We are looking at a 30-unit built in the 1960's, and the current building is set up with two oil boilers, one for the hot water, and one for radiator heat.

No one wants to do business with someone radiating negativity.

When he visited the houses to see if there was needed improvements, to his surprise, the radiators, and much of the iron piping in the kitchen, including the kitchen sink, were gone!!!

I am highly confident you have a radiator system or terrible leak in your water system. 

My plumber checked the connections for the radiator in the apartment but he did not think the valves at the radiators were leaking, and the carpet is not wet either. 

I can tell you that the house next door which is 1930's vintage and is a big old farm house with 4 bedrooms and a couple bathrooms and had a oil boiler with radiators was just retrofitted with a gas furnace and vents run throughout the home so they can also add central air and they were quoted $24,000 by a local HVAC company. 

And because they have dispensed with HVAC (some will have a single ductless mini-split), there is more usable floor and wall space - no vents, no radiators, no baseboards.

In 2008 I sold my commercial property formally known as Buffalo Radiator (63est Utica..

There are some things I can do (replace the fan in the bathroom; build wonky looking radiator covers; tile a shower), but many things I can't do and I have a full time job.It also helps to find a contractor who can work with you and vis versa.

I did everything from roof to hvac.so this inherited tenant is now complaining bc she is the only one with radiator heat. only thing I did for her is minor repairs and she benefitted from communal renov. she had financial difficulties, she is now only 1 month behind. but pays monthly.if she paid 900-1000.