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A Detailed Comparison of Indoor Air Quality in LEED v5 and LEED v4.1 Certification

Liam Bates

How Is Indoor Air Quality in LEED v5 Different From LEED v4.1?

LEED v5 now incentivizes real-time, continuous monitoring of indoor air quality (IAQ) and awards up to 10 points for this feature. This is a significant upgrade from the maximum of 4 points available for periodic spot-check air testing.

LEED v5 also offers additional points for a range of IAQ improvement strategies, including outdoor air quality monitoring and compliance with ASHRAE 241 standards, among others. A total of 13 points are available for the IAQ performance credit.

What is LEED v5?

LEED (Leadership in Energy and Environmental Design) Certification 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. Specifically, the analysis centers on Building Operations + Maintenance: Existing Buildings. 

The Importance of Indoor Air Quality

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, as well as massively impacting cognitive performance. Buildings should serve the well-being of their occupants as well as being environmentally sustainable. Learn more about the impact of IAQ on our health, productivity, and workplace experience here.

IAQ in LEED v4.1

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. 

Indoor air quality 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.

Limitations of LEED v4.1 Approach

  • A very limited range of IAQ parameters are measured. For example, PM2.5, a harmful pollutant, is not included in the assessments.
  • Annual readings offer an incomplete picture of IAQ.
  • Overemphasis on occupant surveys: Human perception is not reliable for detecting harmful pollutants, yet it accounts for 50% of the score.

IAQ in LEED v5 (Beta)

As with previous versions, LEED v5 also has an IEQ core category, within which several credits addressing air quality are found.

EQ Prerequisite: Verification of Ventilation and Filtration

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.

EQ Credit: Indoor Air Quality Performance

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 13 points, available through 3 different options:

Option 1: Measure and meet IAQ (up to 10 points)

Option 2: Meet ventilation & filtration standards (up to 6 points)

Option 3: Strategies to improve IAQ (up to 4 points)

These options can be combined to achieve the full 13 points.

How to Achieve Maximum Points for IAQ In LEED v5

There are multiple pathways to achieving the full 13 points, as outlined in detail below. Our recommendation for the most effective way to achieve this is:

  • Install IAQ monitors that measure CO2, TVOC, and PM2.5 to achieve 6 points.
  • Meet IAQ thresholds using continuous monitoring data to achieve 4 points (your IAQ monitoring provider should help with this)
  • Meet ASHRAE 62.1 to achieve 2 points
  • Install MERV 13 filters to achieve 1-2 points.
Calculate Your LEED v5 IEQ Credit!
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Full Details of LEED v5’s Indoor Air Quality Performance Credit

Option 1 (Up to 10 points)

Option 1 is a major update that allows continuous monitoring of IAQ to earn up to 10 credits in LEED. 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 10 awarded for continuous monitoring.

Installation of monitors is rewarded by up to 6 points, and the remaining 4 can be achieved by meeting targets for IAQ with the data. See the appendix for the exact thresholds.

The key takeaways are that an air quality monitor measuring CO2, TVOC and PM2.5 continuously within the building and hitting reasonable thresholds can deliver the maximum of 10 credits. The new thresholds generally align with WELL v2. 

Note that a RESET or UL2905 certified monitor must be used for measurement in this option.

Option 2 (Up to 6 points)

This option awards points for meeting and/or exceeding ASHRAE 62.1 for ventilation rates, and/or using MERV 13 filters.

Up to 4 points are available for exceeding ASHRAE 62.1 by 30%, and another 2 points are available for using MERV 13 filters on all outdoor and recirculated air.

Option 3 (Up to 4 points)

A number of options (see appendix) are available to gain additional points (one point per strategy), including implementing ASHRAE 241’s Infection Risk Management Mode, allowing for operable windows, and installing outdoor air quality monitors.

Given that 10 points are available by monitoring and meeting basic air quality targets, only 3 points are needed from options 2 and 3. Thus, simply meeting ASHRAE 62.1 and installing MERV 13 filters is enough to meet the maximum number of points for this credit.

Occupant Surveys

In LEED v4.1 indoor air quality was assessed via a combination IAQ measurements and surveys. Though still present, occupant surveys are now optional, providing up to 5 additional points.

Implications for Building Owners and LEED v5 Applicants

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.

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

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