Thermal performance and embodied energy of cold climate wall systems

The purpose of this study was to compare the predicted thermal performance and embodied energy tradeoffs for a number of different wall systems used in cold climate regions of the United States. Eleven different wall systems were modeled and compared against a reference standard (wood 2 by 4 construction). The wall systems studied included several variations of standard wood stud construction, EPS structural insulated panels, steel stud construction, two "historic vernacular" building systems (plastered strawbale, cordwood masonry), and two non-conventional systems (autoclaved cellular concrete, EPS insulating concrete forms). A detailed materials inventory was used to estimate total embodied energy for each wall system. Thermal performance was modeled on HOT-2000 software, and long-term energy savings were calculated. Within the parameters of this study, the wall systems of conventional materials showed the best long-term energy savings. Wall systems made from non-renewable materials such as concrete, steel, or synthetic foams showed generally poorer long-term energy performance. One of the vernacular systems (plastered strawbale construction) appears promising in terms of long-term energy savings.