Characteristics of thermal environment in a full-scale indoor space utilizing an Under-Floor Air Distribution (UFAD) system are investigated by conducting and analyzing experimental measurements. The indoor air stratification of different locations in the steady state for three supply flow rate options is presented. This research focuses on the influence of supply air flow rate, and its corresponding momentum and buoyancy fluxes, on the vertical temperature profile in the indoor environment. Temperature measurements show that the indoor vertical temperature profile is influenced highly by the distance away from the supply diffuser position. Experimental results also show that the supply air flow rate has a strong effect on the vertical temperature profile. When the supply air flow rate of a given diffuser increases, and then the supply air momentum flux increases as well, the gradient of the vertical temperature profile becomes gentler. The stratification height in the indoor environment ascends with a higher total flow rate. The almost same throw height at the supply diffuser is observed for the identical flow rate option in two sets of experiments with different total flow rates. (C) 2014 Elsevier B.V. All rights reserved.