my post and link was to clarify to the readers that solar power does not require 10 years to repay the initial cost , if the initial cost is lower per watt.
If it really pays for itself in 4 years then anybody planning on staying in the same house for that long should use them!
But I think your calculations were a little optimistic. Little-no power on cloudy days, and probably not getting the advertised power output unless it's facing the sun, which it won't be for 8 hours.
And without batteries, you have to use that power in the middle of the day or it's wasted. What's consuming 1500 watts all day while you're at work? Forgot to turn the oven off?
With batteries that introduces a whole new ongoing cost of replacement, as well as power loss through charge/discharge inefficiency.
