Solar-Absorbing Façades: Turning Buildings into Energy Sources

A new solar façade technology developed by AkzoNobel, Emergo, and TNO is transforming the way buildings generate and store energy. Known as Calosol, the system integrates a solar-absorbing coating into façade panels, enabling walls to harvest heat from both visible and invisible (near-infrared) sunlight. This allows energy capture even on cloudy or rainy days.

A Smart and Aesthetic Energy Solution

At the heart of the Calosol system is a special AkzoNobel coating that converts solar radiation into usable heat. This heat is then transferred via liquid-filled tubes behind the panels to a heat pump, providing thermal energy for the building. Unlike traditional systems that rely solely on roof-mounted panels, Calosol makes it possible to transform façades—often an untapped surface—into energy-generating components.

The technology is suitable for both new builds and renovation projects, offering a pathway to reduce reliance on gas networks. According to AkzoNobel, buildings using Calosol can cut their electricity use by 20–30% compared with standard air-to-water heat pumps. In some cases, the system may even make homes and public buildings energy neutral or energy positive.

Sustainable Performance and Design Freedom

Calosol not only performs efficiently but also enhances the aesthetic potential of building envelopes. The panels are available in a range of colours—thanks to new pigment technology that allows even light or white façades to absorb solar heat. This makes the system particularly appealing to architects and developers seeking design flexibility alongside energy efficiency.

For housing associations, public buildings, and commercial developments, Calosol offers a scalable solution that contributes to BREEAM and LEED certification goals. Early pilot projects in the Netherlands, including housing complexes and a sports hall in Almere, have already demonstrated the system’s real-world potential.

Unlocking the Potential of Building Surfaces

With an estimated 60 billion square metres of unused façade surface across the European Union, technologies like Calosol present a major opportunity for the energy transition. By combining visual quality with technical performance, the system redefines façades as active, productive layers of the built environment.

As sustainability becomes a core driver of architectural innovation, façade-integrated solar systems like Calosol could play a key role in reshaping how designers think about materials, energy, and aesthetics.

Source: AkzoNobel, Emergo, BNR News