28 April 2026
Article by Stephen Richardson, Senior Impact Director, World Green Building Council. Read ‘Building Retrofits: Why upgrade our existing buildings’.
I’ll never forget my first encounter with the global Green Building Council network because of one mic-drop moment. In a conference venue in Barcelona, the speaker looked out at a room full of seasoned sustainability professionals and said:
“Raise your hand if you’ve done a deep retrofit of your home.”
Silence… followed by a smattering of awkward laughter. Then one or two confident hands rose, trailed by a couple more, less sure of themselves. “Depends what you mean by deep,” someone muttered, sheepishly half-raising their arm.
We were the supposed experts, dedicating our careers to sustainable buildings. And yet barely any of us were really walking the talk in our own homes. That memory remains fresh for me because, in the almost dozen years since that moment, we’ve barely moved the needle on retrofit.
Sure, if we asked that same group now, the result would be better. And no doubt more of you reading this today could raise your hands than would have done then. But the data is clear: to meet climate targets, we need to double, and in some regions triple, the rate of deep renovation. In most parts of the world, we are still a long, long way from that.
What that room of sustainability experts shuffling awkwardly in their seats told us, and what many of us in the sector have long known, is that the retrofit challenge is not primarily a technical one. If it were, we’d have solved it by now. Retrofit is one of those particularly knotty, complex, multifaceted systems challenges — sometimes called wicked problems — that defy simple solutions.
That’s why the latest WorldGBC publication on ‘Building Retrofits‘ is deliberately not a technical guide. Instead, it takes aim squarely at that wicked problem, distilling insights from across the WorldGBC global network on how we begin to unpick the knots and genuinely move the needle.
Policy and regulatory frameworks in many countries still focus overwhelmingly on new buildings, with limited application to existing stock. Financing barriers, fragmented ownership, split incentives, skills gaps and a lack of reliable performance data all continue to constrain action. As the publication argues, overcoming these barriers requires coordinated, systems-level solutions.
If asked that question again today, I could now raise my hand. I can share firsthand just how far-reaching the benefits of retrofit can be — from upgraded windows and insulation to electrified heating, solar panels and batteries — especially as we enter the second energy crisis of the decade. But I know too that this makes my family one of the privileged few.
The publication is clear: retrofit can be a powerful just transition tool, but only if initiatives are explicitly designed to reduce energy poverty, tackle health inequality and improve resilience for those most exposed to climate shocks. That means inclusive finance, supportive policy frameworks and delivering retrofit at community scale, not just asset by asset.
The publication’s case studies — from Qaddura Camp in Palestine to the Kenya schools programme — reinforce that retrofit can deliver social value, dignity and opportunity alongside emissions reductions. And, examples like the 1 Triton Square retrofit in London and the San Martín Building in Bogotá demonstrate how, across very different markets, deep retrofit can outperform business-as-usual on pure commercial terms.
In every part of our global network, we see that businesses are recognising the value of upgrading their existing buildings: from shopping centres and schools to museums and offices, they’re all reaping the comfort and cost benefits of retrofit.
That moment in Barcelona still matters because it tells us where the real work lies. Retrofit will not scale simply because we publish better standards or develop smarter technologies, important as those are. It will scale when we redesign the systems around finance, regulation, skills and delivery so that doing nothing is no longer the default and acting is no longer a privilege.
The examples in this publication show that this is possible: retrofit can cut emissions, lower bills, improve health, reduce risk, preserve culture and strengthen communities at the same time. The synthesis of national climate action roadmaps highlights that the momentum and understanding that we need to take a systems approach are building.
The question now is not whether retrofitting works, but whether we’re willing to make it work for everyone, at the pace that businesses, communities and the climate demand.