compensated for by the massive amount of sun. Almost all panels are affected equally by heat despite the fact that almost all marketing materials claim their panels work better in high heat. Production lost can be 7-9% in the absolute hottest temperatures, but this is made up for by longer days and more intense sunlight. Production, even with the heat, can be 14-16% greater than a similar location in San Diego. The quotes from REC take all these into consideration and the systems will outperform the quotes. Also, the higher efficiency panel options (mostly used on roofs where you want to maximize the space available) have a thin film component on top of a normal panel component, and they are particularly heat resistant.
