Mind the gap – Deriving a compatible user mental model of the home heating system to encourage sustainable behaviour

• A novel approach to specify the ‘scaffolding’ underlying Norman's 7 stages of activity.
• Development of a compatible user mental model of the domestic heating system that supports sustainable behaviour.
• Demonstrating how different mental model elements are applied at the 7 stages of activity to target climate change strategies.

Householders' behaviour with their home heating systems is a considerable contributor to domestic energy consumption. To create a design specification for the ‘scaffolding’ needed for sustainable behaviour with home heating controls, Norman's (1986) Gulf of Execution and Evaluation was applied to the home heating system. A Home Heating Design Model (DM) was produced with a home heating expert. Norman's (1986) 7 Stages of Activity were considered to derive a Compatible User Mental Model (CUMM) of a typical Heating System. Considerable variation in the concepts needed at each stage was found. Elements that could be derived from the DM supported stages relating to action specification, execution, perception and interpretation, but many are not communicated in the design of typical heating controls. Stages relating to goals, intentions and evaluation required concepts beyond the DM. A systems view that tackles design for sustainable behaviour from a variety of levels is needed.