‘The stakes are high. Buildings are long-lived assets – a building constructed today will likely stand for 30 to 40 years, if not longer.

‘That means the decisions we make now […] will lock in performance for decades to come,’ says Marloes Reinink, founder and director of sustainability consultancy Solid Green, highlighting the importance of integrating green principles into the design of buildings from the get-go. However, getting the message across is easier said than done.

‘One of the major hurdles to adopting green building best practice and certification is the perceived additional cost premium when compared to a conventional building,’ says the Green Building Council of South Africa (GBCSA). To counter that perception, the GBCSA, working with the University of Pretoria and the Association of South African Quantity Surveyors, started producing its ‘cost of green report’ in 2014. The 2025 report, released at the beginning of September, shows that the green building cost premium (GBCP) of new, green-certified office buildings compared to their non-certified counterparts has continued to narrow to an average of only 2.4% for the 2022–2024 period from an average GBCP of 5.95% in 2009–2014.

The report also features a comparison of two hypothetical office buildings (similar in every respect except that one is green certified), which shows the return-on-investment for the green-certified building is 240 basis points, or 63.7%, higher than for the non-certified building, despite the total capital outlay of the green building being 2.1% higher. Not only that… the capitalised value of the green-certified building is 74.1% higher than its non-certified counterpart.

‘Property owners need to understand that certification isn’t the end goal,’ says Lisa Reynolds, CEO of the GBCSA.

‘It’s how you prove that a building is actually performing in practice and on paper. It gives owners, investors and tenants confidence that a building will deliver environmental and financial value over time,’ she says.

The GBCSA has issued more than 1 500 certifications since its inception in 2007. While most of these are Green Star certifications, the GBCSA also confers the Edge – the IFC’s global standard for Excellence in Design for Greater Efficiencies – and Net Zero certifications.

The Green Star certifications range from One Star (‘On the journey to a better, greener building’) to Six Star (demonstrating ‘world leadership’) and offers four rating tools –existing building performance (EBP); new buildings and major refurbishments; interiors; and sustainable precincts.

The GBCSA’s EPB certification ensures that existing buildings measure and monitor their performance for both energy and water.

‘Buildings can be certified at any level – One Star ratings and onward. Sustainability is a journey, and GBCSA encourages building owners to measure where their building lies in that journey and constantly improve on it,’ says Reynolds. She explains that buildings can be retrofitted with low-cost interventions to start, which can have a payback period of less than two years. Not only does a retrofitted building benefit from the lowered cost of utilities, but it also results in job creation possibilities, she says.

‘Quite a few of the big property portfolio owners and some owner/tenant companies have committed to a large percentage of their buildings being Net Zero carbon in the next 5 to 10 years. The bulk of these portfolios are existing buildings,’ says Reynolds.

For example, Balwin Properties’ head office at 105 Corlett Drive opposite Melrose Arch in Johannesburg – achieved an As Built 6-Star Green Star rating in April 2025. The project also earned a 6-Star Green Star rating for design as well as Net Zero Level 1 ratings for waste and carbon.

‘The Net Zero waste is a unique rating which has not been achieved for a retrofit of this scale before. This rating is achieved by diverting all waste from the construction process away from landfill,’ according to Matthew Whalley, Balwin Energy MD.

Reinink reinforces the case for retrofitting existing buildings. ‘The greenest building is always the one that already exists. Demolishing and rebuilding comes with enormous embodied carbon costs, whereas retrofitting allows us to extend the life of buildings and improve performance at a fraction of the environmental impact,’ she says. And retrofitting does not have to mean an enormous capital outlay.

For example, she says Solid Green recently worked on an existing building where a simple remedy to correct control settings (such as preventing air conditioning from running over weekends) ‘delivered a 40% saving on HVAC consumption without any major capital investment’.

Reinink warns that relying purely on technology, such as solar PV and more efficient HVAC systems, to chase green goals has its drawbacks.

‘If we rely on technology alone, we risk treating the symptoms instead of addressing the cause. By prioritising climate-appropriate design, we create buildings that inherently perform better – and then use technology selectively to fine-tune that performance,’ she says.

‘The real starting point is good design that responds to the climate in which the building sits. Passive design strategies – such as orien-tation for natural light, cross-ventilation, shading and thermal mass – deliver the biggest and most cost-effective savings.

‘These are not expensive add-ons; they are design choices that should be integral from the outset,’ says Reinink.

‘Once those first principles are in place, technologies can play an important supporting role. In South Africa, we see increasing uptake of solar PV with storage, efficient HVAC and heat pumps, and alternative water systems. But these should be viewed as enhancements to an already efficient building, not the core solution.’

She points out that, surprisingly, many older buildings in SA are already efficient by design, thanks to heavier structures, natural ventilation and passive features.

‘In these cases, the main opportunities for improvement lie in retrofitting outdated services – such as HVAC, lighting or water sys-tems – and in optimising building operations.’

Other factors are at play when it comes to building the case for building green.

In SA, companies’ environmental, social and governance (ESG) commitments are also increasingly driving them to seek certification. ‘Most companies are doing ESG reporting, and having a green-certified building – new and existing – assists with the reporting,’ says Reynolds.

Not only that, but new regulations introduced in 2020 in SA demand minimum performance standards from buildings.

By 8 December 2025, public- and private-sector buildings of a certain capacity and size will be required to publicly display Energy Performance Certificates (EPCs) to empower potential investors, buyers and tenants to make well-informed decisions. They include public-sector buildings greater than 1 000 m² and private-sector buildings greater than 2 000 m² that fall into six categories – entertainment and public assembly; theatrical and indoor sport; places of instruction, such as primary and secondary schools; other places of instruction, for instance, buildings where school children assemble for the purpose of tuition or learning; large multi-storey office buildings; and, lastly, stand-alone office blocks ‘and/or campuses of buildings that form an office park but operate separately’, according to the GBCSA.

Reinink says the key regulation for new buildings is SANS 10400 Part XA, ‘which establishes minimum energy performance requirements. Importantly, it also sets a trajectory towards net zero for all new buildings by 2030 – a significant step in aligning with global climate commitments’.

Reynolds says that while there is little indication that landlords of green-certified buildings in SA can achieve higher rentals, non-green buildings do get subjected to ‘brown discounts’. A brown discount, according to the World Economic Forum, is ‘where a building without green credentials sees its value fall because it wouldn’t meet a tenant’s low-carbon targets’.

Vacancy rates for non-certified office buildings are also higher than their certified counterparts. The MSCI South Africa Green Annual Property Index 2024, released earlier this year, showed that green-certified Prime and A-grade offices had a vacancy rate of 11.1% last year compared to 14.8% for non-certified offices. In addition, Green Star-certified offices have a lower gross operating cost of 30.1% of gross income, compared to 46% for non-certified offices.

‘Additionally, certified buildings outperformed non-certified buildings by 28.2% over the nine-year period (2016–2024),’ says the report. ‘Certified green buildings achieved a 45.7% higher capital value per square metre supported by 48.3% higher net operating income per square metre when compared to non-certified buildings.’

Reynolds says that while offices make up the majority of building typologies that are green certified, ‘over the last few years, many different building typologies have been certified’, such as hospitality, precincts, shopping centres (including super regional shopping centres), retail and banking (interiors ratings), and even some healthcare buildings.

For example, in 2020, the Cintocare Hospital in Pretoria achieved Africa’s first Green Star rating for a healthcare property, notching up a 5-Star Green Star Custom Healthcare design certification.

In one interesting project still under way, the University of Cape Town, whose campus features a number of green-certified projects, is working towards a 4-Star Green Star rating and Net Zero certifications for water, carbon and ecology, not for a building but a green precinct, with an on-site water recycling plant to treat wastewater from nearby residences and academic buildings. It will also offer a garden, which the university describes as ‘a healing space; a space of meaning’ for students. Most importantly, the site will serve as a ‘living laboratory’ for the university’s Future Water Institute.

Reynolds says that a big part of the GBCSA’s challenge has been ‘demystifying the concepts of green and sharing the solutions in this space – demonstrating that they are doable and actionable’.

Its 1 500 green certifications are living proof that it is on the right track.

By Robyn Leary
Images: Gallo/Getty Images