Insulation

Because we spend a great deal of money and energy generating heat and cold, it's important to squeeze every bit of comfort out of it before it escapes through walls, ceilings, roofs and floors by these methods. The idea is to trap heat or slow down its flow. Materials that resist heat flow better than others-insulation materials-are installed in a house's shell to keep winter warmth in and summer heat out.

Thermal resistance-the ability of a material to resist heat flow-is measured by an R-value. The higher the R-value, the more the material resists the movement of heat.

Materials intended to serve as insulation have millions of tiny air cells that slow heat's movement. In addition, some have facings of foil that reflect radiant heat and retard the movement of water vapor that travels in heated air. A vapor retarder, faced toward the warm-in-winter side, is very important to keep moisture from condensing inside walls, ceilings and floors and damaging both insulation and the structure itself.

MORE ABOUT:
/ Attic insulation / / Types of insulation / / R-values /

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