First purchase- two family long island

[Tara M.]

Finally in contract for my first investment property! I was looking to invest out of state for a while, but I ended up going with a duplex in Suffolk County, NY. Upstairs is a 2 bedroom and a 3 bedroom +basement for downstairs unit. closing on july 1st! 

There is minimal work to be done to the house but my one concern is only one hot water boiler. I am worried about how much it will cost me to pay for heating the house every winter, there will easily be 8+ people living in the house. any suggestion on if i should convert to to gas with separate meters? its a big costly job, is it worth it?