In conversation with Stephen Hill, CIBSE Engineer of the Year

After his success at the CIBSE Building Performance Awards on 1 March 2023, we caught up with Stephen Hill, Associate Director in Arup's Building Performance Team and winner of the CIBSE Engineer of the Year.

Stephen Hill (centre) wins CIBSE Engineer of the Year at the Building Performance Awards 2023

Tell us a bit about yourself...

As an Associate Director in the Sustainability team at Arup, I get involved in everything from portfolio level sustainability strategies and masterplan frameworks through to delivering sustainability on individual development projects. For most of our clients the biggest challenge in the sustainability arena is understanding and navigating the transition to net zero carbon, whether for a portfolio or an individual building. With a background as a mechanical engineer, my area of expertise is operational energy and carbon, which  is focused on NABERS UK on many of our commercial projects. In my role as NABERS UK lead for Arup in London, I help our project teams implement NABERS across our commercial projects, working on embedding an operational performance focus right through from briefing stage through design to construction delivery and beyond looking at how we can improve the transition into operation. As a member of the NABERS UK Independent Design Review panel, I act as an expert reviewer for projects designed by other consultants, helping to spread the knowledge and skills needed to successfully implement NABERS on projects.

Can you tell us about your journey as an engineer so far?

I’ve been at Arup for just over 25 years. For the first 10 of those years, I was a mechanical designer. I then gradually transitioned into sustainability, although still with a strong focus on engineering. I worked for several years in our Building Performance team, focusing mainly on performance improvement for existing buildings and portfolios. My biggest client at that time was The Crown Estate, where I was focused on improving the performance of the Central London portfolio. This time working on buildings in an asset management context was invaluable, and something I would advocate for all building services designers to spend time doing. It gave me a very different take on the design process having seen how buildings are operated and used, what works well and most importantly what doesn’t.

The culmination of this period was a research project that I led, working with experts both from Arup and from the FM industry, looking at how digital technology could revolutionise facility management.

I have now come back to the design side of our business, leading sustainability across a range of development and refurbishment projects of different scales and in different sectors. I’ve brought my asset management experience with me, and this has helped me to focus on the really important building performance outcomes – energy, carbon and wellbeing – and how we need to change the way we deliver buildings if we are to achieve these outcomes.

Are there any initiatives that you would like to draw people's attention to?

The last 5 or so years have seen a clear shift away from a focus on compliance, with performance in operation coming much more into the limelight. Over this period, “Net Zero Carbon” has really caught on as a concept. The climate penny has finally dropped, and organisations across the property sector and beyond are declaring climate emergencies and setting net zero targets. Yet our understanding of what net zero is and how it can be achieved is still evolving, whether for a building, portfolio or organisation. In 2021, I co-authored an Arup publication that addressed this issue of what Net Zero is and how we get there:

Since then, we have seen gradual improvement in clarity (although there’s more to do), and increasingly we see that Net Zero is becoming a factor in decision making. This is most obvious in the commercial property sector where NABERS UK has really driven that shift. But it is happening more broadly, and tools such as CRREM for example are also playing an important role, giving us a language that links environmental performance with commercial risk. This alignment of commercial and environmental outcomes is a critical factor in driving change across the sector – Carbon Stranding Risk is starting to become common parlance in the investor community and is shining a light on operational performance as a result.

Over the next 2-5 years, what do you think the biggest challenges for the construction industry will be?

The next 5 years need to be about a different transition: broadening out from operational performance to whole life carbon impact as a key driver. As the grid decarbonises, the proportion of a building’s whole life carbon footprint that is due to operational energy reduces. Currently for many commercial buildings operational energy demand is around a quarter of the total footprint, with the remainder being the embodied carbon of materials, including construction, maintenance and refurbishment. The danger we face now is that by focusing too much on operational energy performance we drive up embodied carbon emissions, and over the short to medium term we may not save any carbon at all. 

We can mitigate this by evaluating whole life carbon on all our projects and looking at all our key decisions – from whether to refurbish or demolish to which HVAC system to choose – through a whole life carbon lens.  Arup has been looking at this whole life carbon balance across a range of products and servicing solutions. This work was recognised this year at the Building Performance Awards, where Maria Benazzo and colleagues won the Embodied Carbon Award for consultants. The biggest challenge I see in bringing this kind of thinking into the mainstream is that it requires us to unlearn a lot of what we already know. Decisions made from a whole life carbon perspective often feel counter-intuitive for those of us who have spent a long career focused mainly on energy efficiency. The “fabric first” principle comes under pressure when viewed from this perspective, because of the amount of embodied carbon in facades, both in terms of when to replace facades, and also the pursuit of the highest levels of environmental performance. In the UK, triple glazing often requires more carbon to manufacture than it saves over its lifetime, and VRF systems look quite different when the lifecycle carbon impact of refrigerant leakage is taken into account. These are just a few of many examples where the optimum solution is quite different when viewed through a whole life carbon lens. 

This change will take a lot more of the kind of research work Maria Benazzo and colleagues have been doing, but in addition to that what we really need as an industry is to move away from thinking about embodied and operational carbon separately, and towards a single whole life carbon metric.  If we can make that shift, and link that overarching metric to property value, then we really will be on the right path.

What are you optimistic about?

The last 5 years have shone a light on our ability to change rapidly. The Covid pandemic, tragic though it was, forced a change in the way we live and work that showed how adaptable we humans are.  Some of the changes were thankfully temporary, but other aspects endure. In the property sector, the rise of Net Zero over a similar timeframe has been equally startling, bringing climate change out from the more radical fringes firmly into the commercial mainstream. Of course, a change in attitudes is not the same as a change in outcomes, and there is undoubtedly a rocky road ahead, paved with difficult decisions to get to those outcomes. But I can’t help but think that we have turned a crucial corner, and are edging cautiously in the right direction.

What does winning CIBSE Engineer of the Year mean to you?

Winning Building Performance Engineer of the Year was of course an honour and a privilege, and I am delighted to have the  work I’ve already done recognised for helping our industry navigate a path towards Net Zero.  But we are only a little way down that path and there is much more careful navigation to do.  Ultimately what I am most grateful for with this award is the opportunity to do more. I look forward to working alongside  many others across the industry (including some notable previous winners of this very award) to help us navigate that path.

Find out more...

Arup also won the award for the Embodied Carbon - Consultancy category at this year's CIBSE Building Performance Awards. You can find out more about their winning entry via 

Catch up on the recent CIBSE #GrowYourKnowledge Webinar, Less is more: Building services through a whole life carbon lens, with Stephen and his colleagues at Arup, Maria Benazzo, Sarah Bousquet, and Rowan Bell-Bentley.


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