an imageINSULATING SIDE WALLS OF EXISTING HOMES

U nless they’re insulated, the exterior walls of your home provide an ideal escape route for precious heat in the winter and absorb the sun’s energy during the summer. During the winter, without insulation, heat travels right through your walls in its

natural quest to join the cold outside. Insulation slows down this migration of heat and saves you money on your utility bill. For Montana ’s cold climate, the U.S. Department of Energy recommends insulating existing house exterior walls to an R-value of at least 11. R-value is the measure of an insulation material’s ability to resist heat flow. It’s measured per inch of the material’s thickness, and the higher the R-value, the better the insulating ability. For example, glass-fiber batt or blanket insulation has an R-value of around 3.2 per inch; the R-value of loose-fill cellulose is about 3.7 per inch, and rigid polystyrene board has an R-value of 4.5 to 5.5 per inch. All of these insulation types are commonly used to insulate walls. Which type works best depends on what kind of walls your home has