Homeowners’ preferences regarding sustainable residential heating systems

Abstract

Resulting from the Dutch commitment to the 2015 Paris Agreement, the Dutch government has set the goal of making all 7.9 million Dutch houses natural gas-free. The present study has focussed on the challenge of removing the currently predominantly installed natural gas fired central heating boiler since such residential heating systems (RHS) are responsible for 78% of the natural gas demand in houses. Municipalities are responsible for this so-called heat transition and use public participation to gain insights into the needs and wishes of citizens, which will help to speed up the transition towards natural gas-free RHS. The present study focusses on homeowners in the municipality of Delft and argues that a variety of insights cannot be obtained by the current participation process in Delft. The main research question of this study is: How do different classes of Delft homeowners make trade-offs between attributes of substitute residential heating systems and how do these trade-offs change due to relocation? This question has been answered with a context dependent latent class discrete choice model for which a stated preference survey was conducted. In this survey, respondents were asked eight times to choose between three natural gas-free RHS which each varied on six characteristics. The varied characteristics are: the type of RHS (all-electric heat pump, district heating, and hybrid heat pump with green gas), investment costs, operational costs, popularity in the neighbourhood (as a percentage of people with a particular RHS), required inside space (compared to the space required for a conventional central heating boiler), and construction time (needed for the installation of the RHS and insulation work). The results of the present study show that the RHS choice of Delft homeowners is positively influenced by higher values for the popularity in the neighbourhood. The higher the value for investment costs, operational costs, required inside space, and construction time the lower the chance that a homeowner chooses that RHS. Although all homeowners show similar reactions with respect to these five characteristics, the severity of these reactions does differ between homeowners. The model results show that Delft homeowners can be separated into two groups which each make different trade-offs. The first and largest group is characterised by homeowners with a relatively high income living in poorly insulated houses. These homeowners base their natural gas-free RHS choice primarily on investment costs, operational costs, and required inside space. Moreover, this group prefers district heating. The second group is likely to be consisting of low income homeowners living in relatively well insulated houses. This group is, similar to the first group, heavily influenced by investment costs and operational cost, but also by the type of RHS (preference for all-electric heat pumps and hybrid heat pumps with green gas) and popularity in the neighbourhood. When homeowners are moving to a new house, they pay less attention to investment costs, while paying more attention to construction time. The effect of relocation is especially strong in the second group of homeowners. Given the results for investment costs and operational costs and that the national government is responsible for the affordability of the heat transition, the municipality of Delft should try to influence the national government. It should do this via four ways: the Association of Netherlands Municipalities, the G40 city network, the Metropolitan Region Rotterdam The Hague, and via the inter-government layer lobby connections between municipal aldermen and national ministers of the same political party. The inside space requirement concerns of the first group of homeowners should be mitigated by Energieloket Delft and 015 Duurzaam. The municipality should also have citizen organisations (Platform Energietransitie Delft and neighbourhood associations) to gather and spread information to the second group of homeowners about the popularity in the neighbourhood. The municipality of Delft should take advantage of the window of opportunity that relocation provides by starting partnerships with real estate offices. In this way, new homeowners can be made aware of the heat transition in an early stage and can account for the extra required construction time and investment costs for a natural gas-free RHS in their bid. The municipality and real estate agent should have an advisor from Energieloket Delft or 015 Duurzaam to formulate a plan in which is stated what the best natural gas-free RHS is for a to-be-sold house, including an overview of the required investment costs and construction time. The advisor should consider increasing the investment costs in order to decrease the required construction time.