What's the best way to deal with uninsullated exterior walls in a 1950s house?
My home was built in the 1950s and the exterior walls have no insullation at all (discovere this while doing full renovations of both bathrooms). The exterior walls are half and half stonework and vinyl sideing while the interior walls are plaster over 1/2" sheets of drywall. I am considering drilling holes in the stud cavities and blowing in cellious, then probably just covering the whole wall with 3/8"drywall so I can add actual window frames (as oppose to my current rounded corner no frame look) and cover up other craked/problem areas in the plaster. Does this sound doable to cut my energy bills or is there a better option I should look into?
Blown in cellulose is an excellent product for that scenario.
A dense packed blown cellulose (3.5 lbs/ft^3) will add R-Value to your wall but even better will help with air infiltration/exfiltration as well. Although dense pack does not technically meet the standards to be rated as an air barrier material it comes extremely close and performs much better than many other products out there.
If you are going to overlay Sheetrock and case the wiondows, take the time to cut out the Sheetrock around the windows and seal the gap between the window and framing with a low expansion foam.
For more information:
Read "We have inadequate wall insulation. What is the best approach to insulate our walls?" a Q&A answered by Michael Holcomb.