Spatial diffusion of residential heat pumps in Switzerland

Diffusion of granular renewable energy technologies is known to be spatially heterogeneous within countries. We investigate patterns in the distribution of 319’341 residential buildings with heat pumps in 2’148 Swiss municipalities in 2021. Using stepwise regression and spatial statistical analysis, we identify influential technical and socio-economic factors of residential heat pump diffusion as well as associated spatial traits. The results show that residential heat pumps primarily have a higher diffusion level in sparsely populated areas where the shares of agricultural area and detached houses are higher, hinting at an urban-rural difference. Economic factors, like income and electricity price, have a limited impact on residential heat pump diffusion in Switzerland, except for unemployment rate that has a negative impact. Some Swiss cantons (states) have a distinctly higher or lower residential heat pump diffusion level than others, a phenomenon possibly induced by cantonal policies. The spatial diffusion of residential heat pumps also tends to be spatially clustered, not only within cantons but also at the inter-cantonal level, indicating spatial spillovers. These findings could help policymakers promote heat pump diffusion in a more effective and precise manner.