This is another case of why you should always budget more than you expect for a project. You see we had started out assuming that the insulation in the walls would be fine. However after tearing down some of the Sheetrock I noticed that the insulation said ‘1.5″ Economy’. That means that instead of the recommended R11->R28 for a outside wall in our climate, we probably had about R6. So I checked out the insulation at Lowes and since it would only be 20 bucks or so to replace it, I figured it would be a good idea. Picked up a couple of rolls of 15″ wide, 3.5″ deep (since we have 2×4 walls) R13 insulation, and was happy to find that its quite easy to install. It fills the stud bay completely, and has nice little flaps that make it easy to staple to the studs. Hopefully the added insulation will keep the bathroom nice and toasty warm in the winter time!