Robert Flores, [senior scientist in the Advanced Power & Energy Program], a solar expert at the University of California, Irvine, said it’s smart to upgrade any old appliances before going solar. … Monocrystalline panels are generally considered the “best bang for your buck,” according to Flores. … Aso consider space … “The worst place would be to install on north-facing roofs, especially if those roofs have a high pitch.” For example, if the only place you can install is a north-facing roof with a 30-degree pitch, your cost of going solar will increase by 30% to 40%.