Pretty much anything in a pre-1980 house will a nightmare to retrofit. Houses in the 1945 to 1965 era (in the US) especially were mostly built as quickly and as

Pretty much anything in a pre-1980 house will a nightmare to retrofit. Houses in the 1945 to 1965 era (in the US) especially were mostly built as quickly and as cheaply as possible. The concept of energy efficiency didn't really exist before the 1973 oil crisis as oil use per capita was steadily going up and up until then. Energy Star, for example, was only established in 1992. Energy efficiency is very very recent.