States that underfloor air distribution is now being used in open-plan offices. Supplying conditioned air from the floor provides the opportunity for localised conditioning with individual control, known as 'task conditioning'. States that this environmental control strategy can be viewed as encompassing a combination of several more conventional strategies occupant-defined comfort, use of occupancy-sensors, temperature stratification, increased ventilation efficiency and thermal storage. Provides an overview of task conditioning in offices, describing existing system types and the most common applications. Outlines the current state of understanding concerning the comfort and energy effects of these systems and identifies important questions that must be addressed to complete the understanding of this strategy.

KEYWORDS: air conditioning, local ventilation.