Again as Adam said ideally now you would be modernizing by renovating one apartment at a time and increasing rent but you may not be ready.Rents are under market.. yes. 

Thanks Duplex units on the west side of Cleveland in high demand so long as you update them with modern fixtures.

Maybe speak with a realtor about whether renters are accustomed to living in a unit with a radiator, or whether a more modern HVAC system is expected. .

People just don't run a shop and live upstairs like they used to, so these buildings don't make as much sense in the modern age.

Condition is not unlivable just not modern looks.Is there anything I left out that I'm not looking at?

Preserving the 1950's solid wood doors, original back door, stained glass window and keeping as much of the original charm as possible, blending the fixtures and appliances that my previous clients had intended to use, and finally adding a little of my own flare with calming paint tones, modern flooring, and mismatched metal hardware.

Here is how we solved our problem:First to check for leaks, turn off all water in both units and make sure the water meter is not still spinning. if it has not already been done, replace toilets with 1.28 gpf toilets (or better).Check the washing maching models and hook ups and require tenant supplied models to meet modern water efficiency standards.After doing these things, if the unit is set up with a separate shutoff valve for each unit, you can install flow meters.

Indy has transformed from a Rust Belt city to a thriving, modern metropolis. 

Removed interior walls opening up the living space and giving a very modern touch.

Today, Brooklyn Brewery is surrounded by modern apartment buildings, trendy bars, shops and restaurants.