You technically give all your power back to the grid, you can't run your house off of a solar system when the power is out (without a backup battery system due to variability of solar output).6) I wouldn't install on an old roof, no issues otherwise.7) solar company will discuss location and output before instillation, non issue.  

If you work in Oregon, check out the CCB's naughty list of contractors with a history of complaints. http://www.oregon.gov/CCB/Pages/buyer-beware.aspxYou can also search specific contractors and see their history, insurance status and complaints: https://www.ccb.state.or.us/search/If you have a residential developer's license, (which highly recommend if you are flipping homes in Oregon), you can set up a watch list of all your contractors and get alerts if their insurance or license lapses. https://portal.ccb.state.or.us/Modules/eWatch/@Mathew Wray, I'll second your echo for Ambience Remodeling, Daniel is a worked for a number of our RareBird Investor Network members and they all have great things to say about him! 

I've worked as a W2 employee in between starting businesses as a web development for a battery company.

There has been a lot of suggestions here of various technology solutions, most of which would seem to rely on electricity and possibly a battery for backup.A generator is an expensive option, and you may be relying on the tenant to get it running.

To get better coverage, we put on one of our buildings, then we put a post away from the buildings towards the back.If the battery (lasts about 3 years) runs out, you get a call.

It will go away as a standalone and become a module within apartments. 

Most other units can store around 30ish codes. 3) the battery life is better. 

Otherwise, look at Boxable module ADUs cost is about $250 per month without installation costs. https://www.boxabl.com/reserve...

Accounting module. 

No wireless cameras with batteries to replace.