The team needs to understand how decisions about ventilation, water, light and sound translate into conditions in the finished space. WELL performance verification assesses defined environmental conditions on site. The design and operational approach described in documents is considered alongside measurements and site records. For the client, the priority is to understand what testing will show and how its results fit into certification. IWBI — What is performance verification?
What does performance verification include?
WELL certification treats documentation review and performance verification as complementary processes. Documentation review assesses how design strategies and operational practices relate to requirements. Performance verification includes performance testing, on-site photographs and independent third-party review. This distinction helps the team understand where each type of evidence will be used.
The approach described through drawings and declarations is connected with the conditions tested on site. Preparing the test plan, arranging access to testing areas and coordinating relevant system settings are therefore important. Clear records make it easier to trace a finding to the area or conditions concerned during review.
Which topics may require on-site measurement?
WELL v2 works with a framework of ten topics covering air, water, nourishment, light, movement, thermal comfort, sound, materials, mind and community. The same topics are not measured in every project; the scope is determined by the features a project targets and demonstrates compliance with during documentation review. IWBI's description states that a performance testing agent collects real-world data across environmental parameters within the topics of air, water, light, thermal comfort and sound. This list shows that on-site testing is not limited to indoor air quality. Indoor air quality is also not, on its own, equivalent to the broader concept of indoor environmental quality; the verification method of each parameter is addressed separately.
How does the measurement process proceed?
The final documentation report prepared after documentation review shows which feature parts will be verified on site; reviewing this report helps the team share a common expectation of testing. Depending on the project version and test type, testing can be coordinated through IWBI or directly with an approved Performance Testing Provider. Measurements are carried out by an authorised Performance Testing Agent working for that provider. Scheduling and site preparation are planned with the project team. When planning the schedule, it is appropriate to allow time for processing results and remediation if needed. IWBI — Performance Verification coordination. On testing day, the performance testing agent measures the defined parameters under the space's real operating conditions and documents situations requiring visual confirmation with photographs. After testing is complete, the results are shared with the project team. IWBI — Performance verification timeline.
Reporting results and retesting
Measurement results are assessed on a feature-part basis. Documentation for parts that achieve compliance is uploaded for the next review cycle. If a feature part does not achieve compliance, the project team can address the issue and retest only those specific items. When reading reports, results should be assessed together with the timing, location and conditions of the measurement. A single measurement reflects the condition at the time of testing and does not represent the entire operating period. Occupancy density, seasonal transitions and changes in operating patterns can affect the results. Read together with maintenance records and monitoring data, measurement results provide a more reliable basis for decisions.
The distinction between measurement and certification verification
On-site measurement is a component of the verification process; it is not a certification decision on its own. Certification assessment proceeds once documentation review, performance testing and independent review have been completed together. A passing measurement result does not mean other requirements are met; the reverse is also true. Measurement also provides no guarantee of the building's performance in later periods; continuity is maintained through operational discipline. Following the steps from the official guidebook makes preparation easier: IWBI's performance verification guidebook applies to WELL v1, the WELL v2 pilot, WELL v2 and the WELL Performance Rating. IWBI — WELL Performance Verification Guidebook.
Certification goals and AECO's contribution
In projects with WELL objectives, consulting and measurement are two complementary lines of work. WELL consulting supports the project team from defining objectives to documentation preparation and managing the assessment process. Testing and measurement services build a scope of work for planning on-site measurement needs and reading results alongside operating data. The testing itself is carried out by an authorised provider under IWBI's processes; discussing this distinction from the outset keeps expectations aligned. For an overview of the scope and verification of WELL certification, see our WELL certification: scope and verification article. Recording which work belongs to consultancy, authorised testing and independent review at the outset gives the teams a clearer preparation plan.