Survey method

A survey questionnaire was posted to all participants at the beginning of the trial prior to installation of monitoring equipment, and a follow-up survey was sent to those participants who had received a control system in late March 2015, towards the end of the trial period. Pre-trial and post-trial surveys had already been developed by HomeTech for use in the trial, but it was agreed (with HomeTech) that limited additions could be made to these for the purposes of the current research.

The full questionnaires are available in appendices 10.11 and 10.12. Both collected information on age and number of occupants and occupancy patterns. The pre-trial questionnaire asked about current methods of heating control and satisfaction with current controls, while the post-trial questionnaire asked about usage of and satisfaction with the new control system. With the limited space available for additions, it was decided (for the purposes of the current study) to include a reduced version of the extended TAM scale developed for the survey presented in chapter 5. It was shortened to included one item for each of the extended TAM constructs (excluding intention to use), giving a total of seven items (see Table 6-1).

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Table 6-1: Items added to the HomeTech questionnaire. Responses were: strongly agree, somewhat agree, neither agree nor disagree, somewhat disagree, strongly disagree.

Survey Construct Item

Pre-trial

Spending control I will be in charge of my spending on electricity for heating

Timing control I will be able to do things when I want to do them Autonomy I will be too dependent on automation

Comfort control I will be able make sure my home is warm enough

Perceived

usefulness I can see myself saving money Perceived ease of

use I would find it easy to control my heating Attitude towards

use Overall, the controller is a good idea.

Post-trial

Spending control I felt in charge of my spending on electricity for heating

Timing control I felt able to do things when I wanted to do them Autonomy I felt too dependent on automation

Comfort control I felt able make sure my home was warm enough Perceived

usefulness I saved money Perceived ease of

use I found it easy to control my heating Attitude towards

use Overall, the controller is a good idea.

All except one of the items chosen were those used in the final analysis of the survey research (chapter 5). The exception was autonomy, where the item dealing with automation was considered preferable to ones dealing with a sense of control in life in general. This was because it applied more specifically to the scenario being experienced in the trial. Further small alterations were also made to the items:

• Items were rephrased in the future tense for the pre-trial survey and the past tense for the post-trial survey to reflect future expectations and past experience.

• Reference was made to ‘the controller’ rather than ‘this plan’ where relevant.

• The ‘spending control’ item was changed to refer specifically to spending on electricity for heating, since this is the only area in which the controller would

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be expected to act (rather than in a time of use tariff, which would affect all electricity spending).

Unlike in the previous survey, the outcome measure could not be whether the participant would sign up to the tariff presented. It was also not possible to ask whether the participant would like to retain the controller, even in principle, since this was not an option in the trial and it was important to be clear about this when communicating about the benefits of participation with participants. Instead, it was decided to present participants with three hypothetical options. An introductory text was included before the edited TAM items as follows (in the post-trial survey it was worded in the past tense):

The HomeTech heating controller that we are trialling is designed to run your heating more cheaply and efficiently. For example, it can turn down the heating when no-one is at home and use weather forecasts to work out just how much heat will be needed. It can also help reduce “peaks” in electricity use on the national grid (these peaks make electricity more expensive and polluting for everyone). It can do this by heating more when demand for electricity is low, and less when demand is high – while always sticking to the temperatures you have set.

Following the TAM items, participants were asked if they would choose to have the following features of the controller turned on or off: turn heating down when no-one is at home; respond to weather forecasts; reduce peaks in electricity use. In this way participants could indicate whether or not they were happy in principle with those capabilities of the controller. In the post-trial questionnaire, an existing question asked participants whether or not they would recommend the HomeTech system to a friend. While responses to this would not necessarily reflect the participants’ own preferences (for example, they may think it is more well suited to a friend than to them personally), it could give a further indication of whether or not they were generally accepting of the system.

The surveys were sent out in hard copy by post, printed double-sided on A4 paper.

Hard copy questionnaires were used (rather than online) as it was known that not all participants had access to the Internet. Included in the envelope were a cover slip explaining the purpose of the questionnaire and thanking participants in advance for their response, along with a stamped addressed return envelope.

Please see appendix 10.13 for these additional materials. Pre-trial questionnaires were posted to all participants, while post-trial questionnaires were only posted to

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those who had received the control system (since its purpose was to gauge use of and satisfaction with that system). As well as returning questionnaires in the post, some completed questionnaires were also collected by operatives installing the monitoring equipment or during the conduct of the post-trial interviews.

Questionnaires were returned to HomeTech, the data coded and anonymized by participant number, and passed to the author for analysis of the relevant sections.