The characteristics of usable room temperature control

Individual thermal control is important for handling individual differences in thermal preference. Several studies have shown that comfort, health and productivity in offices can be improved by individual thermal control. Local controls for temperature are commonly available in modern office buildings. However, office occupants are often still dissatisfied with thermal environments and control options. The overall aim of the work is to improve office occupants’ control over room temperature by improving the usability of interfaces of heating and cooling systems. Both qualitative and quantitative methods were employed to study office occupants as users of room temperature controls. The work started with qualitative interviews taken in actual context, in the offices of the participants. Twenty-seven office occupants were asked to show and tell us how they use the controls in offices. The problems with thermostats were found to be diverse and fundamental. Office occupants do not always even know they have a possibility to individually control the room temperature, because the device is not recognised at all, or the purpose of the device remains unclear. Although the room thermostats in offices are simple, symbols in the user interface are often not understood correctly, and it is not always known whether the temperature control is operating or not. In general, users are not satisfied with the feedback they get from the systems. The main reason for many of the problems is that the systems are planned and constructed without a realistic view of their users, i.e. users are supposed to have knowledge they do not have. Next, in a quantitative interview survey, users were studied with a large and nationally representative sample: 1 000 Finnish office occupants answered questions concerning the office environment. Additionally, to simulate the real