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

esidential buildings, while the residential building codes include low-rise multi-familyresidential buildings. In China, the residential standards regulate multi-family residences.This difference is important because, typically, commercial building requirements aresomewhat more complex and cover more issues than those for residential buildings.Specific RequirementsThe specific energy efficiency requirements for new buildings vary between countries.For example, regarding lighting efficiency requirements in commercial or large buildingsin the APP region, Australia has the most stringent requirements (7 to 10 watts per squaremeter), followed by India and the United States (both 10.8 to 11.8 watts per square meter),and China (11 watts per square meter). Japan and the Republic of Korea (South Korea)do not regulate lighting power density per se, although they regulate other aspects oflighting efficiency. It is more difficult to compare energy efficiency requirements for thebuilding envelope because of varying climate conditions and construction practices.When comparing specific requirements for building components in similar climate zones,no single APP country consistently has the strongest requirements. India has particularlystringent requirements for walls, and in warm climate zones, it has the most stringentrequirements in this area. Japan has the most stringent requirements for windows incommercial buildings, while in the United States requirements for roofs of single-familyhomes are particularly strong.It is important, however, to consider the specific requirements in context. A highenforcement rate can have a larger impact on building energy efficiency than a smallimprovement in the requirements. Also, the requirements are based on the ratedefficiency of the building components. Differences between countries in test protocolsused to rate the efficiency of these components may result in higher or lower ratings forequipment that objectively has very similar efficiency. A comprehensive approach tobuilding energy codes creates the most significant improvements in energy efficiency.Means of Attaining ComplianceBuilding energy standards typically provide property owners some flexibility in meetingthe energy efficiency requirements. This is important because the standard can be morestringent without impinging too severely on the ability of property owners to adaptbuildings to their needs. There are several approaches to providing this flexibility. Inmany countries including India, the United States, Canada and Australia, the codes havefour classes of requirements. The first are mandatory requirements that must be satisfiedregardless of any other factors for a building to be considered in compliance. Themajority of these codes are then made up of prescriptive requirements that are similar tothe mandatory requirements in that they provide specific values and details. However,building designers may be allowed to “trade-off” some of the prescriptive requirementswith others regarding the building envelope. The codes then provide rules on what can betraded-off and how. Finally, these codes also provide an option for compliance based onbuilding energy performance instead of the prescriptive requirements. This last optionallows a building designer to install less energy-efficient windows but a more energy-5