Octo by Psaros, is a mixed use development of commercial and residential space in the heart of Subiaco, Perth. Featuring 8 apartments above two levels of commercial space, the complex offers modern green living surrounded by beautiful heritage architecture. Both the apartments and commercial space have undergone an eTool LCA assessment and achieved 70% and 31% savings against the benchmark respectively.

Octo by Psaros incorporates a number of green initiatives including solar PV, energy monitoring, energy efficient lighting. appliances and water efficiency. It is conveniently located close to cafes, shops, bars and food markets and a short walk to Subiaco Train Station will get residents into Perth CBD in 7 minutes. These local amenities and public transport links work towards the social sustainability of  the development and extending its design life.

  • Date: July 2013
  • Developer: Psaros
  • Location: Subiaco, Perth

Results Summary – Residences

Impact AreaTotal CO2e / Year / occupant (kg CO2e)% Saved Against BenchmarkeTool Medal
Embodied Carbon73121 %etool_bronze_medal
Operational Carbon50284 %
Total Carbon1,23270 %

Results Summary – Commercial

Impact AreaTotal CO2e / Year / m2 (kg CO2e)% Saved Against BenchmarkeTool Medal
Embodied Carbon1132 %
Operational Carbon15031 %
Total Carbon16031 %

Project features

Design life

The high density mixed use development located in a region with high redevelopment potential and designed with very high quality achieved a 100 years life expectancy in eTool LCA.

Commercial Energy Use

eTool LCA results identified the commercial premises as the biggest opportunity for improvements to lower the total Global Warming Potential and reduce costs at the same time. Offices usually have high energy demand especially for HVAC and lighting. A detailed Thermal Performance analysis was conducted in collaboration with ODS Engineering to improve building fabric insulation and glazing specifications. Lighting control was included in the design with a combination of motion sensors and lux sensors with responsive dimmable lamps that operate according to natural light levels.


High efficiency heating and cooling system were used  in the residential and commercial premises. Residential apartments are designed with split systems with COP (Coefficient of Performance) greater than four. The commercial HVAC design consists of high efficiency performance central system. Automated temperature controls and increase of natural air flow have been considered in the commercial HVAC design.

Solar Energy

Hot water will be supplied with a solar and gas boost distributed system. Solar collectors will be located on the roof and tanks in the carpark. All roof services were optimised to increase the space available for solar energy for hot water and also for electricity generation using photovoltaic panels. A solar PV system will cover all available roof area and provide electricity to the common areas of the building including lighting and other mechanical systems as well as for individual apartment use.

Electricity Monitoring

Each apartment and office space will include the ability to preview energy use in real time via a web based monitoring system. This will help occupants to manage and take action to conserve electricity and save on electricity bill. The most energy efficient commercial space will be rewarded with a display in the foyer to encourage a bit of competitive conservation.

Additional Features

  • BubbleDeck  will be used on all elevated floors to reduce the use of concrete.
  • Car stackers will reduce the number car parking levels. They will also reduce the embodied impacts and energy use for lighting and ventilation.
  • Custom ventilation at the base and top of fridge cabinetry will be used to improve the efficiency of the condenser. More information about this can be found here – link to blog post.
  • High efficiency common area lift will use regenerative energy and standby lighting and fan solutions.

This assessment was conducted by Henrique.