Sustainability in construction is evolving from a challenge to an opportunity for innovation. The INBUILT project is at the forefront of this transformation, integrating bio-based recycled materials and smart technologies to improve building performance. Among these innovations, bio-based polyurethane (bioPUR) window with plasmochromic (PLSMS) smart glazing represent a breakthrough in energy-efficient and adaptable window solutions.

BioPUR Window Frame: A Sustainable and High-Performance Solution

The bio-based polyurethane window frame offers a high-performance, sustainable alternative to traditional materials, combining durability with exceptional thermal and acoustic insulation. Its dense structure ensures superior energy efficiency, with low thermal transmittance (Uf = 0.81 W/(m²K) that enhances indoor comfort. The frame’s advanced acoustic insulation significantly reduces noise, making it ideal for urban environments. Designed to withstand harsh weather conditions, it provides excellent water tightness and wind resistance, ensuring long-term reliability. Additionally, its recyclable and lightweight nature makes it an environmentally friendly choice as it requires minimal maintenance compared to conventional timber frames.

Integration with Plasmochromic Smart Glazing

Within the INBUILT project, INDRESMAT effectively integrates a bioPUR frame with plasmochromic smart glazing, which is developed by LEITAT. The smart glazing is capable of selectively controlling the incoming solar radiation and dynamically adapting to light intensity changes. In this way, the windows permit indoor occupants to dynamically filter out the amount of thermal radiation passing through the window by blocking the solar heat gain during hot summer days and allow radiation heating in winter conditions. This system not only enhances energy efficiency, but also optimizes visibility, and reduces glare.

The integration follows this structure:

Smart Glazing Setup: A plasmochromic glazing unit (600x800x31 mm) is connected to a power control unit via cables – anode and catode terminals - through the window profile.

Control Unit Installation: The control unit is mounted on the bioPUR sash with hidden cables routed through the sash, or alternatively, it can be mounted in the wall around the window, offering flexibility in its installation.

Sensor Integration: A pyranometer is connected to the control unit, dynamically adjusting the tinting state based on sunlight levels.

How BioPUR Window Frame with Smart Glazing Resolves Current Market Challenges

Windows & doors are among the most critical weak points in a building’s thermal envelope. Consumers increasingly demand durable, high-performance solutions, as many highly energy-efficient frames rely on hollow multilayer structures that deform over time. These traditional frames suffer from dimensional instability, thermal bridging through air convection, and moisture infiltration, leading to performance loss.

BioPUR window frame addresses these issues by offering a homogeneous solid-frame design, eliminating the structural weaknesses of hollow profiles. It ensures long-term stability, improved thermal and acoustic insulation, and reduced environmental impact — all key factors for energy-efficient and sustainable construction.

Moreover, integrating plasmochromic glazing technology to bioPUR window frames can offer dynamic solar and heat control. This enables the window to automatically adjust its light transmission and heat absorption. In warm weather, it can block excessive heat, and in cooler conditions, it may allow more sunlight to pass through, contributing to energy efficiency and comfort. Additionally, it helps maintain comfortable indoor lighting conditions by adjusting to the intensity of natural sunlight, reducing glare, and enhancing visibility without overexposing rooms to sunlight.

This article was written by Guzide Aslankaya and Pablo R. Outón from INDRESMAT for the INBUILT project. For more information, please contact: info@indresmat.com