One of the key considerations when building an energy-efficient home is pinpointing effective ways to reduce airflow and heat transfer. That means paying close attention to wall assemblies. While traditional wall assemblies are four-sided structures, considerable gains can be made by opting for six-sided assemblies. This simple enhancement dramatically increases home efficiency and comfort, and it’s also one of the energy-saving features required for earning an EPS^TM.

In order to stop airflow and reduce heat transfer, walls need interior and exterior rigid or semi-rigid air barriers, often coming in the form of gypsum board, oriented strand board, plywood, Thermo-ply® and rigid insulation. For a wall to be truly efficient, the air barrier and insulation must also be aligned to work in tandem. Six-sided wall assemblies make this possible.

With a traditional four-sided assembly, there’s a bottom plate, studs and a top plate. Drywall and sheathing make up the other sides. Problems can arise if these wall sections face unconditioned spaces such as attic knee walls and skylight wells. Other problematic areas include the space behind gas fireplace inserts and behind showers and tubs on exterior walls. While insulation will fill the gaps between studs, heat transfer can occur when a side of the assembly is open to air and enables the air to move through the insulation. The six-sided assembly solves this issue. It simply requires adding a rigid or semi-rigid air barrier on the side of the wall assembly that’s not boxed in.

The combination of six-sided assemblies and properly installed insulation brings many benefits, including lower energy use, less demand on the heating and cooling system, and comfortable, even temperatures throughout the home.

For builders looking to receive an EPS, six-sided assemblies meet the requirement for fully aligned air barriers with insulation and will help improve the home’s score. Download the EPS Field Guide for more information on this and other energy-saving EPS requirements.