I have a 1970s home in Southern California with stucco exterior. On the inside, the exterior walls feel cool to the touch in the winter, so there is probably no insulation, which was corraborated by my neighbor. I want to add some insulation, mainly just in the bedrooms, but I want to do it myself, if possible.

I was considering using expandable foam (Great Stuff is one type, Hilti has another) and drilling a small hole from the inside through the drywall (since easy to repair)and injecting it between the studs - above and below the lateral fireblocks.

I have worked with this type of foam before, but not in an application like this.

Has anyone done this? How much do I use? Are there any drawbacks, like odor or others?