Turning Walls into Power Generators

In a pioneering step for sustainable construction, AkzoNobel has become the exclusive paint supplier for Calosol, a solar-absorbing façade technology developed in collaboration with Dutch innovation partners Emergo and TNO. The system converts façades and roofs into energy-producing surfaces, capable of capturing solar heat even on overcast days.

Across the European Union, an estimated 120 billion square metres of surface area – mainly roofs and façades – could be harnessed to generate electricity and heat. Calosol aims to unlock this potential, offering a cost-effective route to make existing buildings energy-positive.

Innovative Coating at the Core

At the heart of the system lies an advanced coating co-developed by AkzoNobel. Traditional architectural paints reflect sunlight to keep buildings cool; Calosol’s innovation reverses this principle. By fine-tuning the paint’s spectral properties to absorb rather than reflect solar radiation, the coating captures energy from the portion of sunlight invisible to the human eye.

This means façades can be produced in a full range of colours — even a shade of white that absorbs over 30% more solar energy than conventional formulations. Combined with heat-retaining panels, the system can utilise between 40% and 100% of available sunlight, depending on configuration.

Energy-Positive, Affordable and Scalable

Around 60% of the energy consumed by European buildings is used for heating — a figure that underscores the scale of opportunity. With the Calosol system, walls and façades can supply much of this energy, reducing the need for external power sources or gas heating.

The technology is particularly valuable for Europe’s older building stock: more than 80% of EU homes were built before 1990, with limited insulation. Retrofitting these properties with modular Calosol panels offers a simple, low-cost path to energy-positive performance — often paying for itself faster than air-source or ground-loop heat pumps.

EU-Backed Development

The Calosol technology forms part of ENVISION, an EU-funded project led by TNO that promotes modular renovation solutions for sustainable housing. The concept involves wrapping existing homes in prefabricated structures equipped with solar façades, roof-mounted photovoltaic panels and energy-harvesting windows. Demonstration projects are underway across Europe, validating the model’s technical and economic potential.

A Collaborative Step Towards Net-Zero

“The built environment accounts for around 39% of global energy-related carbon emissions,” says Wijnand Bruinsma, Director of Sustainability at AkzoNobel. “This partnership is another important step in helping to decarbonise the buildings that will still be standing long after 2050.”

Emergo’s Director Hendrik-Jan Weggeman adds that Calosol complements sustainable prefab façade and roofing systems, particularly for renovations of residential and public buildings with significant heating needs.

With 60 billion square metres of unused façade surface and an equal expanse of roof space across the EU, the potential is immense. For AkzoNobel, which has built its reputation on coating innovation since 1792, the project reinforces a simple but transformative idea: façades are no longer just protective layers — they can power the buildings of tomorrow.