I think your math is off my an order of magnitude somewhere. Your $25k can buy a 40Kw kit according to this¹ South African retailer (excl installation, but my point still stands.
Also, don't unferestimate painting a roof. I recently had my ~400m^2 roof painted, and the final bill was 50k ZAR (~3k USD), and this is in a country with dirt cheap manual labour costs. It's a very labour intensive operation if done properly.
Also, don't unferestimate painting a roof. I recently had my ~400m^2 roof painted, and the final bill was 50k ZAR (~3k USD), and this is in a country with dirt cheap manual labour costs. It's a very labour intensive operation if done properly.
1 - https://www.sustainable.co.za/collections/grid-tied-solar-po...