- Client: Blair and Julie Mackinnon
- Type: Residential
- Location: New Zealand
- Date: October 2020
26 Aroha apartments have undergone a life cycle design process. The idea of the project is to create a place for tenants and families to experience a truly sustainable and cooperative living, while retaining the independence of self-contained apartments.
The results of the Life Cycle Assessment demonstrated a 38% savings when compared to business as usual, code compliant practices. 26 Aroha project is different to others through the 90% re-use and recycle of the old house, not using any fossil fuels, minimizing the use of power, water, waste, using eco-friendly building materials, solar energy, etc.
Environmental design initiatives in the project are summarised below.
- 10kw solar PV array
- 30m2 of solar hot water panels providing up to 75% of the building’s hot water energy from the sun
- Support for living without a private car – large secure bike space, a shared electric car, located next to public transport, shops, schools etc
- Thermally designed for low heat and cooling costs, and fitted with low energy lighting and appliances to keep for power use low
- Low water use appliances, shower and faucet fittings, and rainwater tanks to collect water for the gardens to reduce water costs
- Shared organic food gardens with compositing systems designed to accommodate all food waste on site
- Waste separation systems built into the kitchen units and private collection contract, with targets to support Auckland’s zero waste 2040 target
The key result of the whole of building Life Cycle Assessment is a figure of 1112 kg CO2-e per year per occupant. This assessment is based on an estimated building life of 100 years.
It is observed through the LCA modelling that the following areas have the greatest impact to the overall environmental footprint of the building:
HWS: Solar Thermal and Electric Boost
As well as harnessing the suns energy to make electricity it can also be effectively used to heat hot water. Modelling of the development shows that installing 30m2 of solar hot water panels and 3.0kL of tank storage capacity can meet 50-75% of the hot water demand including tank losses.
Improved Thermal Performance / Passive Heating and Cooling
The carbon emissions associated with heating and cooling account for approximately 13% of the total operational carbon. Thermal performance may be improved by any combination of the following:
- Increase insulation
- Attention to detailing around thermal bridges
- Reduced air permeability
- Reduce glazing areas Increase glazing performance (double glazing)
Reduced Car Park Spaces from 13 to 4 (Car Sharing Program)
Car parking facilities contribute to a large amount of embodied and operational energy when considering the concrete walls, floors and large lighting and ventilation demands required for the space.
Car sharing is an initiative to reduce the required space for automobiles on the roads and their holding facilities. For this recommendation eTool have assumed a parking facility allowing for one parking bay per unit resulting in a basement parking facility of 240m2. Through running this recommendation this parking space has been reduced to 171m2 of ground floor parking as proposed in the design documentation representing 4 parking bays for the 13 unit dwelling.
|Impact Area||Total CO2e/ Year/occupant||% Saved Against Benchmark|
|Embodied Carbon||665 kgCO2e||-38%|
|Operational Carbon||447 kgCO2e||-86%|
|Total Carbon||1,112 kgCO2e||-73%|
Cork floors finish, 50% Fly-Ash Blend Concrete and 90% recycling of the old house
Apartment finishes changed to cork based flooring called corkoleum.
Fly-ash is a by-product of power generation in coal fired power stations and can be used to directly replace Portland cement in varying proportions up to 50%. Fly-ash is also cost competitive with standard cement depending on the application.
90% recycling of the old house, and even included a small quantity of the recovered materials into the kitchen and bathrooms of the new apartments and kept the old bathtub to use as a worm farm.