Given that it’s World Green Building Week, it’s a sensible time to be asking some probing questions about what makes a building truly ‘green’. This year, I think we should use real performance data to answer questions such as those posed here last week by Romilly Madew of Green Building Council of Australia (GBCA) about whether the age of a building determines how much energy and water it will use.
The media and commentators spend column inches on buildings that are attractive young things, but what about a graceful old dame, maintained with love?
This graph shows the average electricity use of over 45 buildings in Australia, categorised by how old the buildings are.
It’s fairly obvious that recently-constructed buildings are designed to use less energy and water than their counterparts. There are a number of schemes and certificates around the world that encourage ever-higher design standards, like LEED in USA, Green Star in Australia, BREEAM in the UK, and CASBEEin Japan.
But why do the buildings that are more than 30 years old appear similar to new buildings in this visualisation? I think it is mainly because the typical life of plant and equipment is less than 30 years. Most of the older buildings now have more modern equipment installed, thanks to repairs and refurbishments. But many mid-aged buildings were constructed to provide premium, but energy intensive, services like air-conditioning. Today, they are not yet old enough to warrant an upgrade of plant and equipment.
From data like this, portfolio managers can see that a pretty good place to start improving performance would be those buildings that are approaching their 30-year limit. This is where some substantial gains for the environment can be made. Usually, upgrading old equipment like chillers has a fast return on investment, through the savings and waste cuts.
We created this visualisation by classifying Investa office buildings into age classes to investigate this issue of age and performance. But we really need more data, from other portfolios, to answer Romilly’s question in full. Green Buildings Alive offers all of us an opportunity to collectively share data so that we can more systematically determine whether the age of a building really matters for performance.
There are more interactive visualisations on this site that can tease out interesting trends or correlations in the data.
JOIN US – Interactive blogging here on Green Buildings Alive. Members of the ISI team and others will be online to answer questions and create visualisations based on comment threads. Wednesday 22nd September, 12 noon Australian EST (GMT +10).
The buildings' attributes could also help explain why some older buildings are performing better than newer buildings. It seems like older buildings (>30 years) generally have more concrete and less glass in their facades, whereas many newer buildings have fully glazed facades (and often poorly insulated framing). This could have a big impact on the amount of light and heat penetrating the buildings’ and on their insulating and thermal properties. What do you think?
Interesting point Jesse. It looks like the EPSRC (Engineering and Physical Research Sciences Council) in the UK is doing some preliminary work into this question, considering the building attributes and age of thousands of domestic buildings, as well as non-domestic buildings. Perhaps they would be interested in telling us more? See more information about the project here: https://www.ucl.ac.uk/energy/energy-news-publication/PDFs/EBDF_Workshop/EBDF_Workshop_Info.pdf
A recent article by the Australian Bureau of Statistics indicates that newer dwellings were more likely to have water and energy efficiency technology or building fabric elements but were similar to older houses in terms of the use of resources including water, mains gas, and air conditioner ownership and use. See: http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/1367.2Feature+Article1Jun+2010
A worrying trend in both residential and commercial buildings is the growing intensification of energy use. Household air-conditioning use has skyrocketed, new plasma TV's can be chewing around 300W and we are constantly expanding the appliances in our house. This means that even though we have more energy efficient technologies, our appetite continues to exceed our energy savings. Commercial buildings are increasing their use of air-conditioning and also their use of feature lighting. But what about tenant behavior? As well as building attributes, we need to remember to consider our behavior when measuring a building's performance.
It's no secret that the biggest challenge for building owners looking to upgrade an existing asset is finding and/or justifying the capital. The article mentions upgrading a chiller can provide fast returns. True, but not always. A typical 1200kW high efficiency chiller installation in a commercial building will cost up to $400,000 inclusive of professional fees. As an average a chiller replacement of this size will save about 300MWh per annum. With this data and assuming electricity costs $100/MWh, the simple ROI equates to 7.5%, which is lower than most Portfolio Managers are willing to accept for projects classified “non critical” However, if the chiller is due to be replaced as part of its life cycle in the near future (say 2-5 years), and a return can be demonstrated through reduced energy costs, the project has a better chance of getting off the ground sooner. If an escalation factor is applied to predicted energy costs the story gets better. When done correctly the Portfolio Manager may be left with a very compelling argument to replace the chiller sooner rather than later. My point is, I think its important that Building Managers have the tools & skills to clearly demonstrate potential returns to Building Owners. Will Green Buildings Alive consider providing any data/tips around this?