what are the reasons for double the cost?
would it be possible to buy panels, mounting systems, cables, inverters,
breakers, etc. yourself and have them installed by a company?
(like building a house and you only pay the labour costs)
does it really have to be an approved installer? is there no other way?
the costs for the permit (paperwork etc) itself can't be that high ... or am i completely wrong?
the alternative with batteries is not cheap either ... especially when you consider
the lifespan of batteries!