The EU-funded DigiFab project combines digital tools, adaptable prefabrication and occupant co-creation to reduce uncertainty, costs and disruption in energy renovation, while improving the efficiency and sustainability of the renovation process.
Author
Carlos Ernesto Ochoa Morales, Senior Researcher at Tyndall National Institute
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(Note: Opinions in the articles are of the authors only and do not necessarily reflect the opinion of the European Union)
Prefabrication has been suggested as a feasible solution for energy renovation (Maduta et al., 2022) to benefit a higher proportion of the EU population (Eurostat, 2026). Current barriers to wider implementation that increase costs include high variability of building features, missing or poor information, inadequate planning of the renovation activity, uneven application of rules under the Energy Performance of Buildings Directive (EPBD), and misunderstanding occupants’ wishes and expectations.
Addressing these issues, the EU-funded DigiFab project is developing a digital energy renovation process chain that will provide a single source of information accessible to project stakeholders from project start to delivery and adapt to different situations by transferring this same data to different tools for energy analysis and life cycle assessment (LCA), indoor air quality improvement and optimisation of façade subdivision for panel production. Costly installation errors and material waste will be reduced. Co-creation is also introduced in the planning process to identify occupant expectations and translate them into prefabricated panel design. It also helps to understand what they value in the energy renovation process and the best times for the renovation to take place to reduce disturbance and wasted days.
Advanced planning of the installation is also included to reduce disturbance and waste sent to landfill, thereby reducing the environmental impacts of construction. Site safety is also considered by reducing risks to workers through specialised noise and equipment proximity sensors. Panels are tracked for delivery and installation using quick response (QR) codes.
Circularity approaches in the manufacture of the prefabricated panels reduce the carbon footprint and energy use, including through lightweight concrete mixes with insulating and recycled materials, bio-based materials, active envelope heating technologies, plug-and-play building-integrated photovoltaic panels.
The process will reduce installation time, achieving two days per unit of 200m2 surface, with 30% lower costs than conventional renovation by reducing labour and soft costs.
The most common energy upgrading methods include manual attachment of individual insulation panels to the building envelope, which are cut to measure on site and covered with render layers. Such procedures, although widespread nowadays, are slow and impractical for achieving the goals of the EPBD, such as renovating 16% of the worst energy-performing stock in the EU by 2030 (European Commission, 2026). At the same time, building energy renovation is expensive and in many Member States currently depends on financial incentives to be viable for broader segments of building owners and operators, as the current level of energy renovation is insufficient to benefit the wider EU population (Eurostat, 2026). It is also time-consuming, which increases hidden costs, since it involves a process of convincing different stakeholders (owners, inhabitants, occupants) to change their routines or even lose income due to prolonged disruption of activities and modifications of the space. This process can also result in misunderstandings about occupants’ expectations. They might reject a renovation perceived as an imposition. Basic building information that is used as input for the energy renovation (e.g. floor and elevation measurements and drawings, assessment of structural condition) also needs to be gathered by several parties, since records for older buildings are often missing or outdated. Having different measurement methods and parties involved also results in the need for data verification to avoid discrepancies, which adds to the overall costs of planning energy renovations.
Prefabrication, understood here as the installation of self-contained insulating panels produced off-site and attached to the building envelope to complete the energy upgrade, has been suggested as a suitable way to accelerate the renovation rate, reduce costs and contribute to national renovation plans (Maduta et al., 2022), as it allows mass production of building components with shorter installation times . It is also currently used by several construction manufacturing companies as part of their commercial offering to renovate buildings.
Nevertheless, specific barriers hinder widespread application of prefabrication and prevent the achievement of the desired goals of reduced construction costs and streamlined installation. These include high variability of building typologies preventing mass production, missing building information, poor installation planning and logistics, and lack of communication between parties involved. Such factors add to the final cost of the renovation and undermine its competitiveness compared to traditional energy renovation.
To address this, a consortium of 15 partners in the EU-funded DigiFab project (DigiFab, 2026) is developing a digital energy renovation process chain to accelerate energy renovations in buildings using adaptable prefabrication. It is based on work carried out under the International Energy Agency (IEA Energy Conservation in Buildings and Community Systems (ECBCS) Annex 50 (IEA ECBCS, 2011). The seminal work is updated to integrate current energy analysis and LCA tools and perspectives, novel prefabrication technologies to save weight and space, control and monitoring strategies, and the incorporation of co-creation techniques to recognise the expectations and experiences of stakeholders (owners, builders, designers and residents) and integrate them into the design process, supporting a user-driven innovation approach to energy renovation. It also expands the approach to include worker safety, environmental impacts and reductions in soft and hard costs by reducing time spent on site. Sustainability is also considered in this process by tracking and reducing any recyclable construction waste produced. This will contribute to achieving an energy renovation process with lower overall costs through reduced uncertainty, minimal waste production and optimisation of time spent on site through stakeholder cooperation. The project will be demonstrated in three different types of buildings located in Austria, Greece and Spain.
Figure 1. Summary of prefabricated modules and digital tools to be developed by DigiFab. Source: Susana Martín.
A single source of information with trackable and transferable information from the start of an energy renovation project to delivery will reduce hidden costs from constant corrections and verifications of data generated in the previous stages, reducing delays and accelerating design decisions. One way to achieve this goal is through a common data cloud or platform accessible to and updated by parties involved in the renovation activity. In this way, different software tools can access the most up-to-date version of this information to produce their own results and feed them back to the data platform for use by another tool at a later stage. Currently, this is not usual practice. The format of the platform is currently under development by project partners.
Since the quality of analysis depends on the quality of data entered, updated information is entered in this data cloud using state-of-the-art methods. One example is the use of laser scanning to measure target surfaces and create the basis for a digital twin based on building information modelling (BIM) for subsequent energy and sustainability analysis and manufacturing optimisation, reducing personnel costs by avoiding the creation of multiple models by consultants. A complete record of initial external wall conditions is kept to choose the most appropriate structural supports and anchoring elements. This will help to improve budgeting and planning of the interventions. Prefabricated panel manufacturers have access to the BIM geometry and selected measurements to apply adaptive surface subdivision techniques, optimising material use while minimising installation waste and errors. Panels are tracked for delivery and installation using QR codes.
Based on the information entered during the data gathering stage, energy analysis can start semi-automatically, since several factors (desired cost, results from co-creation, etc.) still need to be specified by consultants. Well-known software such as TRNSYS and EnergyPlus can be adapted to this analysis as modelling engines. The energy analysis processes data to recommend packages of energy renovation measures, using the characteristics of the prefabricated modules suggested by the research project. This will also define key manufacturing parameters such as insulation thickness to help reach nearly zero-energy building levels, which will help achieve EPBD goals.
Due to the nature of the buildings being renovated, which can be several decades old, data uncertainty is almost unavoidable and needs to be addressed to minimise errors that might have an impact on the installation or commissioning stages. Uncertainty in input data for energy modelling is addressed through techniques such as Monte Carlo simulation, with the analysts being made aware of the assumptions and tolerances. The data can also support LCA to inform decision-making on the long-term implications for sustainability and emissions. Data interoperability between formats and data loss during conversion from BIM formats to energy-modelling formats are still being analysed.
Circularity approaches are used in renovation panel manufacture to reduce the carbon footprint and energy use. This will help comply with upcoming regulations regarding the embodied energy of building components. New developments for prefabricated panels and controls within the project include lightweight concrete mixes with insulating and recycled materials, bio-based insulating materials using wood, active envelope heating technologies, plug-and-play building-integrated photovoltaic panels, and heating, ventilation and air-conditioning control algorithms that improve indoor air quality. The insulating wood panels will also incorporate the active heating envelopes, reducing time and space for installing both types. The overall panel developments will also influence the final price of the renovation by making the solutions more adaptable to a wider range of buildings.
Panel manufacture and installation can be tracked using QR codes to reduce uncertainty regarding the physical location of the panels and their position within the façade. This feature helps reduce costs by aiding quality control.
Often, inhabitants or building occupants are not enthusiastic about energy renovations since traditional renovation processes usually do not consider their wishes and expectations, even if in abstract terms they might recognise the benefits of decarbonisation and energy efficiency. Building users usually must weigh economic and non-economic benefits of energy renovation against disturbances brought by the process, such as waste generation, noise and dust, lack of guarantees regarding disruption to daily routines and possible loss of revenue in the case of commercial buildings.
To solve this, DigiFab proposes a co-creation approach tailored to the types of buildings being renovated. The approach is not limited to an information workshop or survey but uses these elements as tools tailored to the occupants’ level of involvement with their building. The co-creation process begins by explaining to occupants and inhabitants the benefits of the technologies and how they work. It also uses the sessions to collect their viewpoints in structured formats such as interviews, surveys or diaries. Key points and pain points in occupants’ expectations and wishes are identified. These are conveyed to designers for consideration during the analysis. The co-creation sessions also provide insights into occupants’ routines to plan the best times for installation, thus reducing disturbances and optimising time spent on site. This provides a rare opportunity for two-way dialogue between users and designers on energy renovation.
Installation workers are also protected through advanced planning of the construction site. This reduces health and safety risks that could cause stoppages (and subsequent unexpected costs). A workplace solution incorporating noise and bulky equipment proximity sensors monitors whether safe levels are maintained throughout the installation activity. The building site also contributes to the circular economy by identifying potential construction waste that could be reused, such as packaging and concrete.
An additional result from the project is a comparative analysis of EU legislation, regulations and standards that affect energy renovation using prefabrication. It is useful to compare the conditions for application as part of the market analysis and assess whether costs differ between markets as a result.
An in-depth analysis was carried out in the consortium countries. It found that although European directives provide the framework to incentivise and implement energy renovation (such as the EPBD, which provides the target level for energy use in a renovated building), approaches to transposition and implementation vary across Member States.
In some Member States, enactment and approval of the requirements to be met for energy renovations are carried out at the national level, while in others they are carried out at regional level (states, provinces, regions). As another layer of regulation, in some countries and regions specifications are contained in legally binding building codes, while in other cases the legally binding code refers to a non-binding standard. In addition, at the time of writing, the current version of the EPBD has not been transposed to national legislation in all Member States.
This has consequences for the final cost of panel manufacture and time spent on site and on analysis, as the digital chain approach must adapt to the specific rules and regulations. Indirectly, it can influence the cost of the solutions, as approval of the renovation project can follow different administrative timelines.
Figure 2. Aspects addressed by norms and non-binding documents at the EU and national level with a focus on the DigiFab consortium countries: Spain, Poland, Italy, Ireland, Greece, Belgium and Austria. Source: Orfali Soria et al., 2026.
Overall project outcomes will help make financing of energy renovation processes easier to access. Reductions in direct and hidden costs, time requirements and rejection of renovation proposals will improve uptake and make the DigiFab approach more attractive for financing.
It is expected that the digital process chain will reduce installation time, achieving two days per unit of 200m2, with 30% lower costs than conventional renovation. It also offers a customisable approach for diverse building types. The process will facilitate adoption of digital tools by small and medium-sized construction enterprises and prefabricated panel manufacturers, giving them access to a single source of digital information. Higher satisfaction levels are expected by considering user expectations in the process design.
Digitalisation of construction processes is essential to achieve an energy renovation process with controllable and trackable costs. Together with lower levels of disturbance, this will facilitate financing by lowering costs to a level that is more accessible and acceptable to those responsible for decisions on energy renovations. Technologies that can support the achievement of this goal while meeting targets for emissions, decarbonisation and upcoming sustainability legislation are also necessary, such as novel materials for prefabricated modules made from recycled or bio-based materials. The digitalisation process must be open to new technologies and improved data exchange formats.
