What is innovative about this project?

  • Project planning and management: Ensuring cost-neutrality for residents after the renovation operation.
  • Technical: Promoting industrialised packages.
  • Technical: Putting in place modular building systems

Sociale Energie Sprong is a renovation concept based on economies of scale to speed up the retrofit of social housing buildings, while maintaining the overall cost affordable. The pilot project in Hoeselt, Belgium, was based on the usage of industrially prefabricated external cladding and energy modules, attached externally to the buildings’ façades. This process allowed an extraordinary 9 days of renovation works onsite, allowing tenants to remain in the building throughout.

Local Partnership

  • Company: BAM interbuild; energinvest; Enervalis; Veb
  • Municipality: Hoeselt
  • Housing provider: Cordium
  • Other: Flux50; Flanders Innovation and Entrepreneurship

Key Facts

  • Year of construction: 1970s
  • Renovation period: 2021-2022
  • Area of intervention (m²): N/A
  • Number of dwellings (before/after): 4
  • Housing typology: semi-detached
  • Housing tenure: Social (non-for-profit) rental housing
  • Number of residents: 7
  • Shared facilities:  Collective grey water recycling facility

Financial information

  • Funding sources: Cordium
  • Total cost of renovation (€): 460,00€
  • Subsidies received (€): 86,125 €
  • Rent before and after renovation (€/month): Before renovation: 319.16€ After renovation: 427.08€
  • Energy bill (€/month): Before renovation: 210€ (2528€ per year) After renovation: 48€ (576€ per year)

Context

The Sociale Energie Sprong is a renovation model for the social housing sector in Flanders, currently struggling with a mostly antiquated building stock. Given a sustained demand for affordable housing, the last couple of years saw a refocusing towards increasing supply of social housing, with a target to build 50.000 new dwellings by 2025 as well as on retrofitting the existent ones. As a result, the available budget for renovation increased substantially. However, the financial subsidies in Flanders are mostly directed to ownership, and the social housing sector has been lagging behind in terms of dedicated budget, which endangered reaching the mentioned targets. Sociale Energie Sprong has been put forward as an answer to this problem. The renovation of buildings through an industrialised concept, where a factory-based standardised model and the economies of scale enable to keep the costs for each individual renovation lower than average.

Goals

  • Accelerate energy-neutral renovation of social housing in Flanders towards 2050 climate objectives.
  • Relieve social housing companies of both technical and financial constraints during the deep renovation of their building stock.
  • Ensure a balance between energy production and consumption at home to reduce energy costs.

Interventions

  • Energy renovation of four dwellings including electric power supply. Homes are heated (possibly also cooled) with green electricity (100%). There is also the option of energy storage, individually or at district level. Flexible energy management ensures supply and demand are kept levelled.
  • Usage of BIM modelling during the planning and design phase. At the start, preparatory research was carried out involving tensile and destructive tests and 3D scanning by drones.
  • Installation of solar panels for energy generation.
  • Installation of an anchor system to attach the prefabricated panels during renovation works.
  • Integration of new technologies in an ‘energy module’. This energy module works exclusively within an electrical system (heat pump, balanced ventilation system, inverter, etc.), and ensures the building is zero-emission.
  • Re-use of rain- and greywater through different recovery systems (i.e., Hydraloop; IBA treatment plant).
  • Installation of an insulating building envelope with a prefabricated façade (including windows) and roof. The envelope was prefabricated. As the installation per se lasted just 9 days the tenants were able to stay at home during renovations.
  • Installation of an intelligent energy monitoring system with daily reports and an alert mechanism.
  • Usage of standardised prefabricated façades and energy modules. Tenants were able to stay at home during the renovation period, which lasted 9 days. Tenants were also given a schedule of the renovation works and consulted frequently.

Impact

  • The energy savings balanced the verified rent increases after renovation, which ensured an overall rent-neutral operation.
  • Residents are saving approx. 2,000€ per year compared to their previous energy bill.
  • Heat demand decreased by 89% which reflected in a reduction of 80% on the energy bill.
  • Water demand experienced similar trends. By re-using grey water, through IBA-systems (bacteria-based) and Hydraloop technologies water use drop by around 35%.
  • Carbon emissions have nearly been neutralised with a 90% reduction per household.
  • Today residents benefit from better living conditions in terms of thermal comfort, air quality and sound reductions.
  • The project results convinced the Flemish government to upscale the Sociale Energie Sprong renovation concept to other social housing dwellings in the district.

Advice to future “Lighthouse Districts”

  • Ensure effective collaboration with stakeholders and companies in the local construction ecosystem. This was decisive for Cordium to deliver the renovation at record-breaking speed.
  • Learn from past projects (mistakes and successes). Having taken note of problems and solutions in previous projects, delivering Sociale Energie Sprong was facilitated, as the design process incorporated all the lessons learned.