Energy-Efficient Retrofit at UKZN’s Oliver Tambo Building

Project Partners: REHAU | Cape Windows Group | GVK-Siya Zama | Saint-Gobain | National Glass

As part of a national pilot study into energy-saving construction methods, the University of KwaZulu-Natal (UKZN) selected REHAU to take part in an ambitious retrofit of the Oliver Tambo Building on its Westville campus.

The aim? To test the real-world performance of modern double-glazed uPVC window systems and external thermal insulation on an older building — and measure the impact on energy usage and costs.

High-Performance Retrofit

Nine north-facing aluminium windows on the first floor were replaced with 20 mm double-glazed uPVC units, fabricated from REHAU’s UV-resistant Ecotec profile. These windows were manufactured by Cape Windows Group, a REHAU Authorised Partner, with National Glass supplying the glass. Installation was handled by GVK-Siya Zama, who managed the full replacement process, from removing the old aluminium frames to precision-fitting the new REHAU windows.

To complement the window upgrade, the team applied Saint-Gobain’s ETICS thermal insulation system — polystyrene panels mounted externally to help regulate internal temperatures.

Real Results, Tangible Benefits

This specific section of the building was selected due to its direct sun exposure, which previously caused excessive heat build-up and over-reliance on air conditioning. After the retrofit, UKZN Energy Management head Greg Diana reported a 20% reduction in energy costs in just one month (May 2014), thanks to the improved thermal performance of the new window and insulation system.

Thermal imaging comparisons revealed a stark contrast in heat gain: at an outside temperature of 35°C, the REHAU double-glazed uPVC windows registered just 38°C — versus 52°C for the original aluminium windows. That’s a 36% improvement in thermal efficiency.

What This Means for Future Projects

For developers and contractors, this project offers clear proof: upgrading to REHAU uPVC double-glazing and pairing it with external thermal insulation can dramatically reduce energy loads in existing buildings — without major structural changes.

As energy regulations tighten and operational costs climb, energy-efficient retrofits like this present real opportunities to add value, meet compliance, and future-proof building portfolios.

UKZN will release full performance data as the study continues, but early results already highlight the significant benefits of specifying REHAU uPVC systems for sustainable building upgrades.