The omni-directional hot sphere anemometer, that applies a separate reference point for the temperature correction, currently is the most practical device that is used for the measurement of indoor air flows. The anemometer has been investigated, experimentally and numerically, with regard to stationary and transient aspects for application in the indoor air flow field. Significant deviations result when specific stationary restrictions and corrections are not recognised. The transient investigation shows a significant influence of the damping on the measurement signal in the frequency range that also prevails at indoor air flows. The measured turbulence intensity can be underestimated by approximately 20%. This may result in a 50% deviation of the percentage of dissatisfied (PD) as is found in the definition of draught.