WELL Building Standard (WELL) is a healthy building certification program, developed by the International WELL Building Institute PCB (IWBI), a California registered public benefit corporation.
History The WELL Building Standard was launched in 2014 by Paul Scialla of Delos company, becoming the first well-being focused standard. By 2016, over 200 projects in 21 countries adopted the certification. In 2014, Green Business Certification Inc. began to provide third-party certification for WELL. By 2024, WELL says that it is being used across more than 5 billion square feet of space in 130 countries, supporting an estimated 25 million occupants in nearly 74,000 commercial and residential locations.
Performance Scientific research provides information about the standard's performance. Existing research focuses on the evaluation of indoor environmental quality (IEQ) parameters. The certification requires post-occupancy evaluation, which allows occupants to provide feedback to building owners and management on these IEQ parameters. For buildings with 10 or more occupants, the Occupant Indoor Environmental Quality (IEQ) Survey from the Center for the Built Environment at UC Berkeley (or an approved alternative) is completed by a representative sample of at least 30% of occupants at least once per year. The survey covers the following topics: acoustics, thermal comfort, furnishings, workspace light levels and quality, odors and air quality, cleanliness and maintenance, and layout.
In 2020, researchers analyzed 1,121 post-occupancy evaluation surveys conducted in nine offices, two WELL-certified and seven not WELL-certified. Results of the study were mixed, with higher occupant satisfaction in the WELL-certified buildings for spatial comfort, thermal comfort, noise and privacy, personal control, and workspace comfort, but lower satisfaction for visual comfort and connection to the outside in comparison with non-WELL certified buildings. These findings may be attributable to the types of non-WELL certified buildings used in the comparison, as they may already be high-performance buildings in other regards which do not necessarily satisfy all of the WELL certification's criteria.
In 2021, another study on surveys compared the results of three rounds of occupant IEQ satisfaction surveys reported by three groups of employees who moved from three non-WELL (two BREEAM and one non-certified) to three WELL-certified office buildings. For two out of the three building pairs, there was a statistically significant increase in building and workspace satisfaction after relocation to WELL buildings. However, for 55% of certification parameters for the three compared cases, there was an insignificant difference upon relocation. Results found higher occupant satisfaction for building cleanliness and furniture but no increase in satisfaction with noise and visual comfort.
Another 2021 study investigated indoor air quality (IAQ) before and after relocation to WELL-certified office buildings. The results indicated there was no significant concentration difference for the majority of measured air pollutants between non-WELL and WELL buildings.
In 2022, researchers conducted a pre- versus post-occupancy evaluation of approximately 1,300 workers transitioning to WELL-certified offices from non-WELL certified offices. Using pre- and post-occupancy surveys, overall satisfaction rates improved from 42% (pre-occupancy) to 70% (post-occupancy) across all parameters. The largest increases in satisfaction were for cleanliness and access to nature, while occupants were most satisfied with maintenance and lighting in WELL-certified offices.
In 2023, researchers analyzed 1,403 post-occupancy evaluation surveys from 14 open-plan offices (10 of which were WELL-certified and four of which were uncertified) in Australia, New Zealand, and Hong Kong. The five offices that achieved the highest satisfaction in interior design, indoor air quality, privacy and connection to the outdoor environment were WELL-certified. No significant differences in health were found between WELL-certified and non-WELL certified buildings as quantified by questions about physical and mental health presented in the post-occupancy evaluation surveys.
In 2024, researchers used a statistical matching approach to compare occupant satisfaction from 3,268 surveys from 20 WELL-certified and 49 LEED-certified buildings. Overall building and workplace satisfaction was found to be high in WELL-certified buildings (94% and 87%). Statistical analysis revealed that there is a 39% higher probability of finding an occupant that is satisfied with the building overall in a WELL-certified building than a LEED-certified building. Although satisfaction was found to be higher in WELL-certified buildings, satisfaction in LEED-certified buildings with the building, workspace, and most IEQ parameters was still relatively high. Temperature and sound privacy in LEED-certified buildings are the only parameters with mean satisfaction values less than "neutral" amongst all studied parameters in LEED- and WELL-certified buildings.
Principles & concepts
WELL v2 met best practices on four tenets: evidence-based, verifiable, implementable, and feedback-focused. The principles in WELL v2 are equitable, global, evidence-based, technically robust, customer-focused, and resilient. WELL is a performance-based system which Performance Verification is completed by an authorized WELL Performance Testing Agent.
Certification
There are two types of certifications, the WELL Certification for Owner-occupied and the WELL Core Certification. The WELL Core is for the building that provide tenant occupation more than 75%, and not needed to achieve minimum points from every subjects.
The WELL Silver, Gold, and Platinum level must achieve at least 1, 2, and 3 points per subject, but the WELL Bronze has no minimum points' rule. For WELL core, there are no minimum point.
The optimization point requirement from the WELL Bronze, Silver, Gold, and Platinum are ranging from 40, 50, 60, and 80 points. The rating system limits 12 points per subject, except the Innovation which limit under 10 points. Total points must not be over 100.
Assessment
The WELL certificated buildings must pass all precondition requirements and they could get optimization points available from extension subjects. Assessment Area Preconditions Optimization Points Air indoor air quality, smoke-free environment, adequate ventilation design, construction pollution management 18 Water water quality indicator, drinking water quality, water quality monitoring and legionella management 14 Nourishment availability and visibility of fruit and vegetable 16 Light light exposure by daylight or circadian lighting, provide visual comfort and enhance visual acuity 18 Movement facilitate exercise, ergonomic design workstation 21 Thermal Comfort acceptable thermal environment 16 Sound acoustic design plan and label of acoustic zones 18 Material restriction, management and addressing of hazardous material such as Chromated copper arsenate, asbestos, mercury, polychlorinated biphenyl and lead 18 Mind provide mental health support, integrate local nature art and culture 19 Community communication of WELL feature to users, integrative design by stakeholders, emergency management, occupant surveys 43 Innovation - 28 Total Points 229
Air
Because users spend 90% time in interior, they can expose to indoor air pollutions that lead to headaches, dry throat, eye irritation, runny nose, asthma attacks, infection with legionella bacteria and carbon monoxide poisoning. It leads to thousands of cancer death and 100,000 of respiratory issues annually. Avoidable costs in the U.S. could be over 100 billion dollars annually 45% from radon and tobacco and 45% from lost productivity, and 10% respiratory diseases. Combustion sources such as candles, tobacco, stoves, furnaces, fireplaces producing carbon monoxide, nitrogen dioxide, and small particles are common. Furnishings, fabrics, cleaning product emit volatile organic compound (VOCs). It could be resolved by eliminate problem sources and design solutions. Air pollution leads to 7 millions premature deaths, around 600,000 of those were children under 5 years old in 2012.
A01-A04 Precondition A01 Air Quality topic, the WELL conducts to limit level of particulate matter both PM2.5 and PM10 under 15 and 50 for normal region or 25 and 50 microgram/cubic metre or 30% of 24–48 hours average of outdoor levels for polluted region and thresholds for volatile organic compound (VOC) such as benzene, formaldehyde, toluene to 10, 50, and 300 microgram/cubic metre or total VOC of 500 microgram/cubic metre. Inorganic gases such as carbon monoxide and ozone are also limited to 10 milligram per cubic metre and 100 microgram/cubic metre. Radon is limited under 0.15 Becquerel/Litre. WELL makes sure that all air quality shall be monitored with a digital platform, except for radon parameter.
A02 Smoke-free Environment topic, smoking and using of electronic cigarette indoor is not allowed, except for outdoors at only ground level further than 7.5 m from project apertures including air-intake area.
A03 Ventilation Design topic, the WELL assured building to have existing or new mechanical ventilation systems following ASHRAE 62.1-2 or EN standard 16798-1 or AS 1668.2 or CIBSE Guide A: Environmental Design. Naturally ventilation can also be used without mechanical ventilation system if the design follows Natural Ventilation Procedure in ASHRAE 62.1, CIBSE AM10, AS 1668.4 at least 90% of the project area. Ventilation monitoring can be only solution if carbon dioxide level is met under 900 ppm indoor and 500 ppm outdoor.
A04 Construction Pollution Management topic, the contractor is to ensure that ducts are cleaned and protected from contamination. Contractor shall filter with more than 70% efficiency for particles 3-10 micrometers on the installed ventilation system during construction. Contractor must implement dust and moisture management such as using of temporary barriers, dust guards for saws, walk-off mats on entryway.
A05 - A14 Optimization A05 Enhanced Air Quality topic, enhancing threshold of particulate matter both PM2.5 and PM10 under 12 and 30 for 1 point, 10 and 20 for 2 points. Enhancing volatile organic compound such as benzene, formaldehyde, toluene under 3, 9, 300 microgram/cubic metre and additional acetaldehyde, acrylonitrile, caprolactam, naphthalene under 140, 5, 2.2, 9 microgram/cubic metre would receive 1 point. Inorganic gases such as carbon monoxide and nitrogen dioxide under 7 milligram per cubic metre and 40 microgram per cubic metre receives additional 1 point.
A06 Enhanced Ventilation Design topic threshold of mechanical and natural ventilation or with demand controlled ventilation (DCV) or engineered natural ventilation system to keep CO2 levels low, or at least 50% of workstations are supplied in the breathing zone with an airspeed under 50 fpm at user's head receives 2 points. Displacement ventilation system implement or air diffusers located 2.8 m above the floor receives additional 1 points.
A07 Operable Windows, providing openable windows to access to outdoor air, available to access outdoor air by 75% of regularly occupied areas or 4% of the occupied areas of there are many floors receives 1 point, another 1 point, if there is outdoor air quality for PM2.5, temperature, relative humidity display near windows.
A08 Air quality monitoring and Awareness topic, installing air quality sensor and submitting data to WELL provides 1 point and display screens available in the building to promote awareness provides another 1 point.