The performance gap between how buildings are designed to perform and how they actually perform in operation remains a significant challenge for the built environment. CIBSE’s new Who owns the performance gap? free in person event series will bring together industry professionals to examine the causes of this gap and explore practical ways to reduce it.
Taking place across four sessions at CIBSE HQ, 91–94 Saffron Hill, London, EC1N 8QP, the series will examine the performance gap from different perspectives, including equipment sizing, controls, metering, energy performance, heat network design, modelling and software, and post-occupancy evaluation.
Through research findings, technical guidance, real-world case studies and industry perspectives, the series will consider how better design decisions, measurement, commissioning and operational feedback can help buildings perform more closely to their intended outcomes.
Session 1: Equipment sizing, controls and metering
5 November 2026 | 13:00–17:00
How the performance gap is affected by oversizing/undersizing equipment and how controls and metering can improve it. The first session will examine how equipment sizing, controls and metering can influence building performance.
Speakers will draw on research findings and real-world case studies to explore the causes and consequences of over- and under-sizing equipment, as well as the challenges involved in defining and measuring building performance.
The session will also consider how smarter controls, effective metering and recommissioning can help reduce the performance gap and improve operational outcomes.
Speakers:
- Paul Mickleburgh, Hamworthy Heating – Assessing Existing Plantrooms: What decades of site visits reveal about plant oversizing
- Lawrence Leask, Kaizen Energy - HVAC Performance in Practice: What years of site surveys reveal about system performance
- Barrie Daniel, Arup - BMS Recommissioning in Practice: What field experience reveals about system optimisation
- Vic Tink, Klimatica - Measuring What Matters: What occupant experience reveals about building performance
- Speaker TBC - Unlocking Existing Smart Assets: What connected systems reveal about untapped value
Session 2: Energy performance and heat network design
12 November 2026 | 13:00–17:00
How the performance gap is affected by Energy Performance and Heat Network Design. The second session will focus on the design and delivery of heat networks and retrofit projects that perform as intended.
Speakers will explore the importance of early-stage design decisions and operational performance, sharing lessons learned from comparing design expectations with measured, real-world building performance.
Technical guidance and data-led case studies will provide practical insight into how projects can be designed and delivered to achieve better outcomes in operation.
Speakers
- Hamish McDonald, Sorted-IT - Closing the heat network performance gap
- Huw Blackwell, Energetic - Why district heating systems should own the heating system’s performance gap
- Douglas Norton, SAV Systems - Uncovering opportunity: lessons from the data
- Henry Metcalfe, Etch Associates - Measuring the electrical load performance gap
- Xiaofang Xu, Arup - The building and its heat network interface
- Emeka Efe Osaji, University of Hertfordshire - Analysis of energy certification compliance for public buildings urban sustainability
- Xohan Duran, Squires & Duran Plumbing and Heating - How to have a more efficient heating and hot water system
Session 3: Modelling and software at design stage
18 November 2026 | 13:00–17:00
How the performance gap is affected by modelling and software at design stage. The third session will explore how modelling, simulation and software used during the design stage can influence building performance outcomes.
Through industry case studies and research-led presentations, speakers will examine areas including predictive modelling, weather data, ventilation, controls and performance assessment.
The session will highlight both the challenges and opportunities associated with using modelling and software to better understand how buildings will perform in reality, helping to reduce the gap between design intent and operational performance.
Speakers
- Will South - Predictive Modelling and Certification
- Hugh Gordon, Hilson Moran & Darren Coppins, Built Physics – NABERS and IDR assessments
- John Mardaljevic, Daylight Experts – Increased weather data resolution from the EU satellites
- Ian Highton, EDSL - CFD and DTM integration to reduce the performance gap
Richard Tibenham, IES - Closing the Performance Gap with IES Dynamic Simulation & In-Use Performance Monitoring Tools - Nishesh Jain, Design-Builder - Performance Modelling and Calibration with DesignBuilder: Complying with CIBSE TM54, TM63, ASHRAE Guideline 14 and IPMVP
- Chris Twinn, Twinn Sustainability Innovation - Simplifying the Controls - a naturally ventilated, humidity-controlled archive building case study
- Esam Elsarrag, Hoare Lea - Modelled to Measured: Evaluating Early Building Performance
Session 4: Post-occupancy evaluation and the vision for the future
1 December 2026 | 13:00–17:00
Series conclusion: Who owns the performance gap? Post-occupancy evaluation and Vision for the Future. The final session will bring the series to a close by looking at how post-occupancy evaluation, operational data and occupant feedback can be used to drive better building performance.
A keynote presentation provides a historical perspective of the performance gap in the UK, along with case studies and industry reflections exploring practical approaches to improving accountability and closing the gap between design intent and operational reality.
The session will consider what needs to change across the industry and how different stakeholders can take greater responsibility for building performance throughout the whole life of a project.
Attendees will come away with a greater understanding of the factors contributing to the performance gap and, importantly, how we can all play a role in addressing it.
Speakers:
- Bill Bordass, Adrian Leaman, Usable Buildings Trust – Keynote: Why, oh why, do we still have performance gaps?
- Hua Zhong & Joshua Vasudevan, London South Bank University - From Digital Twin to Continuous Intelligence — A Data-Led Case for Closing the Performance Gap
- Tom Randall, Arup - Analysis and insights from BUS occupant surveys
- Graham Lewis, Cardiff Metropolitan University - Behind-the-meter innovation: closing the performance gap to mitigate grid costs and constraints
- Matthew Huggins, Sodexo - Performance gap ‘lessons learned’ from the FM sector
- Derek Clements-Croome (CIBSE Fellows), Bill Bordass and Adrian Leaman (Usable Buildings Trust), Tom Randall (Arup), Matthew Huggins (Sodexo), Jennifer Cox (Cundall), Khizar Moti (Arup), and Aashika Shibu (Etude) – What must we do on our own projects to close this gap? Panel discussion with audience Q&A
Who owns the performance gap?
Across the four sessions, the series will ask an important question for everyone involved in the built environment: who is responsible for ensuring that buildings perform as intended?
From early-stage design and modelling through to construction, commissioning, operation and post-occupancy evaluation, closing the performance gap requires collaboration and accountability across the whole project team.
The Who owns the performance gap? series will provide an opportunity to explore these issues, share lessons from practice and consider how the industry can move towards buildings that deliver the performance promised on paper.
All four events are free to attend and will take place in person at CIBSE HQ, 91–94 Saffron Hill, London, EC1N 8QP.