The actual performance of energy renovations in the Dutch residential sector: An Analysis of Measured Energy Performance and Resident Perceptions in Monitored Renovation Projects

This report starts with summarizing large scale national studies about the energy renovation performances in the Dutch social housing stock and continued with the analysis of well documented renovation projects. 46 renovation projects representing 4.404 houses projects were analysed, with the goal of developing an understanding of the current state of data collection and monitoring in the Netherlands on the subjects of energy performance and residents’ perception.
Current energy models appear to not accurately predict energy savings in dwellings, as a result of not accounting well for occupant behaviour, poorly determined physical characteristics of buildings and issues with the installation and commissioning of systems. Based on data that is currently collected at a housing stock and individual housing level, it is difficult to determine the exact causes of the discrepancies. Better models – digital twins – are therefore needed to predict the actual energy performance of renovation measures in dwellings.
Through this study, it was found that the nature of the data which is gathered varies significantly. For example, some organization gather data on energy performance, some on indoor climate, some on resident preferences and opinions, but none are examining the complete picture. It makes it difficult to comment about which renovation concepts performed specifically well or less well. In most cases where it was documented that renovation concepts outperformed or underperformed compared to expectations, there was insufficient data to determine why this was the case. However, from the point
of view of energy performance, many monitored project appeared to perform much better than expected. This may be a direct result of the monitoring and is also surely a result of expressing targeted performance in terms of absolute energy usage instead of energy savings.
Monitoring was generally not at the level that it could be used to diagnostic and solve technical problems in a standardized way, as submetering was often missing. The desk research also shows that the satisfaction of residents with the renovation process was often monitored, but not to a level allowing for a good understanding of their needs and interactions with the technical systems.
The causes for dissatisfaction were mostly related to residents’ dissatisfaction with communication, nuisance, and overall renovation process, especially regarding planning and delays. Residents relocated during the renovation seemed to be more satisfied with the overall process. Participation and involvement were higher when more resources were freed by the housing associations to have residents’ opinions heard. t is also concluded that there is a need for better introduction to the home’s systems, better manuals and follow up information and support to the residents after renovation. Not understanding the use or maintenance of the systems can in some cases led to discomfort situations, and to complains about noise from the systems. However, these
complaints should not be waved away as being caused by the occupant. It may also be caused by malfunctioning and poor interfaces of the systems themselves. In the end 13 recommendations about monitoring, analysis, modelling of installations and residents’ understanding are formulated.