Multifamily HVAC Situation

[Kevin W.]

Hey All,

Long time lurker but first time poster. I feel confident saying that this forum gave me the confidence to close on my first duplex.

So naturally, I now have to come back to the forum with questions! This home is a 2 story 2 family, previously occupied by parents/kids who grew a family and moved upstairs. This home only has 1 zone on 1 hot water boiler. I'm in a dilemma on whether or not to simply add 1 zone on the boiler, as its clearly able to heat both stories. Or, split up the piping, install a gas meter, and install 2 separate smaller (60,000 BTU) boilers to keep units independent. I will be living on the first story of this home. 

If I keep the boiler the same, I would charge a flat rate monthly and "include" utilities. If I split the units, I would make tenants responsible for utilities. 

Can someone who's dealt with a similar situation please chime in? Maybe there are other options on the table?