Duplex Unheated Basement Laundry & Storage

[Joe Schaak]

I have a duplex with laundry in an unheated unfinished block basement - in Minnesota. There's also some good storage areas down there that I'll rent to the tenants. 

Does anyone have some suggestions of if/how I should heat the area? I'm replacing the boiler systems (one for each unit) and also updating the electrical so now is the time to do something if I'm going to do it.

Thanks in advance!