going to depend on the season and if your utilities are electric or gas . also will depend on the energy efficiency of the home 

However, items like plumbing and electric would very likely require permits and should be done by a professional

Heating costs go up in winter, as does electricity due to the reduced natural light and more people indoors.

Currently there is no electricity or running water so this is going to be fun.

Is plumbing and electric all working properly? 

Are water/electricity shared bills? 

If you start going into electrical, plumbing, cutting in for new doors, roofing, HVAC, etc. then you would potentially need to pull permits.

The electricity is in his name.

The 2nd and 3rd floor needs rehab work including, - Full Painting Flooring (Vinyl/Linoleum)- Replace Kitchen cabinets- Renovate the Bathrooms (replace tiles)- Drop a wall and make a corridor- Electrical throughout My question is, do I need to apply for a permit for all of this work?

Also electric bikes would rent better but are also more expensive and require more maintenance.