The WELL Building Standard v2 (IWBI) is a performance standard for occupant health, and ventilation is one of its strongest levers. Where energy codes set a floor for “acceptable” air, WELL rewards going well beyond it. This article covers the Air Concept features most relevant to recovery and ventilation design.
Feature A06 — Enhanced Ventilation Design
The core credit exceeds the minimum outdoor-air rate in ASHRAE 62.1:
| Option | Requirement | Points (Cert / Core) |
|---|---|---|
| Increased air supply | Exceed ASHRAE 62.1 by 30% | 1 / 2 |
| Increased air supply | Exceed ASHRAE 62.1 by 60% | 2 / 3 |
| Demand-control ventilation | CO2 < 900 ppm (or outdoor +500) | 1 / 2 |
| Demand-control ventilation | CO2 < 750 ppm (or outdoor +350) | 2 / 3 |
More outdoor air means more recoverable energy — so a membrane ERV or wheel is what keeps the higher ventilation rate affordable.
Supporting Air Features
- A03 / A05 (Air Concept): fundamental and enhanced IAQ, including minimum ventilation and source control.
- A09 / A12: particulate filtration — MERV 13 or better on ventilation systems, with pressure-drop monitoring so filters are changed before they choke the fan.
- A08: continuous monitoring and annual reporting to maintain certification.
- A13: enhanced supply air, e.g. activated-carbon filtration for VOCs.
Why CO2 Is the Proxy
WELL treats CO2 as a stand-in for cumulative indoor pollutants because it is cheap to sense. Holding CO2 below 900 ppm (or 750 ppm for the higher point) signals adequate dilution. But more air is not free — pair the credit with recovery and DCV so the energy penalty stays small, the same logic used for LEED energy-recovery credits.
Recovery Link
WELL’s higher ventilation rates make the recovery device even more valuable than under energy code minimums. Size the core in the AHU selection calculation on the WELL ventilation rate, not the bare code minimum, to capture both the health and energy wins.
Frequently Asked Questions
How does WELL v2 drive energy recovery?
Its enhanced ventilation features exceed ASHRAE 62.1 rates, and the higher outdoor-air load is what a wheel or membrane recovers to stay affordable.
What are the Enhanced Ventilation options?
Exceeding 62.1 by 30 or 60% outdoor air, or CO2-based demand-control ventilation below 900 or 750 ppm.
Why is CO2 used as a proxy?
It is a cheap indicator of cumulative indoor pollutants and adequate dilution, though more air still needs recovery to control energy cost.
Should recovery be sized on the WELL rate?
Yes. Size the core on the WELL ventilation rate, not the bare code minimum, to capture both health and energy wins.