It’s only a matter of time before all clients start expressing interest in net-zero energy buildings. With energy prices climbing, building owners are increasingly looking to cut their consumption—with the prized goal of developing new facilities that produce as much power onsite as they use. Government and institutional facility managers are especially focused on achieving high energy efficiency given their constricted operating budgets and the green mandates many of them face.
Although solar panels and wind turbines capture the public’s attention, the Zero Energy Commercial Buildings Consortium (CBC) states, “viable low-energy or net-zero energy buildings must first aggressively maximize energy efficiency before integrating renewable energy.” For new facilities, this means creating a tight building envelope.
The historic approach to construction has been to erect the building, insulate it and seal the gaps. This method results in a multitude of areas for potential air leakage and thermal bridging, such as between exterior wall studs and roof joists and where wall and roof sections join. Given the variability in building designs and site conditions, getting the envelope tight can be difficult.
An Alternative Approach
Rather than installing the structural elements and insulation separately, a faster and more effective approach is to use wall and roof components that integrate these systems. Commonly available examples include structural insulated panels (SIPs) and insulated concrete forms (ICFs). Many contractors use ICFs below grade and SIPs above ground to create high-performance building envelopes.
U.S. Department of Energy research shows SIPs are 15 times more airtight than stick framing and have higher whole-wall R-values. The agency’s tests found that a wall built with 3½-inch thick foam core SIPs was R-14.1, while a two-by-four stud wall at 16 inches on-center with fiberglass insulation was R-9.6—a 47 percent higher R-value for SIPs. Additionally, because insulation is continuous throughout each SIP, there is less thermal bridging than with many other building methods.
The high-performance insulation of SIP walls and roofs helps reduce heating and cooling energy consumption up to 60 percent. A tight SIP envelope saves utility costs throughout the building’s life; plus, because the equipment cycles on and off less frequently, the SIPs reduce HVAC maintenance and replacement costs. read more