Greeny Flat 2017

Greeny Flat
Mittagong NSW 2575
Full address will be displayed on 05 Sep 2019
10am to 4pm
Housing Type
Granny Flat
Project Type
New Build
Jane Lemann
House Size
Number of bedrooms
Number of bathrooms

The Greeny Flat has achieved a number of significant milestones since we opened for SHD2014. In April 2015 we completed our first full year of operation and monitoring during which time the Greeny Flat exported to the grid almost three-and-a-half times as much energy as it imported. We also used one-and-a-half times more tank water than town water for the year and our entire running cost was $311. Also in 2015 the Greeny Flat won a Green Globes Award for “Excellence in Sustainability” in the residential category!

Over the last year the Greeny Flat has continued to prove highly successful as well as delightful to live in. Last year we added a Plug-in Hybrid Electric Vehicle which allows us to use a lot of our surplus solar power for sustainable transportation.

Since SHD 2016 we’ve also begun the process of doing a complete Energy Retrofit on the old fibro cottage next the Greeny Flat. So far we’ve removed the fibro, insulated the walls, replaced the windows with double glazing, reclad the walls and added a shade awning and deck.

The “Greeny Flat” began as a full-scale living experiment to see if it’s possible to build a small, comfortable, healthy, energy positive, low-maintenance, fire-resistant, water-efficient, elderly-friendly infill house at an affordable price.

Set on a beautiful site near downtown Mittagong the Greeny Flat features passive solar design; durable, low-maintenance materials, renewable energy systems, rainwater catchment and reuse, healthy materials and systems, local and reclaimed materials, energy efficient appliances, water efficient fixtures and landscaping, and is located within easy walking distance of services, bushland, and public transportation.

More information is available at our website here.

The Greeny Flat is located in the Southern Highlands of NSW not far off the freeway between Sydney and Canberra and close to the towns of Bowral, Moss Vale and Berrima.



Previously Open
Cost estimate of sustainable home/features
Estimate of annual savings
Universal Design Features
Disability access
Adaptive design
Window and door types
Double glazing
Low-e, films
Recycled and reused
Entire house is designed and built to be easily dismantled so that all materials can be reused or recycled.
Sustainable materials
"Eco-ply" local, sustainably-harvested plywood use for wall linings. All materials highly durable, low-maintenance and reusable.
Insulation - Ceiling
Type: SIPS panel
Rating: R3.7
Insulation - Internal/external walls
Type: "Ecoply" interior wall lining, timber wall framing with polyester batt insulation, sealed "E-therm" reflective insulation exterior wrap, galvanised corrugated steel exterior cladding
Rating: R2.4
Healthy home
Low VOC plywood, low VOC paints and sealants, no MDF, controlled "earth=tempered" ventilation
Energy star rating type
Energy star rating
Energy Positive
Connected to gas?
Renewable energy
Solar PV grid connect
Size of PV system
Water heating
Solar hot water (evacuated tube)
Passive heating cooling
Cross ventilation
Passive heating via site selection, orientation, window placement, room layout, thermal mass, insulation, air-sealing, and landscaping. Passive cooling via shading, ventilation, insulation, air-sealing and reflective exterior and lightweight structure
Active heating cooling
Ceiling fans
No active heating system installed
Energy efficiency
Efficient lighting
Draught proofing
Efficient appliances
Energy monitoring
Small, simple, Passive Solar design. Infill site close to all services and public transportation reduces energy used for driving.
Water harvesting and saving
Above ground storage
Low flow shower heads
Low flow taps
Storage connected to
Garden / Outdoors
Water wise plants
Edible garden