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Cosgroves specialist ESD group

Cosgroves have a team of engineers whose specialities include the consideration and inclusion of sustainable design elements into projects. To assist this process we have developed a matrix of opportunities to be reviewed for each new project.


Cosgroves has a number of staff who have trained as accredited professionals for the NZGBC Green Star Rating System.

Stephen French
Associate Mechanical Engineer
Stephen has been a Green Star Accredited Professional for many years, providing ESD feasibility studies and advice across a wide range of projects in New Zealand.

Steve Langley
Mechanical Design Engineer
Steve qualified as a Green Star Accredited Professional back in 2011. He has a strong background in ESD and low carbon technologies, having previously been an accredited CIBSE Low Carbon Consultant in the UK.

Evan Owens
Electrical Design Engineer
Evan has been actively involved in Green Star projects since 2011, and is currently lead Green Star Accredited Professional on the proposed 4* Rated 5 Sir William Pickering Drive building in Christchurch.

Troy Bennett
General Manager - Auckland
Troy is a Green Star Accredited Professional with a keen interest in energy efficiency, energy management and environmentally sustainable design. He has been involved in offering sustainable design advice in the areas of lighting design; including automatic lighting control system design, daylight modelling and energy metering / monitoring, on numerous projects over a number of years. He strives to ensure that all designs he is involved with minimise energy consumption and environmental impact within the constraints of the project budget and brief.


The NABERSNZ rating scheme was implemented in 2015 and can be used to assess how well a building uses its energy. It uses a similar ‘star’ rating system to the Green Star system, ranging from 0-6 stars. It acts as a post-occupancy tool and aims to provide a ‘real world’ rating system.

Cosgroves have staff who are able to provide feedback on the use of the NABERSNZ Rating process in order to achieve a certified rating for their clients.


Cosgroves work closely with EECA approved energy consultants to provide EECA funded feasibility studies, design reviews and post-occupancy energy monitoring on commercial projects across New Zealand.


Computer modelling allows us to undertake analysis and calculations that ensure optimum design solutions. Our modelling capabilities include:

  • Thermal performance and insulation modelling
  • Building orientation and solar shading features
  • Daylight harvesting
  • Energy efficient lighting
  • Energy modelling
  • Modelling internal space temperatures
  • CFD (computational fluid dynamics) modelling completed with a partner consultant to model airflows, air quality, and internal temperatures.


We are experienced in the design of energy efficient, sustainably designed buildings. We can provide detailed advice on form and fabric, to optimise thermal performance of the building envelope.


Selwyn District Council Headquarters
Selwyn District Council's main office located in Rolleston, incorporates many green engineering features which minimise waste and energy consumption whilst maximising the use of sustainable materials. Systems include high efficiency solar collectors for domestic hot water generation, rainwater harvesting, mixed mode ventilation with passive vents, and under-floor heating by way of a high efficiency heat pump connected to the Council water reticulation.

Man Street Carpark, Queenstown
CFD modelling was also successfully applied to an alternative car park ventilation design using impulse ventilation: the first installation of its type in Australasia. By showing that adequate air quality could be achieved, ventilation installation costs were effectively halved.


Cosgroves has an extensive library of technical guides and application manuals which describe ESD design methods from the UK, Europe and USA: regions that are leading the world in sustainable design.

Past ESD Achievements

  • The Press building was awarded a NZGBC 4 Green Star office design rating.
  • The Solid Energy Building was awarded a NZGBC 5 Green Star office interiors fit-out rating in keeping with the 5 Star Office design that it won earlier.
  • Selwyn District Council offices won the Property Council Excellence Award in the Special Purposes Category in addition to the NZIA Public Architecture and Sustainable Architecture Awards.
  • Club Tower was awarded a NZGBC 5 Green Star office design rating.
  • 5 Sir William Pickering Drive - this work in progress will be targeting a four star 'as built' rating.

Talk to the experts

We have offices in Auckland, Christchurch and Queenstown, enabling us to service the whole of New Zealand.

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