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Holistic Energy and Architectural Retrofit Toolkit

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Novel toolkit and innovative management system improve old buildings’ energy efficiency

Europe must retrofit millions of buildings to make them energy efficient. A synergistic energy retrofit toolkit, driven by a cloud-based management system, helps make this goal possible by optimising buildings’ energy performance.

Climate Change and Environment

Buildings account for 40 % of all energy consumption and a third of greenhouse emissions. Europe’s buildings are generally quite energy inefficient, and although the EU has introduced guidelines for greater efficiency, meeting them is not simple. In parallel, previous efforts to improve buildings’ thermal efficiency have focused on heating. Yet as summers become hotter and longer, Europe faces an increasing need for cooling as well. This greatly adds to buildings’ energy consumption. The EU-funded HEART project developed a toolkit for the retrofitting of buildings to improve their year-round energy performance. The project targets European multistorey residential buildings dating from the second half of the 20th century, located in mid-latitude regions having a moderate climate. This category includes over one million buildings. Using the toolkit, the HEART team will transform most of these buildings to comply with Europe’s building energy guidelines called nearly zero energy buildings (nZEBs). In part, nZEB means that the building produces at least 50 % of the energy it consumes. In a few cases, the retrofitted buildings will use zero energy. To achieve all this, the project updated and optimised the existing products of its partner members.

Cloud computing management system

The central element of the toolkit is a cloud-based computing platform. It runs various active and passive subsystems, thereby transforming an old building into a highly efficient smart building. The platform also supports planning- or design-stage and operational decisions concerning the energy management of buildings. The system is automatic, but building managers and operators can monitor it via user interface tools developed in the project. Not only does the cloud platform manage building operations, it does so transparently. “This is a strategic factor, for operation and maintenance,” explains Professor Niccolò Aste, project coordinator, “but it also facilitates alternative forms of financing. For example, private investors can fund renovation work and profit from energy savings. The transparency increases confidence in the investment.”

Many supporting subsystems

The cloud system is the controlling brain. It connects and optimises the functioning of numerous other components. For example, the system monitors external weather conditions and adapts the operation of heating, ventilation and air-conditioning installations to provide maximum comfort with minimum energy consumption. The system additionally produces its own energy using photovoltaic roof tiles, and, thanks to the heat pump, stores electricity surplus in the form of thermal energy to heat or cool the building. Even when solar radiation is poor HEART can also exchange energy with the grid. In addition to the photovoltaic roof system and a highly insulating façade cladding, researchers also developed techniques and components for the complete or partial replacement of windows. As of December 2021, the project was nearly finished, with minor additional testing and fine-tuning to go before the system is ready for commercialisation. “For the moment,” adds Aste, “the signals are positive, and there are already operators who want to buy and apply the system, even before the project is finished.” Unlike competitor systems, this one tightly integrates all aspects of managing a building’s energy performance into a single toolkit. This allows Europe’s inefficient old buildings to be retrofitted, ensuring their compliance with nZEB guidelines while substantially reducing Europe’s greenhouse emissions.


HEART, nZEB, management system, cloud platform, retrofitting, nearly zero energy buildings, insulation

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