Heating flexibly with heat pumps : an economic pilot study

We used large-scale surveys and a field experiment to explore households' interest and expectations in schemes that adjust their heat pump to match electricity demand with renewable production. People are interested in such programs: Over 70% of survey respondents expressed willingness to join flexibility schemes, primarily to contribute to environmental goals.The difference in interest between early adopters (energy cooperative members) and the general population is minimal. But they expect money in return for this: In the surveys, we asked how much money people expect in return when a heating interruption of unspecified duration lowers their indoor temperature.Our analysis shows households expect 1.40 to 3.04 for each additional degree of temperature drop.Surveys also showed that households expect to always stay partly in control over their heating, wanting advance notice of interruptions and/or the option to stop them and restore normal heating if needed. In addition to the empirical research based on surveys, we conducted a flexibility program in practice in nine well-insulated homes in Ghent, where a total of 287 heat pump interventions were conducted during the winters of 2022-2023 and 2023-2024.The heating was remotely interrupted until it was either automatically resumed or manually restarted by the household. Flexible heating reduced electricity demand.On average, the net reduction of electricity demand was 1 kWh per intervention per heat pump. Most interventions maintained thermal comfort.Even during the interventions that were manually stopped by households (19%), indoor temperatures had only dropped by 1C on average. In well-insulated houses, there is plenty of room for playing with heating flexibility: Our findings show that when heating is paused or shifted by a few hours, indoor temperatures cool down only slowly.This means households with good insulation can benefit from flexibility without being noticeably discomforted.With a dynamic electricity contract, such flexibility can also save money. Maximum savings on heating bills can be achieved in the future when fully automated systems for smart heat pump control enable frequent interventions on a continuous basis, without households noticing much of it.This is the way to maximize savings from heat pump flexibility in the long term.While this advanced "automation concept" falls outside the scope of our experiment, recent academic studies show that such setups can reduce electricity bills by up to 18%, even when households are allowed to set temperature limits to ensure comfort. Policymakers should focus on encouraging the development of protocols and standards for finer, adjustable settings to optimize heat pump flexibility within each household's comfort boundaries.Not only should the transition to heat pumps per se be facilitated, but also their operation in the smartest possible way to minimize operational costs.