Greeny Flat 2019

Greeny Flat
Mittagong NSW 2575
10am to 4pm
House Open Style
Open House – No booking required
Housing Type
Granny Flat (under 60m2)
Project Type
New Build
Andy Lemann
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. Three years ago 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.

Mitsubishi Outlander PHEV EV on display for SHD


Years Open
Cost estimate of sustainable home/features
Total cost of home when constructed
Estimate of annual savings
Universal design accessability
Adaptive design
Disability access
Universal Design Features
80cm minimum door opening width
Hobless showers
Lever handles for doors (no knobs)
Minimum 110cm wide hallways
BAL Rating
BAL – 12.5: Ember attack with heat up to 12.5kW/m2
Roofing materials
Insulated panel (sandwich panels)
Metal (Colorbond)
Wall materials (external and internal)
Lightweight construction (timber frame)
Window and door types
Double glazing
Low-e, films
Window and door shading
Passive Solar Designed roof overhang
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 - Under roof
Type: Insulated panels
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
Insulation - External walls
Type: Bulk – polyester
Rating: R2.2
Healthy home
Airtight house design
Cross flow ventilation
Low VOC paints/sealer/varnish
Natural light and ventilation
No carpets
Controlled ventilation with solar air heater and earth-tempering to ensure indoor air quality without too much heat loss.
All electric home
Renewable energy
Solar PV grid connect
Size of PV system
Water heating
Solar hot water (evacuated tube)
Passive heating cooling
Cross ventilation
Passive solar designed home
Thermal mass
Passive heating and cooling 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 or cooling system installed
Energy efficiency
Draught proofing
Efficient lighting
Efficient appliances
Energy monitoring
Smart home features
Small, simple, Passive Solar design. Infill site close to all services and public transportation reduces energy used for driving.
Electric vehicle
Manufacturer/type:Mitsubishi Outlander PHEV
Water harvesting and saving
Above ground rainwater storage
Type: Polyethylene tank
Size: 5000L
Low flow shower heads
Low flow taps
Garden / Outdoors
Edible garden
Water wise plants
Average Daily Water Usage Per Person
Waste Reduction
Compost all food scraps
Swap with friends and neighbours