How to make tenants pay for radiator heating and how does it work

[Michelle Bright]

Hi BP!

I need help on radiator heat. I have never lived in a home with it and am just a little confused as to how to how it's expense works. Is there anyway to make tenants pay for the fuel? How can I tell if it is heated by gas or electric? I am looking at a fourplex and there are 5 electric meters, one water heater and a newer (8 years old) energy star boiler. Is one water heater and the boiler enough for all four units to get enough hot water and pressure all at the same time? Thank you in advance.