Problems of house energy rating (HERS) in warm-humid climates

A building thermal response simulation method was developed in Australia by the CSIRO, starting in the 1950s and released as CHEETAH in 1986. This became the 'engine' of the NatHERS (National House Energy Rating Scheme) by 1995. NatHERS works well in the southern states of the country, where the primary use of energy is for heating. The paper first explores the problems of using this scheme for energy rating in the warm-humid climates of northern Australia. The contradictory requirements of air conditioned and open, ventilated 'free-running' houses are examined. Then the recent modifications to the program are outlined and the new version re-named AccuRate is described. The continued hostility to any such rating or regulation relating to thermal performance is discussed and the problem is illustrated by an actual example