Green Building Challenge case study

Horton High School, Greenwich, Nova Scotia

One of three Canadian buildings that were used to test the GBTool environmental assessment system at the Green Buildings challenge was the Horton High School in Nova Scotia. Accommodating 1,050 students, the school opened last fall. It has many environmental features, but one of its most important is that it is expected to use 42% less power than is required by Canada’s Model National Energy Code.

The energy efficiency is due partly to the building’s well insulated envelope which includes a tilt-up wall panel system with a continuous layer of polyisocyanurate applied to the exterior. This system eliminates thermal bridging and gives an RSI value of 3.52 (R23.2).

The school also has a large ground source heat pump system which provides heating or cooling for the spaces, for the 100% fresh air ventilation, and for the domestic water system. The heat is rejected or gained through 40 kilometres of cross-linked polyethylene piping installed horizontally in the ground below the soccer fields (see photo). The 134 air-heat pump units are mounted outside the classrooms. An energy management system controls the equipment and earth loop temperatures.

The energy savings for the $22 million, 15,900-m2 school will be around $47,000 (roughly 22% of the costs of an equivalent reference building), savings which will gladly be picked up by the builder-owner-operator. This is the first school built under a private-public partnership program being promoted by Nova Scotia by which the owner is responsible for all construction, financing, operation and maintenance.

Mechanical and electrical: F.C. O’Neill, Scriven & Associates

Environmental and geotechnical: Jacques Whitford Environment

Structural: Brandys McBride Richardson Engineering

Owner: Hardman Lindsay School Ventures

Architect: Barrie and Langille