April 18 2010 is World Heritage Day, which celebrates the social, cultural and historical development of the cities in which many of us live and work.
Now in its 16th year, the event raises awareness of the efforts required to protect and conserve some of the built environment’s most precious assets, including the importance of improving their energy and sustainability performance.
Arup’s focus on sustainable building design – including how to retrofit existing buildings to make them more sustainable – gives it a unique perspective on these culturally and historically important buildings. While these older buildings often perform poorly in terms of electricity consumption, water usage and occupier comfort, World Heritage Day provides an opportunity to discuss how to create more sustainable futures for existing buildings, by sensitively adapting them to meet modern environmental standards. Doing so is not only culturally important, but it makes good business sense too.
Green retrofitting: Arup’s solution to aging building stock
39 Hunter Street in Sydney’s central business district is a good example of effective adaptation and refurbishment approaches to sustainable building design. It showcases the benefits to building owners, occupiers and the wider community of city retrofitting.
Nearly a century old at the time of refurbishment, 39 Hunter Street is the first heritage-listed building in Australia to achieve a 6 Green Star rating. It retains all the classic features and aesthetic advantages of its era, while design interventions have ensured it meets modern standards for efficiency and sustainability for years to come.
Another good example is the UK's Unilever House, in central London.
Gaining momentum
According to Paul Sloman, Commercial Property Leader for Arup in Australasia and globally “Refurbishing existing buildings to achieve greenhouse gas reductions and improvements in operational performance, is gaining significant momentum”.
“Poorly performing buildings can lead to increased running costs, a decline in competitive advantage, and in some cases, penalties for poor building performance, with a risk of obsolescence” he explains. “It makes a lot of sense, both commercially and environmentally to adapt existing elements of buildings to meet future expectations and standards”.
Other benefits include future-proofing to anticipate future tenant demands, improving occupant comfort and limiting the carbon impact of buildings.
As existing buildings represent around 98% of urban building stock, there is an imperative to address their performance, rather than simply focus on sustainable new build projects.
Return on investment
One of the greatest benefits of retrofitting can be to the bottom line. A key driver for updating existing buildings is to achieve improvements in efficiency. With energy prices set to soar, lowering a building’s reliance on power supply and reducing water consumption can have drastic effects on operating costs.
A major study has shown that sustainable refurbishment produces a return of better than 10% on investment. The study, completed by Arup and Davis Langdon for the Property Council of Australia, adds weight to the push by the property industry for governments to encourage the refurbishment and green adaptation of existing buildings.
Three generic building types were analysed in the study: a 20,000m2 city centre office tower, a 15,000m2 city fringe high rise, and a 2,800m2 suburban office, all built in the 1980s. The analysis documented significant return on investment from sustainable refurbishment. It also suggested that impacts on the property market from carbon emission reduction schemes would make this return even more attractive.
So, there is clear evidence that upgrading an established existing building (to achieve a minimum 4.5 star National Australian Built Environment Rating System (NABERS)) rating can provide a positive return on investment for the building owner.
And tenants prefer green buildings. Floor space in more sustainable buildings – particularly those that have achieved high green ratings – is in greater demand and commands higher letting fees than less sustainable alternatives.
Simply put, sustainable, energy-efficient buildings increasingly make good business sense and this includes heritage buildings being given a new lease of life.