Should it be automatic or manual—The occupant's perspective on the design of domestic control systems

• The level of automation is one of the central issues in designing control systems.
• Occupant attitudes towards different levels of automation were studied.
• The interviews revealed a large amount of mistrust towards automation.
• System characteristics that may improve trust are listed.
• Full automation is not suitable for the control of the indoor environment.

The level of automation is one of the central issues in designing control systems. Occupant attitudes towards different levels of automation in domestic control systems were studied using a qualitative interview method. The following systems were considered: (1) control of indoor thermal environment, (2) peak load management, and (3) own energy production. For each system, four solutions representing different levels of automation were created. The interviewees gave comments on the solutions and chose the alternatives they preferred. The results show that decisions on the level of automation should be made carefully, taking account of the special qualities of each system without neglecting the individual differences between users. Full automation is not suitable for systems that considerably affect indoor environmental comfort. The interviews revealed a large amount of mistrust towards automation. An important question is how to improve the level of trust between the occupants and automation, i.e. how to make the occupants trust the automation in cases where better results would be gained through the utilisation of automation. The following system characteristics may potentially improve the level of trust: (1) carefully chosen level of automation, (2) predictability, transparency and feedback, (3) simplicity and usability and (4) suitability for everyday life.