This is a legacy version of the WELL Building Standard. Please check the latest version here.

Outdoor air systems

Outdoor air systems


To allow buildings to control the outdoor air supply independently from the heating/cooling needs of the building.


Dedicated outdoor air systems (DOAS) remove the constraints associated with linking heating and cooling with ventilation, so that optimal air quality and thermal comfort can be independently achieved. A properly designed DOAS can save energy compared to conventional systems while always supplying the appropriate amount of ventilation.

Part 1
Dedicated Outdoor Air Systems

Dedicated outdoor air systems are used for ventilation and verified as being adequate through one of the following:
The system complies with local codes or standards regarding dedicated outdoor air systems.
A detailed design review of the proposed system is conducted by an independent, qualified and registered professional mechanical engineer (not employed or compensated by the mechanical engineer on record). The review addresses thermal comfort (temperature, humidity, air velocity, etc.) and ventilation rates, as well as overall serviceability and system reliability. Report must demonstrate satisfactory compliance with ventilation standards used in Feature 03 Ventilation effectiveness.