An analysis of embodied energy of office buildings by height

Aims to compare the energy embodied in office buildings varying in height from a few storeys to over 50 storeys. The energy embodied in substructure, superstructure and finishes elements was investigated for five Melbourne office buildings of the following heights: 3, 7, 15, 42 and 52 storeys. The two high-rise buildings have approximately 60 percent more energy embodied per unit gross floor area (GFA) in their materials than the low-rise buildings. While building height was found to dictate the amount of energy embodied in the “structure group” elements (upper floors, columns, internal walls, external walls and staircases), other elements such as substructure, roof, windows and finishes seemed uninfluenced.

Carbon dioxide levels and ventilation strategies in 'green' office buildings

Energy efficient office buildings are intended to provide a comfortable and healthy environment for their occupants as well as reducing the energy consumption of the building. They are often designed as "showcase" buildings illustrating the potential for savings through some innovative design technology. But do such buildings actually deliver the desired energy savings and satisfactory comfort conditions for occupants? Measurements of a "green" University campus building in Victoria, Australia, designed with an innovative fabric energy storage system, demonstrate that the ventilation system is not providing acceptable indoor air quality conditions. The design strategies used to reduce energy consumption have had negative consequences on the air quality of the building. Insufficient fresh air is being drawn into the building leading to an excessive build up of carbon dioxide. It is recommended that monitoring systems need to use a wider range of measurements than temperature alone to guarantee good quality indoor air and working conditions and that commissioning of buildings should include adequate monitoring of the operational performance of the building. Designers need to be made aware of the potential consequences of their decisions when attempting innovative energy-efficient designs.

The business case for incorporating sustainability in office buildings : the adaptive reuse of existing buildings

The effect of climate change and global warming has received increased attention in society with constant reminders about the importance of energy efficiency and sustainability in buildings. Whilst the focus is often placed on smaller items such as plastic bags, air conditioners and motor vehicles, the emphasis has recently shifted to structures in the built environment. Office buildings have been identified as contributing significantly to global warming during their building lifecycle with a substantial contribution to CO2 omissions. In response, building designs and construction techniques have evolved over time to improve energy efficiency and reduce CO2 omissions. Whilst property valuers, managers and analysts must remain up-to-date regarding changes, relatively little research has been conducted about whether and how increased sustainability, such as signified in a Green Star rating affects a property’s highest and best value and long-term lifecycle. This study investigates the degree to which sustainability is understood in the property marketplace, especially in relation to property values with the emphasis placed on a cost- benefit analysis from both an owner’s and tenant’s perspective. Whilst it may be argued that incorporating sustainability into a new office building is cost prohibitive on a financial cost-benefit analysis, often various minor steps can be taken to upgrade the sustainability of an existing building. This project examines recent trends in capital expenditure to increase the sustainability of offices and where Green Star ratings have been applied to establish whether any corresponding increase in value is evident. In order to develop a researchframework, a thorough literature review will be conducted of recent Australian and overseas studies. This will enable links between sustainability and office buildings to be highlighted, and vitally how they affect a property’s value in both the short and long-term.

Investor perception of the business case for sustainable office buildings : evidence from New Zealand

Over recent years the global market for sustainable commercial property has been growing in importance, with rapid growth occurring overseas that has led to substantial changes in the property markets. The New Zealand property industry has been recently introduced to the concept of sustainability, and although still at an early stage is already noticing the accelerating uptake of sustainability in the industry. Although certain measures have been taken by the New Zealand Green Building Council and government mandates, there remains still a common assumption that there is considerable hesitation and skeptism in the market from both an investor’s and a building owner’s perspective.

The research presented in this paper reports on the results of an investigation into the market perception toward sustainable buildings from the investment community in New Zealand. Property developers and investors from New Zealand were surveyed about their perception of sustainable buildings in New Zealand and their actions with regards to their own commercial portfolios, as well as the impact sustainability is having upon investment decisions. This paper presents the results of research conducted into the relationship between the elements of sustainability and the market value of an office building. The paper provides an insight into the rapidly evolving area of sustainability and office buildings, with the emphasis placed on the valuation process that seeks to assess a hypothetical purchaser’s perspective of this relationship.

The relationship between sustainability and the value of office buildings

There is an increasing body of evidence to suggest that the development of sustainability in office buildings and the acceptance of these buildings in the broader property market is increasing. However a gap still remains between the value of sustainability and the value of the building from an International Valuation Standards Committee (IVSC) definition of market value. Current literature is limited in the investigation of the impact of sustainable criteria on value component when undertaking a valuation of a commercial office building. Whilst substantial advances have been made in sustainable design and construction aspects, as well as reducing implementation costs and enhancing benefits associated with sustainability, there appears to be inherent barriers in adopting sustainability in the valuation process for the property industry.

This paper examines the limited previous research into the elements of sustainable criteria that impact upon property value, and in turn should be reflected in traditional valuation methods. The immaturity of the property market for sustainable building is such that current valuation methods do not appear to have significant evidential proof of increased property value through sales or lease evidence for sustainable buildings. Furthermore, this lack of market evidence makes it inherently difficult for valuers to assess the real market value of sustainable buildings through current valuation methodology. In other words, the level of risk associated with incorporating different levels of sustainability into office buildings appears difficult to measure using a market value perspective in today’s property market. Accordingly this paper examines current research that has been undertaken to identify particular sustainable criteria that potentially affects the value of a sustainable building. For example, previous research suggests that sustainable criteria impact upon the valuation equation through rental growth, depreciation, risk premium and cash flow. This paper also examines how other studies have viewed the impact of sustainable criteria and how they are weighted within the valuation equation. The discussion provides an insight into the rapidly evolving area of sustainability and office buildings with emphasis placed on the valuation process that seeks to assess a hypothetical purchaser’s perspective of this relationship.

Office buildings and the environment : the increasing importance of ESD

The links between the built environment and sustainability issues such as fossil fuel consumption and climate change is clear. In developed countries buildings contribute around half of all carbon dioxide emissions and offer considerable scope for a significant contribution to sustainability through ecologically aware design and increased energy efficiency (BRE, 1996). The Australian commercial stock emits 12% of all greenhouse gas emissions however the commercial property market has some inherent barriers to sustainability (DSE, 2005). A substantial proportion of the stock is owned by institutional investors who are unconvinced by the need to improve their stock and pass on running costs to tenants (Callender & Key, 1997). As capital values are not greatly affected by sustainability, owners react by doing little or nothing and the effect is to limit sustainability related investment and undermine efforts to deliver sustainability in the sector.

Furthermore the efficiency of buildings declines over time and whilst energy efficiency is important to new design, the existing stock must be improved if urban built environment greenhouse gas emissions are to be reduced. Much of the property and surveying research has previously adopted an illustrative case study approach advocating the benefits of ESD and energy efficiency in existing buildings. This research adopts a radically different approach and profiles the entire office stock of a global CBD, namely Melbourne, which is seeking to become a carbon neutral city by 2020. The research also employs scenario forecasting to model future changes to the stock over a fifteen year period. This paper sets out the rationale for the research and establishes the methodological approach adopted by the research team.

Office buildings and the environment : the increasing role of facility managers

The Australian commercial stock emits 12% of all greenhouse gas emissions however the commercial property market has some inherent barriers to sustainability (DSE, 2005). A substantial proportion of the stock is owned by institutional investors who are unconvinced by the need to improve their stock and pass on running costs to tenants (Callender & Key, 1997). The links between the built environment and sustainability issues such as fossil fuel consumption and climate change is clear. In developed countries buildings contribute around half of all carbon dioxide emissions and offer considerable scope for a significant contribution to sustainability through ecologically aware design and increased energy efficiency (BRE, 1996). As capital values are not greatly affected by sustainability, owners react by doing little or nothing and the effect is to limit sustainability-related investment and undermine efforts to deliver sustainability in the sector. Facility managers are in an influential position to help address sustainability issues via an increased awareness of energy efficiency and CO2 emissions.

Even though the efficiency of buildings is primarily focused on new stock, with an existing churn replacement rate of approximately 2-3% the existing stock must be improved if urban built environment greenhouse gas emissions are to be reduced – clearly the management of existing stock must therefore contribute to substantial savings in energy use. Much of the property and surveying research has previously adopted an illustrative case study approach advocating the benefits of ESD and energy efficiency in existing buildings. This research adopts a radically different approach and profiles the entire office stock of a global CBD, namely Melbourne, which is seeking to become a carbon neutral city by 2020 (City of Melbourne, 2003). The research also employs scenario forecasting to model future changes to the stock over a fifteen year period. This paper sets out the rationale for the research and establishes the methodological approach adopted by the research team. The results provides a unique insight into the variations between different building types and grades of office buildings, which in turn will allow facility managers to gain a better understanding of where gains in energy efficiency can be made.

Energy analysis of the construction of office buildings /by Graham J. Treloar

Buildings have a significant impact on the environment due to the energy required for the manufacture of construction materials. The method of assessing the energy embodied in a product is known as energy analysis. Detailed office building embodied energy case studies are very rare. However, there is evidence to suggest that the energy requirements for the construction phase of commercial buildings, including the energy embodied in materials, is a significant component of the life cycle energy requirements. This thesis sets out to examine the current state of energy analysis, determine the national average energy intensities < i.e. embodied energy rates < for building materials and assess the significance of using national average energy intensities for the energy analysis of a case study office building. Likely ranges of variation in the building material embodied energy rates from the national averages are estimated and the resulting distribution for total embodied energy in the case study building simulated. Strategies for improving the energy analysis methods and data are suggested. Detailed energy analysis is shown to be a useful indicative method of quantifying the energy required for the construction of buildings.

Balancing comfort expectations and greenhouse gas emissions, thermal comfort in office buildings in a changing climate

According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the construction sector has the greatest potential for climate change mitigation. This work investigates the potential for climate change mitigation in naturally ventilated and mixed mode office buildings, by evaluating the range of influence of building design and occupants on greenhouse gas emissions as well as thermal and visual comfort.

Thermal comfort is evaluated according to the EN 15251 adaptive thermal comfort model, visual comfort is based on daylight autonomy and view. Parametric studies have been conducted based on building simulation for the climate of Athens, Greece. Input data are based on a literature review, and on results from a field study conducted among office occupants and architects in Athens.

The results show that the influence of occupants on greenhouse gas emissions is larger than the influence of building design. Energy saving office equipment, as well as active use of building controls for shading and lighting by occupants are crucial parameters regarding the reduction of CO2 emissions. In mixed mode buildings, the coefficient of performance of the cooling system is an important parameter as well. Regarding thermal and visual comfort, the influence of building design is predominant. A green building, well protected against heat from the sun and able to balance solar and internal heat gains, provides higher comfort levels and is less affected by the influence of occupants. In mixed mode buildings, building design is the predominant influence on the magnitude of cooling loads. A hot summer including heat waves can significantly reduce thermal comfort and increase the resulting greenhouse gas emissions. Green buildings are least affected by these influences.

The EN 15251 adaptive thermal comfort model provides a thermal comfort evaluation method valid throughout Europe. However, for the Mediterranean climate of Athens, Greece, most of the configurations investigated within this study do not meet the requirements according to this model. EN 15251 refers to an adaptive thermal comfort model for naturally ventilated and to a static model for mechanically ventilated buildings. For mixed mode buildings, the static model is recommended, but literature indicates that occupants in those buildings might be more tolerant towards higher temperatures. The hypothetical application of the EN 15251 adaptive thermal comfort model in mixed mode offices, as investigated in this study, shows potential for greenhouse gas emission savings. However, this influence is small compared to that of building design and occupants. Conclusions are drawn regarding the categorisation and exceeding criteria according to EN 15251 adaptive thermal comfort model for offices in a Mediterranean climate.

The results of this work show, that not only green buildings, but also green occupants can significantly contribute to the mitigation of the climate change. Mechanisms of the real estate market as well as the lifestyle of occupants are important influences in this context. Sustainability therefore refers to finding the right balance between occupant’s comfort expectations and resulting greenhouse gas emissions for a specific building, rather than optimisation of single parameters

The business case for sustainable office buildings

The market for sustainable buildings has rapidly gained momentum in the design and construction phases, however it appears that development and investment in these buildings by the private sector is limited. This is further complicated by the limited information available confirming the financial viability of sustainable buildings, with relatively little research conducted into the relationship between sustainability and the market value of commercial buildings. Currently the demand for sustainable buildings in Australia and New Zealand is being encouraged through government legislation and policy, where investment by the private sector has been relatively slow to develop due to the lack of evidential proof of the economic viability of sustainable buildings. Clearly if the progress and uptake of sustainable buildings is to develop within the property market, it is essential that the relationship between market value and sustainability should be understood in order to fully inform the investment industry.

User satisfaction in sustainable office buildings : a preliminary study

Energy efficiency was first mandated for commercial buildings in 2006 in Part J of The Building Code of Australia (BCA) and regulators are already implementing increased measures in 2010 (ABCB 2010). Further increases will follow as part of the co-ordinated effort to reduce building related greenhouse gas emissions. The introduction of the Energy Efficiency Disclosure Bill 2010 will establish a national scheme to promote the disclosure of information about the energy efficiency of office buildings as well as further highlighting the need for efficiency. Increased energy efficiency in the form of insulation, energy efficient light fittings, sophisticated Building Management Systems (BMS), micro-generation such as solar and wind turbines all result in measurable quantifiable reductions in operating costs for owners and tenants. However convincing all building owners about the sound business case for adopting sustainability measures has not been fully realised. To-date the adoption of cutting edge sustainable buildings in Australia is restricted to a few industry leaders, such as Investa and ISPT in Victoria for example. Sustainable building owners and tenants often benefit from reduced operating costs during the building lifecycle although the ‘intangible’ effect on businesses (e.g. employee productivity) is uncertain. This aspect has not been accurately quantified and has not been included as part of the measurement of sustainability in buildings.

This study will allow property stakeholders, including government policy-makers and investors/developers, to better understand the optimal type and level of sustainability to be incorporated into the built environment. In addition this knowledge will enable policymakers to make more informed decisions with regards to the likely impact of the legislative measures they propose in respect of sustainability and buildings in The Building Code of Australia (BCA) and other relevant legislation.

Framework for improving the constructability of raised floor systems in Australian office buildings

Despite the great benefits that it can potentially contribute to modern workplace environment, raised floor system (RFS) encountered many barriers in the process of its applications for the fitout of office buildings in the Australian construction industry. Through a set of comprehensive research activities, the significant influence factors (SIFs) and problems associated with the RFS fitout implementation are identified. Further discussion of these SIFs and problems unearths a range of project level critical factors (PLCFs) pertaining to the RFS fitout design, construction, operation and maintenance, which presents firsthand checklists for the project team to review in the project delivery process. These factors need to be accommodated appropriately in order to enhance the implementation of the RFS fitout in Australian office buildings. Following a constructability study, a framework was developed by integrating these SIFs and PLCFs into the delivery of the RFS fitout in an aim to enhance the project constructability and minimize problems in the RFS service performance.

Examining the perception of tenants in sustainable office buildings

Purpose – The purpose of this paper is to address two major challenges faced by sustainable building owners: first, address the gap between an occupant’s expectations of sustainable building outcomes and what the building actually provides and second, overcome the lack of user knowledge about sustainability design and operation for a particular with regards to performance. Design/methodology/approach – This study used a focus group approach to investigate the gap between: user expectations and sustainable building performance. The study surveyed occupants of sustainable office buildings in Melbourne, Australia. Findings – There is no significant relationship between users’ expectations and users’ experience of sustainable building performance and users’ knowledge about sustainability and the building they were worked in. Research limitations/implications – The research was limited to sustainable office buildings. New office buildings seeking to incorporate sustainability which need to focus on the needs of tenants in order to maximise value. Practical implications – There is an urgent need to ensure sustainable office buildings meet the needs of present and future occupiers without compromising short and long-term occupier satisfaction levels with regards to sustainability and operation of the building. Social implications – Increasing the level of sustainability in office buildings has been a major trend over the past decade however the tenants need to be consulted in the post-occupancy phase. Originality/value – Little attention has been given in the property management literature to sustainable office buildings and value drivers. This is an original and innovative study, partly due to the recent developments in sustainable 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.