Leadership in Energy and Environmental Design

Abad Nucleus Mall, at Maradu, Kochi, is India's first LEED certified gold-rated green mall.

After four years of development, aligning credit across all LEED rating systems and weighing credits based on environmental priority, USGBC launched LEED v3,[19] which consists of a new continuous development process, a new version of LEED Online, a revised third-party certification program and a new suite of rating systems known as LEED 2009. Under LEED 2009, there are 100 possible base points distributed across six credit categories: "Sustainable Sites", "Water Efficiency", "Energy and Atmosphere", "Materials and Resources", "Indoor Environmental Quality", and "Innovation in Design". Up to 10 additional points may be earned: four additional points may be received for Regional Priority Credits, and six additional points for Innovation in Design (which includes exemplary performance credits for existing credit categories).

Taipei 101, the tallest and largest LEED Platinum certified building in the world since 2011.

Buildings can qualify for four levels of certification:

• Certified: 40-49 points
• Silver: 50-59 points
• Gold: 60-79 points
• Platinum: 80 points and above

The LEED 2009 performance credit system aims to allocate points "based on the potential environmental impacts and human benefits of each credit." These are weighed using the environmental impact categories of the United States Environmental Protection Agency's Tools for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI).[20] and the environmental-impact weighting scheme developed by the National Institute of Standards and Technology (NIST).

To participate in LEED 2009, a building must comply with environmental laws and regulations, occupancy scenarios, building permanence and pre-rating completion, site boundaries and area-to-site ratios. Its owner must share data on the building's energy and water use for five years after occupancy (for new construction) or date of certification (for existing buildings).[21]

Each of the performance categories also have mandatory measures in each category, which receive no points.

The weighting process has three steps:[22]

1. A collection of reference buildings are used to estimate the environmental impacts of any building seeking LEED certification in a designated rating scheme.
2. NIST weightings are used to judge the relative importance of these impacts in each category.
3. Data regarding actual impacts on environmental and human health are used to assign points to individual categories and measures.

This system results in a weighted average for each rating scheme based upon actual impacts and the relative importance of those impacts to human health and environmental quality.

The LEED council also appears to have assigned credit and measure weighting based upon the market implications of point allocation.[22]

From 2010, buildings can use carbon offsets to achieve Green Power Credits for LEED-NC (New Construction Certification) :[23]

Additional performance categories in the LEED for Homes rating system are Locations and Linkages (recognizing the importance of transportation access, open space, and physical activity outdoors) and Awareness and Education (recognizing the need for buildings and settlements to educate occupants). These Guidelines were also adopted by the DOE Net Zero Energy Homes Project JD Polk Brought to the DOE. R&D lead by EPHOT inc.[24]

For LEED BD+C v4 credit, the IEQ category addresses thermal, visual, and acoustic comfort as well as indoor air quality. The thermal comfort credit applies one point to the following certification types: New Construction, Schools, Retail, Data Centers, Warehouses and Distribution Centers, Hospitality, and Healthcare. The intent of this credit is to "promote occupants' productivity, comfort, and well-being by providing thermal comfort."[25] Occupants' satisfaction and performance is directly affected by a building's thermal conditions as shown by laboratory and field research.[26] Energy reduction goals can be supported while improving thermal satisfaction. For example, research has shown providing occupants control over the thermostat or operable window allows for comfort across a wider range of temperatures.[27][28]

In 2003, the Canada Green Building Council received permission to create LEED Canada-NC v1.0, which was based upon LEED-NC 2.0.[29][30] Many buildings in Canada are LEED certified in part due to their Rainwater harvesting practices.

LEED certification is granted by the Green Building Certification Institute (GBCI), which handles the third-party verification of a project's compliance with the LEED requirements.

The certification process for design teams is made up of two consecutive applications: one including design credits, and one including construction credits. All of the LEED credits in each rating system are assigned to either the design application or the construction application. The design credits include those that are the purview of the architect and the engineer, and are documented in the official construction drawings. The construction credits include those that are predominantly under the purview of the contractor, and are documented during the construction and commissioning of the building.

A fee is required to register the building, and to submit the design and construction applications. Total fees are assessed based on building area. Fees range from a minimum of $2,900 to over $1 million for a large project.[31] "Soft" costs, i.e., added costs to the building project to qualify for LEED certification, range from 1% to 6% of the total project cost. The average cost increase was about 2%, or an extra $3–$5 per square foot.[32]

The application review and certification process is handled on LEED Online, USGBC's web-based service that employs a series of active PDF forms to allow project teams to fill out credit forms and upload supporting documentation online. The GBCI also utilizes LEED Online to conduct their reviews.

Design teams have the option of achieving points under the Optimize Energy Performance credit by building an energy model. This energy model must follow the modeling methodologies outlined in Appendix G of the ASHRAE 90.1 building energy standard. The guidelines in Appendix G require that the team make two energy models: one representing the building as designed, and a second “baseline” building. The baseline building must be modeled in the same location, and have the same geometry and occupancy as the design building. Depending on location (climate) and building size, the standard provides requirements for HVAC system type, and wall and window definitions. The goal of this methodology is to provide a baseline building to use as a reference point to compare the design building against. It is a way to standardize the baseline, while putting weight on important factors that heavily influence building energy consumption (e.g., location, geometry, and occupancy patterns). The number of points achieved in this credit is correlated with the percent predicted energy cost savings demonstrated by the difference between the design and baseline energy models.

This method of energy modeling has been criticized for inaccurately predicting actual energy usage of LEED-certified buildings. The USGBC admits that "current information indicates that most buildings do not perform as well as design metrics indicate. As a result, building owners might not obtain the benefits promised."[33]

Today, increasing demand towards environmental safety forces LEED certification to play major role. The process of the LEED for Homes Rating System, available in the United States,[34] Canada and Sweden,[35] is significantly different from the LEED NC rating system. LEED for Homes projects are low rise residential and are required to work with either an American Provider Organization[36] or a Canadian Provider Organization[37] and a Green Rater. A Provider Organization helps the project through the process while overseeing the Green Raters. Green Raters are individuals that conduct the two mandatory LEED for Homes site inspections; the Thermal Bypass Inspection and the Final Inspection. Although LEED for Homes is typically viewed by the construction industry as a simpler rating system, especially when compared to LEED NC, LEED NC does not require an on-site inspection. The Provider and the Green Rater do not certify the project, but rather assist in the certification process.

In 2009 Newsham et al. analyzed a database of 100 LEED certified (v3 or earlier version) buildings.[41] In this study, each building was paired with a conventional "twin" building within the Commercial Building Energy Consumption Survey (CBECS) database according to building type and occupancy.[41] On average, LEED buildings consumed 18 to 39% less energy per floor area than their conventional "twin" buildings, although 28 to 35% of LEED-certified buildings used more energy than their "twin.”[41] The paper found no correlation between the number of energy points achieved or LEED certification level and measured building performance.[41]

The Empire State Building in New York City is one of the tallest and most well-known LEED-certified buildings, certified as an existing building[42]

In 2009 Scofield published an article in response to Newsham et al., analyzing the same database of LEED buildings and arriving at different conclusions.[43] In his analysis, Scofield criticized that Newsham et al.'s study only considered the energy per floor area instead of a total energy consumption. Scofield considered source energy[44] (accounting for energy losses during generation and transmission) as well as site energy, and used area-weighted energy use intensities, or EUIs (energy per unit area per year), when comparing LEED and non-LEED buildings to account for the fact that larger buildings tend to have larger EUIs.[43] Scofield concluded that, collectively, the LEED-certified buildings showed no significant source energy consumption savings or greenhouse gas emission reductions when compared to non-LEED buildings, although they did consume 10-17% less site energy.[43]

Scofield in 2013 analyzed 21 LEED-certified buildings in New York City.[38] He found that buildings that had achieved LEED Gold used, on average, 20% less source energy than did conventional buildings. Buildings with LEED Silver or LEED Certified ratings actually used 11 to 15% more source energy, on average, than did their conventional counterparts.[38]

In 2014, Fuertes and Schiavon[45] developed the first study that analyzes plug loads using LEED documented data from certified projects. The study compared plug load assumptions made by 92 energy modeling practitioners against ASHRAE and Title 24 requirements, as well as the evaluation of the plug loads calculation methodology used by 660 LEED-CI[46] and 429 LEED-NC[47] certified projects. In general, energy modelers considered the energy consumption of plug loads of equipment that are constantly running (such as refrigerators) as well as monitors and computers predictable. Overall the results suggested a disconnection between energy modelers assumptions and the actual performance of buildings. In conclusion, the study suggests LEED or ASHRAE to develop guidelines for plug loads calculations.

Energy model might be a source of error during LEED design phase. Stoppel and Leite[48] evaluated the predicted and actual energy consumption of two twin buildings using the energy model during the LEED design phase and the utility meter data after one year of occupancy. The study's results suggest that mechanical systems turnover and occupancy assumptions significantly differing from predicted to actual values.

Most of the current available energy consumption analysis of LEED buildings focuses on LEED v3 (2009) or even earlier versions certified buildings instead of the newest LEED v4 (2014) certified buildings. According to Newsham et al., these analyses should be considered as preliminary and should be repeated with longer data history and larger sample buildings,[41] including new LEED v4 certified buildings. Newsham et al. also pointed out that further work needs to be done to define green building rating schemes to ensure more consistent and substantial energy consumption reduction success at the individual building level in long term.[41]

The Center for Disease Control defines Indoor Environmental Quality (IEQ) as "the quality of a building's environment in relation to the health and wellbeing of those who occupy space within it."[49] The USGBC includes the following considerations for attaining IEQ credits: indoor air quality, the level of volatile organic compounds, lighting, thermal comfort, and daylighting and views. In consideration of a building's indoor environmental quality, published studies have also included factors such as: acoustics, building cleanliness and maintenance, colors and textures, workstation size, ceiling height, window access and shading, surface finishes, furniture adaptability and comfort.[39][40]

In 2013, a paper published by S. Schiavon and S. Altamonte studied LEED verses non-LEED buildings in relation to occupant IEQ satisfaction.[39] Using occupant surveys from the Center for the Built Environment[50] at Berkeley database,[51] 65 LEED-certified and 79 non-LEED buildings were studied to provide an analysis of 15 IEQ-related factors in the overall building and specific workspaces. These factors include the ease of interaction, building cleanliness, the comfort of furnishing, the amount of light, building maintenance, colors and textures, workplace cleanliness, the amount of space, furniture adjustability, visual comfort, air quality, visual privacy, noise, temperature, and sound privacy. The results showed occupants tend to be slightly more satisfied in LEED buildings for the air quality and slightly more dissatisfied with the amount of light. The overall finding was that there was no significant influence of LEED certification on occupant satisfaction in consideration of the overall building and workspace ratings.[39] The "Limitations and Further Studies" section states that the data may not be representative of the entire building stock and a randomized approach was not used in the data assessment.

Based on similar dataset (21,477 occupants), in 2013, Schiavon and Altomonte,[52] found that occupants have equivalent satisfaction levels in LEED and non-LEED buildings when evaluated independently from the following nine factors: (1) office type, (2) spatial layout, (3) distance from windows, (4) building size, (5) gender, (6) age, (7) type of work, (8) time at workspace, and (9) weekly working hours. LEED certified buildings may provide higher satisfaction in open spaces than in enclosed offices, in smaller buildings than in larger buildings, and to occupants having spent less than one year in their workspaces rather than to those who have used their workspace longer. The study also points out that the positive value of LEED certification from the aspect of occupant satisfaction may tend to decrease with time.

In 2015, a study on indoor environmental quality and the potential health benefits of green certified buildings was developed by Allen et al.[53] showing that green buildings provide better indoor environmental quality with direct benefits to human health of occupants of those buildings in comparison to non-green buildings. One of the limitations of the study was the use of subjective health performance indicators since there is a lack of definition on such indicators by current studies.

G. Newsham et al. published a detailed study on IEQ and LEED buildings in August 2013.[40] Field studies and Post-Occupancy Evaluations (POE) were performed in 12 “green” and 12 “conventional” buildings across Canada and the northern United States. On-site, 974 workstations were measured for thermal conditions, air quality, acoustics, lighting, workstation size, ceiling height, window access and shading, and surface finishes. Responses were positive in the areas of environmental satisfaction, satisfaction with thermal conditions, satisfaction with view from the outside, aesthetic appearance, reduced disturbance from heating, ventilation and air-conditioning noise, workplace image, night-time sleep quality, mood, physical symptoms, and reduced number of airborne particulates. The results showed green buildings exhibited superior performance compared with similar conventional buildings.[40]

Current latest study published in 2017, by Altomonte, Schiavon, Kent and Brager, specifically investigated whether a green rating leads to higher occupant satisfaction with IEQ.[54] Based on the analysis of a subset of the CBE Occupant IEQ including 11,243 responses from 93 LEED-certified office buildings, this study found that the achievement of a specific IEQ credit did not substantially increase the satisfaction with the corresponding IEQ factor. In addition, the rating level and version of the certification has no impact on workplace satisfaction. There are some possible explanations. Many intervening factors in the time between design and occupancy can alter the existence or performance of the strategies that LEED awarded. IEQ certification metrics also face the challenges from substantial differences that characterize the modern workplace in terms of spatial needs, task requirements, users’ characteristics, and disciplines of product design and marketing, etc. Survey participants may also misinterpret the satisfaction with an IEQ parameter, or bias with personal attitudes.[54]

The daylight credit was updated in LEED v4 to include a simulation option for daylight analysis that uses Spatial Daylight Autonomy (SDA) and Annual Sunlight Exposure (ASE) metrics to evaluate daylight quality in LEED projects. SDA is a metric that measures the annual sufficiency of daylight levels in interior spaces and ASE describes the potential for visual discomfort by direct sunlight and glare. These metrics are approved by IES and described at the LM-83-12 standard.[55] LEED recommend a minimum of 300 lux for at least 50% of total occupied hours of the year for 55% or more square meters (square feet) of the floor occupied area. The threshold recommended by LEED for ASE is that no more than 10% of regularly occupied floor area can be exposed to more than 1000 lux of direct sunlight for more than 250 hours per year. Additionally, LEED requires window shades to be closed when more than 2% of a space is subject to direct sunlight above 1000 lux. According to Reinhart[56] the direct sunlight requirement is a very stringent approach that can disable good daylight design from achieving this credit. Reinhart propose the application of the direct sunlight criterion only in spaces that require stringent control of sunlight (e.g. desks, white boards, etc.)

Innovation generally needs to come with the idea of new designs and high-quality construction technology for LEED architecture. When we mention about the cultural heritage buildings, innovation made a big change in them by using the nanoparticle technology for consolidation and also conservation effects.[57] Inheritance from the past experiences could be sufficient also for the high tech building design, regarding LEED architecture.

For cultural heritage buildings, the consolidation and conservation innovations began with the idea of using calcium hydroxide nano-particles for the porous media structures. By this way, the strength and mechanical strength improvement could able to get managed. Also, some other innovation studies could be possible by using titanium, silica, and aluminum-based compounds.[58] For the LEED architecture buildings, when the issue is innovation, the material technology and the construction techniques could be also the first issues to consider on. For the facade of the high rise buildings, such as the Empire State Building in the United States, the surface area give the opportunity to make it possible to design innovation.[59] Empire State that has been completed in April 2013, is one of the well-known and highly reputed skyscrapers of the United States. In New York, there are also 5 other high rise green buildings; Bank of America Building (One Bryant Park), Hearst Building, One World Trade Center, The New York Times Building and Condé Nast Building.[60] VOC compounds and the risk of the volatile chemical evaporation from the construction materials through to the air is another challenge to deal with.[61]

In Milan/ITALY, sustainable energy and LEED standards high rise buildings also the main issue for so well-qualified companies and university studies.[62] On the point of the high rise skyscraper design, such as with the same idea of all the possible glass facade buildings, there is a great opportunity to consider for the innovative use of glass facade systems in terms of gaining energy from the solar technology. Also to create the "luminescent discovery" for solar concentrators as the innovation by using nanoparticle technology has been released.[63] Anyway, photovoltaics technology in combination with the chemistry and nanotechnology could be the main idea of the innovation in each cases, in terms of solar energy, for energy star and LEED architecture buildings.[64]

LEED Gold awarded project in Istanbul/Turkey - Manzara Adalar, Kartal/ISTANBUL - a great innovation for the LEED architecture and the skyscraper technology.[65] Before this project, Kartal region of the Asian side of the Istanbul has been known with the middle-class housing construction systems and the industrial area of Istanbul. The general architecture in Kartal seaside part was 3-4 storey housing systems and actually the most important role was the contribution to the Turkish industry with the factories that have been established in the last 35-50 years time. After the architectural competition of Kartal Urban Transformation Project, the public view of the Kartal region has been changed. Architect Zaha Hadid has won the competition with an extereme design of totally high rise buildings.[66] This new concept of Kartal, has been the starting point of the innovations and design for the high quality building systems in this old industrial transformation region. Today, Kartal has been gained a complete innovation with the LEED Gold project of "Manzara Adalar". Some other projects that has been awarded with the LEED certificate in Turkey are, Antakya: Palladium Antakya Shopping Center - LEED Gold awarded, Istanbul: Ronesans Tower- LEED Platinum Awarded, Konya: Konya Science and Innovation Center, LEED Gold Awarded, Istanbul (Maslak): Spine Tower, LEED Gold Awarded, Istanbul: Torun Tower, LEED Gold Awarded.[67]

Extreme structures that have been awarded with the LEED certificates are: "Amorepacific Headquarters in Seoul" by David Chipperfield Architects,[68] "Project: Brave New World: SFMOMA by Snøhetta" by Snøhetta in San Francisco, CA,[69] "Project: UFO in a Sequinned Dress: Centro Botín in Santander" by Renzo Piano Building Workshop in Zusammenarbeit mit Luis Vidal + Architects, in Santander (ES),[70] "Project: Vertical factory: Office building in London" by Allford Hall Monaghan Morris in London.[71]

A 2003 analysis of the savings from green building found from a review of 60 LEED buildings that the buildings were, on average, 25-30% more energy efficient. However, it also attributed substantial benefits to the increased productivity from the better ventilation, temperature control, lighting control, and reduced indoor air pollution.[72]

As of 2008, LEED (and similar Energy Star) buildings had mostly been evaluated by case studies. From a purely financial perspective, in 2008 several studies found that LEED for-rent office spaces generally charged higher rent and had higher occupancy rates. CoStar Group collects data on properties. The extra cost for the minimum benefit has been estimated at 3%, with an additional 2.5% for silver.[73] More recent studies have confirmed these earlier findings in that certified buildings achieve significantly higher rents, sale prices and occupancy rates as well as lower capitalization rates potentially reflecting lower investment risk.[74][75][76]

LEED focuses on the design of the building and not on its actual energy consumption, and therefore it has suggested that LEED buildings should be tracked to discover whether the potential energy savings from the design are being used in practice.[77]

The U.S. Green Building Council provides an online directory of U.S. LEED-certified projects.[11]

The Canada Green Building Council provides an online directory[78] of LEED Canada-certified projects.

In 2012 the USGBC launched GBIG, the Green Building Information Gateway,[79] in an effort to connect green building efforts and projects from all over the world. It provides searchable access to a database of activities, buildings, places and collections of green building-related information from many sources and programs, as well as, specifically provides information about LEED projects.