Passive Energy Efficiency: The Building Envelope

From top to bottom, inside and out, the new residence is built to conserve energy through its innovative use of materials and highly efficient design.

The exterior of the building echoes the Georgian aesthetic so identified with Berea’s campus while utilizing a highly insulated building envelope and double-pane, operable windows. Overhead, the standing-seam metal roof has a high reflectivity (lighter & cooler) rating, which means it heats up less in the sun and further improves thermal performance. Even the building’s orientation (on an east-west axis) helps to lower heating and cooling energy costs.

Reducing energy loss and heat gain through the envelope, or building “skin”, is a vital step toward meeting the project’s LEED Energy Goals and target EUI (energy use intensity) of 32.8. One key is insulation: using a wall system with continuous insulation from its footings to the roof eave. To achieve this, crews apply 4-inch spray foam into the exterior metal stud wall framing, then cover with 3-inch rigid insulation. This helps to minimize air infiltration from outside and reduce “thermal bridging” through the studs. Another key is the window system: made up of insulating, solar control glass and thermally-broken frames for a high R-Value. The building also includes sensors that automatically turn off the HVAC when a window is open.

According to our latest energy model, the building envelope, heating and cooling systems, and photovoltaic power generation all add up to a 63.5% improvement in efficiencies over the ASHRAE/US Department of Energy’s base average for residence halls nationwide. Building commissioning provides additional quality control to ensure that window installation, insulation and waterproofing meet our high energy performance standards.

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