Insulation is the ability to resist heat transfer through a material. This prevents a surface that is in contact with heat from conducting it through the material quickly. Materials with high conductivity allow heat to transfer easily through them. Materials with a lower conductivity value resist the flow of heat through the material. This ability can affect the amount of money you spend for energy each year, both in cold season when heat is escaping from heated homes and in summer when the sun and heated air flow inward to the interior of the home.
Insulation Ability of Brick
Houses made from full brick, that is, normal size and shape bricks rather than half-brick facades, are heavy, dense and conduct heat and cold slowly, according to the Acme Brick website. This conduction process is called “thermal lag,” and it reduces the need for heating and cooling during peak usage periods. Though brick construction costs twice the amount of wood construction, it pays off in energy savings over time. Brick is essentially maintenance-free but does need occasional tuck-pointing to repair broken mortar and chipped brickwork.
Insulation Ability of Wood
Wood also has good thermal resistance because the fibers are composed of open cells where air is trapped. This air helps insulate the material, preventing the transfer of heat. Wood is much less expensive than brick for home construction, which is why it is so commonly used in communities throughout the United States. Wood allows for inexpensive housing with relatively easy maintenance and good insulating ability.
Improving Insulation in Wood Homes
The most commonly used insulation material is fiberglass batts or rolls that are laid into the spaces between the wooden joists in walls. Foam polyurethane is another material often used for insulating houses. This material is sprayed into walls to fill up these spaces between the joists. The insulation ability of these materials is rated in R-values, which is their resistance to heat flow. The Department Of Energy recommends increasing insulation in climate Zones 5 through 8, an area that includes the Midwest and northern parts of the United States, and to R5 to R6 values by adding insulative wall sheathing under siding.
Improving Insulation in Brick Homes
Adding insulation to brick houses can be a more difficult and expensive endeavor than in wood homes. Older homes may have two layers of brick without any wooden structures to hold the insulation. These houses were built in the days when energy was cheap and the brick itself was considered sufficient insulation. Insulation is often blown in through interior walls into spaces behind the plaster. This can be a messy undertaking that should be done by a professional insulation contractor.