​​​​Testing, Adjusting and Balancing (TAB)

​The purpose of Testing, Adjusting and Balancing (TAB) is to assure that a Heating, Ventilating and Air Conditioning (HVAC) system provides maximum occupant comfort at the lowest possible energy cost.

Building owners, facility managers and tenants are concerned that the indoor environment of buildings operate comfortably and safely.  TAB (which includes both air and hydronic balancing), insures that HVAC systems operate properly, safely and energy efficiently.


Established in 1971, NEBB is the premier international certification association for firms that deliver high performance building systems.  EBCx Services is certified by NEBB in the following disciplines:

  •           Testing, Adjusting and Balancing (TAB) of Environmental Systems

  •           Whole Building Systems Technical Commissioning

  •           Technical Retro-Commissioning of Existing Building Systems

  •           Building Enclosure Testing

TAB in Existing Buildings
TAB is a critical part of the Existing Building Commissioning (EBCx) process, since there are few buildings in existence that have not experienced changes in internal loads and space layout changes since they were designed and built. TAB and EBCx go hand-in-hand.  These buildings should periodically have their HVAC systems rebalanced to achieve maximum comfort, operating performance and efficiency.

TAB work conducted in existing buildings generally discover significant opportunities towards system enhancements that increase occupant comfort and decrease building operating costs. An obvious example would be discovering simultaneous heating and cooling occurring with variable air volume (VAV) or constant volume (CV) systems.  Until an experienced TAB professional investigates how components, equipment and systems are operating, energy waste can run rampant. 

TAB in New Buildings
TAB of HVAC systems in a new building is needed to complete the installation and to make the system perform as the designer intended. Assuming that the system design and installation meets the comfort needs of the building occupants, testing, adjusting, and balancing of the HVAC system fine tunes occupant comfort levels while keeping energy use to the lowest level possible.

The TAB phase of any building construction or renovation is intended to verify that all HVAC water- and air-flows and pressures meet the design intent and equipment manufacturer's operating requirements. It is rare to find an HVAC system of any size that will perform completely satisfactorily without the benefit of final adjustments. This is why it is considered a "best practice" for the designer to specify that TAB work be part of the overall HVAC system installation.