So I've also given this a lot of thought. A few gotchas to consider:


1) Do you need to remove any trees? I live in a forest, so this is a big problem for me.


2) What happens to your note if you decide to sell the house?



3) Will the system work in a blackout? Oddly, many installations won't work off-grid.


4) Is your payback tied to selling excess power back to the utility? This may turn into a problem, as the rate paid by the utility may end up being different from the rate it charges. Net metering will become more controversial as more solar homes join the grid.



5) Will you have a battery to carry you through the night? The battery won't last 25 years.


6) How will you access the roof? I need to walk the roof a couple of times a year to clear leaves from the gutters and wash the skylights.



7) What is the expected maintenance cost? I have doubts about a 25 year warranty offered by a two year old company.