Partner: WSP

Real estate accounts for 39% of society’s total carbon, and three quarters of that comes from the operation phase. The UK has some of the most ambitious Net Zero targets in the world, but at the same time buildings use about three times as much energy as design models anticipate. This is a problem, and new materials and technologies can only take us so far, but there is one mechanism that is always in our control: the way we work.

Construction is a traditional field, pretty set in its ways, and too often departments are isolated in their thinking, working in silos. In this article we will look at how two departments, if they communicate effectively, could reduce the energy use of buildings in operation.

Closing the energy performance gap means the difference between actual energy usage vs what is expected in design, but could also refer to a missing conversation between the façades designers and the mechanical, electrical, plumbing engineers.

We spoke to three experts in the field to kickstart that missing conversation.

Key issues in the performance gap

Michael Trousdell, WSP’s Sustainability and Smart Buildings Lead sees the performance gap as a misalignment between expectations and what people want to see, and what happens in practice. As it is something that cannot be seen, a building user would naturally just expect all the people in their facilities team to be sorting everything out.

Michele Sachelli, WSP’s Technical Director for Support for Facades adds, “Most of the time, we work in silos. So we are separated. Not because of any particular reason, just common practice, we end up forgetting that at the end users will be using our own buildings we design, and the way they act will have an impact.”

Sachelli says that teams need to think holistically, and more accurately include how people will actually operate the structure in their design.

Justin Brand, Asset Management Director for the property developer Sellar. He has 20 years of experience in asset and investment management, and is currently leading a team mobilising the 430,000 square foot Paddington Square development, which is directly adjacent to the new mainline station and also the new Elizabeth Line station in London. For him, it is essential to pause and look back at earlier projects to see how they have performed in use. Constant monitoring of the building stock is key.

“As an industry, we are constantly looking for improvement. So from a design perspective, from planning perspective, from a statutory perspective, we are driving in the right direction,” says Brand. “So for example, the operational team that run Paddington Square need to be involved as early as is humanly possible. And for me, that’s at RIBA stage 2, we need to have an understanding of why you’re designing, what you’re designing, and when.

“Don’t build it and then give it to us. Because we will then have to start retrofitting and answering questions that we could have answered when we could have designed-out way, way in advance. And for me, that is the single biggest, easy win that we can do, engage with the operational bodies and teams that are going to run these buildings as you are designing them.”

User-centric design

Since the pandemic building-use has changed dramatically, which complicates this assessment of how users will use buildings. And the answer to designing for a changing world is flexibility.

But one question that emerges is how much control is handed to the tenants, for example with the temperature controls of a building. Trousdell says there is a tension here.

Brand says, “There has to be a relationship that runs the whole way through the design team, you know, the investors, the operators, and the occupiers. So we all understand how the building works. And we have to have a data analytics package that gives us the ability to see how it’s performing, because I’m sure day one it won’t perform how it was designed to perform.”

Sauchelli adds, “We also need to avoid the risks of over-engineering elements to give too much flexibility. So it’s always a trade off. But definitely everyone needs to be involved.”

The move towards performance-related targets is a good thing, NABERS from Australia is a popular addition, but there is still a worry that designers are not thinking about this controls aspect enough.

Sauchelli says, “we also need to remember that the design process is not always straightforward. It’s not always easy to deal with […] I challenge everyone to walk around Central London, and you see fully glazed buildings. If we’re lucky, there are blinds inside, most of these blinds are down because users are getting glare. And the electricity use goes up, because everyone will switch on the lighting to see.”

Trousdell adds, “Blind control is a big, big topic for building services and façade engineering.”

What supports the silos

There is an inertia that keeps people working in silos. The construction industry is a juggernaut, says Trousdell. “The systematic change we need, I think will happen slowly. But if we want to accelerate it, we’ve really got to think about these moments in the process, where intervention can happen. And you know, it’s getting the right people involved at the right time.”

But time kills return on investment, so a developer wants to do everything as quickly as possible. So without deliberate effort, silos spring up everywhere.

“There are so many moving parts,” says Brand. “If you’re going to go from a brownfield development site through to something lovely and shiny and beautiful. There are so many constituent parts to get from A to B. And yeah, time and cost is an integral part of that.”

But he adds that understanding that a better product will come from a holistic approach is important. And it is important to resist the temptations of a short-sighted approach.

“We are now having products that have to have the right carbon analysis, the right carbon performance, that will drive us into an environment where we have to talk to each other. It’s not just a pounds, shillings and pence conversation, it is about “that has got to be correct”. But also we have to have a building obsolescence rate that is as slow as possible, and is right for investors, for occupiers, for the construction world that builds it, but also the communities within which it sits. And you’ve got to get all of those things right. And it’s a challenge. It is a huge challenge. But we’ve all got to head in that direction.”

Sauchelli adds, “Unfortunately, we live in a short-sighted industry. So we tend to be focused on stages. First we need to get the minimum design team and investment to go through planning, then get planning to get more investment to build the building. But I believe this is short-sighted, because if we bring in expertise early, we can save moment later in the process.

“We launched a motto which is called: “small change, big impact”. And we saw that for example, if you take an average office building in London and you work very early on to save 1% of embodied carbon in the façade. In one very specific case [we are working on] you save half a million trees.”

The value of investment early on can have serious impacts to the end effect, across a number of performance indicators.

Picking priorities for change

Asked to pick priorities for a change in the way the property development business works, Trousdell says he would want to have the right targets to leverage change, and he reiterates the controls point.

He adds, “I’ll just offer an example from the Paddington Square project that we’re working on to illustrate this. We have this excellent mechanical system that we’re really proud of. It is a hybrid heat pump system, where we can get up 88% of the heating could from the heat pump. And only peak winter loads need to be met with a boiler.

“And so that’s all great, we’re very happy that we can do that. But if we don’t work really closely with Sellar’s teams to make sure the operations of that heat pump are working properly […] It’ll just be the regular boilers all the time. And so that’s why the controls are just going to be so important in practice.”

For Brand it is flexibility and clarity, “if you don’t understand how your building works, then, it’s like a plug-in hybrid car that you never charge up. [It becomes] just a car that’s petrol-driven, with a load of heavy batteries in it. So the operational team have to have clarity from the design team of exactly how it works. And that is where the clarity and the and the flexibility of running the building as efficiently as we possibly can, in a world where we’re going to get 48 retailers and restaurateurs and a load of office occupiers who will all treat the building differently, and will have slightly different drivers for what they want to deliver from the building.”

For Sauchelli it is the holistic approach and the early engagement to get key stakeholders on board early in the process.

“Because the investment you do early is actually a saving later on. And what you don’t realise sometimes is that when you commit later on in your design, you’ve already committed to a lot at the end. You need to then retrofit and retrofit may have implication of costs, but also [practical] limitations because you didn’t think about it early in the process.”