Zillow does carry FSBO, auction homes, estate sales and some other unique situations so it can be good for that if you are purposely trying to avoid working with a realtor. 

Read books on investing in real estate, listen to the podcasts, attend webinars and stay active on the forums while connecting with other investors in your area and pick a niche.

What is your niche going to be?

It's a question of developing your specific investment goal, developing the confidence required by educating yourself and surround yourself with others who've done it, and developing your unique strategy to meet that, whether it's in state or out.You should be able to trace ALL your activity back to your specific investment goal.  

However, in certain niche rental models; student housing, short-term corporate rentals or senior living where the landlord takes on the burden of utilities management (for a higher than normal rental rate), then solar could make sense.

You might consider Niche or Specialized Housing like student housing.

You might consider Niche or Specialized Housing like student housing.

If you are looking for real estate business advice and someone with years of experience in accounting, we are a unique duo that you may not find anywhere else. 

Unique little cottage on a huge corner lot, lots of little perks, charming historic aesthetic.

I am sure I have a unique answer to your question that asks why?