Understanding the performance of green commercial buildings: a Sustainable Built Environment National Research Centre (SBEnrc) briefing report

Efforts to reduce carbon emissions in the buildings sector have been focused on encouraging green design, construction and building operation; however, the business case is not very compelling if considering the energy cost savings alone. In recent years green building has been driven by a sense that it will improve the productivity of occupants,something with much greater economic returns than energy savings. Reducing energy demand in green commercial buildings in a way that encourages greater productivity is not yet well understood as it involves a set of complex and interdependent factors. This project investigates these factors and focuses on the performance of and interaction between: green design elements, internal environmental quality, occupant experience, tenant/leasing agreements, and building regulation and management. This paper suggests six areas of strategic research that are needed to understand how conditions can be created to support productivity in green buildings, and deliver significant energy consumption reductions.

Impact of cool roof application on commercial buildings: A contribution to sustainable design in Australia

This study investigated the cool roof technology effects on annual energy saving of a large one-storey commercial building in Queensland, Australia. A computer model of the case study was developed using commercial software by using the appropriate geometrical and thermal building specifications. Field study data were used to validate the model. The model was then used to extend the investigation to other cities in various Australian climate zones. The results of this research show that significant energy savings can be obtained using cool roof technology, particularly in warm, sunny climates, and the thesis can contribute to provide a guideline for application of cool roof technology to single-storey commercial building throughout Australia.

Indoor air quality and energy management through real–time sensing in commercial buildings

Rapid growth in the global population requires expansion of building stock, which in turn calls for increased energy demand. This demand varies in time and also between different buildings, yet, conventional methods are only able to provide mean energy levels per zone and are unable to capture this inhomogeneity, which is important to conserve energy. An additional challenge is that some of the attempts to conserve energy, through for example lowering of ventilation rates, have been shown to exacerbate another problem, which is unacceptable indoor air quality (IAQ). The rise of sensing technology over the past decade has shown potential to address both these issues simultaneously by providing high–resolution tempo–spatial data to systematically analyse the energy demand and its consumption as well as the impacts of measures taken to control energy consumption on IAQ. However, challenges remain in the development of affordable services for data analysis, deployment of large–scale real–time sensing network and responding through Building Energy Management Systems. This article presents the fundamental drivers behind the rise of sensing technology for the management of energy and IAQ in urban built environments, highlights major challenges for their large–scale deployment and identifies the research gaps that should be closed by future investigations.

Towards productivity indicators for performance-based façade design in commercial buildings

Decision-making in the façade design process has a significant influence on several aspects of indoor environment, thereby making it a complex and multi-objective optimisation process. There are two principal barriers in the process of indentifying an optimal façade solution. Firstly, most existing indoor environmental evaluation methods do not account for all the indoor environmental quality (IEQ) aspects relevant to façade design. Secondly, the relationship between the physical properties of a particular façade design option and the resulting economic benefits accrued during its service-life is unknown. In this paper, we introduce the bases for establishing relationships between occupant productivity and the combinatorial effects of four key façade-related IEQ aspects, namely, thermal comfort, aural comfort, visual comfort and air quality, on occupant productivity. The proposed framework's potential is tested against seven existing experimental investigations and its applicability is illustrated by a simple façade design example. The proposed approach ultimately aims to provide a quantitative economic measure of alternative façade design options that would be applicable to early design stage. Aspects of the work that require further experimental validation are identified. © 2012 Elsevier Ltd.

Green noise or green value? Measuring the price effects of environmental certification in commercial buildings

This paper investigates the price effects of environmental certification on commercial real estate assets. It is argued that there are likely to be three main drivers of price differences between certified and non-certified buildings. First, certified buildings offer a bundle of benefits to occupiers relating to business productivity, image and occupancy costs. Second, due to these occupier benefits, certified buildings can result in higher rents and lower holding costs for investors. Third, certified buildings may require a lower risk premium. Drawing upon the CoStar database of US commercial real estate assets, hedonic regression analysis is used to measure the effect of certification on both rent and price. We first estimate the rental regression for a sample of 110 LEED and 433 Energy Star as well as several thousand benchmark buildings to compare the sample to. The results suggest that, compared to buildings in the same metropolitan region, certified buildings have a rental premium and that the more highly rated that buildings are in terms of their environmental impact, the greater the rental premium. Furthermore, based on a sample of transaction prices for 292 Energy Star and 30 LEED-certified buildings, we find price premia of 10% and 31% respectively compared to non-certified buildings in the same metropolitan area

Environmental design : incorporating a rating tool into the design of commercial buildings

Environmental performance assessment or green building rating tools for commercial buildings are one of the more recent responses to encourage green solutions for commercial buildings. This paper discusses the initial stages of a research project that looks at the impact of a rating tool, such as Green Star, on design. There are numerous ways in which an architect can design commercial buildings, but environmental design solutions have consistently failed to become accepted practice. Therefore, how will this tool be incorporated into the building design process? Developed to assist the designer can the inclusion of a rating tool such as Green Star provide an effective framework to encourage the inclusion of environmental design strategies in commercial buildings? A field study, recording the design process of a commercial building, anticipates that a whole building assessment approach towards design, as proposed through the Green Star Rating Tool, will provide an effective framework to set and monitor design targets in order to optimise the environmental design goals in commercial buildings.

Estimating the increasing cost of commercial buildings in Australia due to greenhouse emissions trading

The ratification of the Kyoto Protocol by most industrial nations will result in an international greenhouse emissions trading market by or before 2008. Calculating the quantity of embodied energy in commercial buildings has therefore taken on added significance because it is in the creation of energy that most greenhouse gas that causes global warming is released. For energy efficient commercial buildings in Australia, the embodied energy can typically represent between 10 and 20 years of operational energy. When greenhouse emissions trading is introduced in Australia the cost of energy will rise significantly, particularly electricity which relies primarily on burning fossil fuels for generation. This will affect not only the operating energy costs of buildings (light, power & heating/cooling) but also the cost of building materials and construction. Early estimates of the potential cost of future greenhouse emission permits in Australia vary between $IO/tonne to $180Itonne. This cost would be imposed primarily on the producers of energy and passed on by them to consumers via higher energy costs. For a typical commercial building this could lead to an increase in the total procurement cost of buildings of up to 20% due to the energy embodied during the construction or refurbishment of the building. To assist in evaluating these potential cost increases McKean & Park, Sinclair Knight Merz and Deakin University have developed a web-based Carbon Cost Calculator for commercial buildings.

Valuation of sustainable commercial buildings

Valuation is critical to sustainability take-up in commercial buildings because the combined monetary value of the building and land, as identified in the valuation process, remains an important consideration for many stakeholders. These stakeholders include investors and owners who refer to the market value on behalf of their shareholders, as well as financiers who rely on the value for lending purposes.

This article examines the valuation of sustainable commercial buildings and why it requires a broader consideration of what constitutes value, compared with 'traditional' valuation processes. Definitions relevant to the valuation of sustainable commercial buildings are listed, and the importance of sustainable buildings to the broader property industry is emphasised. The article covers traditional valuation methodology and how sustainability is included in each of the valuation approaches.

Consideration is given to the globally accepted definition of market value, and what the individual components of the definition refer to. The article outlines opportunities for incorporating sustainability considerations into the valuation process, and examines what the future direction for the valuation of commercial buildings may be.

By increasing knowledge about the approach to valuing sustainable office buildings, this article is designed to benefit three groups:

* It will equip valuers, financiers, investors/owners, and other stakeholders with a better understanding of the varying levels of sustainability, and how sustainability affects the level of risk, and subsequently the value, associated with a commercial building.
* It will allow owners, investors and tenants to appreciate the role of a valuer, their exposure to liability, and their challenging task of assessing the current and future risk, and subsequently the value, of a sustainable commercial building.
* This higher level of understanding should mean that the benefits of sustainability will be fully reflected in the valuation process, therefore contributing to support for those developers and investors who are leading in the provision of sustainable solutions.

Delivering sustainability through the adaptive reuse of commercial buildings : the Melbourne CBD challenge

The City of Melbourne is aiming to be carbon neutral by 2020 (Arup 2008) and have set a target of adapting twelve hundred commercial buildings to incorporate sustainability initiatives to reduce greenhouse gas emissions from the sector (AECOM 2008). In order to meet this target the City of Melbourne is taking a proactive approach to establish strategies to deliver sustainability in the built environment within the 2020 timeframe. With regards to upgrading and building maintenance 71% of investment is used for such works (Department of the Environment 2008) and the total Australian property stock was worth over $6 trillion in June 2008. Given that building services in commercial buildings typically lasts between 20-30 years and the average age of the stock is 31 years – it appears that many properties are due for adaptation and there is major opportunity for adaptation that alleviates the impact of global warming and climate change.

Uncertainty surfaces such as; how much adaptation of existing stock is typically undertaken? And is the target of 1200 adaptations before 2020 achievable? Furthermore how could the City identify which buildings are most probable to be adapted prior to 2020? This paper details the configuration of a database of Melbourne buildings populated with data about physical, social, economic legislative and environmental attributes. There is a discussion about how the database will be used to determine; how much adaptive reuse has been undertaken historically; if any triggers to adaptation can be identified; and whether any relationships between adaptation physical, social, economic, legislative and environmental attributes and adaptation exist. The relevance of this research is obvious to all policy makers where adaptation of existing commercial buildings is perceived a as key component of delivering sustainability.

Examining and quantifying the drivers behind alterations and extensions to commercial buildings in a central business district

The drive to undertake building adaptation has increased in momentum, the primary reason being adaptation can be less expensive than new build and conventionally result in faster project delivery times. The issue of sustainable development is another clear driver for adaptation and collectively buildings contribute around half of all greenhouse gas emissions. At the same time governments seek effective and efficient ways of reducing the contribution of cities to climate change and building adaptation appears to offer a practical means of reducing building-related emissions. One example is the ‘1200 building program’ which aims to increase adaptation rates with a target of 1200 city centre office adaptations by 2020 as part of the strategy to achieve carbon neutrality. Through a longitudinal examination of building adaptations it is possible to identify the nature and extent of typical levels of adaptation, as well as determining the inter-relationship between different types of adaptation and building attributes. Melbourne city centre was used for a case study which analysed 5290 building adaptation events between 1998 and 2008. The findings promote the adaptive reuse of buildings in specific circumstances and are directly applicable for increasing sustainability in the built environment. The case study focused on existing buildings in a global city to ensure relevance to urban centres where existing commercial buildings can become part of the solution to mitigate climate change.

Form versus function : a study into interactive learning process affecting the implementation of sustainability in commercial buildings

Owners and tenants of sustainable buildings are now realising the sustainable building that they own or occupy and also how they use the building have a significant impact on their work practices. These stakeholders are demanding sustainability outcomes such as improved occupant health and performance, lower energy and material consumption use as well as encouraging healthy ecosystem in their sustainable building. Clearly the level of user knowledge about a sustainable building and its technologies makes a difference about the actual behaviour towards sustainable buildings (Knott 2007, Stenberg 2007) There remains two major challenge faced by sustainable building occupants: (i) addressing the gap between an occupant's expectations of sustainable building outcomes and what the building actually provides and (ii) overcoming the lack of user knowledge about sustainability design and operation for a particular with regards to performance (Jailani et. al, 2011). This is an innovative study designed to address these challenges. It uses a focus group approach to investigate the gap between (a) user expectations and (b) sustainable building performance, with reference to the relationship between interactive learning process and the level of implementation of sustainability in commercial buildings. The outcome from the study will provide a post-occupancy evaluation of the perception of occupants in sustainable buildings. Most importantly, this information can then assist architects and designers in private and government organisations to successfully develop future sustainable design and policy which can fully capitalise on the original intention when delivering sustainable buildings, as well as providing an innovative feedback mechanism between occupiers and architects.