I gutted the kitchen and replaced it with a modern style kitchen.

In addition, I use certain modern tech tools to automate pre-auction research, servicing of liens and monitoring portfolio.

Our dream, however, is to build high energy-efficient modern homes. 

Restoration of historic articles/structures of the building might also costs way more than replacement but it you can't replace, then you will have to eat up the significant cost upcharge.Utility costs might also be higher than modern, better insulated buildings specially if you get below freezing weather.Historic buildings might be cheap but renovating them usually cost a LOT higher than the usual buildings.

(I got a couple of gas ranges on a Black Friday deal last year.)New appliances also help with marketability at showings: more modern appearance, more energy efficient.  

We were able to redesign this dated ranch (including flipping the basement staircase around to make room for a huge pantry) and sell it as a modern Ranch into our heated sellers' market.

We were able to redesign this dated ranch (including flipping the basement staircase around to make room for a huge pantry) and sell it as a modern Ranch into our heated sellers' market.

These older buildings were designed to stay warm despite modern day insulation.Renters will be paying their own utilities anyways and since the property has a history of long term tenants that indicates nobody's too inconvenienced trying to keep their unit heated.  

Lead based paint was phased out and modern HVAC, plumbing, sewer lines, and electrical codes were used.

the costs involved for building a legal MIL would be a lot more if you had to correct issues like these rather than if the home had a full height basement,  modern foundation, and existing roughed in plumbing for example.Depending on what your father (or you) want and how long the home has been owned by your father,  selling and rolling that money into something bigger could be a good move,  though on the other hand Phinney is one of the most desirable areas in the city.