Solar panels on the most visible house in America send a powerful message. Not every president wants that.

Press conferences at the White House tend to occur in predictable locations: The Briefing Room, the Rose Garden, the South Lawn. In 1979, President Jimmy Carter chose a loftier venue: the roof. He didn’t do it for the view over Washington, D.C.; he wanted to show off a brand-new array of 32 solar panels.
The solar panels installed by Carter weren’t going to change the world by themselves – they were merely going to help heat water for the White House. Their real power was as a symbol. If they’re good enough for the White House’s roof, they’re good enough for yours.
Read more: https://www.universityofcalifornia.edu/news/strange-tumultuous-life-solar-power-white-house