Challenges and rewards of green building retrofits

Friday, 10 March 2017

205 Queen St, Auckland has a five Green Star Design rating.

A speaker at a green building conference in Auckland in two weeks will talk about his experience retrofitting the Empire State Building in New York.

Engineer Paul Rode worked on the renovation in 2010 with the aim of reducing the skyscraper's energy use by 38 per cent.

The Empire State Building in New York as depicted by a tourist taking a selfie using his 360-degree camera.

In the face of often-suppressed scepticism about the veracity of auditing and information, Rode does not overcook the benefits of green buildings.

He acknowledged green buildings cost 5 per cent more to build and savings don't always translate to higher rents, but there were other benefits.

* New Christchurch home amongst greenest in NZ**

In New Zealand there have been questions about green standards that were initially based on Australian standards, particularly over water conservation, arguably less of a problem in this country.

Regardless, elements of green building are now integral to most building projects and have spawned a certification industry.

There are now 15 staffers at the New Zealand Green Building Council which is largely funded by industry members including some governmental organisations.

The council staff carry out training, certification and marketing work - one of them has the title of 'director of market transformation'.

They are preparing for the March 29 forum in concert with the Property Council, another advocacy organisation funded by the private sector with considerable support from councils.

Rode said while data showed rents were not higher, there was economic justification based on lower vacancy and maintenance, tenant preference, reduced energy costs, and better cash flows for owners.

Green buildings were also recognised as socially responsible, appealed to a younger workforce, and had become the 'new normal' for property developers, Rode said.

Retrofitting older buildings had also become big business, and ironically it sometimes involved enhancing passive qualities sought in new green building - natural light, dense walls that hold heat, and attractive architecture, he said.

Renovating held special challenges because often buildings remain tenanted while the work went on, and sometimes there were unexpected discoveries when walls were removed revealing mould or structural defects, and old wiring.

Rode will provide detailed costs during his address at the upcoming conference.

He said on average the return on investment on green retrofit projects is about 20 per cent.

Other aspects of good design included open spaces and walking paths allowing people to move easily, encouraging stair use, and locating conference rooms in the centre of floorplates to give everyone an open view from their work spaces.

Choice of appropriate materials reduced volatile organic compounds circulating in air systems, and water treatment and monitoring should ensured clean air and water.

Several extensive retrofits have been completed in New Zealand buildings including 205 Queen St, and 79 Carlton Gore Rd, Auckland; Square Centre in Palmerston North; and Te Puni Kokori House in Wellington where owner Argosy saves $80,000 a year, according to green standard measures.

The 1931 Empire State Building that Rode worked on took more than three years to complete at a cost of about $20m, which ws one component in a total $500m makeover of various features in the 102-storey building with 6500 windows and 73 lifts. The owner expected a payback period of about three years.

It is estimated about 78 per cent of New York City's greenhouse gas emissions come from the city's buildings, with commercial buildings contributing 25 percent, mostly from the use of electricity and natural gas.

The largest energy consumption at the Empire State Building was from lighting, cooling and heating, Rode said.

About half the reduction in energy use would be achieved in the first two years of the project by retrofitting the double hung operable windows, insulating behind radiators, and rebuilding chillers in the cooling plant in the basement.

A layer of coated film was installed between glass panes to increase insulation, and there were upgrades to the electrical and ventilation systems, and installation of sophisticated electronic instruments.