LEED is a design tool and as such has focused on energy modeling, rather than being a performance-measurement tool that measures actual energy consumption. Research papers provide most of what is known about the performance and effectiveness of LEED models and buildings. Much of the available research predates 2014, and therefore applies to buildings that were designed under early versions of the LEED rating and certification systems, LEED v3 (2009) or earlier. Research papers have tended to address performance and effectiveness of LEED in two credit category areas: energy Many early analyses should be considered as at best preliminary. Studies should be repeated with longer data history and larger building samples, include newer LEED certified buildings, and clearly identify green-building rating schemes and certification levels of individual buildings. Buildings may also need to be grouped according to location, since local conditions and regulation may influence building design and confound assessment results.
Energy performance research (EA) Because LEED focuses on the design of the building and not on its actual energy consumption, it has been suggested that LEED buildings should be tracked to discover whether the potential energy savings from the design are being used in practice. In 2009, architectural scientist Guy Newsham (et al.) of the
National Research Council of Canada (NRC) re-analyzed a dataset of 100 LEED certified (v3 or earlier version) buildings. The data included only "medium use" buildings, and did not include 21 laboratories, data centers and supermarkets which were expected to have higher energy activity. Researchers further attempted to match each building with a conventional building within the Commercial Building Energy Consumption Survey (CBECS) database according to building type and occupancy. Scofield criticized the earlier analysis for focusing on energy per floor area instead of a total energy consumption. Scofield considered source energy (accounting for energy losses during generation and transmission) as well as
site energy, and used area-weighted energy use intensities (EUIs) (energy per unit area per year), when comparing buildings to account for the fact that larger buildings tend to have larger EUIs. Results differed with certification level. LEED-Gold buildings were found to use 20% less source energy than conventional buildings. However, buildings at the Silver and Certified levels used 11 to 15% more source energy, on average, than conventional buildings. (Data was not available for Platinum-level buildings.) In 2014, architect Gwen Fuertes and engineer
Stefano Schiavon 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, and the evaluation of the plug load calculation methodology used by 660 LEED-CI and 429 LEED-NC certified projects. They found that energy modelers only considered the energy consumption of predictable plug loads, such as refrigerators, computers and monitors. Overall the results suggested a disconnection between assumptions in the models and the actual performance of buildings. In a 2019 review, Amiri et al. suggest that judging energy efficiency based on source energy may not be appropriate where the availability of energy types depends on city council or government policies. If some types of source energy are not supported locally, there is no opportunity to choose the types of energy promoted by the LEED scoring system. Amiri emphasizes that many studies have weaknesses due to the lack of randomly selected samples of LEED buildings, and the difficulty of selecting comparison groups of non-LEED buildings. Amiri also notes that the standards for building design have changed significantly over time. For example, newer non-LEED buildings may routinely use features such as high-quality windows which were rarely used in older buildings. Comparisons of LEED and non-LEED buildings therefore need to consider age as well as size, use, occupant behavior, and location aspects such as climate zone. Interest in
Post‐occupancy evaluation (POE), the process of evaluating building performance after occupation, is increasing. This is due in part to concerns about differences between energy models in the design phase and actual use of buildings. POE research emphasizes the need to collect and analyze actual occupancy data from existing buildings, to better understand how people are using spaces and resources. Asensio and Delmas (2017) carefully matched and compared buildings that did and did not participate in LEED, Energy Star, and Better Buildings Challenge programs in Los Angeles, California. They examined data for monthly energy consumption between 2005–2012, for more than 175,000 commercial buildings. Buildings from all three programs displayed "high magnitude" energy savings, ranging from 18–19% for Better Buildings and Energy Star to 30% for LEED-rated buildings. The three programs saved 210 million kilowatt-hours, equal to 145 kilotons of CO2 equivalent emissions per year.
IEQ performance research (IEQ) The
Centers for Disease Control and Prevention (CDC) 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." The USGBC includes the following considerations for attaining IEQ credits:
indoor air quality, the level of
volatile organic compounds (VOC), 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. The most widely used method for post-occupancy evaluation (POE) in IEQ-related studies is occupant surveys. to study IEQ occupant satisfaction in 65 LEED buildings and 79 non-LEED buildings. They analyzed 15 IEQ-related factors including 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. Occupants reported being slightly more satisfied in LEED buildings for the air quality and slightly more dissatisfied with the amount of light. Overall, occupants of both LEED and non-LEED buildings had equal satisfaction with the building overall and with the workspace. found that occupants have equivalent satisfaction levels in LEED and non-LEED buildings when evaluated independently from the following factors: office type, spatial layout, distance from windows, building size, gender, age, type of work, time at workspace, and 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. This study suggests that the positive value of LEED certification as measured by occupant satisfaction may decrease with time. reviewed studies of indoor environmental quality and the potential health benefits of green-certified buildings. He concluded that green buildings provide better indoor environmental quality with direct benefits to the human health of occupants, compared to non-green buildings. Statistically significant measures from different studies included decreased symptoms of sick building syndrome, decreased sick days, decreased respiratory symptoms during the daytime and asthma symptoms at night, and lowered levels of PM2.5, NO2, and nicotine. However, Allen noted that the frequent use of subjective health performance indicators was a limitations of many of the studies reviewed. He proposed a framework to encourage the use of direct, objective, and leading "Health Performance Indicators" in building assessment. In 2024, Kent et al. compared satisfaction of people in buildings that had received either
WELL certification or LEED certification. Ratings of buildings certified with WELL and LEED were matched on six dimensions: award level, years in building, time in workspace, type of workspace, proximity to a window, and floor height. Satisfaction with the overall building and one's workspace were high under both rating systems. However, satisfaction with LEED‑certified buildings (73% and 71%) tended to be lower than that for WELL‑certified buildings (94% and 87%). This may be because WELL is a human-centered standard for building design that focuses primarily on comfort, health, and well-being. In contrast, only 10% of the credits in LEED certification relate to indoor environmental quality (IEQ). Differences may also reflect age of buildings, which were not matched for in the design.
Water Efficiency (WE) Water systems involve both water and energy as resources. Outside buildings, the acquisition, treatment, and transportation of water is involved. Inside building, onsite water treatment, heating, and wastewater treatment are issues. Data on the energy use of specific water and wastewater systems is becoming increasingly available. Energy use can sometimes be estimated from public sources. LEED v4 includes a number of credits related to Water Efficiency (WE). Points are awarded for Outdoor Water Use Reduction, Indoor Water Use Reduction and Building-level Water Metering based on predetermined percentage reductions in water or energy use. There has been criticism that the LEED rating system is not sensitive and does not vary enough with regard to local environmental conditions. For example, there are 16 climate zones in
California, with unique weather and temperature patterns. The availability of electricity, water and other resources differs widely in different regions, making it important to consider interconnected systems and supply chain issues. Greer et al. (2019) reviewed renewable energy assessment methods and examined the effectiveness of LEED v4 buildings in California. They examined relationships between the climate mitigation points given for water efficiency (WE) and energy efficiency (EA) and used baseline energy and water budgets to calculate the avoided
GHG emissions of buildings. Their calculations both demonstrate mitigation of expected climate change and also indicate high variability in environmental outcomes within the state.
Innovation in design research (ID) The rise in LEED certification also brought forth a new era of construction and building research and ideation. Architects and designers have begun stressing the importance of occupancy health over high efficiency within new construction and have been trying to engage in more conversations with health professionals. Along with this, they also create buildings to perform better and analyze performance data to upkeep the process. Another way LEED has affected research is that designers and architects focus on creating spaces that are modular and flexible to ensure a longer lifespan while simultaneously sourcing products that are resilient through consistent use. Innovation in LEED architecture is linked with new designs and high-quality construction. One example is use of
nanoparticle technology for consolidation and conservation effects in
cultural heritage buildings. This practice began with the use of
calcium hydroxide nano-particles in
porous structures to improve
mechanical strength. Titanium, silica, and aluminum-based compounds may also be used. Material technology and construction techniques could be among first issues to consider in building design. For the facade of
high-rise buildings, such as the
Empire State Building, the surface area provides opportunities for design innovation. VOC released from construction materials into the air is another challenge to address. In
Milan, a university-corporate partnership sought to produce semi-transparent solar panels to take the place of ordinary windows in glass-facade high-rise buildings. Similar concepts are under development elsewhere, with considerable market potential. The Manzara Adalar skyscraper project in
Istanbul, designed by
Zaha Hadid, saw considerable innovation through the use of communal rooms, outdoor spaces, and natural lighting as part of the Urban Transformation Project of the Kartal port region.
Sustainable Sites (SS) Remaining credit areas Other credit areas include: Materials and Resources (MR), and Regional Priority (RP). Proponents argue that these higher initial costs can be mitigated by the savings incurred over time due to projected lower-than-industry-standard operational costs typical of a LEED certified building. This
life cycle costing is a method for assessing the total cost of ownership, taking into account all costs of acquiring, owning and operating, and the eventual disposal of a building. Additional economic payback may come in the form of employee productivity gains incurred as a result of working in a healthier environment. Studies suggest that an initial up-front investment of 2% extra yields over ten times that initial investment over the life cycle of the building. developers have begun to use LEED certification and a building's green status as selling points. LEED has been developed and continuously modified by workers in the green building industry, especially in the ten largest metro areas in the U.S.; however, LEED certified buildings have been slower to penetrate small and middle markets. From a financial perspective, studies from 2008 and 2009 found that LEED for-rent office spaces generally charged higher rent and had higher occupancy rates. Analysis of
CoStar Group property data estimated the extra cost for the minimum benefit at 3%, with an additional 2.5% for silver-certified buildings. More recent studies have confirmed earlier findings that certified buildings achieve significantly higher rents, sale prices and occupancy rates as well as lower capitalization rates, potentially reflecting lower investment risk. ==Incentive programs==