An Evaluation of Energy Performance of Green Buildings and Occupant Behaviour in Public Housing Estates in Hong Kong

香港公共屋邨中綠色建築的能源消耗和居民行為評估

Student thesis: Doctoral Thesis

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Award date11 Aug 2020

Abstract

With its landscape of dense high-rise buildings and a large portion of its population living in public housing estates, Hong Kong has long faced significant challenges meeting global standards for becoming a sustainable city. To date, electricity consumption per capita in public housing is 1072 kWh. Public housing is affordable social housing to cater to low-middle-income citizens' housing needs. However, this group of people is always left out by the policymakers to improve citizens' wellbeing and quality of living. The literature argues that green building would be creating an energy-efficient and better living environment. However, certifying a public housing estate would cost public money as high as HK$ 2.6 million. I propose two primary methodologies – co-benefits approach and post-occupancy evaluation - to study whether the green certification of public housing estates could improve the occupant behaviors and to what extent the green buildings perform in energy performance. This thesis could help understand whether green public housing would be the solution to urban social problems, and the building energy performance in achieving design intent.

Today, Hong Kong has more than 1300 certified-green buildings, but I found that many buildings have been equipped with green technologies without undergoing green certification. I categorize the green building into three groups as case studies: green buildings with certification and without certification, and non-green buildings. Surprisingly, the energy performance of certified-green housing estates does not perform according to design intent. Certified-green estates consume 24% extra energy than non-green buildings. The design intent of green buildings should achieve at least 3% to 20% energy savings than the latter. The analysis resulted that EUI for case studies was 724 MJ/m2, an addition of 37.1% compared to the benchmark level. There is no association between green certification and energy performances compared to green certification and the effect of building design. The second part of the analysis showed that residing in uncertified green case studies induces better occupant behaviors than certified-one, including water consumption, user perception, and satisfaction with the living environment. Through this thesis, I summarise the research findings and propose recommendations to the existing regulations of Hong Kong, hoping to shed light on how to improve green building assessment tools for residential properties for elevating the city's sustainability standards.