Keeping your home warm in winter and cool in summer depends on a whole system of comfort engineering. Chief among the components is insulation, the blanket of material in the walls and attic that resists the flow of heat transference from outside to inside and vice versa. Technology and the move toward greater environmental awareness have brought great improvements to insulating material. Here’s a look at what’s available.
Understanding “R” value. Stuffed inside the outside walls and covering the attic spaces, insulation serves as a blanket to hold heat in place where you want it. Insulation is stuffed or blown into the spaces between wall studs, beams and joists. Insulation, which varies in thickness and quality, is measured in “R” factor. The accepted standard for the insulation in walls in most of the country is R-13. For attics, the accepted measure is R-38.
Fiberglass and its improvements. For three or more generations, fiberglass insulation has been dominant. It has served well but health concerns have surfaced over airborne fibers when it is disturbed. Manufacturers now make fiberglass available in sealed bags. Recycled materials are also now being used. The insulation can be blown in or rolled out like a blanket stuffed between studs or joists.
Cellulose. Made of ground-up newspaper and other paper products and treated with a flame-retardant chemical, cellulose was introduced about 25 years ago. It is inexpensive and has a higher R value than fiberglass. Typically it is blown in with a machine.
Recycled denim. Cotton treated with fire retardant is also used as insulation — the most neutral material for people with allergy sensitivities. Some of the recycled material used comes from discarded blue jeans. Similar products are being made with sheep’s harvested and cleaned wool, which is treated to be water- and mold-resistant.
Spun minerals. Providing excellent R factor, mineral-based insulations such as basalt are multipurpose insulators. This type of insulation has the added bonus of being impervious to damage from water, fire and termites.
Sprayed foam. Made from a variety of materials, spray foam insulation gets pumped into wall spaces and between studs where it hardens and forms a virtually solid barrier to heat loss. Foam board can also be used for the sheathing on the outside wall studs. These foam panels form both an extra layer of insulation and a moisture barrier.