Splitting Utilities (HVAC & Electrical) for Duplex Conversion

[Griffin Doninger]

Hello Good People of BP!

I recently purchased a large two family home in New Britain CT. It is a rather large house (3700+ SF) that appears to have been originally built for a wealthy family in the early 1920s. It was later converted to a duplex (maybe late 90s), but none of the utilities were split at the time of conversion.  I would appreciate any advice on how to approach this scenario. I am considering mini-splits for the 2nd unit, or converting entire place to baseboard heaters. 

Current Setup:
     - Electrical - Single 200A panel: Current plan is to trace all circuits and, provided they can be easily divided I would add a 100AMP sub-panel and a local sub-meter to avoid engaging the power company.... of course this means I would need someone to physically check the meter monthly and I would still have the service in my name...) Should I bite the bullet and request a second electrical meter be installed, then feed a second panel?

     - HVAC - No AC (window units). Heat is all traditional column hot water radiators fed from a single boiler. I don't know much about how they used to pipe these things but I'll have a better idea after basement demo. All radiators are currently functional. I don't think my luck would have these in anything but a single loop. 

- Domestic Hot Water - All fed from a single thankless instant hot water heater

Important Information:

- There is a full basement which will provide good first floor access. After demo down there I will have a better sense of radiator pipe routing. 

- There is a semi-finished 3rd floor which could provide access to 2nd floor ceiling if needed. 

- This is a VERY old house, so there is abundant vertical MEP access (abandoned stairwells), but punched sheet metal lathe plaster makes for challenging wall entry.

- I am a career construction professional, so I have a good understanding of what's involved here. However, I work primarily on the commercial side and would very much appreciate any insight you all have on this specific (historic!) residential scenario. 

- Because of the size, age and owner neglect, the utility bill is in excess of $500/month. I think it should be closer to $150/month per unit. I plan to ventilate roof joists and insulate exterior walls with cellulose, and basement floors with fiberglass.

- I live out of state so permitting and utility company coordination would be a challenge 

Thank you all in advance!