What's the impact of an incorrectly sized system- Temperature in the home never went above 65 on that cold 4 degrees Chicago daysProblem 3- Didn't insulate outside plumbing walls.

This biggest challenge and cost is probably running the plumbing.

We replaced siding, windows, doors, flooring, trim, paint, light fixtures, interior hardware, installed HVAC, enclosed carport/storage to make a laundry room, repaired bathrooms, plumbing, and electric.

Talk to the other trades make connections with carpenters, electrical, plumbing, finishes... way to go

If it has the infrastructure (plumbing, electrical etc.) to hold mobile homes that’s awesome!

I'm very particular with types of systems, electric, and plumbing. 

Mostly cosmetic, although it did have some plumbing issue, which was why this property was "cash only" and not available as a conventional purchase.

I am currently working at a plumbing company and pursuing my goal to start my own plumbing business one day.

Things like new roofs, plumbing, and electrical don't have a very good ROI but cosmetic things do. 

Put up a new wall, within that wall is new plumbing to a bathroom.