Structural insulated panels (SIPs) are an energy efficient building system consisting of rigid foam insulation sandwiched between two structural facings. SIPs were conceptualized in the 1930s but came into widespread use in the 1960s. SIPs provide a tighter, more energy efficient structure that reduces energy bills by 40-60% compared to traditional stick-built construction. Enercept Building Systems is a manufacturer of SIPs that provides customized panels, on-site assistance, and a lifetime warranty on their materials.