I grew up in a house built in 1929. It was COLD in the winter. I remember being covered with so many quilts that I couldn't even turn over. My parents had insulation blown in, probably in the early 60s. I know it was before I graduated from high school in 1964. I don't know any of the details, but I know the house was considerably warmer after that in the winter. It also seemed to make it cooler in the summer. Good luck with your decision. I would think insulation blown in/used today would be much, much better than that in the 60s.