@Ryan Kopf The way most modern solar works, is pannels have grid tie power inverters on the back of the panels feeding backwards through the meter essentially producing you an electric credit. This is the most inexpensive form and can be installed most anywhere. If the power goes out, your power is still out as they produce no energy without grid energy to wave match. ROI is usually 8-20 years for a home owner, and usually those super low interest rates or "no money down" are often secured by a first lein against your house (no thanks.)
If you had tenant separated meters, they could gain benefit from this and some may be willing to pay you a fee for the "green" energy but I think you would be looking for a niche within a niche.
The next way this is done is all the panels are fed through one large inverter that is tied to the grid and backfeeds your meter. This would have to be a freaking huge inverter $$$ for a 4plex and you likely don't have enough roof to offset the entire energy bill. If your tenants have separate electric you would need an inverter per unit. $$$. Either way, even with federal, state and local tax credits you would likely spend $100k and still have an electric bill. You CAN spend even more money and get battery backup with this mode... so if the power goes out you can have a small amount of energy to run things other than the HVAC or stove... like a medical device. That could be an amenity you could upsell.
You do not have enough roof to go "off grid" 100% solar and in most places it is actually illegal to do so. Even if you did, it would likely cost more than the building.
So... to sum it up:
If you want to poney up the $ to lower your tenants electric bill with solar, you may be able to recoup some of your expenses via fees. If you save me $50 a month I'd personally be ok paying you back for a net even. Some people may not want this additional hastle. It will largely depend on your market.
If you want to spend the big bucks and offer tenants battery backup in a power outage, you could likely sell this service. Especially to people with medical equipment.
If you want to lower your landlord paid electric bill, enjoy the tax rebates and incentives.... AND want your tenants to pay you 10% more in rent because there is a science experiment sitting on their roof.... I think that would be a heck of a hard sell anywhere.
Also.... one final thing to think about: Iowa is a crappy place to install solar. The state enjoys about 4.5 peak solar hours per day on average. Contrast that to Arizona averaging about 8... this means you will be looking at the longer side of ROI. Like analyzing property.... its a good idea to check the numbers people trying to sell you a system are using. If the system puts out 20kWh per day in Arizona you are going to get half that, IF your roof is optimally positioned for solar. Most arent.
