One of the older metrics for comparing 4v lead acid battery solar home panels to their installation cost was to assume
that you'd sell the house at some point during the 'buy-in' period; depending
on the state of the housing market, that may or may not be a valid assumption,
but a home solar electricity installation will always attract buyers and
increase the value of your house. However, making and/or installing the solar
home panels yourself will obviously reduce this 'buy-in' period - it's
surprising how economically you can build your own home solar electricity
installation.
One should also avoid getting 'locked into' the idea that
sunlight has to be stored as electricity in batteries; you can get a lot of
benefit from energy storage inverter solar home panels on a smaller scale, even if all they do
is power attic fans and circulate hot air out of your house in the heat of the
day. These can provide significant savings over the course of the summer, and
can pay for themselves faster than a full-on home solar electricity system. This
would be a good start if you decide to build up your system in stages.