An evaluation of the nationwide house energy rating scheme (NatHERS)

In January 2003 Amendment 12 to the Building Code of Australia (BCA) included energyefficiency provisions for Class 1 (detached dwellings) and Class 10 (garages, sheds and the like). In January 2007 the stringency of the BCA provisions were increased and the second generation rating tool AccuRate was introduced. There is however little evidence to support the usefulness of the regulations in meeting the objective “to reduce greenhouse gas emissions by efficiently using energy”, or in simple terms, as described on the NatHERS website, “The more stars, the less likely the occupants are to need cooling or heating to stay comfortable.” This paper reports on a recent investigation to assess the effectiveness of the regulations. Energy consumption data were collected from 22 households in and around Adelaide. From this information heating and cooling energy use was estimated and compared with the House Energy Rating derived from the AccuRate software. The results are discussed and conclusions drawn on how a more effective energy-efficiency building regulation may be framed. Conference theme: Performance