This study introduces a systematic framework to facilitate decision-making in selecting renovation options for preparing existing Dutch dwellings for utilising lower temperature heat (LTH) supplied by district heating (DH) systems. The framework was applied to an archetype terraced intermediate house built between 1945 and 1975 to identify the renovation options required for transitioning from existing High-Temperature (90/70℃) supply from gas-boilers to Medium Temperature (70/50℃) supply from DH systems. The framework's effectiveness was demonstrated by systematically assessing the readiness of the archetype dwelling for LTH use, reducing the number of viable renovation options, evaluating the financial feasibility using a life cycle costing approach and generating decision support insights through comparative analysis. The framework identified an optimised solution involving cavity wall insulation, exhaust ventilation and switching to low-temperature radiators. This solution incurs low initial investment and global costs while significantly reducing space heating and underheated hours. As a result, the framework provides tangible solutions for the specific use case and can serve as a valuable tool for dialogue among stakeholders during the decision-making process.@en

The Dutch government aims to eliminate natural gas for residential heating in 1.5 million homes by 2030. One strategy is connecting existing dwellings to lower-temperature district heating (DH) systems, although these dwellings might require energy renovations. The heterogeneous dwelling stock causes varying renovation needs that complicate the energy transition. The present study addresses this issue by assessing the building-level parameters affecting the readiness of the Dutch terraced-intermediate and apartment types for lower-temperature heating (LTH) supplied by DH systems. A sampling-based approach was employed to capture variability within these dwelling types, addressing the limitations of archetype-based methods. The findings suggest a sample size of 1300 to represent the variations in these dwelling types. Parametric simulations and machine learning methods were used to identify significant building-level parameters for medium-temperature (MT: 70/50 °C) and low-temperature (LT: 55/35 °C) supply levels. These include heating setpoints (desired indoor temperature) and ventilation-related parameters (ventilation system type and air infiltration rate), followed by fabric-related parameters (roof, glazing, wall, ground, and door insulation) and geometric properties (orientation, compactness ratio, and window-to-wall ratio). Additionally, radiator oversizing also impacts LTH readiness. These results broadly apply to the studied dwelling types, although feature importance varies by supply temperature and dwelling type. The findings can guide stakeholders in assessing current conditions and prioritising renovation measures, aiding the development of targeted renovation solutions. Encompassing the representative variations within studied dwelling types enhances the robustness of the results. However, incorporating more refined data could improve the accuracy of the findings, better supporting the energy transition of these dwellings.@en

Lower temperature heating (LTH) involves using the lowest possible supply temperatures to meet residential heating demands, thus supporting the integration of sustainable heating sources and decarbonising the existing residential stock. However, choosing appropriate energy renovation options to prepare existing dwellings for LTH presents decision-making challenges due to the heterogenous dwelling stock with varying building characteristics, numerous renovation options, and various performance indicators for evaluating trade-offs. This study aims to review the scientific literature on integrating LTH into existing dwellings to identify the building characteristics for evaluating the potential of using LTH and the necessity for renovations, presents a systematic method for organising renovation options and summarises key performance indicators. The study employed the SALSA (search, appraisal, synthesis and analysis) framework for systematic review and identified 24 scientific publications. Findings show that dwelling characteristics such as compactness ratio, thermal insulation, thermal bridges, airtightness, ventilation systems, space heating system capacity and supply temperature level are essential for investigating LTH potential and the need for renovations. Most research lacks qualitative renovation criteria and product-level information for selecting renovation options. Key performance indicators related to energy efficiency, thermal comfort and quality-of-services can help indicate the possible solutions, while those related to environmental and economic performance indicate the feasibility of possible solutions. Nevertheless, there is a lack of standard set of criteria for indicating the dwelling's readiness for using LTH. These findings can help address the decision-making challenges of selecting appropriate renovation strategies to enable the use of LTH and contribute to decarbonising the built environment.@en

This study presents an approach to determine the extent of renovation interventions required for existing Dutch dwellings aiming to transition to lower-temperature district heating (DH) systems. The proposed method is applied to a typical intermediate terraced house built before 1945 in the Netherlands, and it consists of two steps: first, assessing the potential of a dwelling to be heated with a lower temperature supply from DH systems and subsequently developing and evaluating alternative renovation solutions if necessary. This study defines a set of criteria for evaluating the readiness of a dwelling for lower-temperature heating (LTH), considering energy efficiency and thermal comfort as non-compensatory criteria. The application of the approach reveals that the case study dwelling is presently unsuitable for a medium-temperature (70/50 °C) and low-temperature (55/35 °C) supply compared to a high-temperature supply (90/70 °C), thus requiring energy renovations. Furthermore, this study indicates that moderate intervention levels are required for the dwelling to be lower-temperature-ready in both supply temperature goals. These interventions include strategies and measures that upgrade the building envelope to the minimum insulation levels stipulated by the Dutch Building Decree, improve airtightness, and replace existing radiators with low-temperature radiators. By systematically narrowing down renovation options, this approach aids in simplifying the decision-making process for selecting renovations for heating dwellings with LTH through DH systems, which could reduce stakeholders’ decision paralysis.@en

Energy-efficient buildings tend to cause thermal discomfort due to overheating during summers. With the advent of climate change and increasing outdoor temperatures, the risk of overheating will be exacerbated. Henceforth, the building design must be future proof or robust for climate change. Passive design strategies applied to the building envelope are crucial in reducing the energy demand and provide thermal comfort. However, it is essential to determine their performance in the presence of climate uncertainties, especially in the early design stage. Therefore, the paper illustrates an assessment method for investigating the robustness of the building envelope in curbing the risk of overheating in future climate change scenarios of 2050 and 2085. The study focused on educational buildings as thermal discomfort due to overheating affects students' productivity. The study analysed the performance of different passive design strategies applicable at building envelope in reducing overheating risk and evaluated the robustness using the statistical method of “best-case and worst-case scenario”. The robustness assessment method found fixed or dynamic shading, reduced window to wall ratios, albedo effect of the building envelope, and mixed-mode ventilation strategy with P.C.M. panels as the most robust design solutions. However, ventilative cooling would have limited application towards the latter part of the century@en

In the Netherlands, district heating with a lower temperature supply (<70°C) will play a crucial part in accomplishing the energy transition goals of delivering natural gas-free sustainable heating to dwellings. The existing dwellings often require energy renovations to make them suitable for lower temperature heating. However, choosing renovation strategies that promote the transition to lower temperature district heating while improving energy efficiency and thermal comfort is challenging. This study aims to identify minimum renovation requirements for comfortably heating homes using lower temperature heat from district heating. Identifying minimum renovation strategies to prepare existing dwellings for lower temperature district heating would be vital in addressing the European Renovation Wave's target of improving worst-performing buildings. For the same, the study uses a typical intermediate terraced house built before 1945 as a case study to investigate renovation strategies based on four levels of renovation intervention (no renovation, basic, moderate and deep). The impact of renovations on space heating demand and thermal comfort was tested with medium (70/50°C) and low supply (55/35°C) temperatures against key performance indicators (KPIs) using dynamic simulation. The study found that for the case study dwelling, moderate renovation strategy of upgrading the building envelope insulation by 0.40 W/m2K for opaque parts and 1.5 W/m2K for glazing, improving the airtightness by 0.3h-1 and replacing existing radiators with LT radiators can be considered as a no-regret solution for comfortably heating homes with both medium and lower temperature supply from district heating.@en