The HeriTACE project develops technical renovation solutions for historical buildings. By the end of the project, the solutions aim to reach a higher Technology Readiness Level (TRL), and target set. Below, there is the summary of the twelve technical renovation solutions, divided into three major groups, that are developed in the HeriTACE project.
The methodology involves evaluating the building envelope through qualitative and quantitative analyses, considering heritage value, thermal performance, and durability. These assessments establish the baseline condition and inform potential interventions across various building typologies, encompassing both traditional and innovative materials. Façade improvements—such as interior and exterior insulation (ETICS) and window upgrades—receive particular focus due to their challenges in conservation practice. Proposed solutions aim to reduce environmental impact by reusing existing components, incorporating low-carbon materials, and optimising interactions between indoor climate, HVAC systems, and hygrothermal behaviour to balance performance and risk. Targets:
Development of Innovative ETICS with historical appearance considering using bio-based insulation materials.
TRL: TRL 3 → TRL 5 (The solutions are tested and validated in test cell and subjected to real weather.)
The project aims to create and test long-lasting exterior insulation that preserves the original look of building façades, both new and aged. Designs include thin and thick finishes using traditional and modern materials, compatible with natural insulation like wood wool. Visual checks ensure the façades maintain their historic appearance over time.
The insulation systems are tested for how they handle heat and moisture, using a combination of real measurements and computer models. This approach ensures accurate predictions of performance across different climates and future weather conditions. Testing take place in three stages:
The data refines models to predict long-term performance and reliability under changing climate conditions, helping ensure insulation solutions remain effective and visually authentic for years to come.
Development of solution where a modern triple glazed window are used instead of old interior window frame and part of the old jamb. Historic window frames are optimized for airtightness performance.
TRL: TRL3 →TRL4 (The window prototypes tested in lab)
Historic windows often have high heat loss and air leakage, which significantly affects a building's energy performance. Improving airtightness is a relatively simple way to enhance comfort, reduce energy use, and support HVAC efficiency, but technical guidance for heritage window types is limited.
Where exterior appearance must be preserved, solutions may include retaining the original frame with double glazing; where only the exterior matters, parts of the frame can be replaced to accommodate modern triple-glazed windows. HeriTACE develop this innovative heritage window systems with improved thermal and airtight performance are being developed and tested, evaluating airtightness, water resistance, thermal efficiency, and condensation risk through experiments and modeling. New rapid testing methods are also being explored to enable faster on-site airtightness assessment for quality control and maintenance.
Climate resilient and moisture safe envelope solutions for wooden structures are developed.
TRL: TRL3 → TRL5 (The solutions are tested and validated in test cell and subjected to real weather.)
Targets:
The project aims to develop a model for monitoring and managing moisture in renovated walls, and to explore ventilation strategies that reduce the risk of mold in historical wooden structures by incorporating new control parameters.
TRL: TRL2 → TRL4-5 (ventilation strategies tested by means of simulation)
We are developing innovative strategies to balance indoor comfort, mould prevention, and energy efficiency. In Northern climates, we use building simulations to test ventilation and air-treatment methods for historic wooden buildings. Two approaches are being explored:
Optimized ventilation strategies and control logics for historical houses are developed and validated using Internal Air Quality (IAQ) management rating methods, while minimizing the number of system components and ductwork
TRL: TRL2 → TRL6 (concept performances quantified by means of simulation)
Traditional central ventilation systems are often hard to integrate in historic buildings. New approaches, like cascade ventilation, aim to ensure good indoor air quality with fewer components and less ductwork. The choice between natural ventilation, mechanical exhaust, or balanced systems with heat recovery depends on climate, building use, layout, and airtightness. Smart controls that respond to humidity and pollutants can improve both air quality and energy efficiency—studies show up to 60% reduction in ventilation related heat losses compared to constant-flow systems.
The HeriTACE project optimizes existing best-practice ventilation designs for historic houses using simulations to predict air quality, humidity, and energy performance for typical uses. Key design principles include reducing direct supply points, allowing air circulation between spaces, and using components with integrated sensors and controls. The project produce validated ventilation concepts, technical specifications, and guidance tailored to climate and building type, helping update future ventilation standards.
Developing the tool into a decision-making guide for specific use of ventilative cooling in historical buildings.
TRL: TRL3 → TRL6 (improved tool demonstrated and extended)
HeriTACE is creating guidelines to explore how ventilative cooling can help cool renovated historical townhouses and make them more climate-resilient. By updating an established ventilative cooling assessment tool, the project provide practical guidance on designing ventilation for these buildings. A key focus is calculating indoor temperatures based on building materials' thermal properties. The project also address a potential conflict: ventilative cooling works best with heavy, heat-retaining structures, while modern smart HVAC systems perform better in lighter, low-thermal-mass buildings.
A method is developed to size hybrid heating systems combining central base-load and local comfort units, with configurations and smart controls for renovated historic homes tested virtually.
TRL: TRL2 → TRL5 (performance evaluation by means of simulations)
The project proposes a base heating system for townhouses that operates at lower water temperatures, using existing radiators wherever possible. Local or additional heating units can be added in rooms that need extra heat. An innovative design method helps size the base system and choose these local components based on both energy use and comfort. The approach uses the concept of energy sufficiency, which aims to provide "enough" heating rather than excessive amounts, helping reduce energy consumption and emissions. Studies suggest sufficiency could save up to 15% more energy than traditional methods. Simulations assess each room's comfort, moisture risk, and energy demand, guiding decisions on room use, heating design, and energy savings. The project also tests smart, demand-based controls that adjust heating according to how rooms are used. This helps prevent the "performance gap" often seen after renovations, where energy savings are lower than expected due to higher average indoor temperatures.
HeriTACE aims to make renewable and residual energy solutions practical, effective, and scalable for heritage buildings. We focus on three main innovations, expanding from single buildings to entire building blocks:
By combining these strategies, even hard-to-decarbonize heritage buildings can become energy-efficient while respecting their historical value.
The BIPV rooftop tile solution combines lightweight laminates, available in a range of colors, with a snap-in mounting frame developed during the previous HEART project. Arranged side by side, the PV tiles create a waterproof and ventilated layer while utilizing the same mounting structure as the tiles they replace. The components are produced in various optimized sizes, ensuring easy adaptation to the most common roofing systems.
TRL: TRL4 → TRL5
HeriTACE researchers are developing a new type of solar roof tile designed for historic buildings. These lightweight, easy-to-install tiles snap into place, ensuring quick installation and waterproofing. They come in various sizes and can adapt to common historic roof styles. Special attention is being given to make them visually blend with traditional roofs, matching colors, textures, and tile dimensions, while requiring minimal changes to the existing structure. The prototype undergoes lab testing to measure its performance.
To make the system more cost-effective, a smart control method called Model Predictive Control (MPC) is used in a new approach to design the system. This approach optimizes the size of the system's components while allowing flexibility, which reduces overall costs. The method is demonstrated through simulations for different building and HVAC setups.
TRL: TRL2 → TRL4
The project explores ways to recover unused local heat in historic city areas, where heritage rules and limited space make standard solutions tricky. HeriTACE has found potential heat sources in large, uninsulated attics of heritage buildings and around underground parking garages. This heat could be tapped through collective energy systems, like heat pumps and seasonal storage. Researchers study these options using temperature data, structural analysis, and virtual simulations.
Historic, less insulated buildings are not well documented and have relatively unimportant internal heat gains. A new method is developed that instead calibrates the more uncertain building parameters.
TRL: TRL2 → TRL6 (Calibration method for supporting MPC in historical buildings)
Ensuring thermal comfort at minimal cost while maximizing renewable energy use requires smart system integration—especially in historic buildings, where preservation rules limit design options. Model Predictive Control (MPC) has proven effective for reducing energy use and CO₂ emissions in buildings and districts. The HeriTACE project tackles three main challenges to apply MPC in heritage buildings:
HeriTACE uses a detailed, physics-based "white-box" model of buildings and energy systems, which offers clear, reliable insights—unlike data-driven "black-box" models. While this approach works well for new buildings, older buildings often have unknown parameters. HeriTACE solves this by calibrating the model with real measurements (like room temperatures), enabling accurate control. The calibrated MPC is tested in a Belgian heritage building, including automated fault detection to catch system issues early and lower maintenance costs.
To maintain high system performance and minimize maintenance costs, automated continuous commissioning is essential. The project compare outputs from a calibrated white-box MPC model with sensor data to detect faults or failures at an early stage. This fault detection approach has been demonstrated in one pilot project.
TRL: TRL2 → TRL5
HeriTACE partners extend MPC to a Mixed Integer Nonlinear Programming (MINLP) framework by incorporating physical models of the buildings and hydraulic circuits. Additionally, short-term MPC are integrated with long-term MPC, and a distributed MPC approach are developed. All these extensions are demonstrated through a virtual case study of a historical building block.
HeriTACE partners are developing smarter ways to control and size energy systems in buildings and building clusters. By looking at the whole system rather than individual components, we can increase flexibility and efficiency. Advanced control methods (Model Predictive Control, MPC) are applied at the building-block level, accounting for complex system behaviors and constraints. Unlike previous approaches, we use physical models of buildings to ensure thermal comfort and maximize renewable energy use.
Energy flows through thermal networks, so hydraulic modeling is included. Short-term and long-term control strategies are combined to make the best use of seasonal energy storage. For larger, more complex districts, we are developing distributed control, where each building or subsystem operates semi-independently but communicates with others to achieve optimal overall performance. This reduces computational load without sacrificing efficiency.
On the sizing side, we aim to avoid oversizing energy components by integrating control strategies into the design process. Optimal sizes for energy supply and storage devices are determined using nested optimization, considering costs, emissions, and system flexibility. Robustness is ensured by stress-testing against extreme scenarios and adjusting sizes as needed. These methods are demonstrated virtually on a historic building block.