Bringing Dynamic Indoor Environments to the Mainstream

As we look for new ways to improve building performance in our efforts to reduce energy use and lower greenhouse gas emissions from commercial buildings, we must also recognize that occupant comfort cannot be sacrificed. While people’s attitudes towards indoor comfort are complex and dynamic, building systems are not designed to respond to these needs.

A new research collaboration at Berkeley focuses on opportunities to use advanced computing to enable “intelligent” building infrastructure. This has primarily been a partnership among researchers from CED’s Center for the Built Environment (CBE) and the Department of Electrical Engineering and Computer Science (EECS). In just a short time a number of fruitful projects have come out of this collaboration.

One of these initial projects is sMAP (Simple Measurement and Actuation Profile), an open-source protocol to easily integrate data from different sources in buildings — such as energy and building system operations data — into a uniform and accessible platform. Buildings usually have little data on comfort levels and operational efficiency. sMAP has helped by creating a method for gathering these data efficiently. The platform has been deployed in buildings across the UC Berkeley campus as well as at Lawrence Berkeley National Laboratory.

Based on this work done while they were Ph.D. researchers in computer science at Berkeley’s LoCal Group, Andrew Krioukov (M.S. Computer Science ’13) and Stephen Dawson-Haggerty (Ph.D. Computer Science ’14) developed Comfy, a learning thermostat designed for commercial buildings, and the first product to come out of their Oakland-based startup, Building Robotics. While currently working on my PhD in Building Science at the CED, I also co-lead Building Robotics — along with co-founders Andrew and Stephen, and VP Design & Communications Beau Trincia (M.Arch ’06) — guiding an interdisciplinary team focused on re-inventing building controls with advanced computing and thoughtful user experience.

The Comfy interface
The Comfy interface, designed to be more understandable than a typical control. Enlarge [+]

The Comfy software works on the philosophy that is central to CBE: preferences for temperature vary considerably over time, in different climates, and across populations. In other words, there is no “one size fits all” for temperature. Some of CBE’s most current work looks at the related principle of alliesthesia, explained in this recent paper.

Currently, buildings are not run dynamically — most buildings typically condition spaces between 70–73 degrees throughout the day. The Comfy software enables dynamic and demand-based conditions, providing both an immediate response from the building (either warm or cool air, temporarily) and machine learning to optimize zone temperatures based on user preferences, time of day, day of the week, and the temperature of the space. When no user feedback is seen, the space is left less conditioned to save energy. The software also provides the ability to control lights in a similar fashion.

One interesting aspect of our work is the direct interface between people and the dynamic building space around them. Figure 1 shows the Comfy interface, designed to be more understandable than a typical control. In this way, Comfy has become a wonderful field study in thermal comfort.

Supporting previous CBE findings, we’ve found that people use Comfy to set temperatures in a far broader range than normal — as cold as 65 degrees and as warm as 80 degrees. We see seasonal preferences change as well, especially in the summer when many office buildings tend to be over-cooled. As we dress for the summer, so we prefer our work environments to be warmer. Figures 2 and 3 show our initial data on these issues, showing how people’s temperature preferences can vary significantly more than we may imagine. Importantly, we’ve found a strong persistence over time in the use of the tool, indicating that people build a lasting relationship with the building through this interface.

Comfy data showing temperature preference variations.
Comfy data showing temperature preference variations. Enlarge [+]
Comfy data showing morning to afternoon variations.
Comfy data showing morning to afternoon variations. Enlarge [+]

Technologies like Comfy will increasingly redefine how people experience and interact with buildings in the coming years, allowing a much deeper relationship between the human body and the world around us. What other possibilities will this capability allow? We are looking forward to seeing how this growing field evolves into this new exciting frontier.

The Comfy Platform
The Comfy Platform Enlarge [+]

Learning From Experience

Ask anyone who designs, owns, or manages an office building if they want the occupants of their building to feel comfortable, healthy, and productive, and the answer would of course be ‘yes’.   But ask again if they know what the occupants actually feel about the space, and the answer will be quite different.

Photo_Carnegie_rainbowThe facility manager is most likely to have a sense, but often it’s only anecdotal. The building owner might eventually have an inkling about occupant sentiment if they see a financial effect because an environment is inadequate. Yet, sadly, very few architects or other members of the design team are likely to know how well their building is working after it is completed and occupied, the fees have been paid, and they are on to another project. Without learning from experience in an objective way, building industry professionals are less likely to make design or economic decisions that will truly enhance the performance and experiential quality of their buildings.

And while this information would be valuable for any project, it is particularly essential if one is claiming to have designed or built a green building, where the quality of the indoor environment is a critical dimension of sustainable design. The only way to back up those claims is to evaluate a building’s actual performance, in terms of energy consumption or indoor environmental quality, and compare the performance to design intent.

Without question, it is absolutely crucial to reduce energy consumption in buildings and help avoid the potentially devastating impacts of climate change. But in terms of the building owner’s pocketbook, energy costs are still relatively small compared to worker salaries, which represent over 90% of the total operating costs of a commercial building. In addition, the cost of worker recruitment and retention is significant. Thus, from the building or company owner’s point of view, perhaps the most persuasive argument for sustainable design is one that makes the connection between a higher quality indoor environment, and increased comfort, health and productivity of the workers.

So, how does one learn about the quality of the indoor environment? While there are many physical measurements one can take, they need to be interpreted in terms of the impact on occupants. Occupants themselves are a rich yet underutilized source of direct information about how well a building is working, but the challenge is how to collect both the positive and negative feedback in a systematic way. This has been at the core of research underway at UC Berkeley.

 Center for the Built Environment

The Center for the Built Environment (CBE) is a collaborative research organization that links faculty, researcher, and students with a consortium of firms and organizations that share a commitment to improving the performance of commercial buildings. The Center has two broad purposes, represented in a wide range of research projects of relevance to the building industry. First, we develop ways to “take the pulse” of occupied buildings, looking at how people use space, what they like and don’t like, and we link those responses back to physical measurements of indoor environmental quality. Secondly, we study technologies that have the potential to make buildings more environmentally friendly, more healthy and productive to work in, and more economical to operate. These range from envelope and HVAC systems, to controls and information technology. Our industry partners represent architects, engineers, contractors, manufacturers, utilities, building owners, and government organizations. Our current CBE Industry Partners are Armstrong World Industries, Arup, CA Dept. of General Services, CA Energy Commission, Charles M. Salter Associates, CTG Energetics, Flack + Kurtz, Guttmann & Blaevoet, HOK, PG&E Pacific Energy Center, Price Industries, RTKL Associates, SOM, Southland Industries, Swinerton Buildings, Stantec, Steelcase, Syska Hennessy Group, Tate Access Floors, Taylor Engineering, Trane, US Dept. of Energy, US General Services Administration, Webcor Buildings, and York International.

Survey Page_acoustics The CBE Survey

CBE has developed a web-based indoor environmental quality survey to help designers, building owners and operators, and tenants evaluate how well their office buildings are working from the occupants’ perspective. Advantages of the web-based format are: 1) it is quick and inexpensive to use; 2) it facilitates more focused and detailed feedback (particularly, when the occupant indicates dissatisfaction with a certain area); and 3) survey results can be accessed using an automated, advanced reporting tool that allows users to filter, aggregate, compare, or benchmark their data. The core CBE survey measures occupant satisfaction and self-reported productivity related to nine environmental categories: office layout, office furnishings, thermal comfort, air quality, lighting, acoustics, cleanliness and maintenance, overall satisfaction with the building, and with the workspace. Additional, custom survey modules can be added, which would enable you to gather data about additional topics, depending on available building features or the client’s particular issues. Examples of existing modules include accessibility, safety and security, daylighting, and operable windows.

To date, the CBE Survey has been implemented in nearly 300 buildings, with over 41,000 individual responses, making it the largest database of its kind. The survey can be used as a diagnostic tool for individual buildings, to enable designers or building owners to evaluate specific aspects of their building design features and operating strategies, identify problem areas, and help prioritize investments for improvements. Users can do both before and after surveys to evaluate the effectiveness of changes in the design or operational improvements, or before and after a move. The database is also useful for evaluating trends across many buildings. By using a standardized instrument to collect data from a wide variety of office buildings, we are able to mine the data to look for trends or comparative analysis in the performance of particular design strategies or technologies. By utilizing the full database, clients can also evaluate how their building is doing in comparison to groups of buildings in the same or different categories.

The CBE Survey is being used in a wide variety of contexts, for both private and institutional clients. In some cases, we are contacted directly by architecture and engineering firms to study their buildings (recent examples include Arup, Chong Partners, EHDD, ELS, Enermodal Engineering, Glumac, HKT, HOK, Keen Engineering, Moseley Architects).

The U.S. General Services Administration (GSA) is using the CBE Survey to evaluate tenant satisfaction in up to 100 buildings each summer as part of their facility management assessment program, replacing their previous paper-based survey administered by Gallup. We are also developing and administering new surveys as part of GSA’s Workplace 20/20 initiative, which focuses on the interrelationships between people, space, technology, knowledge, work process, and organizational effectiveness.

With UC San Francisco, we have developed a new module to evaluate laboratories. We completed several baseline surveys of UCSF facilities, and we will continue to evaluate many of their new lab facilities.

As a one-year promotion, we offered the CBE Survey free for LEED-certified buildings, to improve our understanding of how green buildings were performing in the field. We have also been contacted independently by architects or building owners who can use the CBE Survey to achieve a LEED-NCv2.2 credit for thermal monitoring.

Internationally, we have collaborated with Indoorium, a Finland-based consulting firm specializing in indoor air quality, lighting, and acoustics, to evaluate 20 buildings and develop multi-lingual capabilities for the survey.

And here on the UC Berkeley campus, in Cris Benton’s Arch 249: Secret Life of Buildings, students surveyed 13 campus buildings and discovered that the deferred maintenance of recent years is keenly felt!

We are currently embarking on new projects to use the CBE Survey to evaluate some of the recent AIA-COTE Top Ten Green Projects, and to survey occupants of the new San Francisco Federal Buildings, both in their current spaces and then after they move later this year.

And finally, we utilize the CBE Survey extensively in our own research projects investigating technologies such as underfloor air distribution, operable windows, demand response technologies, and high performance facades — often combining the survey with detailed indoor physical measurements.

Survey Results_Avg ScoresLessons Learned

Looking at the entire database, of all the environmental attributes evaluated in the CBE Survey, acoustics consistently receives the lowest ratings, followed by thermal comfort and air quality. The most common sources of dissatisfaction with acoustics relate to sound privacy (people overhearing others’ private conversations) and distractions from hearing people’s conversations while talking on the phone or to others in neighboring areas. Much less frequent were complaints about excessively loud sounds, noise from the HVAC system or office equipment, or outdoor noises (even in buildings with operable windows). Not surprisingly, people with private offices are significantly more satisfied with acoustics that those in open plan spaces. However, when we looked at the influence of open plan design, we were surprised to find that the absence of partitions provided higher satisfaction scores than having partitions, yetpartition height itself had no discernible effect. This suggests that visual privacy may lead to unrealistic expectations of acoustic privacy. When people have a full view of their co-workers, they are either more courteous at keeping their voices lower, or change their expectations and are therefore not disturbed by the lack of privacy.

ASHRAE publishes standards for both thermal comfort and acceptable air quality in buildings (ASHRAE Standard 55-2004, and 62.1-2004, respectively), both recommending conditions in which 80% of the occupants are satisfied. But when we look at satisfaction scores from our database, we find that buildings are falling far short of these standards. It was disturbing to find that only 11% of the buildings met the intent of the thermal comfort standard, with an overall average of only 59% of the occupants expressing satisfaction with the thermal environment. Thermal dissatisfaction was most commonly related to people feeling that they did not have enough control over their environment, in addition to complaints about air movement being too low. This is particularly interesting given that thermal comfort standards are geared towards limiting air movement, mistakenly believing that drafts are a more common problem.

Responses to air quality were only slightly better, with only 26% of the buildings meeting the intent of the standard, and on average 69% of occupants are satisfied with the air quality. The most common complaints were that the air was stuffy or stale, or smelled badly, with the most frequently identified sources being food, carpet or furniture, or other people.

Not surprisingly, we found that satisfaction with both thermal comfort and air quality increases significantly in buildings that provide people with some means of personal control over their environment, such as thermostats or operable windows. The opposite was true for people with portable heaters and fans, indicating that the presence of these devices may have been a result of inadequate performance of the centralized HVAC system. Given the relative energy intensity of these portable devices, it is clear that providing for personal control should be a thoughtful and integrated part of the overall building design, rather than an afterthought.

We also did a comparative analysis of 21 green buildings, 15 of which were LEED-rated. In comparison to the rest of the database, occupants in these buildings expressed higher rates of satisfaction with thermal comfort and air quality, and with the building overall. Contributing reasons for this include improved ventilation, green materials with reduced off-gassing, solar gain control, operable windows, task-conditioning, and other means of personal control. In contrast, we didn’t see any significant improvement in lighting and acoustic quality in the green buildings. With regard to lighting, occupants consistently enjoyed and valued higher levels of daylight and access to views, but there were often problems with glare (particularly on computer screens), and inadequate electric task lighting or provision of controls over the lighting. High levels of dissatisfaction with acoustics in the green buildings were often attributed to problems with sound privacy and noise distractions, often exacerbated by the high ceilings and open plan layouts that are beneficial for daylighting and natural ventilation. Additional factors influencing the acoustics in these buildings were often harder surfaces associated with minimal use of textiles as a way of avoiding the off-gassing.


Providing workers with a quality indoor environment should be a goal of any building design, but is particularly important for green buildings that claim to be more responsive to supporting occupant comfort, health and productivity. Improving the quality of our buildings critically depends on accountability and learning from experience – what works, what doesn’t, and what choices about building design or operation can make the biggest difference. The voices of the occupants are an invaluable component of that assessment. As we move towards embracing high-performance, green buildings as the industry standard (as we must), we must also insist that post-occupancy evaluations be a natural part of that process. In the end, everyone benefits from learning how a building performs in practice.


I’d like to acknowledge the members of CBE who have contributed to this work, including Charlie Huizenga, Leah Zagreus, Sahar Abbaszadeh, David Lehrer, and CBE Director, Ed Arens. We also acknowledge the numerous students from Architecture and other departments on campus who have contributed to and received financial support from the Survey project.

For more information:

To see a demo of the CBE Survey and reporting tool, or to find out how to use the CBE Survey in your building, see:

Or send us an e-mail at:

For more detailed discussions of this subject see:

Abbaszadeh, S., L. Zagreus, D. Lehrer and C. Huizenga. Occupant Satisfaction with Indoor Environmental Quality in Green Buidlings. Indoor Air 2004; 14 (suppl 8) December 2004. 65-74.

Huizenga, C., S. Abbaszadeh, L. Zagreus and E. Arens. Air Quality and Thermal Comfort in Office Buildings: Results of a Large Indoor Environmental Quality Survey. Proceedings of Healthy Buildings 2006, Lisbon, Vol. III, 393-397.

Zagreus, L., C. Huzenga, E. Arens, and D. Lehrer. Listening to the Occupants: A Web-based Indoor Environmental Quality Survey.   Indoor Air 2004; 14 (suppl 8) December 2004. 65-74.

Gail Brager is Professor of Building Science in the Department of Architecture, and Associate Director of the Center for the Built Environment.


The Impact of Energy Consumption on the Environment

What is the Biggest Culprit? Concerns about the impact of energy consumption on the environment, especially global climate change, have finally penetrated public consciousness to the point where significant political action is beginning to happen.

USEnergy3 copyAny number of events can be cited as triggering this step change in consciousness. Al Gore’s movie An Inconvenient Truth, numerous cover articles by our leading weekly magazines, a continuous stream of newspaper articles, scientific reports from prestigious committees, appeals to the President by business leaders, politicians, and scientists, etc., have outlined the risks and challenges to the planet in compelling detail. As Governor Arnold Schwarzenegger commented when he introduced Executive Order S305 on greenhouse gas reduction, “I say the debate is over. We know the science. We see the threat. And we know the time for action is now.”

The question is: where should we focus our efforts? We can begin by asking: where are the biggest culprits and what are the most immediate cost effective strategies, but the challenge is more fundamental than the idea of mitigation or conservation, as important as they are. Ultimately, we must rethink and convert our 200-year-old fossil fuel economy to renewable sources. An even more fundamental question is: can we do it in time to avoid catastrophic change and human hardship?

The recent announcement at UC Berkeley of a $500 million grant by oil giant British Petroleum (BP) to develop biofuels is not only by far the largest alliance between industry and the academies, but also the kind of investment and vision necessary to bring renewable energy swiftly to market. BP’s grant will fund hundreds of researchers in 25 teams, 18 at UC Berkeley and Lawrence Berkeley National Laboratory (LBNL) and 7 at University of Illinois Urbana-Champaign, while BP will assign up to 50 of its own researchers to join the teams. The potential of this landmark interdisciplinary effort is planetary. LBNL Director Steve Chu has estimated that if the acreage which American farmers are currently subsidized not to cultivate were planted in “switch grass” and if ethanol from this cellulose source could be brought to market at the efficiencies demonstrated in the lab, it could provide as much as 100% of the country’s transportation fuel needs. UC Berkeley Chancellor Robert Birgeneau has characterized the effort as “our generation’s moon shot.” Charles Zukoski, Vice Chancellor of Research at the University of Illinois Urbana-Champaign, described it as launching “a new age for agriculture, altering the energy economy of the planet.” As essential and groundbreaking as this effort is, how big an impact will it have on the problem?

World Energy Supply Bar GraphAn examination of our energy consumption by broad sectors reveals the following approximate breakdown: 27% transportation, 30% industrial, 22% commercial, 21% residential. Almost all the energy consumed (90%) comes from fossil fuels, with the remainder from nuclear and renewables, including wind and hydro. When each sector is examined in greater detail, some surprising facts are revealed. Within the transportation sector, only 16% is consumed by cars and trucks, the remaining 7% goes to trains and planes. Thus, if all the transportation fuel for cars and trucks (as big a number at that is) were converted to biofuels, it would still only address 16% of the problem. So what is the biggest culprit?

As Ed Mazria has pointed out in his “2030 Challenge” to design and construction professionals, if you add up the residential and commercial sectors with the portion of the industrial sector consumed by buildings, it totals 48% of the total energy consumption! If you look at electric consumption by itself, 75% goes to operate buildings. With the projected increase in electrical demand planned to be met by coal-fired power plants, the impact of buildings is even more important. Quite simply, buildings are both the biggest problem and opportunity.

Mazria also points out that over the next 30+ years, we will build approximately half again as much new square footage as already exists and we will renovate about 50% of the existing square footage. This means that in the year 2035, three quarters of the built environment in the U.S. will be either new or renovated. This gives design and construction professionals the largest responsibility for making a real difference, but as Schwarzenegger has said “the time for action is now.”

We know from over 30 years of research and development since the last oil crisis in the early 1970s, that we can reduce the energy consumption in buildings by 50-70% through intelligent conservation and the application of passive solar heating, natural ventilation and careful daylighting. The question becomes how do we get the rest of the way to zero carbon buildings — i.e., buildings which generate all of their energy needs from renewables. This is the “moon shot” challenge to design and construction professionals.

With the loads for heating, cooling and lighting reduced dramatically by the strategies above, the remaining challenge is the electric loads for building equipment, appliances and especially the so-called “plug loads” for computers, televisions, kitchen and office equipment. Conservation in lighting and appliances, especially refrigerators, are the reason why electric consumption in California has been flat for the last 20 years in spite of population growth. This phenomenon has been called the “Art Rosenfeld Effect” because he pioneered the “energy star” rating system for all appliances, especially refrigerators. Natural competition in the market place, as a result, reduced energy consumption by 50%. His colleagues at LBNL pioneered in the development of high efficiency light bulbs with a similar

To achieve the goal of zero carbon buildings, the country will need the next generation in conservation technologies in all areas of electric usage, including lighting, appliances, televisions, computers, etc. Fortunately, many of these technologies are in the development phases and are on the way. As demonstrated in California by the “Rosenfeld Effect”, conservation will remain the single most cost effective first step. Nonetheless, buildings will still require electric power; even with reduced loads, and the challenge is can it be met by renewables?

Through our research at the college on the application of photovoltaics and wind technologies to buildings, we have discovered recent commercially available breakthroughs which are extremely promising. By integrating photovoltaics (PV) directly into building assemblies, like roofs and curtain walls, i.e., substituting existing materials with PV materials, the cost effectiveness of PV is already competitive in some markets, especially when compared with peak power. When the next generation of efficiency achieved in the lab (20%-40%) is brought to market in 3-5 years, the integration of PV into building assemblies should become a matter of course for designers.

The story about the integration of small-scale wind machines into building design is equally promising. A new generation of vertical axis machines, double-helix spiral-like rotors, seems to have solved many of the prior problems. Quiet, non-vibrating, effective at low speeds and multi-directional, their applications on roofs and facades offers multiple design opportunities.

When both of these technologies are combined, we have discovered that they have the potential of providing more than 100% of the total electric loads, on an annual average basis, after careful conservation. Yet, the final challenge is overcoming the intermittent timing of these renewables. What do you do if there is no sun and no wind, and you are unable to capture excess energy (when available) by running the meter backwards, i.e., using the grid as storage?

The final step to zero carbon buildings, for instance providing the backup to wind and solar, comes from a surprising source — the waste streams. In our research work on sustainable neighborhoods in China, we have discovered that food wastes, the sludge from primary sewage treatment and green wastes from the landscape, urban gardening and agriculture together generate a significant energy resource in the form of biomass. New technological breakthroughs in biogas generation use a two-stage anaerobic process to convert as much as 80% of the potential energy in the biomass into biogas — methane and hydrogen. This energy source can be put to many uses, for example: providing gas for cooking, compressed gas for gas-powered vehicles, or powering gas-electric turbines for the base or back-up electric loads.

solarFor this technology to be cost effective, however, it needs a minimum flow of biomass material equal to about 8-10 tons per day, or the waste created by a mixed-use, high density neighborhood of approximately 5,000 units of housing (15,000 people). While the construction of such a neighborhood is the exception in the U.S., 10-15 of these kinds of neighborhoods are completed every day in China. We have discovered that the three renewable energy sources, wind, solar and biomass together can provide all the energy for such a neighborhood. Indeed, the neighborhood can be a significant energy exporter to the grid — especially at peak demand during summer afternoons. The challenge of realizing such an integrated and self-sustaining system of energy supply is that it requires a whole new way of doing business for the design and construction industry. The developer, architect, landscape architect, civil engineer, mechanical engineer, city departments of planning and public works, have to operate under a whole new paradigm of collaboration and integration. But the rewards are planetary; zero carbon neighborhoods could become a reality.

In the end, the goal of achieving a carbon neutral future in the building sector is at least several years off, at the building scale. It will take multiple technology breakthroughs in all areas of energy conservation and renewables before the building will be an appropriate scale for supplying all of its own energy needs. On the other hand, a carbon neutral future is already achievable at the neighborhood scale. The question is: will planning, design and construction professionals seize the opportunity?

At CED we are striving to provide the educational foundation for our students which will prepare them to seize a leadership role in this effort. UC Berkeley tops a short list of institutions with the unique combination of breadth and depth needed to develop innovative design solutions and approaches to public policy. It requires not only the collaboration of multiple faculty in our three disciplines, but also reaching across campus to civil engineering, the energy and resources group and anthropology, listed below. CED is the only school in the country where this new paradigm has a chance of being realized and is exemplified by:

  • Elizabeth Deakin and Robert Cervario’s work in transit-oriented development and the making of walkable and bikeable cities with Michael Southworth
  • Tim Duane and Randy Hester’s work to reconcile competing demands on the ecosystem on the island of Hawaii
  • Judith Stilgenbauer’s work on green infrastrutures — the multi-functional and productive features of landscape
  • Galen Cranz’s examination of the social and cultural bases of a sustainable lifestyle
  • Our building science faculty – Cris Benton, Gail Brager, Ed Arens, and Susan Ubbelohde — work on energy conservation, daylighting, lighting controls, interfloor mechanized systems, dual mode buildings and user response to environmental quality
  • Our collaboration with The Berkeley Institute of the Environment (BIE) and Energy Resources Group (ERG) faculty – Inez Fung, Dan Kammen, — on renewable energy systems, solar, wind, and biomass
  • Anthropology Ph.D. student Shannon May’s work on the post occupancy evaluation of China’s fact eco-village

The greatest challenge is developing the institutional structure and pedagogy to create an effective framework for this interdisciplinary collaboration to flourish. The impact that the built environment has on our planet’s future has never been more critical to our survival and presents us with our greatest opportunity for change.