Optimization of Net Zero Energy Houses

Designing a Net Zero Energy House (NZEH) is easy - the difficulty lies in achieving the goal of zero net energy use without spending an excessive amount of money. This requires careful analysis with an emphasis on quantitative design optimization - how much insulation to use in the various envelope components, how much glazing to employ, what type of mechanical systems to use, etc? And, perhaps most importantly, knowing when to stop using energy conservation and knowing when to switch to renewable energy sources to supply the balance of the house’s energy.

This paper examines the issue of NZEH design optimization for houses located in Canada. Over 50 different Energy Conservation Measures (ECM) were evaluated by performing annual energy analyses for three representative house types in four different climatic zones. By comparing energy savings and incremental construction costs, detailed recommendations were produced for each of these house/location combinations. The intent is that these guidelines can be used to produce a first draft of the energy-related design features of a NZEH house which can then be further refined by modeling the actual house, with its unique architectural details, in its intended geographic location. In addition, a procedure was developed which permits the designer to identify at what point renewable energy sources should be used in lieu of further energy conservation upgrades.