Rooftop units might not be the least expressive, but they are absolutely the way to go. The less we rely on the utilities, the more demand we take off of their adding grid, that they refuse to upgrade. It also means more energy independence. A friend of mine has a small rooftop setup that has completely offset his electricity isn’t to the punt that he bought a plugin hybrid that never goes out battery for his day to day travels and costs him nothing to charge.