If they will allow the change, you'll need to submit proper drawings and plans and obtain permits for plumbing, electrical, mechanical (heating), and any other permits as required by your jurisdiction (often required to be done by licensed/insured contractors).Keep in mind you will need to change out your electric service panel to a 3-service entrance--1 meter for each apartment, 1 meter for 'common area'--exterior lights, etc. 

We haven't made final decisions on exactly what we'll do to it, but one thing's for sure - we're upgrading the electrical service.That's a 100 amp panel.

There is currently a program out for solar that makes panels cheaper than grid energy, in my market, so I did have one of my rentals equipped with solar, however, even that was a financial equation.

For frequent usage and a lot of doors and users, it's worth it to go with the professionally installed system - it might set you back about $1,500-2,500 per door, and will integrate with your security system and fire panel.

Unfortunately, that's not the way it works today: - People like Sarah Palin are complaining that the current bill advocates "death panels."

I had a solar panel on my roof at my previous house.

Its used in everything from toothpaste, to solar panels, to cell phones, to antibacterial products.

The panel thus helps to further the reliability, professional quality, and transparency of the agency's work.Yeah, right!

The biggest possible gotcha is the LV wiring between panels and to the inverter. 

So until I see those popping up everywhere and the cost of electric is about the same as gas for a purchase I do not see mass change in use by consumers.Personally I would love to see self charging cars using mini solar panels on the roof of a car that leave reserves for night driving.