Retrofitting for Resilience – FMs Must Future-Proof Buildings Now

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• Retrofitting for Resilience – FMs Must Future-Proof Buildings Now

07 October 2025

With extreme weather a recurring operational risk, facilities management teams must retrofit existing buildings to keep them comfortable, compliant and cost-effective.

Laurie McKelvie, Technical Delivery Lead at IES, explores how prioritising retrofit can deliver year-round resilience, protecting occupants, cutting costs and meeting tightening regulations while progressing towards net zero.

Laurie has worked within the building services industry for over 10 years. With extensive experience in leveraging IES’s digital twin technology, Laurie helps building owners and operators identify quantifiable energy, cost and carbon savings, while developing deliverable net-zero roadmaps.

 

"For facilities management teams, it is no longer enough to achieve “good enough” performance; buildings must now demonstrate year-round resilience to an increasingly volatile climate."

 

Resilience is a Facilities Management Issue

 

This year confirmed what many facilities management professionals already know: extreme weather is no longer an occasional challenge, but a recurring operational risk.

Provisional figures show the UK has just experienced its hottest summer on record, with four separate heatwaves and repeated amber Heat-Health Alerts. Now, as we move into the colder months, the challenge flips. Facilities managers must ensure the very same buildings that overheat in summer are also capable of retaining warmth efficiently in winter. The task ahead is clear: adapt existing stock to meet changing weather patterns quickly, affordably, and in line with tightening regulations.

Poorly performing buildings expose occupants - whether tenants, patients, staff, or visitors - to discomfort and, in some cases, serious health risks or fatality. In summer, high indoor temperatures can lead to fatigue and worsen chronic conditions. In winter, draughts, inadequate insulation and inefficient heating systems drive up bills and leave residents vulnerable to cold-related illnesses. 

At the same time, the regulatory bar is being raised. The imminent update to CIBSE TM59 sets stricter rules on overheating and promotes a passive-first approach, supported by future climate datasets. Alongside this, PAS 2035 establishes a mandatory framework for retrofit, ensuring measures are installed and monitored correctly to avoid unintended consequences such as poor ventilation or trapped heat. For facilities management teams, it is no longer enough to achieve “good enough” performance; buildings must now demonstrate year-round resilience to an increasingly volatile climate.

 

Retrofitting for Year-Round Comfort

 

The majority of the buildings facilities management professionals oversee today will still be in operation in 2050. The obligation for building management teams, therefore, lies in retrofitting them. Often, the most effective measures are not the most expensive, but the ones that are carefully chosen to address future weather conditions, be they extreme heat or enduring cold.

Take a mid-rise office block in a city centre. On hot days, its glass façade traps solar gains, while in winter, poor insulation can let warmth escape. A retrofit programme that adds external shading to cut overheating, while upgrading insulation and glazing to retain heat, transforms comfort across the whole year. Cooling loads fall in summer, heating demand drops in winter, and staff enjoy a more stable working environment.

Or consider a 1970s healthcare facility. During heatwaves, wards regularly climb above comfort thresholds, and in cold snaps, the outdated heating system struggles to cope. By introducing secure night-purge ventilation and reflective roofing, the building is better equipped for summer. At the same time, replacing inefficient boilers with heat pumps and improving pipe insulation makes spaces warmer and cheaper to run in winter. For clinical staff, this means safer conditions and a reduced strain on already stretched budgets.

In housing, the balance is equally important. A top-floor flat with large south-facing glazing may require shading and reflective measures to manage summer heat. Yet if insulation is not upgraded alongside, tenants will still face high energy bills when temperatures fall. Dynamic thermal modelling can identify retrofit packages that deliver year-round performance, ensuring homes remain safe in summer and warm in winter without resorting to costly mechanical solutions.

 

From Data-First Improvements to Capital Projects

 

The first step in many buildings is not large-scale retrofit, but optimising day-to-day operations. Using available data and live monitoring technology, facilities managers can often uncover low-cost, quick-win improvements, such as adjusting control strategies, fixing poorly timed schedules or reducing unnecessary ventilation, that can achieve at least 10 per cent operational savings with minimal capital expenditure, often delivering ROI in under a year.

This is where data-driven technology like IES Live plays a vital role. By integrating data streams from building systems into a single platform, such technology enables facilities teams to visualise performance, share insights with sustainability or capital projects teams, and track whether implemented measures are truly delivering savings. Once operational opportunities are exhausted, the same data-driven collaboration can then guide larger retrofit projects, ensuring budget is directed where it will have the highest impact.

 

The Role of Digital Twins in Retrofit

 

Knowing what to prioritise is the hardest part of retrofit. Calibrated digital twins — physics-based virtual replicas that integrate live data — allow facilities management teams to map risks, test packages of measures across different seasons and future weather conditions, and track ongoing real-time performance. This ensures that interventions don’t solve one problem while creating another.

For example, say shading and boosted ventilation are added to a building to control summer overheating, without additional roof insulation, simulations may reveal high heating demand in winter. By testing different options using performance modelling technology before work begins, facilities managers can strike the right balance and avoid costly mistakes.

 

Compliance, Cost and Carbon: The Facilities Management Triple Win

 

Adapting buildings to manage both heat and cold is about more than occupant wellbeing. It allows facilities management leaders to stay ahead of regulatory change, protect budgets, and progress towards net zero. Compliance with TM59 and PAS 2035 can be demonstrated with clear modelling evidence. Energy bills can be reduced by minimising both excessive cooling in summer and wasted heating in winter. And every kilowatt saved reduces carbon emissions in line with ESG commitments.

The reputational benefits are equally important. Occupants who feel that their comfort and safety are being prioritised are more satisfied and engaged. Organisations that can show regulators, investors and the public that their estates are resilient and efficient stand out as leaders rather than laggards.

 

FMs on the Frontline of Climate Resilience

 

Facilities management professionals are on the frontline of climate resilience. The buildings they oversee are where heat and cold risks are felt most acutely, but they are also where solutions can be delivered at scale. Retrofitting for resilience guided by data and simulation is not optional. It is how facilities management can protect people, stay compliant, and cut costs in a world of increasingly volatile weather.

The tools already exist. What’s needed now is a shift in urgency: from waiting for regulations to force action, to proactively future-proofing the buildings we rely on every day.

Picture: an image showing a blue wireframe digital model over a photograph of the same building. Image Credit: IES

Article written by Laurie McKelvie | Published 07 October 2025

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