Consumers often find it hard to assess how much electricity is used by their household appliances. Providing a ‘reference point’ (or how much electricity is used by another appliance, such as a single lightbulb) can be a simple yet effective strategy to improve the accuracy of consumers’ perceptions of appliances’ electricity use. The aim of this study is to test whether the provision of single or multiple reference points improves consumers’ perceptions of appliances’ electricity use.
In a US online survey, 504 participants reported their perceptions of electricity use (in Watt hours) for nine different appliances (e.g. air conditioner, electric oven, dishwasher, coffee maker, freezer, refrigerator, laptop, TV and cell phone charger) as used over the course of one hour. Participants were randomly assigned to receiving one of five experimental conditions: (i) no reference point, (ii) a single low reference point (light bulb), (iii) a single high reference point (electric dryer), (iv) two reference points, one low and one high (light bulb and electric dryer) and (v) three reference points, including one low, one medium, and one high (light bulb, washing machine and electric dryer).
We found that providing one low or more reference points (rather than no reference point) influenced the accuracy of perceptions of electricity use across all of the appliances presented. Specifically, participants who received a single low (e.g. light bulb), or two or three reference points reported more accurate perceptions of electricity use for specific appliances. Also, in conditions with two or three reference points, participants were more confident in their estimates and perceived the task as less difficult. Furthermore, participants in our study underestimated the use of high electricity consuming appliances (e.g. air conditioner, dishwasher) but overestimated the use of low electricity consuming appliances (e.g. laptop, TV).
Our findings suggest that reference points play an important role in improving the accuracy of perceptions of electricity use across different appliances. We discuss the importance of incorporating reference points in the design of effective electricity feedback for consumers.