See Also: Insulation
Insulation is measured in R-Values. The higher the R-Value, the better the
insulation is at blocking Heat loss. Different materials have different R-Values, so you can’t measure the insulation strictly in terms of inches. For example, blown-in
cellulose is a good insulator. Six inches of cellulose rates an R-19. On the
other hand, six inches of concrete, a poor insulator, has an R-Value of only 0.5.
Insulation not only keeps the heat in during the winter, but it keeps the cool
in during the summer. The greatest source of heat loss is through ceilings,
floors and walls. Across the country, the recommended R-Values range from R-30
to R-49 in ceilings to R-11 to R-19 in walls and in floors over crawl spaces or
unheated basements.