Insulation
Photo by Paul Stainthorp
A properly insulated house will keep its inhabitants comfortable.Chosen insulation must be installed properly to touch all six sides of the wall cavity. Some types of insulation-such as foam board and dense-packed cellulose insulation-can be effective at reducing air flow as well as heat flow, fiberglass does not stop air leakage, in older homes, dirty fiberglass insulation is a telltale sign of air movement (it collects dirt like a filter).
Insulation represents an inherently green building material because it is designed to save energy. Still, while any insulation is better than none, the many choices present a broad range of benefits, with certain products inherently more ecological than others.