do consumers know how much electricity is used by their appliances?
Vedran Lesic, University of Leeds, Phone: +44 7432 060 122, email:
Ines Lima Azevedo, Carnegie Mellon University, Phone: +1412 268 3754, email:
Tamar Krishnamurti, Carnegie Mellon University, Phone: +1412 268 7735, email:
Wandi Bruine de Bruin, University of Leeds, Phone: ++44 113 343 8839, email:
Matthew Davis, University of Leeds, Phone: +44 113 343 6831, email:
Overview
The Intergovernmental Panel on Climate Change (IPCC, 2014) warns that global greenhouse gas emissions from the energy sector must be drastically reduced within the next 50 years to curb the risks of climate change. In the EU and USA, residential and commercial sector energy consumption accounts for almost 40% of total energy consumption (Eurostat, 2012; U.S. Energy Information Administration, 2014).Policy makers are increasingly encouraging households to save electricity, so as to reduce greenhouse gas emissions and improve the reliability of the electricity grid. However, such encouragements may be ineffective if consumers are unaware of how much electricity is used by different appliances (such as their air conditioner, refrigerator, and others). We therefore examined the difference between consumers’ perceived and actual residential electricity use for specific appliances.
Methods
Consumers (n=118) were recruited from Texas households with appliance-specific electricity meters installed by the Pecan Street Research Institute. We measured their electricity use for a set of appliances, over the course of three summer months (June, July, and August of 2014). Appliances included their air conditioner, refrigerator, dryer, clothes washer, dishwasher and oven. Participants received our survey about electricity use in October of 2014. They were randomly assigned to assess their appliance-specific electricity use in terms of dollars or kilowatt-hours, for an average summer month. Each participant estimated the electricity use or cost by six appliances over the course of average summer month with a 100-W incandescent light bulb as a reference point. They also provided open-ended responses to explain their assessments.
Results
We compared participants’ assessments of their appliance-specific electricity use for an average summer month with their actual appliance-specific electricity use as averaged over the course of three summer months, by transforming all observations into kilowatt-hours. Results were no different when all observations were transformed into dollars. Specifically, we computed difference scores by subtracting actual use from assessed use. We conducted repeated-measures ANOVA to compare these difference scores, with within-subject variable for the six appliances and a between-subject variable for the dollar vs. kilowatt-hour group. Participants who assessed their use in dollars overestimated their electricity use for all appliances and were less accurate in perceiving their electricity consumption. Their open-ended responses revealed salient memories of high electricity bills due to blasting air conditioners during hot Texas summers, following the availability heuristic. By contrast, participants who assessed their use in kilowatt-hours underestimated their electricity use for high electricity consuming appliances (such as their air conditioner) and overestimated their electricity use for lower energy consuming appliances (such as their refrigerator). Their open-ended responses suggested a more reasoned approach.
Conclusions
Our findings suggest that consumers may not be aware of how much electricity is used by specific appliances in their households. When they think about their electricity use in dollars, their assessments are especially inaccurate, due to the availability of unpleasant experiences with high electricity bills. We discuss implications for the design of effective electricity feedback for consumers.
References
Attari, S. Z., DeKay, M. L., Davidson, C. I., & de Bruin, W. B. (2010). Public perceptions of energy consumption and savings. Proceedings of the National Academy of Sciences of the United States of America, 107(37), 16054-16059.
Chen, V. L., Delmas, M. A., Kaiser, W. J., & Locke, S. L. (2014). What can we learn from high-frequency appliance-level energy metering? Results from a field experiment. Energy Policy.
Dietz, T., Gardner, G. T., Gilligan, J., Stern, P. C., & Vandenbergh, M. P. (2009). Household actions can provide a behavioral wedge to rapidly reduce US carbon emissions. Proceedings of the National Academy of Sciences, 106(44), 18452-18456.
Intergovernmental Panel on Climate Change (2014). Climate Change 2014 - Synthesis Report. Report, Available for download at: