"Insulation efficiency is based on an "R" value, homes built in different
years will generally have different "R" values depending on builder and code at the time. The code today
is set at "R" 50 which is about 16 inches of cellulose (looks like shards of paper), e.g. a home built
in 2000 has and R value of 32 however the quality of insulation used at the time would have deteriorated
to about an R18 value. Homes built in the 1950's will have an R12-R14 value in today's standards.
See our FAQ's."