44 RACA Journal I July 2026
WINDOW RETROFITS technical units are decommissioned and loads are absorbed by the internal systems. This incremental approach minimises disruption, spreads capital cost over time and allows future technologies to be incorporated as they mature.
Although the full transition is expected to take up to 20 years, the building is already realising energy and comfort benefits – and critically, it has a clear pathway to electrification that would not have been possible without addressing the windows.
Beyond energy performance, the window upgrades delivered substantial comfort improvements. With reduced heat loss and gain, occupants can now sit closer to the façade without discomfort, reclaiming previously unusable perimeter space. The removal of noisy induction units further improved acoustic comfort.
Interestingly, tenant feedback focused less on energy savings and more on daylight quality, temperature stability and noise reduction. The new glazing appeared clearer than the old tinted film, improving views and occupant satisfaction – a powerful driver in premium commercial space.
RELEVANCE FOR SOUTH AFRICA While the One Maritime Plaza case study is based in a temperate US climate, the principles are directly applicable to South Africa:
• Many commercial buildings still rely on single glazing or poorly performing façades
• HVAC electrification is increasingly constrained by electrical supply limitations
• Envelope upgrades can significantly reduce peak demand, easing pressure on both plant and grid
• Secondary glazing and films offer cost-effective retrofit options with minimal disruption
As renewable energy and electrified HVAC systems become more prevalent, reducing thermal demand will be as important as improving plant efficiency.
The key lesson from this project is clear: energy-efficient HVAC systems cannot be designed in isolation. Windows, insulation and controls are not peripheral considerations – they are central to system feasibility, affordability and long-term performance.
For engineers, contractors and building owners alike, window upgrades have moved from being a‘ nice-to-have’ to a strategic tool in achieving energy efficiency, electrification and occupant comfort. In the drive toward a lower-carbon built environment, the path forward may be clearer than we think – if we are willing to look through the glass. RACA
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44 RACA Journal I July 2026
AIR CONDITIONING