It will do this without loosing energy that was used to heat and cool the house. 3.

What kid of heat is used?

It would be my primary residence for at least a year, so I'd want it to be nicer than a standard rental rehab i.e. hardwood floors throughout (maybe bamboo to cut some of the cost), exposed brick walls, 1.5 baths, subway tile in full bath, central air/heat with exposed ductwork, rooftop deck if city approves & budget allows (not a necessity though).

Condo fee is high but includes water and heat, it is well managed, and already knew rent is high and easy to find renters, plus selling price was low so it made sense, so I jumped on it immediately. 

They had no electric or heat for over a year!

The tenant is 19, pregnant, appears to party a lot, and she claims she has no lease (she does) and seems to be clueless about utility bills (her lease says she is responsible for heat and electricity).

My hunch is that the townhouses would have lower maintenance costs because there is no interior common areas/hallways to heat or maintain.

Tenants are billed directly from the utility companies so this also applies to water and heat.4.

Despite having a newer roof, siding, windows, water heaters, and good heating systems, we were always fixing something.

Even then, $500 buys you a lot of pipe insulation and heat tape.