I'm looking to buy a home and curious if there are general guidelines as to when a home was built and what kind of insulation it might have? For example our current home built in 1915 had no wall insulation when we bought it. Ended up getting some cellulose blow in. When did fiberglass batts started being used in new home construction? Was there any kind of insulation being used between none and fiberglass batts? I'm guessing this may vary depending upon region and a variety of other factors, but curious nonetheless as I start looking at houses to buy. I am located in SE Wisconsin if that would matter.