Paper targets abound; performance less so. What distinguishes the current moment is a growing impatience with the gap between what buildings promise on paper and how they actually behave once people move in. For Ruth Kerrigan, chief operating officer at IES, closing that gap has become the organising principle of her work.

“For me, the most meaningful impact has been working with a great team to help move building decarbonisation from ‘good intentions and compliance paperwork’ to measurable, in-use performance,” Kerrigan says. Her emphasis is on action, on tangible results rather than aspirational commitments. It is a perspective rooted in data, evidence, and the kind of rigorous analysis that turns lofty targets into real-world outcomes.

“At IES, we’re focused on shifting industry attitudes to make whole-life performance modelling the default. That means taking the data and models created in building design and turning them into practical tools that facilities teams can use to cut energy, carbon and cost throughout the entire building lifecycle.”

The heart of Kerrigan’s work is the operational digital twin platform, IES Live. “I’m particularly proud of our work to develop IES Live,” she explains. “I was responsible for developing the go-to-market plan, aligning sales and delivery around clear targets, and tightening the product roadmap so we could move quickly from launch to real deployments.” The results, she notes, speak for themselves: “Since launch, it has been deployed across 10 projects, including a pioneering University of Liverpool initiative that supported a 23% reduction in energy use and £25k in savings in eight months during an HVAC refurbishment.”

Such success underscores a critical truth in the wider industry: designing a building is only the first step. Predicting outcomes on paper is not enough. The real challenge lies in ensuring that buildings operate as intended once they are in use. Kerrigan’s focus is on bridging this “performance gap,” and she believes the key is evidence-based action.

“I’m driven by creating real outcomes that can be evidenced – whether that’s energy saved, carbon reduced, comfort improved, or decisions de-risked with robust analysis,” she says. For Kerrigan, sustainability is not an abstract ideal but a measurable set of results.

She stresses that the path to net zero depends on more than technical solutions alone: “If we want credible progress to net zero, we have to close the performance gap between what we predict and how buildings actually perform in practice – and we have to make that process simple enough so that busy teams can benefit from and act on it.” In other words, decarbonisation strategies must be usable, actionable, and integrated into everyday operational decision-making.

Influence, Kerrigan says, is about removing obstacles as much as promoting ideas. “Influence, for me, is about building alignment and removing friction. Internally, that has meant leading through change – integrating teams, streamlining delivery, strengthening Consultancy and R&D, and embedding an Objectives and Key Results (OKR) framework so people can see how their work ladders up to impact.”

Externally, her role blends technical insight with guidance: “I try to help clients and partners act with confidence by translating complex building physics into clear options and next steps. And through my work as an Expert to the European Commission, I also contribute to shaping the policy and innovation landscape that enables better decisions at scale.” In other words, Kerrigan’s work is not just about individual buildings; it is about creating systems, frameworks, and incentives that allow better decisions to ripple across the industry.

Yet for all the progress made, she sees an urgent need for bolder change. “The bold change I want to see is a decisive move to designing, building and operating for performance – where operational outcomes are planned for, measured and continuously improved and not treated as somebody else’s problem after handover.”

Over the next decade, Kerrigan hopes that operational digital twins and whole-life performance modelling will become standard practice. “Over the next decade, I’d like operational digital twins and whole-life performance modelling to become standard practice for buildings and estates, so that decarbonisation plans are grounded in real data and can be verified over time.” The ambition is clear: to shift the sector from compliance-driven checklists to outcome-focused practice.

Her contribution is both technological and organisational. “First, I’m focused on scaling tools that make this practical – including IES Live, which connects real-time operational data with physics-based modelling to identify what’s working, what isn’t, and what to do next.” But the change cannot rely on software alone. She adds: “Second, I’m helping to build the organisational foundations that allow IES to deliver this at pace and at scale. That might include funding-led innovation through R&D, aligning teams around measurable outcomes, and ensuring our technology and consultancy support customers across sectors to exceed sustainability goals.”

Kerrigan’s approach reflects a growing recognition in the property sector: sustainability cannot be outsourced, deferred, or treated as a box to tick. It requires persistent oversight, actionable intelligence, and leadership willing to tackle both culture and technology simultaneously. By linking measurable outcomes to clear organisational goals, and by providing tools that translate complex building physics into usable guidance, Kerrigan and her team are demonstrating a new model of accountable, evidence-driven decarbonisation.

For a sector long criticised for overpromising and underdelivering, the lessons from Kerrigan’s work are stark. Buildings, she shows, will only deliver on their promises when operational performance is planned, measured, and continuously improved. Tools like IES Live provide the data; leadership, alignment, and organisational clarity provide the framework to act on it. Closing the performance gap, she argues, is not merely an aspiration — it is the only credible path toward a net-zero built environment.

In the end, Kerrigan’s work is both pragmatic and visionary. By focusing on evidence, operational outcomes, and the organisational structures that make them achievable, she embodies a shift in the industry from “good intentions and compliance paperwork” toward tangible, measurable impact. In a world where promises of sustainability too often evaporate after handover, her message is clear: mind the performance gap, or risk leaving decarbonisation on paper alone.