Vivian Loftness

Carnegie Mellon University | CMU · Department of Architecture

Outlier detection plays a critical role in building operation optimization and data quality maintenance. However, existing methods often struggle with the complexity and variability of building energy data, leading to poorly generalized and explainable results. To address the gap, this study introduces a novel Vision-based Outlier Detection (VOD) a...

Monthly energy benchmarking supports identifying trends, improving energy efficiency, and conducting cost management for building owners, managers, and policymakers better than annual or hourly benchmarking. Annual data cannot fully reflect operation utility status, and hourly data poses the issue of high-cost data mining and incomparability due to...

This study proposes a generalized building energy and carbon emissions benchmarking approach. Leveraging eleven years of real-world data from twelve U.S. cities, an advanced ensemble learning model is employed to predict building site, source energy, and carbon emissions. The generalizability is validated across seven climate zones, yielding R2 val...

Developing a generalized building energy and carbon emissions benchmarking tool that can be applied nationwide is critical for building performance, policy-making, and realistic decarbonization goals. However, the lack of enacted energy benchmarking programs in the majority of U.S. cities hinders progress in establishing effective benchmarking. Mea...

Indoor acoustic quality is one of the critical indicators for occupants’ health, comfort, and productivity in contemporary office environments. Post-occupancy evaluation (POE) is usually employed to examine in situ acoustic measurements to ensure indoor acoustic quality. However, prevailing acoustic performance evaluation does not often consider th...

A research team at the Carnegie Mellon University Center for Building Performance and Diagnostics has developed a Smart Surfaces Guidebook for city policymakers to use as a decision-making guide. Rapid urbanization is replacing natural land with dark, impervious surfaces. This has led to dire urban consequences including rising temperatures and sto...

Research Team FHC-02 conducted two case studies to illustrate how Triple Bottom Line (TBL) analysis can help organizations outgrow the traditional dependence on first costs to guide design decisions. TBL’s life cycle calculations help decision-makers see the long-term superiority of the high-performance systems used in these two new buildings by co...

Earthen building materials are a critical future for sustainable construction because they are locally available, minimally processed, and waste-free. However, despite their advantages, earthen materials still face challenges for comprehensive implementation. First, their technical data vary significantly, making it challenging to quantify their tr...

Building management systems in commercial spaces commonly operate on predefined temperature setpoints and control schedules. These systems typically do not consider the individual occupant’s thermal preferences, which often leads to high thermal dissatisfaction rates, especially in shared spaces. Recent studies target human-in-the-loop personalized...

Rapid urbanization is replacing natural land with dark, impervious surfaces. This has led to dire urban consequences including rising temperatures and stormwater deluge, resulting in significantly higher energy costs, greater stormwater damage, and associated health and comfort impacts. These issues can be mitigated using smart surfaces, those with...

Experiencing nature provides a multitude of health benefits. Biophilic design has emerged as a design approach that aims to reconnect occupants with the natural environment. We evaluated the impact of a multisensory biophilic environment on occupants' cognitive performance, stress, productivity, mood, connectedness to nature, and attention. Thirty-...

Buildings account for 40% of the energy consumption and 31% of the CO2 emissions in the United States. Energy retrofits of existing buildings provide an effective means to reduce building consumption and carbon footprints. A key step in retrofit planning is to predict the effect of various potential retrofits on energy consumption. Decision-makers...

Natural earthen and bio-based building materials are critically needed to dramatically reduce energy-intensive and extractive construction practices that are the hallmark of the modern building industry. Building assemblies such as cob, light straw clay and rammed earth were shown to provide an optimal indoor environment for occupant comfort and he...

Buildings currently account for 39% of energy-related carbon dioxide emissionsannually, worldwide. Despite the acceleration of climate change, architecture isincreasingly designed as hermetically sealed boxes, requiring increased conditioning,which in turn further contributes to the greenhouse gas emissions warming up ourplanet. In addition to disa...

For visual quality, the traditional focus on illuminance for paper-based tasks and brightness contrast for visual acuity is becoming less relevant in modern offices with backlit computer screens and sporadic use of paper. This research aims to investigate critical correlations between user satisfaction, workstation lighting conditions, and the phys...

The work presented in this paper provides an in-depth assessment of the earthen building situation in the field, obtained from earthen building professionals and end users. Additionally, a comparative LCA of a suite of earthen and conventional residential building assemblies is presented. Using a functional unit of 1 m2 of a typical one- or two-sto...

Ein Großteil der aktuellen Fortschritte im Lehmbau entwickelt sich auf Grund des Engagements einzelner, bei dem diese Pioniere und Befürworter mit technischen, wirtschaftlichen und politischen Zwängen konfrontiert sind (Woolley, 2006). Trotz der zahlreichen ökologischen und sozialen Vorteile von Lehmbaustoffen zögert die Mainstream-Bauindustrie imm...

This volume in the Encyclopedia of Sustainability Science and Technology, Second Edition, describes the breadth of science and engineering knowledge critical to advancing sustainable built environments, from architecture and design, mechanical engineering, lighting, and materials to water and energy, public policy, and economics. Covering both buil...

：The quality and controllability of the building façade can significantly contribute to building indoor environmental quality (IEQ) as well as the building’s energy efficiency. Advanced technologies that support a façade’s dynamic response to climatic changes, such as electrochromic (dynamic) glazing, have emerged as smart systems for IEQ and envir...

Earthen building materials offer an environmentally sustainable alternative to conventional materials because they are locally available, minimally processed, and waste-free. However, they have not been comprehensively implemented because their technical data is highly variable, and they are not fully represented in building codes. To address these...

Windows provide access to daylight and view, both of which have been linked to positive outcomes for occupants, including improved satisfaction, well-being, and performance. However, window access can also cause discomfort and eyestrain from glare. This controlled crossover study tested the occupant impacts of two modern shading systems designed to...

Indoor air quality of the workplace is highly linked with occupants' health, comfort and satisfaction. To maintain the good indoor air quality of buildings, Post Occupancy Evaluation (POE) is often combined with environmental measurements to holistically examine existing performance conditions in relation to occupants’ satisfaction. The Center for...

Thermal adaptation can play a significant role in defining thermal comfort levels for evaporatively cooled office buildings commonly found in India. However, there are no dedicated studies to record the occupant perception and indoor thermal comfort in these buildings. The contribution of adaptive thermal comfort theory on occupant perception remai...

The built environment must meet the highest demands of human habitation, resource management and community enrichment. To achieve these goals, modern built environments should adopt restorative environmental and biophilic design principles which seek to reconnect the human built environment with nature. In this paper, the biophilic aspects and envi...

Cob is an earthen building material that offers a minimally processed, low carbon, and locally available alternative to conventional building materials and methods. This paper provides a framework for a comparative Life Cycle Assessment (LCA) from an embodied perspective of energy and air emissions, using cob earthen wall construction as well as be...

Biophilic design is one of a number of trending design practices that rely on nature-based systems, engineering principles and design cues to improve environmental quality, health, and efficiency. Biophilic design integrates but does not appropriate the contributions of other nature-based design techniques precisely because it can act as a platform...

Earthen building materials offer an environmentally sustainable alternative to conventional materials because they are locally available, minimally processed, and waste-free. However, they have not been comprehensively implemented because their technical data is highly variable, and they are not fully represented in building codes. To address these...

Building Bio Climatic Design Charts (BBCC) are essential for understanding the thermal conditions prevalent inside occupant spaces and aid in assessing the potential of passive and low-energy cooling strategies like evaporative cooling. An intensive field study carried out in 10 selected office buildings using direct and two stage indirect/direct e...

The indoor environmental quality (IEQ) of buildings can have a strong influence on occupants’ comfort, productivity, and health. Post-occupancy evaluation (POE) is necessary in assessing the IEQ of the built environment, and it typically relies on the subjective surveys of thermal quality, air quality, visual quality, and acoustic quality. In this...

An integrated approach to building performance evaluation mandates that post-occupancy evaluation subjective tools be matched by metrics (POE + M). While leveraging occupants as sensors to quickly capture indoor environmental quality or IEQ conditions in a work environment is valuable, the addition of measured environmental conditions across all va...

Office workers' productivity and well-being are reduced by interruptions, especially if they occur during an inconvenient moment. Interruptions in phases of high cognitive load are more disruptive than in phases of low cognitive load. Based on an explorative study, we suppose the presence of social codes that signal office workers' interruptibility...

Earthen Building Materials and Methods (EBMM) exhibit excellent environmental, health, indoor air quality and affordability benefits. Despite these advantages, EBMM are not yet broadly implemented in mainstream construction. The main barriers and gaps to implementing earthen construction are analyzed through 126 survey responses and 10 in-depth int...

Office workers tend to waste energy at work due to little motivation for saving energy. This study investigates the effectiveness of online feedback (e.g., self-monitoring, advice, comparison) and control strategies (e.g., online remote control, scheduled control) that can promote voluntary energy conservation in the workplace. Eighty office worker...

Earthen building materials and methods offer a low-impact, truly sustainable alternative to conventional materials and methods currently used in mainstream construction of residential homes. However , the absence of adequate codes and standards for these methods is a barrier to broader implementation in mainstream construction practice. This paper...

The integration of humans into smart buildings raises challenges between meeting individual preferences and the generic rules set to optimize energy effectiveness of interest to organizations. Merging the individual preferences of multiple occupants that share thermal zones compounds the challenge. To address related challenges, we have developed F...

Thermal comfort standards such as ASHRAE 55-2013 defines comfort boundaries which are based on the experimental results conducted in climatic chambers and field studies. The current comfort standards do not reflect the cultural and climatic diversity of India. A thermal comfort field study was conducted in 32 naturally ventilated buildings, collect...

Energy consumption in Indian building sector is increasing at high rate. The National Building Code of India specifies a narrow comfort temperature range between 21 °C and 26 °C for all types of buildings and for all seasons. A thermal comfort field study was conducted in 32 naturally ventilated buildings, collecting a total of 2610 samples spread...

Occupant thermal comfort is a key performance metric for green buildings. Although numerous studies have used thermal comfort as a criterion to control mechanical systems and optimize their energy consumptions, few studies examined individual thermal comfort preferences and their implications. This study aims to investigate the individual thermal c...

Model predictive control (MPC) has been studied in the building science realm for about three decades. However, the following two aspects of the building control have not been studied thoroughly in MPC research. One is the impact of the mixed-mode cooling system on the active heating ventilation and air conditioning (HVAC) energy consumption, and t...

Whereas eco-feedback has been widely studied in HCI and environmental psychology, online manual control and automated control have been rarely studied with a focus on their long-term quantitative impact and usability. To address this, an intervention was tested with eighty office workers for twenty-seven weeks. Through the long-term field test, it...

Plug load energy consumption represents up to 40% of the total energy consumption in efficient buildings. Occupant behavior has a huge impact on plug load energy consumption. Studies have shown that up to 40% plug load energy savings can be achieved through users' engagement in sustainable behaviors. To save energy from plug loads, either a company...

Lighting is the largest percentage of electric energy demand in commercial buildings, with the greatest potential for substantial energy savings, peak load shaving, and human benefits. Proper integration of skylights into commercial building design represents an important potential approach for capturing these potentials. Sixty-five percent of all...

The occupants’ health, comfort, and productivity are important objectives for green building design and operation. However, occupant behavior also has “passive” impact on the building indoor environment by generating heat, CO2, and other “disturbances”. This study develops an “indirect” practical data mining approach using office appliance power co...

Office workers typically don’t know how much energy they consume at work. Since the workers don’t pay the energy bills, they tend to waste energy. To support energy conservation and motivate workers, the Intelligent Dashboard for Occupants (ID-O) was developed using multiple intervention strategies – eco-feedback (self-monitoring, advice, and compa...

Prior research on stage-based, behavior-change models investigated intervention effectiveness for stress management, smoking cessation, weight management, adherence to lipid-lowering drugs and the like. Few sustainability centered studies identify people’s stage-based levels for energy use reduction or sustainability. In this paper, we investigate...

The objective of this article is to provide a methodology for optimizing the envelope of a building with respect to the triple objective of heating load, cooling load and daylight. The variables to optimize are the window to wall area ratio (WWR) and the window type characterized by its visual and thermal characteristics (visual and solar transmitt...

Office buildings don’t have opinions about saving or using energy; their occupants do. Of the total energy consumed by commercial buildings, an increasing proportion is directly under the control of building occupants, who to this point have rarely been challenged to conserve energy in any consistent way. While improved devices and controls achieve...

Buildings consume a significant amount of energy to maintain the indoor thermal comfort. One way to reduce the energy consumption in buildings is to improve the overall energy efficiency through integrated advanced controls. It is undoubted that incorporating a model and utilizing future information in real-time building operation offers great ener...

This paper presents a simulation effort to assess the impact of lighting load reduction on overall building energy use and the relation of lighting load to other building parameters. Also, a preliminary assessment of the energy-related implications of different thermal zoning in relation to lighting system options, enclosure configurations, and con...

Indoor environmental quality (IEQ) of buildings can have strong effects on occupants’ productivity and health. Post occupancy evaluation (POE) and associated processes have been emphasized as a crucial stage for energy conservation and occupants’ comfort and satisfaction of the building. Preliminary research has shown that POE supports opportunitie...

Transformative change in the energy consumption of the built environment, whether commercial or residential, can be achieved through the coordinated actions of building owners and occupiers, government policy makers, developers and manufacturers of efficient building components, utility companies, and other public and private entities in response t...

Triple Bottom Line cost-benefit analysis is critical to accelerate market adoption of energy efficient retrofits of commercial buildings. While 5-15 year energy payback analyses should be sufficient to prompt greater investment in lighting upgrades, the addition of triple bottom line (TBL) calculations - to capture the economic, environmental and h...

In the United States, over three billion dollars are spent due to office equipment being left on when not in use during the weekend and at night. There is very little incentive for office workers to save energy because utility bills are not directly their responsibility. Our goal is to find ways to reduce the negative impact of this pervasive pheno...

Human activity creates some of the greatest environmental challenges on the planet. Human-Computer Interaction (HCI) research on sustainability increased dramatically in the past five years. Researchers argue that technology plays a critical role in changing people's belief and behavior towards sustainability. Much of the sustainable HCI research c...