Why the Greeny Flat? We built the Greeny Flat because we believe that the time has come to move towards a fossil-fuel-free future and to build small, simple structures that meet our needs without compromising the ability of future generations to meet their needs. We wanted to show that it is easy and affordable to build an energy positive house which will allow us to live comfortably in harmony with our environment. By proving that anyone can achieve this then the question really becomes, “Why not?”

Link to Video Tour of the Greeny Flat for Sustainable House Day 2021

Video Tour of the Greeny Flat

Link to video tour of the Fibro Cottage Deep Energy Retrofit for Sustainable House Day 2021

Video Tour of the Fibro Cottage Deep Energy Retrofit









PASSIVE SOLAR DESIGN – Click here for the Ten Simple Steps to good Passive Solar Design

HOME ENERGY RETROFIT – Click here to follow the progress our latest project via a series of short YouTube videos

PHEV! – Click here to read about our Plug-in Hybrid Electric Vehicle

The Greeny Flat is:

  • Small (57 sq.m, 2 bed/1 bath)
  • Simple (rectangular floor plan, gable roof, timber frame, concrete floor, off-the-shelf materials and equipment)
  • Solar (passive solar design, solar hot water, solar power)
  • All Electric (allows us to make our own energy)
  • Energy-positive (exported over three-and-a-half times more energy to the electricity grid than imported during first year of monitoring using only a small, 3kW solar power system)
  • Cost-effective ($130,000 to build, total running cost for entire year of $311)
  • Low-maintenance and durable (no paint exterior, tough/ easy-care materials and finishes throughout)
  • Comfortable (interior stayed between 13 and 27°C with no additional heating or cooling while exterior temps ranged from -5 to 41°C over a year)
  • Healthy (careful attention to Indoor Air Quality, natural light and ventilation; encourages walking and biking; raised vegetable garden beds for healthy eating)
  • Fire-resistant (no combustible materials on exterior)
  • Water-efficient (rainwater harvesting, low-flow fixtures and appliances, low-water-use landscaping, used 60% more harvested rainwater than town water over a year)
  • Adaptable and elderly-friendly (designed for single person, young family, or aging couple)
  • Heritage Sensitive (built in the Mittagong Heritage Conservation Area and local council award winner for “Sympathetic Addition to a Heritage Place”)
  • Infill development (increases density; conserves open space and resources; makes use of already developed land, roads, sewers, water and electricity supplies; easy walking distance to shops, restaurants, schools, supermarkets, churches, parks, and railway station; dramatically reduces driving; easy walking and biking)
  • Sustainable (REDUCE-less materials, waste, resources and cost to build; less energy, water and cost to operate; less energy and cost for transportation; REUSE – doors, tiles, paving, retaining walls made from reused materials; RECYCLE – entire house can be unscrewed and reused or recycled; RENEW – energy positive with renewable energy; renewable materials used in construction including timber frames and EcoPly interior)

Conceived, designed, and built by Andy Lemann with lots of help from Jane, Martin, Cintia, George and Cate Lemann. The Greeny Flat is based on a Triple Bottom Line philosophy which aims to improve the Environmental, Financial and Social outcomes of the choices we make. A big part of what makes it ‘affordable’ is the low operating and maintenance costs which add up to huge savings over the life of the home (and its occupants) and a big part of what makes it sustainable is the fact that it is ‘energy positive’ i.e. it produces more energy than it uses over a year.

As you browse through this website, please bear in mind that it is not the ‘look’ of the Greeny Flat that is important but the ‘way it works’. We chose to use galvanised cladding on the exterior because it doesn’t hold heat and doesn’t require painting and we chose to use plywood on the interior walls because it allows the whole building to be taken apart and repurposed at the end of its useful life. These were personal choices and the same goals of building a small, comfortable, healthy, energy positive, low-maintenance, fire-resistant, water-efficient, elderly-friendly home can be achieved with different materials and a very different look both inside and outside if that is what you prefer.

To read more about the goals for the project and what they mean click here or on the ‘Goals’ tab at the top of the page.

Click here or on the ‘Gallery’ tab to view a photo diary of the project.

For those who like to get down to the nitty-gritty click here or on the ‘Details‘ tab for more in-depth information about the project, the philosophy behind it, and the systems used.

Click here or on the ‘Results tab to view a table of the Results of the Greeny Flat experiment.

Or to immerse yourself in our shining wit (thank you Dr Spooner) about the ongoing status of the experiment click here or on the ‘Newsletter’ tab above (or on any of the links to the right).

If you are interested in building an energy positive home or business for yourself, or in what you can do to make your existing home or business more like the Greeny Flat, we offer consulting services for both new and retrofit projects. Click here or on the ‘Consulting’ tab above for more information about our Consulting Services

Thanks for visiting and feel free to contact us if you have any questions after you’ve read through all this malarkey.