Successful retrofits build in room for the unknown

Planning the future of a building is a daunting task. There’s no single path to success, but Andy Pearson finds out where to start.

Embarking on a retrofit can be a daunting prospect. Plan it right, and the scheme will cut energy use, reduce running costs, and improve the comfort and productivity of the people who use the building day to day. For a company, it could enhance the brand by showcasing its commitment to a low-carbon future. But get it wrong, warns the Carbon Trust, and a refurbishment can actually lead to an increase in energy consumption through changes in the way a building is used.

Knowing where to start isn’t easy. Sunand Prasad of London-based architects Penoyre & Prasad counts five main things to consider. First, you have the occupants: how they use the space, and the changes they would like to see. Then there’s the fabric of the building as it stands, and the way in which it has been piped and wired. Zooming out, there’s also the local infrastructure it draws upon (utilities and plants), and the question of renewable energy generation on-site.

No building is an island: changes in the wider economic and political landscape will also have an impact. How might policy and legislation affect its running costs in the future? What targets will have to be met? How might advances in technology affect the way it’s used? With so many questions to negotiate, it’s important to know who to ask.

“The key to a successful refurbishment is getting the right people on board before you start ruling out options, and even before you set a final budget”, says Doug King, Principal of low-carbon consulting engineers King Shaw and a visiting professor of building physics at the University of Bath. “You need everybody round the table”, he argues. “The architects will be able to advise on occupancy and space planning; the structural engineers will be able to assess the degree of possible alteration or whether an existing structure can accommodate additional loads or the building can be extended. And the building services engineer can advise on how to achieve a comfortable internal environment.”

You also need to consider the materials you’re going to be using, adds Emma Hines, Sustainable Construction and Development Manager at Lafarge A&C UK, as these have an impact on everything from the structure of a building to its aesthetics. “The sooner we’re involved, the more we can help with providing solutions for the client”, she says. “Once a client has seen the plans and said ‘Yeah, I like the look of that’, it becomes much more difficult to suggest changes. The last thing you want is to be going back to the designers and engineers after the plans have been submitted, because you’ve just come across a material with great properties that you didn’t know about before.”

A piecemeal approach to design could not have delivered such a result

Take the case of a ‘hard to heat, hard to treat’ 1950s house in Norfolk. Its CO2 emissions were reduced by 93% and its energy consumption by 81%, thanks to a retrofit pilot called ‘Greening the box’, delivered by Wherry Housing Association and Broadland District Council. Lafarge worked with architect Jeremy Harrell on the plans from the start. Key to the success was a super insulated in situ concrete ground floor, in which thermostatically controlled, low-grade electric underfloor heating was embedded. This works alongside solar water heating and photovoltaics installed on the roof. The refurbished house now functions as a whole system, each innovation feeding into the next. A piecemeal approach to its design could not have delivered such a result.

But there’s another significant benefit in getting everyone together early on, says King: they are more likely to be open to solutions outside their comfort zone. “It helps to be part of a team with experience of doing things out of the ordinary and being imaginative, because they will recognise opportunities that conventional designers wouldn’t.” But, he adds, you have to factor in enough time to explore the options.

For Matthew Kitson, Head of Sustainability at consulting engineers Hilson Moran, you have to start with the people who will actually use the building. As he sees it, “the biggest factor in any refurbishment is achieving occupant satisfaction”. This is particularly true of commercial retrofit, he explains, where a good result “can help attract the best employees, improve productivity and help retain staff”. How people go about their jobs day to day has implications for the best layout of the building, which in turn impacts on its structure, and on services like lighting and temperature regulation.

Of course, any business planning a retrofit will also want clear benefits to present to the board. For Kitson, this means that the design team need a good grasp of the client’s business model and motivations.

One of the most high profile retrofits, literally, has been New York’s Empire State Building. The project turned the 80-year-old skyscraper into one of the most sustainable office blocks in the US. It was driven by hard-nosed financial goals, so that the reduction in energy consumption and environmental impact would simultaneously enhance its profitability for the owners. The result was a cut of almost 40% in the building’s energy consumption – double that of a typical commercial building retrofit. And, with a payback of just three years, it is proof that refurbishment can make economic sense.

However, turning the 80-year-old icon into a flagship for sustainable refurbishment was not without its challenges. A team of specialists was assembled, led by owner Anthony Malkin, President of Malkin Holdings, and including environmental organisation Rocky Mountain Institute and project manager Jones Lang LaSalle. Also on board at the outset was the building’s energy supplier, and building controls manufacturer Johnson Controls, as the custodians of its energy consumption data. It took seven months of audits, brainstorming, energy modelling and financial analysis to determine what it was possible to achieve within strict financial parameters.

One of the team’s key findings was that the most cost-effective way to meet energy efficiency goals would be to integrate the plans with the existing refurbishment programme. A prime example of this was the refurbishment of the building’s 6,500 windows. The owners had already decided to reseal all the windows under the capital upgrade programme, so it made sense to invest a little more money in improving their thermal performance to achieve significantly higher energy savings. And, because the window refit reduced solar gain, it was possible to upgrade the cooling plant with more efficient motors and drives, rather than having to replace it, which brought additional cost savings.

Across the pond in London, a refit at the National Gallery was driven as much by artistic considerations as financial ones. Shedding the right light on a priceless collection is no easy task – and one that a team led by conservation scientist Joseph Padfield of the Gallery’s Scientific Department has been working on for three years.

“I’ve been testing LEDs for a number of years to see how good they have become”, says Padfield. Now, he’s convinced that the technology has advanced to a point where its application will not only save the gallery energy but actually improve the quality of light on the pictures too.

“We measure the levels of light on the paintings continuously”, he explains. “If there is insufficient daylight [from skylights] then we add artificial light.” The current system uses tungsten halogen lamps, which switch on and off in response to natural light levels. But, Padfield says, these changes can be abrupt and “distracting for visitors”.

The new LED system, which will replace existing lighting on all the gallery’s pictures and throughout the adjoining Sainsbury Wing, has been designed to overcome this distraction. The move is expected to cut lighting energy consumption by 85%, which will reduce carbon emissions by up to 400 tonnes a year. And so alongside slimmer bills, it means the gallery will have less to pay in carbon tax under the UK’s mandatory Carbon Reduction Commitment Energy Efficiency scheme.

It’s one thing to plan a retrofit around the purpose of a building today; another to plan for how it might be used in the future. Over time, houses become offices, power stations are transformed into galleries, churches become concert halls… Lifestyles also evolve, changing what we want from our homes, offices and cultural spaces. Just think how recent advances in technology have already influenced the way we communicate or go about research.

Kitson extrapolates from current trends: “We anticipate that most of the IT kit on office desks will not be needed in two years, thanks to cloud computing,” he says. “All you’ll need will be a terminal with a connection to enable it to communicate with the cloud.” These changes affect more than mere clutter, he argues. “It means that there’s no point in spending money on putting in building services to deal with the heat from electronic equipment that will, very soon, no longer be needed.”

A good plan builds in room for the unknown

David Adams, a Director at the capital works, regeneration and support services company Willmott Dixon, agrees: “In ten years’ time, the world will look very different. You have to ask, are you procuring your buildings today thinking about the next 20 years or the last 20?”

However, predicting the impact of technological developments is notoriously difficult. Hilson Moran has a research and development team whose job it is to gaze into the future, but even they “can only look forward probably five years, perhaps eight years tops”, he says.

Perhaps a good plan, then, is one that builds in room for the unknown. Instead of sealing off a fixed solution, it leaves a way in for further changes in the future. It may be a hard balance to strike, but it’s an important one – like the difference between good ventilation and a draught.

Andy Pearson is a former editor of Building Sustainable Design magazine and Building Services Journal. He works as a freelance writer and editor.

For a guide to low-carbon retrofit in non-domestic buildings, see Low Carbon Refurbishment of Buildings – A Management Guide, published by The Carbon Trust.

For domestic buildings, check out the Energy Saving Trust’s guide, Sustainable Refurbishment.

Photo: © National Gallery, London