The statement that sealed the deal was 'better the ghetto we know'.

The fogging means the seals have gone bad and need to be replaced.Probably wait and see if the house appraises for purchase price.

We have used spray in insulation on some projects which costs a little more but also requires special plumbing because the spray in insulation creates a tight seal around your pipes, so make sure your mechanical vendors know what insulation you are going to use before they get started.Spray foam is more efficient but costs a little more. 

We also tend to go deeper in our renovations than other landlords in our area (we will actually insulate and air-seal our old housing stock) which has meant ploughing all free cash-flow back into the property for several years.One thing we do is track repairs/maintenance separate from capital improvement / major renovation.  

Another tenant was complaining because their front door was not properly sealed, and cold air was rushing in, but I assume this is probably an easy fix. 

You will want to know what was done for insulation and air sealing during the renovations.  

Once that's done they powerwash it, point as needed then seal. 

After that the windows just needed some caulk (inside and out) and they looked great and sealed very nicely. 

Some of the challenging work I will be taking on is double stud framing, window installation, hydronic radiant heating, air-sealing, dense-packed insulation, plumbing, kitchen, bath, and siding (cement fiberboard and cedar).

Keep in mind that the general mind frame here is anything porous needs to be sealed or replaced.Windows:These are all based on the frame material.