Green Buildings: Proof is in the Performance

From the work of Min Hall to the 6-star Geyser building rising out of the Parnell ground ‘green’ building has always formed some part of the New Zealand construction industry landscape.

Around five or six years ago however, green building experienced a kind of tipping point with most major projects including some sort of environmental considerations.

What exactly triggered this kind of watershed is probably a combination of factors; the government at the time was comparatively environmentally focussed (having the Green’s as a coalition partner), a few ESD ‘champions’ from various disciplines were starting to emerge which ultimately led to the inception of the NZGBC (New Zealand Green Building Council), and let’s not forget these were heady times – money was easy to come by and the construction industry was enjoying the benefits of clients being prepared to invest in items traditionally perceived as luxuries.

As a result, even in these less buoyant times, sensible features which used to be seen as the domain of the kaftan wearers are now relatively mainstream – rainwater recycling and construction waste diversion for example.  Various studies into the built costs of Green Star buildings have reported that a four star building is now essentially industry standard within the main centres, and most ‘A Grade’ office buildings (and their tenants) are expected to be a minimum of five-star.

This has also led to a general up-skilling of all roles within the industry and the environmental aspects of design decisions are routinely discussed within design team and site meetings – and as part of the greater ongoing dialogue.  The NZGBC and the advent of their Green Star tools deserve a lot of credit for this.

The problem with rating tools

Green Star (or any rating tool) is not without its problems however.  Inevitably when a framework is developed to assess the certain merits of a design, that framework can end up being the design.  To overuse my own tired expression: “people are designing ratings, rather than rating designs”.  This generates a painting by numbers approach, which may well turn out a recognisable likeness of the Mona Lisa, but won’t ever create the next Mona Lisa. 

The use of rating tools as the definition of ‘green’ can also generate a focus on commercial buildings.  While such tools exist for houses they have struggled to gain a foothold.  From BRANZ’s Green Home scheme (started in 1997) to the current Homestar, they all face the issue that the vast majority of existing houses will not rate highly, and therefore need to invest in educating the public and struggle to gain the required support from the real estate industry.

Rating tools of course only make up the carrot, code compliance is the stick.  The third edition of Clause H1 (2007) improved the thermal performance of houses based on the relationship with public health.  Commercial buildings (which technically include hospitals, hotels and aged-care facilities) are deemed to not have this relationship and so the minimum energy efficiency requirements remain too low.

Both the building code and current selection of design / built rating tools only focus on the design of a building for comparative purposes.  While it’s commonly accepted the building code has no business telling occupants how to use their building, a common criticism of rating tools is a good rating does not imply good performance in practice.  We should remember that, similar to the building code, a design (or built) rating is not equipped to measure how a tenant uses a building in practice, though in theory should limit the damage somewhat.  Similar to how a car’s economy rating is decided independent of the driver, and we would hope that a lead-footed driver will use less petrol driving a three star than a five star car, but would still use more petrol than my dear old Grandma in the same vehicle (bless her).

Much cynicism arises from the lack of actual published performance figures for supposed green buildings.  Even when known this data is usually shrouded in commercial sensitivity, but in the cases where we have been involved in the aftercare (typically a 24-month commissioning period) the building has been performing very well – though as always has not been without teething problems.  The success of the Meridian building in this regard is well documented, we hope to return to this building to repeat our Post Occupancy work now the novelty factor will have less influence.

Unfortunately the opportunities to carry out these sorts of studies and actually return to a building to monitor and benchmark performance are all too rare.  As a building scientist I liken this to carrying out a multi-million dollar experiment and not bothering to collect the results.  Even a basic review of user satisfaction, energy and water use creates a feedback loop to the design process from which the design team can learn and incorporate into the next building.  The stumbling block is that clients often don’t have a ‘next building’ and therefore don’t view this as a benefit to themselves – possibly not helped by me trivialising their multi-million dollar investment as an ‘experiment’.


This may all change in the future with the forthcoming New Zealand version of NABERS which could possibly lead to the introduction of mandatory disclosure statements.  Used in the UK, recently introduced in Australia and sure to follow Green Star across the Tasman at some stage, these encourage (and in the case of public buildings; obligate) landlords to measure and report their building’s energy use.  Similar schemes are in place for water, waste and indoor environmental quality.

This shift to actual performance is the acid test for both designers and occupants, and will require a further shift in green building practices.  Architects will have a leading role to play.  The focus on design attributes has tended to reward gadgets and gimmickry.  Highly efficient mechanical systems can be used to hide an underperforming building fabric – it irks that thousands of years of passive design knowledge appears to have been undone since the rise of air conditioning from the deserts of World War Two.  And it is questionable whether this approach will stand up to the rigours of an ‘in-use’ style assessment.

Green architecture is more than a collection of technological features.  Truly successful sustainable design comes from a design team which cooperates and collaborates outside their respective fields of expertise – not one in which the Architect has abdicated leadership to the building services engineers. 

As economies improve the motivators will return; oil prices will rise, resources will run scarce, carbon will turn back into a political football, and many clients will decide they have the financing to ‘do the right thing’.  As an industry we need to be prepared to not only produce good results when the ribbon is cut, but also stand by and learn from our work over time.