In recent decades, commercial buildings have been the major focus of sustainability initiatives in Australia and New Zealand, but there are opportunities to apply this same focus to the increasing number of high rise residential buildings in both countries.
But first, some compelling statistics and trends that underpin comments that follow about the major potential for energy savings in residential high-rise, which can start right at their front door.
More than 550,000 people now live in Australia’s 370,000 high-rise apartments located in buildings of nine floors or more. More than 2.5 million people, or one in 10 of us, now lives in an apartment. Similar trends are spreading south from Auckland in New Zealand.
And while the average population density in this Wide Brown Land of poet Dorthea Mackellar is still only 3.4 per sq kilometre, the figures from the latest Australian Census point us to strong growth in higher density lifestyles in the major urban centres where most of us live.
Of the approximately 11 million Australian private households out there, townhouses now comprise 13 per cent and apartments 16 per cent. The proportion of apartments continues to increase, with apartments accounting for nearly one third of the increase in private dwellings in the five years prior to the Census, reaching 30.9 per cent of construction. Similar trends are emerging in NZ, where of the 50,000 new dwellings for which approvals were given, those were 28,364 multi-unit homes, including townhouses, apartments, flats, and retirement village units, a 24 per cent increase on the previous year.
Vertical living
So it is probably no surprise to architects, builders, and facility managers to see community leaders such as NSW Premier Chris Minns saying we need more vertical living to help end urban sprawl with a shift to more medium and high-rise housing.
“We have to get more comfortable with the idea of going up,” he told this year’s Sydney 2050 Summit.
His comments reflect urgent social needs, in terms of creating a better supply of more affordable housing in areas where more people want to live. And given that this trend to high-rise is inevitable, it is timely also to look at the costs of living in these taller buildings.
Because there are many opportunities to be grasped in terms of major ongoing inputs to such structures, such as energy, to ensure the long-term sustainability and affordability of our ever-upwards urban environment.
So it’s time to look not only at the clean/green credentials of our one million approx. commercial (or non-residential) buildings, but also to take from them some of the valuable lessons we are learning there and see where they might also fit high-rise residential.
It is on Australasia’s commercial buildings (spanning the gamut from office towers and industrial buildings, through to shopping centres, age care and health facilities) where much of the green star sustainability focus has rested over the last decade or so.
Green star commercial buildings, increasingly, are designed and built to perform to the higher standards expected of “tight” buildings (ie, those that don’t have expensively heated or cooled air rushing in and out every time a door, window or building leaks to the environment, in the way that “looser” older buildings do).
High standards are essential in our commercial buildings if we are to reach our climate change goal of Net Zero by 2050, because commercial buildings account for nearly a quarter of national electricity consumption. And HVAC costs in such buildings typically account for nearly 40 per cent of the energy use.
In response, there have been widely understood commercial energy-saving advances. These include engineering and technology improvements such as in the efficiency of HVAC technology, in variable speed pumps and drives services, through heat exchangers transferring heat from systems where it is not needed to other systems where it can be usefully used, through automation of lighting and services, and through energy-saving lift technologies (between about 4 and 10 per cent of a building’s energy is consumed by its lifts). Macro design and construction concepts include ‘tighter” buildings curtailing energy losses, plus building configurations and orientation to welcome natural light while excluding energy-sapping heat or cold, depending on the season and location.
Energy saving starts at the front door
With their always open/always closed functionality, revolving doors are one of the most immediate ways to help achieve energy use reductions in multi-storey buildings by making them “tighter” and curtailing energy losses.
However, the difficulty has been proving and quantifying the gains – even though these ubiquitous door save energy from day one of installation by immediately preventing large quantities of prevent expensively cooled and heated conditioned air that would otherwise escape from the building through wide open doors of entrances and lobbies. We also know losses occur and through what is often described as the “Chimney Effect’ in taller buildings.
Delft University of Technology (TU Delft) partnered with Boon Edam to develop the Revolving Door Energy Saving Tool (REST), an energy saving calculation software.
The software removes a major impediment to architects, builders and building managers who may have wanted to use revolving doors, but lacked the figures to back up their case for doing so.
For both residential and commercial building specifiers seeking to achieve green performance ratings, it can now no longer be a question of ‘What is the cheapest door up front?’. Rather, the smart building equations becomes ‘How can we create a sustainable, secure, and comfortable environment that meets national and global standards of sustainability and returns benefits starting immediately and extending over decades?
In saying this, we don’t claim revolving doors alone are a silver bullet for energy conservation, because that is a multi-faceted question with a mosaic of solutions.
