There are other considerations as well such as appliances....at least for those who wish to be totally off the grid. Water delivery can also be a problem depending on where you are considering converting to solar power. Well pumps don't like to run on less than 220v......so you're stuck with either a public water source or a rain water collection system.....but with La Nina in our immediate future that might work out OK. A lot of considerations and presently with our cheap electricity rates, it's a tough one to beat.