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Better understanding is needed of building thermal performance as a mediator between climate and health outcomes. There is concern that current dwelling energy conservation strategies that focus on keeping warm in winter may lead to overheating and heat stress in summer or an increased use of cooling energy. Drawing on public health methodologies to predict heat related health outcomes, this study has standardised three-day averaged mean indoor to outdoor temperatures from 107 homes in Melbourne, Australia, to test the influence of the residential energy efficiency rating on the living room temperatures in summer. At the heat wave threshold of 25 °C, on average, better rated 6-Star homes were 0.89 °C warmer than 4- or 5-Star rated homes. At this reference temperature, air-conditioned 6-Star homes used 15.84 kWh/day electric cooling energy more to achieve the same living room temperature as 3-Star rated homes. The findings confirm the results of simulation studies that found increased fabric insulation may be associated with increased summer indoor temperatures, risk of heat stress and cooling energy in a mild temperate climate. Hence, it is recommended that residential thermal performance ratings should evaluate the dwelling's performance for each season independently and that cooling through natural ventilation and shading be promoted. [ABSTRACT FROM AUTHOR]

Energy efficiency of buildings is attracting significant attention from the research community, as the world is moving towards sustainable building designs. The average heat gain is the crucial measure for estimating the energy consumption of the buildings. The Envelope Thermal Transfer Value (ETTV) is a simplistic method of determining average heat gain in buildings through its envelopes considering all heat gain components. It also measures the energy efficiency of buildings without inhibiting the design options. The values of ETTV coefficients highly depend on the climatic conditions, geographical locations and the orientation of the buildings. However, no study has been done to investigate the suitability of applying ETTV approach and to develop ETTV formulations for extreme solar radiation with hot and windy climatic conditions like Australian environments. In addition to this, the relevant studies reported in the literature are not comprehensive enough as the coefficient were developed using limited data and the developed formulations were not applied to a variety of real buildings to validate them. Therefore, the main aim of this study is to develop the coefficients of envelope thermal transfer value for commercial buildings, formulate new ETTV equations for buildings with external shadings and estimate the ETTV based annual cooling energy in the sub-tropical climates of Australia. In this study, real life building data relevant to all heat gain parameters of five existing commercial building have been collected and hourly data of wall conduction, window conduction and solar radiation for 11 different types of wall construction and 54 types of window construction have been analysed to determine coefficients of ETTV. Based on these coefficients, the new formulation of ETTV has been proposed to determine total ETTV value of commercial buildings in sub-tropical climate. The developed formulations have been used to estimate the cooling energy loads of 10 real life buildings. A comparative study has been conducted between these estimated cooling energy consumption based on ETTV, actual building load and simulated cooling energy using commercial software. It was demonstrated that developed equations accurately estimate the building cooling load. The computed values of ETTV are within the range 24–42 W/m2, which can be applied in any air-conditioned commercial building in sub-tropical climate like Australia. [ABSTRACT FROM AUTHOR]