Insulation

The house I grew up in had no insulation. The windows
were single pane & developed frost on the inside of the
window. I would scratch my name in the frost every
winter.
The insulation business mushroomed after the oil
shortage in the mid 70s. People began to realize how
much money could be saved by adding insulation to the
attic floor & having insulation blown into the walls of the
house.
Foil faced fiberglass are common place today & I think
that is the way to insulate whenever possible. Blow-in
insulation is fine but it is rarely installed evenly
throughout the area. When building additions, make
sure the insulation is batting & foil faced. It works.