The main goals for the project are listed below (in no particular order) with a brief description of each. Click on any of the links in the text for more detailed information.
MAJOR PROJECT GOALS: Energy Positive, Affordable; Low-maintenance; Water-conserving; Fire-resistant; Elderly-friendly; Healthy; Recyclable; Small footprint (57sm) infill housing close to services and public transport, Sustainable. Click here to view a brief summary of the Goals and Strategies or read more below.
ENERGY POSITIVITY: The Energy-Positive goal is approached from both the energy conservation and renewable energy production ends. The northerly aspect, window placement, room layout, double-insulated walls, double-glazed windows, thermal mass floor, summer shading, reflective exterior, and landscaping are designed to work together to keep the interior cool in summer and warm in winter without the need for any additional heating or cooling (otherwise known as Passive Solar Design). The solar hot water system, low-flow plumbing fixtures and short plumbing runs greatly reduce the amount of energy required to heat water. And the natural lighting, solar clothes drying and energy-efficient electrical fixtures further reduce the overall energy consumption to the point where it is expected that the 3kW solar PV system will be able to make more energy than the house uses in a year. The home’s energy consumption and production along with the interior and exterior temperatures and usage of both rainwater and town water will all be closely monitored over the year following completion of construction to determine whether the goals have been met. If it proves necessary to add more renewable energy production, heating, cooling, rainwater catchment or greywater recycling systems this can easily be done at any point in the future.
AFFORDABILITY: The affordability goal is addressed in terms of both initial construction costs and long-term operation and maintenance costs. Some features of the home, like double-glazed windows and solar power systems, increase the up-front costs but dramatically reduce the ongoing costs over the expected life of the building (100 years +). The energy positive, water conserving, low-maintenance, and recyclability features all help to improve the long-term affordability of the project. Every design decision has been carefully weighed in light of the balance between initial and long-term affordability. At the end of the year-long experiment we’ll be able to provide details about the actual cost of living in the Greeny Flat.
LOW-MAINTENANCE-NESS is achieved by having no wood or painted surfaces on the exterior of the building and using durable materials like steel cladding, concrete floors, treated timber frames, aluminium windows and ‘Ecoply’ interior walls. All plumbing lines can be accessed by either lifting pavers or removing cladding sheets on the exterior of the building and the internal electric lines are surface-mounted to allow for future changes or repairs.
WATER CONSERVATION involves harvesting rainwater from the roof and storing it in a tank for use in all domestic water requirements (with town water back-up). All plumbing fixtures and appliances have been selected for water efficiency, the home has been pre-plumbed for a future greywater system and the landscaping is designed for low water use.
ELDERLY-FRIENDLINESS: The home is designed to be elderly friendly with covered/ramped access, wide doorways, minimum steps, lever handles on doors and taps, grab rails in the bathroom and raised garden beds.
HEALTHINESS: Health is primarily addressed through the protection of indoor air-quality by the use of low or zero emission materials and finishes. Exhaust fans in both the kitchen and bathroom expel stale, humid air to the outside and a constant supply of fresh air is provided via an earth-tempering tube installed beneath the slab. This tube enters the building behind the refrigerator which a) helps to make the fridge more efficient by cooling the area around it and b) further warms the incoming air due to the fridge expelling heat to its surroundings.
SMALL-FOOTPRINT INFILL HOUSING-IVITY is important for many reasons. Building smaller houses reduces both the cost and the amount of materials and energy required for construction as well as making the finished house easier to heat and cool. Infill housing utilises available land in already developed areas. This reduces urban sprawl and limits the loss of valuable natural habitats and agricultural land. It takes advantage of existing services like roads, water, sewer and electricity lines which reduces the costs and impacts of extending these to undeveloped areas. Building close to amenities like shops, schools, parks, natural areas, and public transport means that the occupant’s don’t need to drive cars all the time, which further reduces their living expenses and impact on the environment while improving their quality of life by encouraging walking and bike riding.
SUSTAINABILITY: The first step towards sustainability for this project was to choose an infill site, close to amenities, with good north aspect and solar access. The small size of the home reduces the amount of everything required to build and operate it. Making it energy positive will dramatically reduce its environmental impact over its lifespan and conserving water wherever possible will help to protect the planet’s most precious resource. Recycled, reclaimed and low-embodied-energy materials were used where possible in the construction. The steel, aluminium, and polyester insulation all have significant recycled content. The driveway is made from recycled concrete. The interior doors, ‘urbanite’ retaining wall blocks (chunks of old concrete from the demolished garage), mulch, and exterior paving are all made from reclaimed materials. All materials used in the home were sourced from the local area or as close as possible to the building site. Every possible bit of waste was either recycled or reused during the construction of the Greeny Flat. And finally, the home is designed to be deconstructable and recyclable at the end of its useful life.