I just bought a duplex and it has 2 fuse pannels 1 on each flat with 6 fuses in each now I need to put electric heat in both flats do I need to switch to 2 breaker pannels or can I put 6 1500watt heaters on each fuse box and if I need to change my fuse boxes to breaker pannels what size do I need to run 6-1500w heaters 1-40gal water heater 1 dryer 1 stove and all the general lights and plugs on each flat would I need a 200amp or 100amp or can I use the fuse box

Each apartment will need a 100 amp breaker panel, and the main service will need to be 200 amp, with two new 100 amp meters and disconnects.

This will require that you consult with the power company for their service location and metering requirement, permit from the local code enforcement office, and an electrician to change the service and panelboards.