Starting last year, the U.S. Green Building Council (USGBC) began rolling out v5 of the Leadership in Energy and Environmental Design (LEED) Certification. Compared to LEED v4.1, LEED v5 places a stronger emphasis on a number of green and healthy building initiatives, most notably indoor air quality (IAQ).
However, LEED v5 is still a work in progress, and will likely change in the coming months before its full release in early 2025. This article was last updated on October 16, 2024, based on the requirements outlined in LEED v5 Public Comment 1.
The major difference between LEED v4.1 and LEED v5 is the higher number of points awarded for real-time, continuous monitoring of IAQ. There are more points available for this type of monitoring than periodic air testing. This is great news — instead of performing regular spot-checks, continuous monitoring offers a much easier and less time-consuming way to achieve maximum points for IAQ.
LEED v5 also offers additional points for a range of IAQ improvement strategies, including outdoor air quality monitoring, compliance with ASHRAE 241, and exceeding minimum standards for ventilation, filtration, and air quality parameters, among others.
LEED is the most globally recognized green building certification, boasting over 100,000 certified buildings worldwide. Established in 1998, the standard has increasingly emphasized indoor air quality (IAQ) over the years.
LEED has evolved through several versions since its launch in 1998. LEED v4 was introduced in 2013, and its successor, v4.1, entered Beta in 2019 but has never progressed beyond this stage. LEED v5 is set to replace it, with the Beta version launched at Greenbuild 2023.
This article focuses on a detailed comparison between the IAQ requirements in LEED v4.1 and the upgrades in the LEED v5 Beta. The analysis will be separated into two parts: Building Operations + Maintenance (O+M): Existing Buildings, and Building Design + Construction (BD+C): New Construction.
But first, let’s dive into some background on why LEED is expanding its focus on IAQ, and how v4.1 serves as a jumping-off point for v5’s IAQ requirements.
IAQ is critical for human health, comfort, performance, and productivity. Poor IAQ can lead to a range of health issues, including respiratory problems and allergies, and massively impact cognitive performance. A high-performing building should not only be environmentally sustainable but also serve and promote the health and well-being of its occupants. Learn more about the impact of IAQ on our health, productivity, and workplace experience here.
Indoor Environmental Quality (IEQ) is one of seven core categories that make up the LEED program and is intended to reward positive design choices and operation strategies that emphasize the health and comfort of building occupants.
IAQ in v4.1 is primarily addressed by the Indoor Environmental Quality Performance prerequisite. This credit requires buildings to conduct an occupant satisfaction survey and/or an indoor air quality evaluation.
This credit awards points for the annual measurement of CO2 and TVOC. These two readings are combined with the score from an annual occupant survey to output a final score. The weighting is 50% IAQ measurements and 50% survey results.
As with previous versions, LEED v5 also has an IEQ core category, within which several credits addressing air quality are found.
The intent of this new prerequisite is to understand the amount of outdoor air being delivered by the ventilation systems, exhaust, and filtration, and compare it to ventilation standards for IAQ.
For mechanically ventilated space, this is essentially a benchmarking against ASHRAE 62.1. The nuance in this credit is that ventilation data must be measured, and recommendations and potential corrective actions identified, but changes are not required. The rating of MERV filters installed must also be calculated, and usage of MERV 13 filters is recommended, but not mandated.
This is the major update, and something that should get every building operator excited.
The intent of this credit is to support indoor air quality awareness, identify opportunities for IAQ improvements, and to promote occupants’ comfort, well-being, and productivity via IAQ. The credit can deliver a project a total of 12 points, available through two different options:
Option 1 is a major update that allows continuous monitoring of IAQ to earn up to 12 credits. One-time air testing (spot checks) under an ISO-accredited laboratory is still an accepted solution but only allows for a maximum of 4 credits, instead of the 12 awarded for continuous monitoring.
Up to 10 points can be scored by continuously monitoring these parameters:
Extra points can be earned by demonstrating these parameters meet either minimum or enhanced thresholds. You can earn one point for each parameter that meets the Minimum IAQ Limit (applies to all parameters listed above), and you can earn one additional point each for meeting the enhanced thresholds for CO2, PM2.5, and NO2.
| Continuous Air Monitoring |
Meet Minimum IAQ Limit |
Enhanced IAQ Limit |
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| Parameter | Points | Threshold | Points | Threshold | Additional Point |
| CO2 | 2 | 1000 ppm | 1 | 800 ppm | 1 |
| PM2.5 | 2 | 15 μg/m3 | 1 | 12 μg/m3 | 1 |
| TVOC | 2 | n/a | 1 | n/a | n/a |
| Ozone | 1 | 0.07 ppm | 1 | n/a | n/a |
| PM10 | 1 | 50 μg/m3 | 1 | n/a | n/a |
| NO2 | 1 | 100 μg/m3 (53 ppb) | 1 | 40 μg/m3 (21 ppb) | 1 |
| Formaldehyde | 1 | 20 μg/m3 (16 ppb) | 1 | n/a | n/a |
The key takeaway here is that using a continuous air quality monitor that measures CO2, TVOC, PM2.5, and PM10 and meeting the minimum and/or enhanced thresholds for these parameters can deliver the maximum of 12 points. The new thresholds generally align with WELL v2.
Note that a RESET or UL2905-certified monitor must be used for measurement in this option.
A number of options are available to gain additional points, including meeting ASHRAE Standard 62.1 requirements for minimum ventilation rates, implementing ASHRAE 241’s Infection Risk Management Mode, providing minimum MERV 13 filtration, allowing for operable windows, and installing outdoor air quality monitors.
Each strategy awards one point toward certification, except for the ASHRAE ventilation compliance strategy, which can award up to four points for increasing ventilation by 30%.
Indoor Environmental Quality (IEQ) is one of nine core categories that make up the LEED BD+C certification. In LEED v4.1, there is one prerequisite and three credits for air quality. The prerequisite requires compliance with ASHRAE 62.1 for mechanically and naturally ventilated spaces, and the three credits provide additional points for enhanced IAQ strategies, IAQ management plans during construction, and post-construction air quality assessments.
The highest number of points can be scored with the Enhanced Indoor Air Quality Strategies credit (up to 2 points) and Indoor Air Quality Assessment credit (up to 2 points). Both credits have multiple options to score maximum points, with only 6 out of 10 enhanced IAQ strategies required for full points, and either building flush-outs or IAQ spot-checks required for maximum points for the assessment credit.
IEQ is also a core category in LEED v5 BD+C: New Construction, with one prerequisite and two credits with three possible points.
LEED v5 requires buildings to meet baseline IAQ standards both during and after construction to safeguard occupant health and well-being, with a particular focus on PM2.5 that is created by construction work. This prerequisite includes five requirements that also use ASHRAE Standard 62.1 as a benchmark.
These requirements in this prerequisite are generally preventative — creating an IAQ management plan during construction and preoccupancy phases, implementing entryway systems to collect dirt and other particulates, and ensuring ventilation and filtration systems that deliver outdoor and/or recirculated air to regularly occupied spaces comply with ASHRAE 62.1.
This credit aims to enhance IAQ to protect occupants from adverse health effects of poor air quality. There are two ways to achieve the point for this credit:
1. Exceed ASHRAE 62.1 requirements with additional outdoor air or air cleaning. This can be achieved by either increasing ventilation by at least 15% in occupied spaces (30% is ideal, but not required), or adhering to the lower limits for three key IAQ parameters: PM2.5, formaldehyde, and ozone.2. Install an automatic filter change notification system that monitors pressure changes in outdoor air and/or recirculating filters and notifies the Building Automation System (BAS) when filters need to be changed.
This credit is where continuous air quality monitoring comes into play, not only to optimize air quality management but to also find opportunities to make building design more health-focused. There are three options to achieve points for this credit.
Once construction has been completed, and the building is able to maintain ventilation conditions that are typical during expected occupancy levels, perform a baseline IAQ test before occupants enter the building. The number of measurements ranges from 1 to 10, depending on the total occupied floor area of the building.
The first path (one point) you can take is measuring particulate matter and inorganic gases over an 8-hour period, using an ISO-accredited laboratory to calculate peak concentrations for carbon monoxide (CO), PM 10, PM2.5, and ozone.
The second path (one point) is testing an air sample for VOCs to ensure each compound remains within the required concentration limit and the TVOC level remains below 500 µg/m3. If any parameters exceed their prescribed limits, the problem must be fixed and the building has to be re-tested before earning the point.
Instead of performing spot-checks in option 1, buildings can instead install IAQ monitors that continuously measure CO2, PM2.5, TVOC, temperature, and relative humidity. These monitors must be RESET or UL2905-certified.
Additional points can be earned under the Innovation/Exemplary Performance credit for buildings that also continuously monitor NO2, ozone, PM10, PM1, and formaldehyde in the indoor environment.
In addition to continuous indoor monitoring, buildings can earn an extra point by installing RESET or UL2905-certified monitors that continuously monitor outdoor air. The point for this option can be earned by monitoring at least three out of four parameters: particulates (PM2.5, PM10), NO2, ozone, and CO.
There are multiple pathways to achieving the full points for indoor air quality in LEED v5. Here’s our recommendation for the most effective way to maximize your points:
| LEED v5 O+M | LEED v5 BD+C |
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This is a monumental advancement for LEED, the IAQ industry, and, most importantly, the health of building occupants. The shift from periodic checks to continuous monitoring signifies a pivotal moment for the industry. As more buildings start to pursue LEED v5 certification, continuous monitoring is positioned to become the standard practice for air quality management and optimization.
In summary, continuous monitoring is poised to become the standard practice for all future LEED v5 buildings.
Discover the latest innovations in LEED v5 and the updates to indoor air quality that have come with it in our on-demand webinar: Exploring LEED v5: The Latest IAQ Updates and Improvements