32 Unit Deal - Heat bill is killing it...

Looking at a 32 unit deal in Milwaukee. However, the heating bill is 33K/year. They are newer, but it definitely hurts the investment. It has been sitting for a bit, and I think that number has been their big obstacle in seller the place. 

Has anyone retro-fitted a multi-family to have furnaces in each unit? How much does it usually run per unit? I work in the land of A/Cs (Florida), so I haven't done anything like this.

Thanks for any input,

Steven