Demand response with domestic heat pumps has gained interest in recent years. It is seen as a possible solution to the need to balance electricity grids that are sourcing a higher proportion of their electricity from variable low-carbon electricity sources. Although many modelling studies suggest that demand response with heat pumps will be successful, we have little knowledge of their real-world impacts, including the impact on indoor conditions and the perception of these.
This study compares what happened in three homes of early adopters of heat pumps with demand-side response (DSR). In the three households, the operation of the heat pump was constrained from 4pm to 7pm to provide demand response. Drawing on technical monitoring, we report on indoor conditions in the home and heat pump operation. Drawing on interviews and informed by social practice theory, we explore how comfort at home is experienced and achieved. The focus of the study is on the indoor conditions as the material background for daily practices, and on how these are sensed, interpreted, and created through comfort practices.
The analysis of the results revealed that air and surface temperatures dropped during demand response (air temperature dropped 0.3-1.1 degrees in 3 hours). However, these changes were sensed and interpreted differently by different participants: (1) not perceived, (2) noticed but tolerated without affecting DSR or (3) not tolerated. Although material adjustments were common in (2) and (3), the nature of the adjustment depended on the know-how of the participants and the meaning associated with temperature changes; for example, (2) adopted new materials (e.g., clothes) while (3) changed the operation of the heat pump to produce more acceptable indoor conditions.
The findings challenge conventional modelling assumptions that demand response is unnoticed by people if the indoor temperature remains within the limits of steady-state models of thermal comfort and reveal how demand response is negotiated and incorporated into daily practices