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Energy consumption in conventional, energy-retrofitted and green LEED Toronto schools
Abstract
Green buildings have been marketed as the economical, energy-efficient alternative to conventional buildings. This is despite little existing empirical evidence to prove their energy efficiency, especially in Canada. To overcome this limitation, the electricity and gas consumption quantities and costs of a sample of 10 conventional, 20 energy-retrofitted and three green Toronto schools following the Leadership in Energy and Environmental Design Rating (LEED) System for New Construction were analysed in this study. The analysis conducted over eight years for conventional and energy-retrofitted schools, and since their inception for green schools, showed surprisingly that energy-retrofitted and green schools spent 37% more on electricity than conventional schools. Nevertheless, green schools spent 56% and 41% less on gas than conventional and energy-retrofitted schools respectively. Their total energy costs were also 28% lower than conventional and energy-retrofitted schools. Nevertheless, these savings do not always justify their construction cost premiums. The study showed that more research was needed to overcome the scarcity of data on green buildings in Canada. There was a need to focus on analysing more green buildings, of various types, and over longer study periods in order to better understand why some green buildings do not live up to expectations.
... On the other hand, LEED-certified buildings have a rent premium of 3-5% and a sale premium equal to 25% [48]. In addition to the rent and sale premium, the LEEDcertified buildings have other advantages arising from lower operating expenses related to the use of water and energy, maintenance, insurance, management, and security [48][49][50][51]. It is worth adding that some features of buildings do not require spending extra money but can be considered in the design phase [52][53][54][55]. ...
... On the other hand, LEED-certified buildings have a rent premium of 3-5% and a sale premium equal to 25% [48]. In addition to the rent and sale premium, the LEED-certified buildings have other advantages arising from lower operating expenses related to the use of water and energy, maintenance, insurance, management, and security [48][49][50][51]. It is worth adding that some features of buildings do not require spending extra money but can be considered in the design phase [52][53][54][55]. ...
... • LEED-certified buildings in the NYC with Certified and Silver level LEED certificate use more energy than non-certified buildings • Gold level LEED-certified buildings in the NYC used 20% less energy compared to non-certified Issa et al. [49] Canada - ...
Depletion of natural resources and climate change are undoubtedly the biggest challenges that humankind faces today. Here, buildings have a crucial role since they consume the majority, i.e., 30% to 40% of the total energy resources. Green building certification is one of the solutions to limit the energy use in buildings. In addition, it is seen to indicate a consideration for sustainability aspects in construction. LEED is the most widely used certificate worldwide. However, recently some critics have raised doubts about LEED and whether it actually implies sustainability. Most of the criticism has been targeted to the energy aspects of LEED. Nevertheless, there is no consensus on the usefulness of LEED: is it really beneficial for the environment, and is it worth of the money and time invested on the certification process? In this study a critical analysis of the literature to find an answer to this question is presented. Altogether 44 peer reviewed articles dealing with the abovementioned issue were selected out of 164 search result. Based on the studied material, the different aspects of LEED from the viewpoint of energy-efficiency are discussed. From the 44 reviewed articles, ten articles state that LEED certificate indicates energy efficiency while eight papers end up with an opposite conclusion. The rest of the papers do not take any stand on this matter. The study showed that energy efficiency of LEED-certified buildings is questionable especially at lower levels, i.e., certified. Therefore, it is recommended to modify the Energy and Atmosphere category of LEED in order to improve the actual energy performance of buildings.
... Numerous studies have found that buildings use more energy than projected by their design teams-the well-documented building "energy performance gap" [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Moreover, a decade of LEED building studies have either concluded or have yielded results consistent with the conclusion that the source energy consumed by LEED-certified buildings, on average, is not significantly lower than that for other buildings, [16][17][18][19][20][21][22][23][24][25][26][27]. In short, the methodology demonstrated by the Harvard group is interesting but their conclusions lack validity because they are based on seriously flawed assumptions. ...
... We are aware of 12 peer-reviewed studies published since 2008 that have specifically looked at the measured energy use of LEED-certified buildings as compared with other, similar buildings [16][17][18][19][20][21][22][23][24][25][26][27]. Key aspects of these studies are summarized in Table 1. ...
... Scofield did not find 17% energy savings for LEED buildings. 6 At least eight peer-reviewed studies since 2009 have examined the energy use of LEED buildings [20][21][22][23][24][25][26][27]. Those that specifically considered source energy found that LEEDcertified buildings demonstrated no source energy savings relative to other similar buildings [23,26,27]. ...
MacNaughton et al. recently published an article entitled, “Energy savings, emissions reductions, and health co-benefits of the green building movement” in which they claim to calculate the environmental co-benefits associated with the (assumed) reduced energy use of green buildings. They consider only LEED (Leadership in Energy and Environmental Design) commercial buildings and make two fundamental assumptions: (1) that each LEED building, year after year, achieves the energy savings projected by its design team, and (2) that the fuel mix of LEED buildings is the same as the average mix for other buildings in the same geographic region. Here we show that these assumptions are not supported by data. Numerous studies have shown that buildings, on average, use significantly more energy than projected by design simulations. Furthermore, a decade of research suggests that LEED-certified buildings, on average, achieve little or no primary energy savings relative to other similar buildings. In addition, evidence suggests that any reduction in site energy is typically achieved through increased electric use and corresponding off-site energy loss. The environmental benefits of LEED buildings calculated by MacNaughton et al. have dubious value because they are based on assumptions that are inconsistent with measured LEED building energy performance.
... Despite these large numbers of U.S. LEED-certified buildings for which annual energy data have been collected, measured building energy performance for only a few hundred have been reported in the literature [7][8][9][10][11][12][13][14][15][16][17][18][19] . In most cases these data were volunteered by cooperative building owners, making it highly unlikely that the energy performance of these buildings is representative of the thousands of buildings for which such data have not been volunteered [20] . ...
... Also listed are the relative standard errors (RSE) in these quantities. 13 Note that the gross site and source EUI for Chicago Offices listed in Table 3 are consistent with those found for offices, nationally, based on CBECS 2012 data (discussed earlier). ...
... This has obvious impact on the precision of EUI. 13 Gross EUI and CO 2 intensities are calculated as area-weighted means and relative standard errors (RSE) are the standard deviations of these means divided by these means. 14 The EIA publishes statistics and their RSE for common space types like offices on its web site. ...
The City of Chicago recently publicized energy usage data for 1521 commercial properties with floor area 50000 ft² (4650 m²) or greater for the year 2015. We have cross-referenced the Chicago benchmarking data with the U.S. Green Building Council's LEED project database to identify 132 Chicago properties that were LEED-certified in programs expected to reduce whole building energy use. The numbers of LEED-certified buildings are sufficient for Offices, K-12 Schools, and Multifamily Housing to learn whether these buildings use less energy than do similar conventional buildings in Chicago. For all three building types we find LEED-certified buildings use no less source energy than similar buildings that are not LEED-certified. Further, we find that LEED-certified schools use 17% more source energy than do other schools. For all three building types we find that LEED-certified buildings use roughly 10% less energy on site than comparable conventional buildings. This does not translate into source energy savings because LEED-certified buildings use relatively more electric energy. Finally, when LEED-certified buildings are compared with other newer buildings we find their source energy consumption to be similar. We believe this is the first such study of energy performance for LEED-certified schools.
... Despite these large numbers of U.S. LEED-certified buildings for which annual energy data have been collected, measured building energy performance for only 300-400 have been reported in the literature [6][7][8][9][10][11][12][13][14][15][16][17]. In most cases these data were volunteered by cooperative building owners, making it highly likely that the energy performance of these buildings is not representative of the thousands of buildings for which such data have not been volunteered [18]. ...
... Figure 7 is a Boxplot comparing the distribution of these scores for LEED and Other schools. 12 In general the scores for LEED schools are lower than those for Other schools, though the statistical significance is not large. On average, scores for LEED schools are close to 50 while the average for Other schools is closer to 60. Again, it is important to understand that the median and mean Energy Star score for a set of buildings is not indicative of the energy saved (or not saved) by these buildings. ...
... The 2015 Chicago benchmarking data file includes data for 321 properties identified as Multifamily Housing (MFH). Of these, 11 were identified as LEED certified in programs that address 12 All of the 18 LEED and all but seven of the Other schools have Energy Star scores. ...
... Several studies (e.g. Menassa et al. 2012;Issa et al. 2011) used energy consumption data of similar conventional buildings as their benchmark. Others (e.g. ...
... None of these correlations were statistically significant. This finding suggests the school buildings analyzed as part of this study were more energy efficient than the Toronto schools analyzed in Issa et al. (2011). ...
... These results were also in line with the findings of previous studies (e.g. Burman et al., 2014a;Hong et al., 2013;Issa et al., 2011;Lourenço et al., 2014;Robertson and Higgins, 2012;Thewes et al., 2014). For example, Robertson & Higgins (2012) found average electricity consumption in two new schools in New Mexico to be 105% higher than that in two similar older schools. ...
Buildings contribute 20 to 40% of the world’s energy consumption, making the need to investigate their energy performance a necessity. Given the lack of empirical evidence on the energy performance of school buildings operating under extreme weather conditions, this study aimed to benchmark historical energy consumption over a ten-year period in a sample of 30 school buildings in Manitoba, Canada. Results showed the median total energy consumption of these schools was higher than other Canadian benchmarks. School building age had a statistically significant effect on their energy consumption, with newer schools consuming less gas but more electricity than older and middle-aged ones. The retrofits implemented in some schools did not for the most part have a statistically significant effect on their energy consumption, although a decrease in energy consumption was observed. The results also showed that middle-aged schools were the largest energy consumers, with the results changing depending on the metric used to report on schools’ energy consumption, reinforcing the need to standardize those metrics. There is also a need to investigate how occupancy may be contributing to the increase in electricity consumption in newer schools. This study is the first to provide empirical evidence on existing school buildings’ energy consumption in Manitoba, establishing benchmarks that practitioners can make use of in similar cold climates.
... However, some studies (e.g. [3,4]) indicate these buildings used more electricity than conventional ones which can be attributed to occupant behaviour [5]. Therefore, closing the gap between actual and expected buildings' energy performance is essential by considering all parameters influencing buildings' energy consumption, such as those related to occupancy and usage [6]. ...
... This increase in electricity consumption in newer schools was also observed in other studies (e.g. [3,4]). Total energy consumption was found to be highest in middle aged schools and was also in line with the results of previous studies e.g. ...
... These results were also in line with the ones of previous studies (e.g. [3,4]) which also revealed an increase in electricity consumption in newer schools. Base load electricity consumption during night hours (22:00-7:00) made up ∼42% of daily load consumption in the new and old schools. ...
Previous studies indicate electricity consumption is increasing in new and green buildings highlighting the importance of investigating parameters affecting that increase. The majority of previous studies also focused on studying commercial or residential buildings emphasizing the need to study energy consumption in other building types. This study analyzed historical energy consumption data in a representative sample of thirty schools in Manitoba, Canada. It showed that the decrease in gas consumption for heating in new schools was counteracted by a statistically significant increase in their electricity consumption. Three cases study schools were selected for further analysis of their electricity consumption. Within each school, one classroom, the gymnasium, as well as spaces with significant community use, were sub-metered to collect real-time electricity consumption data. Results indicated total electricity consumption increased in the newest school, although sub-metered spaces in older schools consumed more electricity. Variations in electricity consumption between sub-metered spaces were attributed to occupant behaviour. The study is the first to provide an in-depth investigation of electricity consumption in Canadian school buildings and consider the potential effect of typically overlooked parameters such as occupant behaviour on their overall energy consumption.
... Although school buildings contribute considerably to the total energy needs, few studies have been focused on school buildings in Canada [22,23]. They examined the energy use intensity (EUI) of 129 elementary and junior high schools in Manitoba, Canada, using data collected from 30 school buildings over ten years. ...
This paper presents a general methodology to model and activate the energy flexibility of electrically heated school buildings. The proposed methodology is based on the use of archetypes of resistance–capacitance thermal networks for representative thermal zones calibrated with measured data. Using these models, predictive control strategies are investigated with the aim of reducing peak demand in response to grid requirements and incentives. A key aim is to evaluate the potential of shifting electricity use in different archetype zones from on-peak hours to off-peak grid periods. Key performance indicators are applied to quantify the energy flexibility at the zone level and the school building level. The proposed methodology has been implemented in an electrically heated school building located in Québec, Canada. This school has several features (geothermal heat pumps, hydronic radiant floors, and energy storage) that make it ideal for the purpose of this study. The study shows that with proper control strategies through a rule-based approach with near-optimal setpoint profiles, the building’s average power demand can be reduced by 40% to 65% during on-peak hours compared to a typical profile.
... Previous campus-level investigations mainly focused on energy savings of buildings in Europe, where retrofits are more economically justifiable due to high energy costs [22][23][24][25][26][27][28][29]. However, very few studies investigated the energy and cost savings associated with retrofits in Canadian school/university buildings, where climate, construction practices, building codes, utility costs, carbon emission factors, and carbon taxes are different [30][31][32]. In Canada, building codes are evolving to meet multiple objectives, including reducing energy consumption and greenhouse gas emissions, increasing resiliency and passive survivability. ...
Campus buildings at the University of Victoria (UVic) were largely constructed before the advent of building energy codes. The University is in the process of commissioning vertical building envelope upgrades/retrofits with added intention of addressing potential energy and greenhouse gas (GHG) savings in their building stock. The aim of this paper is to present the methodology adopted to evaluate potential energy savings from vertical envelope retrofits of 49 non-residential buildings across the campus portfolio, and to further validate those savings through more detailed energy models for a subset of buildings. To this end, the thermal performance of a building envelope was quantified based on its heat loss coefficient (UA), obtained from multiplying its surface area (A) by its thermal transmittance (U-value). Heat loss (UA) calculations were used as an energy loss metric to inform envelope rehabilitation prioritization, in addition to data gathered from building envelope condition assessments (BECAs). UA data were also analyzed against other building data such as floor area, vertical envelope area, vertical area to floor area ratio (VFAR), window-wall ratio (WWR), age, and type of construction for potential correlations. Finally, archetype energy models were used to evaluate the impacts of envelope retrofits on energy and GHG savings on three selected buildings. The outcomes of this study allow the University to weigh the benefits of improved energy performance from envelope retrofits against associated capital cost expenditures.
... Other previous studies have compared the energy performance of green-rated buildings with that of conventional buildings. Among those few studies conclude there is no significant improvement in the performance of the green-certified buildings when compared to the conventional buildings (Menassa et al. 2011;Issa et al. 2011;Scofield 2009;Scofield and Doane 2018). This shows the green building rating systems do not essentially capture the true essence of sustainability and hence questions the creditability of the green rating systems being considered for assessing the sustainability of the buildings. ...
Significant amount of resources such as materials, energy, water, and land are consumed during the design, construction, operation, maintenance, and end-of-life phases of buildings. There is an increased focus on reducing the environmental footprints associated with buildings. Green building ratings are used as practical tools for implementing sustainability in construction projects. There are several green building rating tools used across the globe. In India, three green building ratings are used, namely the U.S. LEED, IGBC LEED, and Green Rating for Integrated Habitat Assessment (GRIHA). The certification levels vary across green building ratings. For example, the U.S. LEED rating ranks buildings at “Platinum”, “Gold”, “Silver”, and “Certified”. Similarly, the GRIHA rating ranks buildings at “5 Star”, “4 Star”, “3 Star”, “2 Star”, and “1 Star”. This study examines the relationship between certification levels and sustainability indicators of GRIHA certified green buildings in India. Sustainability indicators such as the energy performance index (EPI), energy use reduction, and water use reduction are considered. The analysis is based on the data collected for 45 GRIHA certified green buildings. This study presents some insights on the relation between certification levels and sustainability indicators of green buildings.
... Scofield (2009) and Oates and Sullivan (2011) do not find evidence for reduction in energy consumption for LEED certified buildings. Issa et al. (2011) find evidence for reduction in gas consumption but increase in the electricity consumption for LEED certified buildings. While the energy consumption decreases, the rate is not enough to justify the investment. ...
This article extends signalling theory to research on voluntary green standards adoption and investigates the firm's value in green buildings. The study analyses the market valuation of investments in sustainable buildings, measuring the market reaction to three different types of leadership in energy and environmental design (LEED) announcements: 1) intent for application; 2) achievement of certification; 3) reinforcement of certification. The study hypothesises the market will react differently to intent, achievement and reinforcement signals. Empirical evidence shows a positive market reaction to LEED announcements in general, with positive but not statistically significant market reaction to the intent signals, and positive and statistically significant reaction to the achievement and reinforcement signals. Theoretical and practical implications are discussed.
... Scofield (2009) and Oates and Sullivan (2011) do not find evidence for reduction in energy consumption for LEED certified buildings. Issa et al. (2011) find evidence for reduction in gas consumption but increase in the electricity consumption for LEED certified buildings. While the energy consumption decreases, the rate is not enough to justify the investment. ...
... This is mainly due to the significant impacts of the construction industry on the environment in both developed and developing countries (Shi et al., 2012;Fuertes et al., 2013;Lichtenstein et al., 2013). These include not only the impacts during the construction process but also during the operation and maintenance stages such as energy consumption and greenhouse gas emission of the building stock (Othman and Mia, 2008;Issa et al., 2011;Ding and Forsythe, 2013). In addition, health and safety issues within the construction sector have raised public concern (Furber et al., 2012;Forman, 2013;Lingard et al., 2012). ...
Purpose
CSR practice and research in construction contractors are comparatively limited. The objective of this research was to identify a series of CSR issues that reflect the major components of CSR, and to determine the perceived importance of these factors in the context of construction contractors.
Design/methodology/approach
A CSR indicator framework was developed based on stakeholder theory. CSR stakeholders and their corresponding CSR performance issues in construction contractors are classified into two levels, i.e. project level and organizational level. This is followed by a questionnaire survey to investigate the perceptions on relative importance of CSR issues of four key stakeholders in typical construction projects in China, i.e. construction contractors, clients, design and engineering consultancy, and supervision firms.
Findings
The study highlighted a number of factors, e.g. ‘quality and safety of construction’, ‘occupational health and safety’, ‘supplier/partner relationship’ were highly regarded, however their relative importance varied according to the type of responding organization.
Research limitations/implications
The findings indicated the major concerns of the different parties in construction projects, thereby providing a pathway for construction contractors to improve their CSR practice.
Originality/value
The priorities of various stakeholders described in this paper provide a useful reference for construction contractors in the selection and adoption of criteria for CSR performance. A better understanding of perceived priorities of CSR factors from different participating parties also serves useful inputs to construction contractors in their stakeholder management process.
In this work, we present results from the largest study of measured, whole-building energy performance for commercial LEED-certified buildings, using 2016 energy use data that were obtained for 4417 commercial office buildings (114 million m2) from municipal energy benchmarking disclosures for 10 major U.S. cities. The properties included 551 buildings (31 million m2) that we identified as LEED-certified. Annual energy use and greenhouse gas (GHG) emission were compared between LEED and non-LEED offices on a city-by-city basis and in aggregate. In aggregate, LEED offices demonstrated 11% site energy savings but only 7% savings in source energy and GHG emission. LEED offices saved 26% in non-electric energy but demonstrated no significant savings in electric energy. LEED savings in GHG and source energy increased to 10% when compared with newer, non-LEED offices. We also compared the measured energy savings for individual buildings with their projected savings, as determined by LEED points awarded for energy optimization. This analysis uncovered minimal correlation, i.e., an R2 < 1% for New Construction (NC) and Core and Shell (CS), and 8% for Existing Euildings (EB). The total measured site energy savings for LEED-NC and LEED-CS was 11% lower than projected while the total measured source energy savings for LEED-EB was 81% lower than projected. Only LEED offices certified at the gold level demonstrated statistically significant savings in source energy and greenhouse gas emissions as compared with non-LEED offices.
Through building performance simulations, previous studies showed the effect of occupants on buildings’ energy consumption. To further demonstrate this effect using empirical evidence, this study analyzed the effect of occupancy on real-time electricity consumption in three case-study schools in Manitoba. Within each school, one classroom as well as the gymnasium were sub-metered to collect real-time electricity consumption data at half-hourly intervals. The study focused on electricity consumption for lighting and plug loads, which make up 30% of energy consumption in Canadian commercial and institutional buildings. A comprehensive method was developed to investigate energy-related occupant behaviour in the sub-metered spaces using four different tools simultaneously: 1) gymnasium bookings after school hours over a four-month period, 2) half-hourly observations of lighting and equipment use in the sub-metered spaces in each school over a two-week period, 3) a daily survey administered to teachers in the sub-metered classrooms over a two-week period, and 4) occupancy and light sensors to evaluate actual recorded occupancy and light use durations over a four-month period. Results showed that recorded occupancy durations over a 4-month period only explained less than 10% of the variations in classrooms’ lighting electricity consumption, meaning that lights may have been used frequently while classrooms were unoccupied. Results also showed the differences in gymnasiums’ electricity consumption were still statistically significant between the three schools, even after school hours and when the gymnasiums were not used or booked for other activities. This study is the first to provide in-depth evaluation of the effect of occupancy on electricity consumption in Canadian schools.
Green building is an essential component of sustainable development, but previous studies have offered little in the way of systematic reviews of green building development from the perspective of project management. This research presents the current research trends in this discipline by analyzing the publications in ten major international journals from 2007 to 2016. The analysis was conducted on papers that have reported relevant investigations during that 10-year period. The analyzed research topics were found to group into five themes: green building management in general, the benefits and barriers to green building development, green building performance, stakeholder behavior with regard to green buildings, and green building strategies. Future directions for research relating to green building are suggested for the areas stakeholder management, policies and incentives, communication platform development, and retrofitting of existing buildings. Green building development will continue to be an important research area, and more comprehensive studies on green building management can help to promote further progress in this field.
Buildings contribute 20 to 40% of the world's energy consumption, making the need to regulate and minimize their energy use a priority. Although green buildings appear to respond to this issue, there is little empirical evidence in the literature demonstrating their energy effectiveness and little consensus over their long-term energy performance. This study involved reviewing the literature on energy consumption in green buildings. It analyzed existing research based on its country of origin, year of publication, the type of building analyzed, the size of the sample of buildings studied, and the green building rating system used for certification. The study also used other parameters such as the availability of actual empirical energy data, the study period for which energy data was collected, and the frequency of the data collected. It also extended to analyzing the degree to which the effects of building occupancy on energy performance were considered in the literature. The review showed that approximately 50% of all studies reviewed were carried out in the US, with only three studies conducted in Canada. Although building samples considered were usually small, existing research investigated a variety of building types. Approximately a third of all studies focused on buildings certified using the Leadership in Energy and Environmental Design Rating system (LEED). Fifty-five percent of all studies considered study periods of two years or less, with a third focusing on analyzing energy data on a monthly basis. Although some studies suggested a strong correlation between occupancy and energy consumption, research in this area remains limited, highlighting the need for more studies on how building occupants' use of green buildings affects their energy performance. Although more than half of the studies reviewed demonstrated energy savings in green buildings, these results varied depending on the reference used for comparison. The goal of this research was to provide a general overview of green buildings' energy consumption as documented in the literature rather than the energy performance of specific green buildings. It highlights the limitations in current research stressing the need to streamline and standardize the methods used in future studies. Standardized research of green buildings' energy performance would ensure the generation of a coherent body of knowledge in the field for future researchers and industry practitioners.
Buildings contribute 20 to 40% of the world's energy consumption, making the need to regulate and minimize their energy use a priority. A standard protocol was developed by the University of Manitoba Construction Engineering and Management Group to evaluate energy consumption across a sample of Manitoba schools in collaboration with the Manitoba Public School Finance Board. The protocol aims to evaluate school buildings' overall historical energy consumption and real-time electricity consumption at the space level. An extensive literature review was carried out to identify relevant parameters, methods and instruments to evaluate buildings' energy use. The protocol identifies school data parameters as well as historical energy data and real-time electricity data parameters to be collected, related methods and recommended values for these parameters. The protocol is currently being validated through its practical application to the sample of Manitoban schools identified. This protocol is expected to be useful to future researchers looking to evaluate other school buildings in other locations and enable buildings operators and managers to track their buildings' energy performance.
This research proposes technical performance over time as a fourth pillar of sustainability theory for infrastructure. It also describes a method that allows us to discover how changes in the technical pillar (operationalized as reduced breakage rates) may moderate the influence of the social pillar (operationalized as repair rates) on sanitation infrastructure outcomes. Oral histories were used to develop a history of sanitation for each of 152 poor households in four rural communities in Bangladesh that have gained access to sanitation in the past decade. Transcriptions and qualitative coding identified reported states of sanitation (for example, broken vs. functional) at three time steps. These were used to develop an initial vector and transition matrix for a Markov chain analysis. The breakage rate in this model was then adjusted to investigate the impact of improved technical durability on sanitation outcomes. For the case analysed here, we found that increasing infrastructure durability by 50% (an estimated increase of two years) increased the rate of functional sanitation system use at model convergence from 54% to 88%. Increases in durability also caused households to use private rather than shared systems. Beyond this specific case, the generalizable theory and method presented here are analytic tools that permit targeted technical accommodation of social contexts specific to individual project sites.
The economic considerations force the building body optimization during its design, as well as during the modernization of existing facilities. The thermal modernization effects are calculated according to the national rules and standards. The theoretical savings from the reduction of heat losses by transmission and ventilation in a secondary school located in Poland were calculated (59–71%) and compared with the real savings (33%), calculated on the base of data from the measurements conducted in several heating seasons before and after modernization. The achieved ecological effect (33%) was also lower that theoretical one (69%). The results of this work are worth taking into account in further schools modernizations and a city planning. The simple model for energy use estimation was proposed. The bigger sample of schools will be analyzed to propose changes in the calculation procedure after the end of the whole study.
Life Cycle Assessment (LCA) is a tool to measure and compare the environmental impacts by human activities of a process or product from cradle to grave. Resources consumption and emission to environment occur at many stages in a product's life cycle from raw material extraction, energy acquisition, production and manufacturing, use, recycling until the disposal. These potentially contribute to climate change, ozone depletion, acidification, euthrophication, toxicological stress on human health and ecosystems, the depletion of resources, land use, and others. This paper introduces the LCA framework and procedure, applications, advantage and limitation of LCA as well as its application in environmental management and pollution prevention scenarios.
This study analyzes the consumption quantities and costs of energy, water, and gas for a sample of 10 conventional and 20 energy-retrofitted public schools in Toronto over a 5 year study period to establish a benchmark for the consumption of energy in traditional versus more sustainable buildings. Through extensive statistical analysis of the data collected, the study demonstrates that electricity and gas consumption quantities and costs decrease more significantly in energy-retrofitted schools than in conventional schools. Whereas energy-retrofitted schools consume and spend on average as much money on energy as conventional schools, energy-retrofitted schools consume and spend more money on electricity and less money on gas than conventional schools. Energy-retrofitted schools also exhibit stronger and more significant positive relationships between the quantities of electricity, water, and gas consumed per user in those schools and the schools’ total number of users than conventional schools.
The notion of Life-Cycle Costing (LCC) is generally recognized as a valuable approach for comparing alternative building designs enabling operational cost benefits to be evaluated against any initial cost increases. However, a host of practical difficulties conspire to limit its widespread adoption. This limited acceptance is particularly important in green building where many of the benefits of strategic choices can often only be understood and justified when cast in a life-cycle context. This paper identifies some of the critical gaps between the theory (and promise) and practice of Life-Cycle Cost analysis to discover strategies that encourage greater use. Il est généralement admis que la notion de coût du cycle de vie fournit une approche utile pour comparer les différentes stratégies de conception de construction car elle permet d'évaluer les avantages en terme de coût d'exploitation par rapport à toute augmentation du coût initial. Une foule de difficultés pratiques contribue néanmoins à limiter son adoption générale. Cette acceptation restreinte est particulièrement importante pour les bâtiments écologiques car de nombreux avantages des choix stratégiques peuvent uniquement être compris s'ils sont replacés dans un contexte de cycle de vie. Le présent document identifie plusieurs lacunes majeures entre la théorie (et la promesse) et la pratique de l'analyse du coût du cycle de vie, afin de découvrir les stratégies qui favoriseront une utilisation plus large.
Thesis (Ph. D.)--University of Dundee, 1991.
This report is a state of the art review of whole life costing in the construction industry. It is the first of a series reporting on-going research undertaken within the research project ‘Developing an integrated database for whole life costing applications in construction’. This project is funded by the EPSRC and undertaken by a unique collaboration between two teams of researchers from the Robert Gordon University and the University of Salford.
The fundamental basics of whole life costing (WLC) are introduced. First, the historical development of the technique is highlighted. Then, the suitability of various WLC approaches and techniques are critically reviewed with emphasis on their suitability for application within the framework of the construction industry. This is followed by a review of WLC mathematical models in the literature. Data requirements for WLC are then discussed. This includes a review of various economic, physical, and quality variables necessary for an effective WLC analysis of construction assets. Data sources within the industry are also highlighted with emphasis on current data collection and recording systems. In addition, the requirements of a data compilation procedure for WLC are outlined.
The necessity of including the analysis of uncertainty into WLC studies is discussed. Attempts to utilise various risk assessment techniques to add to the quality of WLC decision-making are reviewed with emphasis on their suitability to be implemented in an integrated environment.
Essential requirements for the effective application of WLC in the industry are outlined with emphasis on the design of the cost breakdown structure and information management throughout various life cycle phases. Then, directions for further future research are introduced.
IntroductionInitial problemsUsing the weighted evaluation technique as a decisionmaking toolA whole life approach involves a feedback systemWhole life analysisWhole life planningThe relationship between whole life analysis and whole life planningCost relationshipsThe sequence of whole life analysis, whole life planning and whole life managementDocumentation format for whole life planningCosts and benefits
Buildings that have too much glass, overventilated, with air leaks, and are fraught with thermal bridges are actually not green buildings as they do not save energy after all. Buildings should meet the basic provision for ventilation specified under Standard 62.1. Engineers and architects should design buildings that utilize less glass and curtain walls as they are the most expensive component in a building and provide the worst energy performance. It is recommended that using 30% less glazings is actually the optimal level for glazing installations. Enclosures must also be built without big holes while steel stud cavities must be insulated on the outside. Those buildings that feature double facade are also not energy efficient since it not only makes it possible to maximize space, but also they use more energy than a decent facade with less than 100% glass.
2nd report on the performance of GSA's sustainably designed buildings. The purpose of this study was to provide an overview of measured whole building performance as it compares to GSA and industry baselines. The PNNL research team found the data analysis illuminated strengths and weaknesses of individual buildings as well as the portfolio of buildings. This section includes summary data, observations that cross multiple performance metrics, discussion of lessons learned from this research, and opportunities for future research. The summary of annual data for each of the performance metrics is provided in Table 25. The data represent 1 year of measurements and are not associated with any specific design features or strategies. Where available, multiple years of data were examined and there were minimal significant differences between the years. Individually focused post occupancy evaluation (POEs) would allow for more detailed analysis of the buildings. Examining building performance over multiple years could potentially offer a useful diagnostic tool for identifying building operations that are in need of operational changes. Investigating what the connection is between the building performance and the design intent would offer potential design guidance and possible insight into building operation strategies. The 'aggregate operating cost' metric used in this study represents the costs that were available for developing a comparative industry baseline for office buildings. The costs include water utilities, energy utilities, general maintenance, grounds maintenance, waste and recycling, and janitorial costs. Three of the buildings that cost more than the baseline in Figure 45 have higher maintenance costs than the baseline, and one has higher energy costs. Given the volume of data collected and analyzed for this study, the inevitable request is for a simple answer with respect to sustainably designed building performance. As previously stated, compiling the individual building values into single metrics is not statistically valid given the small number of buildings, but it has been done to provide a cursory view of this portfolio of sustainably designed buildings. For all metrics except recycling cost per rentable square foot and CBE survey response rate, the averaged building performance was better than the baseline for the GSA buildings in this study.
This paper details the development of a quantitative life cycle costing model and software for the assessment of financial feasibility of office building projects at the preliminary design stage. The model handles most technical data and financial factors which are required to determine the life cycle costs and economic feasibility of proposed buildings, with basic, minimum input. Three assessment factors are calculated: present worth, annual worth and savings/investment ratio.
The results from a survey examing the extent that Swedish clients in the building sector use life-cycle cost (LCC) estimations are reported. The limits and benefits from the client and user perspectives are also explored. The interest in using LCC approaches for economic evaluation of investment decisions is large. However, constraints exists at a number of levels: uncertainties related to the long term forecasts used, difficulties in achieving relevant input data and lack of experience in using LCC models, incentives for consultants and contractors. Nonetheless, the LCC perspective is proving to be most useful during the design phase where the possibilities of cost reductions related to operation and maintenance are large. LCC can provide motivation for environmental progressive building despite the sometime higher initial cost. The implication for expanding the use of LCC are considered for government, clients/developers, professionals.
Quality of design, material used and workmanship, affects the future operating, maintenance and rehabilitation costs of infrastructure; however, the extent to which quality affects these costs has never been explicitly quantified. The research described in this paper represents a major study in this area and significantly advances the understanding of the impact of quality upon building costs. Building design, construction, operating, maintenance and rehabilitation cost data for 215 buildings were collected from all available sources in the Canadian Department of National Defence. A metric was developed to measure quality in the design, construction, and operating and maintenance phases of a building's service life. An analysis of variance of annual equivalent total costs, for the first 20 years of building service life, clearly indicated that quality had a major impact on total costs when the influence of all other potential factors, particularly age, was minimized or removed. It was found that quality, in particular design quality, has the greatest demonstrable impact on building maintenance and rehabilitation costs.
Over three hundred buildings have been certified under the Leadership in Energy and Environmental Design (LEED) rating system for sustainable commercial buildings as of January 2006. This paper explores the modeled and actual energy performance of a sample of 21 of these buildings that certified under LEED between December 2001 and August 2005, including how extensively the design teams pursued LEED energy-efficiency credits, the modeled design and baseline energy performance, and the actual energy use during the first few years of operation. We collected utility billing data from 2003-2005 and compared the billed energy consumption with the modeled energy use. We also calculated Energy Star ratings for the buildings and compared them to peer groups where possible. The mean savings modeled for the sample was 27% compared to their modeled baseline values. For the group of 18 buildings for which we have both modeled and billed energy use, the mean value for actual consumption was 1% lower than modeled energy use, with a wide variation around the mean. The mean Energy Star score was 71 out of a total of 100 points, higher than the average score of 50 but slightly below the Energy Star award threshold of 75 points. The paper discusses the limitations inherent to this type of analysis, such as the small sample size of disparate buildings, the uncertainties in actual floor area, and the discrepancies between metered sections of the buildings. Despite these limitations, the value of the work is that it presents an early view of the actual energy performance for a set of 21 LEED-certified buildings.
Newsham et al. have recently published a re-analysis of energy-consumption data for LEED-certified commercial buildings supplied by the New Buildings Institute (NBI) and US Green Building Council. They find that, on average, LEED buildings use 18–39% less energy per floor area than their conventional counterparts, consistent with and adding clarity to conclusions originally reached by NBI. These conclusions, however, hang on a particular definition of the mean energy intensity of a collection of buildings that is not related to the total energy used by those buildings. Furthermore, site energy considered by Newsham et al. and NBI, unlike source energy used for the EPA's building Energy Star rating, does not account for the energy consumed off-site in generating and delivering electric energy to the building, whose inclusion is crucial for understanding greenhouse gas emission associated with building operation. Here I demonstrate that both the site energy and source energy used by the set of 35 LEED office buildings and Newsham et al.’s matching CBECS office buildings are statistically equivalent. Hence Newsham et al. offer no evidence that LEED-certification has collectively lowered either site or source energy for office buildings.
In the discussion of energy conservation, a great deal of attention has focused on mandated efficiency standards for cars and energy-using household appliances. (In this article, I will use the term "appliance" in a generic sense to cover household durables). Unfortunately, the estimates of energy savings predicted to result from these mandated standards are derived mechanically.' When mandated standards raise the appliance efficiency by 1 percent, demand is predicted to drop by 1 percent; when they raise efficiency by 2 percent, demand is predicted to drop by 2 percent; and so on. Examples of such results are found in reports by the Department of Energy (1979a, 1980) and by the Staff of the California Energy Commission (1979) on energy demand in California in the coming two decades.
The rapidly growing world energy use has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, global warming, climate change, etc.). The global contribution from buildings towards energy consumption, both residential and commercial, has steadily increased reaching figures between 20% and 40% in developed countries, and has exceeded the other major sectors: industrial and transportation. Growth in population, increasing demand for building services and comfort levels, together with the rise in time spent inside buildings, assure the upward trend in energy demand will continue in the future. For this reason, energy efficiency in buildings is today a prime objective for energy policy at regional, national and international levels. Among building services, the growth in HVAC systems energy use is particularly significant (50% of building consumption and 20% of total consumption in the USA). This paper analyses available information concerning energy consumption in buildings, and particularly related to HVAC systems. Many questions arise: Is the necessary information available? Which are the main building types? What end uses should be considered in the breakdown? Comparisons between different countries are presented specially for commercial buildings. The case of offices is analysed in deeper detail.
We conducted a re-analysis of data supplied by the New Buildings Institute and the US Green Buildings Council on measured energy use data from 100 LEED-certified commercial and institutional buildings. These data were compared to the energy use of the general US commercial building stock. We also examined energy use by LEED certification level, and by energy-related credits achieved in the certification process. On average, LEED buildings used 18–39% less energy per floor area than their conventional counterparts. However, 28–35% of LEED buildings used more energy than their conventional counterparts. Further, the measured energy performance of LEED buildings had little correlation with certification level of the building, or the number of energy credits achieved by the building at design time. Therefore, at a societal level, green buildings can contribute substantial energy savings, but further work needs to be done to define green building rating schemes to ensure more consistent success at the individual building level. Note, these findings should be considered as preliminary, and the analyses should be repeated when longer data histories from a larger sample of green buildings are available.
The view that widespread improvements in energy efficiency can by themselves do anything to halt the build-up of greenhouse gases around the globe is fundamentally unsound. It is based on the same fallacies that underlie the claim that energy savings from improving efficiency can substitute for new energy supply. The paper by Keepin and Kats1 claiming that, per tonne of coal not burned, improvements in energy efficiency are more cost-effective than substituting nuclear for coal-fired power is therefore an irrelevancy as far as this debate is concerned. Reductions is energy intensity of output that are not damaging to the economy are associated with increases, not decreases, in energy demand at the macroeconomic level. Even within the boundaries of their own flawed approach, their attempt2 to refute the critique of their thesis made by Jones3 was little more than misdirected grape shot with no discernable connected thread of argument.
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