Itecons confirms strong thermal performance of Intura SunTube
The thermal performance of the Intura SunTube Daylight Sun Tunnel Systems has been independently assessed in a new report by research institute Itecons. The study calculated the UST values for the ST25, ST35 and ST55 systems, suitable for both flat and pitched roofs.
According to the report, the performance was evaluated in accordance with EAD 220021-00-0402, the French method Règles Th-U Fascicule 3, and the standards ISO 10077-2:2017 and ISO 10211:2017. This means the thermal behaviour of the various Intura SunTube components was analysed using recognised and reproducible calculation methods.
The results show that the Intura SunTube already achieves solid UST values without additional insulation: 2.44 W/m²K for ST25, 2.63 W/m²K for ST35, and 2.70 W/m²K for ST55. When an optional EcoPower insulation element is added, these values improve significantly. With double glazing (Ug 1.1) and a thermally improved spacer, the UST values decrease to 0.93, 0.94 and 0.91 W/m²K. In the best-performing configuration, using triple glazing (Ug 0.6) and a spacer with improved thermal performance, the results reach 0.70, 0.69 and as low as 0.65 W/m²K.
The report explains that the Intura SunTube systems consist of a light-transmitting dome, a curb, a highly reflective aluminium tunnel, a diffuser and, optionally, an additional EcoPower insulation element. For all three systems, this insulation element was included in the calculations as a combination of PIR panels, aluminium tunnel connectors and double or triple glazing.
" Intura Suntube demonstrates that a high-end daylight tube system can set the benchmark for both natural daylight and thermal performance."
With these results, Intura demonstrates that high-quality daylight solutions not only bring natural light deep into buildings, but can also support the performance requirements of an energy-efficient building envelope. The Itecons report is dated 2 March 2026.
Would you like to learn more about the Intura SunTube and the technical performance of our daylight systems? Contact Intura or explore the product specifications on our website.