Most of us know insulation installed in wall cavities, overhead in our attics, and under a home constructed over a crawlspace, contributes to the control of temperature in our homes. In the winter, insulation keeps heated air in our homes; and in the summer, insulation keeps cool air in our homes. End of story, right? If you desire an energy and cost efficient home, new products brought to market in recent years to combat the ever increasing costs of heating and cooling a home warrant some exploration.
Types of insulation vary and building codes only set a minimum standard. The U. S. Department of Energy sets a minimum standard for walls, attics, and crawlspaces defined as a “resistance” value, commonly referred to as an “R” value. For instance, building codes require exterior wood frame walls be insulated to an R-13 value in a home built in Williamson County, Tennessee. When we talk about an R value, our goal is to set a resistance value to inhibit the natural process of heat seeking cold. We use more or less insulation to inhibit heated air from reaching cold air. The higher the R value, the longer it takes heat to transfer to cold. The following chart represents energy code requirements set by the U.S. Department of Energy by zone.
Three common insulation methods used in our climate include batts, blown, and spray foam forms. The most common method of insulating used in middle Tennessee utilizes batts in walls and between floor joists in crawlspaces, and blown insulation in attics. Minimum requirements may be attained using these mediums; however, additional efficiency may be realized by using a combination of spray foam and batts in wall cavities, crawlspaces, and attics. A method referred to as “flash and batt” utilizes spray foam to seal seams and joints in cavities before installing batts. This method costs more than standard batts only, but less than a full spray foam application. Keep in mind that areas in a home that incorporate many windows have less wall space, and spray foam used in these areas provides the best insulation.
An experienced General Contractor will guide you through the selection process when you consider all of the insulation possibilities available.