A field study was conducted during the heating season in nine modern office buildings in the Netherlands. A first objective of the study was to investigate what kind of control Dutch office workers have over temperature in winter (available control), to map how often these controls are used (exercised control) and to identify how much control the office workers perceive to have over temperature in winter (perceived control). A second objective was to objectify the amount of control over temperature in winter with thermostat effectiveness measurements. The third objective was to investigate how available control and exercised control impact the level of control over indoor climate in winter as experienced by office workers (perceived control). The study consisted of (i) a systematic inventory of relevant building and HVAC system characteristics, (ii) a questionnaire among building occupants, and (iii) indoor climate measurements; concerning the latter, to evaluate the effectiveness of controls, dynamic experiments have been performed. These experiments consisted of manual adjustments of thermostats by the researchers. After these interventions, response times and step responses for room temperature were identified to quantify how effective controls were in changing room temperature. The outcomes of the study can be used to improve temperature control in existing and new office buildings.