Shaping the Energy Efficiency in New Buildings - Building Energy ...

Canada and India adopt compliance paths similar to that of the United States includingoptions of simpler trade-offs and building performance standards. Each major section(such as building envelope, HVAC, hot water service, lighting, and electric power)contains mandatory provisions followed by either prescriptive provisions or a buildingperformance approach, which often leads to a separate section. A trade-off approach isintroduced in the section on building envelope. Some differences in building energycodes of these three countries include the following:Canada. The section on building energy performance compliance lists theconditions and limitations of applying the building performance approach andrefers to two other complementary documents for details of calculationprocedures. In the section on building envelope, two trade-off approaches–simpletrade-offs and computer-assisted trade-offs–are alternative options to prescriptiveprovisions. India. An ECBC appendix titled Whole Building Performance Method providesdetails on modeling requirements for calculating a reference and designedbuilding. The building trade-off calculation method for the envelope performancefactor is introduced in another appendix. The building performance approach in the United States’ ASHRAE 90.1-2007uses the energy/cost/budget method, which compares the annual energy costs of areference building and a design building. The cost-oriented building performanceapproach differs from other building performance approaches that often useindicators of energy consumption for comparison. In the section on buildingenvelope, a trade-off approach is introduced and details on the calculation of theenvelope performance factor appear in an appendix. In the HVAC section, asimplified approach 48 is an alternative to the mandatory provisions, prescriptiveprovisions, and the energy/cost/budget method. In the lighting section, thebuilding area method and space-by-space method are two trade-off approachesoffered. The United States’ residential building energy code, IECC 2006, offerstwo alternative compliance approaches (in addition to the prescriptive path): thetrade-off approach for the building envelope and a simulated performanceapproach for the whole house.3.9 RenovationsSome countries require any renovation or addition to meet the code, while othersestablish a threshold. If renovations are required to meet the code, they must typicallymeet all relevant aspects of the code. For example, Canada’s codes specify thatrenovations of at least 10 square meters in buildings and homes must meet the buildingenergy code requirements. In the United States, ASHRAE 90.1-2007 considers anyaddition beyond the existing building envelope or alteration to an existing, regulatedbuilding to fall under the code. IECC 2006 generally requires any additions, alterations,renovations or repairs to meet the code.48 The simplified approach is an optional path for buildings of less than two stories (2323 m 2 or 25,000 ft 2 )and according to where the HVAC system complies with certain provisions listed in the HVAC section.56