Usability and heating controls are two phrases that do no sit well together.
The usability issues of heating controls and programmable thermostats was documented as early as 1982 with the usability of control systems existing at the time proving difficult for some users (Moore and Dartnall, 1982).
In the thirty years since this potential is still hasn’t been realised. The programming of thermostats is still a particular area of user frustration yet is often the best way to reduce our energy consumption.
Although the programming process is not ideal it was expected by Freundenthal and Mook (2003) to remain a part of our heating system. Yet research suggest that 89% of respondents rarely or never programmed the thermostat for a weekday or weekend program (Meier et al., 2011).
How can we make this process easier? Some advanced thermostats such as Nest have done away with the need for programming by ‘learning’ your routine. Other systems take an approach of entering your schedule in a calendar style to work out when your home needs heat. This planning can be really challenging for some user groups though.
There was a really interesting paper on the difference between historic feedback and predictive information which reduced the need for planning and resulted in greater energy savings (when using a prototype smart home interface). My approach was to present users with clear on/off times to help clarify their mental models of the system, to reduce the number of decisions users had to make within the process and hopefully reduce the periods of accidental heating in homes.
Overall the aim was to simplify the process. This seems in contrast to some control manufacturers approaches, where increased functionality and the addition of new features are making thermostats increasingly complex.
Usability is one aspect of the wider acceptability of products, I don’t believe it can be looked at in isolation. Even if a system is usable to some, if not all user groups, factors such as accessibility, cost and compatibility will still provide barriers to effective use (see Nielsen’s System Acceptability Framework 1993 for further details).
As we look to refurbish UK homes and upgrade our heating systems issues such as compatibility and cost may have a greater impact than they currently do. Taking a whole system approach to the design of usable heating controls that are affordable and compatible with existing/future systems and are installed in accessible, well lit locations would result in the greatest benefit to householders.
Freundenthal and Mook (2003) ‘The evaluation of an innovative intelligent thermostat interface: universal usability and age differences’, Cognition, Technology and Work, 5, pp. 55-66. DOI:10.1007/s10111-002-0115-6
Meier et al., (2011) ‘Usability of residential thermostats: Preliminary investigations’, Building and Environment, 46(10), pp. 1891-1898. DOI:10.1016/j.buildenv.2011.03.009
Moore and Dartnall, (1982) ‘Human factors of a microelectronic product: the central heating timer/programmer’, Applied Ergonomics, 13(1), pp. 15-23.
Nielsen, (1993) Usability Engineering, Cambridge, Massachusetts: AP Professional