Fibro Cottage Deep Energy Retrofit 2021

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House Notes – Fibro Cottage Deep Energy Retrofit

Many past SHD visitors will be familiar with the Greeny Flat which has been open almost every year since 2014. Please see our separate listing for “The Greeny Flat” for more information and Part 1 of our two-part video tour.

This year we have something very special to show you. During the last year we completed a deep energy retrofit and renovation of the old fibro cottage next to the Green Flat and we’re proud to show you what we’ve done. So we’ll be (virtually) opening both the Greeny Flat and the cottage for your viewing pleasure this year.

The Greeny Flat.
In April 2015 we completed our first full year of living in and monitoring the Greeny Flat during which time we had exported to the grid almost three-and-a-half times as much energy as we 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!

For the last six years the Greeny Flat has continued to prove highly successful as well as delightful to live in. Five years ago we also added a plug-in hybrid electric vehicle which allowed us to use a lot of our surplus solar power for sustainable transportation. And we were still exporting two-and-a-half times more power to the grid than we were importing! (Note: we sold the PHEV last year and are now looking at our options for a fully electric vehicle).

Fibro Cottage Deep Energy Retrofit
During the last year we also completed the process of doing a deep energy retrofit plus cosmetic renovation of the old fibro cottage next the Greeny Flat. This process took us a few years during which time we: removed the asbestos fibro; upgraded the electrical and plumbing systems; replaced the old fireplace with a slow combustion wood heater; converted the old chimney to a mini-trombe wall; added an energy-efficient reverse-cycle split system for heating and cooling; insulated the walls; replaced the windows with double glazing; reclad the walls with galvanised steel; turned the entire north facing wall into a solar air heater; replaced the dark tile roof with light-coloured Colorbond; added insulation to the roof; installed a 5kW solar power system; insulated under the floor; added an awning and deck on the west side to help with summer cooling and to provide a covered outdoor eating space; removed one living room wall; moved the kitchen to create an open plan living/kitchen/dining space; laid a new floor in this space; converted the old kitchen to a mudroom; added a second toilet; replaced the old paling fence with a wire panel fence; planted a low-water-use hedge inside the new fence; and installed a second water tank and pump so the house can be run on rainwater as well as town water.

We moved in to the cottage about eighteen months ago and, to date, we have exported two times more energy than we have imported. So we have successfully converted an uncomfortable and energy-sucking old fibro cottage into a light-filled, comfortable, low-maintenance, energy positive, retro-styled, modern home. We’re very proud of what we have achieved and we think it sets a great example for what can be done with old fibro houses, of which there are thousands in Australia.

Background Information.
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.


Years Open
    • Energy efficiency:
    • Draught proofing
      Efficient lighting
      Efficient appliances
      Energy monitoring
      Smart home features

    • Energy efficiency:
    • Passive Solar design. Infill site close to all services and public transportation reduces energy used for driving. Plus Plug-in Hybrid Electric Vehicle charged with excess solar power.
    • Passive heating cooling:
    • Cross ventilation
      Passive solar designed home
      Thermal mass

    • Passive heating cooling:
    • Passive heating and cooling via site selection, orientation, window placement, room layout, thermal mass (mini-trombe wall), insulation, air-sealing, and landscaping. Passive cooling via shading, ventilation, insulation, air-sealing and reflective exterior and lightweight structure
    • Active heating cooling:
    • Split system airconditioner

    • Active heating cooling:
    • Entire north wall is a thermostatically controlled solar air heater
    • Water heating:
    • Standard Electric Storage Tank
    • Water harvesting and saving features:
    • Rainwater storage - Above ground
      Low flow shower heads
      Low flow taps
    • Average water consumption per day:
    • 0.1kL
    • Above ground rainwater storage Type:
    • Tanks
    • Above ground rainwater storage Size
    • 5000L
    • Energy Efficient Lighting
    • LED lights throughout
      Natural daylight
    • Window Protection:
    • Awnings (external)
      Honeycomb blinds

    • Window Protection:
    • Passive Solar Designed roof overhang. Porches over front and back doors.
    • Recycled and reused materials:
    • By choosing to retrofit the old fibro cottage we were able to reuse most of the materials except the ones that were either toxic (asbestos) or inappropriate to an energy efficient house in Australia (e.g. tile roof)
    • Sustainable materials:
    • Reuse of most of the old cottage
    • Recycled and reused materials:
    • Basins/sinks
      Copper pipes/fittings
      Kitchen cabinets
      Light fixtures / fittings

    • Insulation Type:
    • Under-roof
      Internal walls
      External walls
    • Ceiling Type:
    • Bulk – polyester
    • Ceiling Rating:
    • R3.5
    • Floor Type:
    • Bulk - polystyrene board
    • Floor Rating:
    • R1.7
    • 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
    • Internal / External Walls Rating:
    • R2.4
    • Under Roof Insulation Rating:
    • R1.5
    • Internal Walls Insulation Type:
    • Bulk – glass wool
    • Internal Walls Insulation Rating:
    • R2.5
    • External Walls Rating:
    • R2.5
    • External Walls Type:
    • Bulk – glass wool
    • All-Electric Home?
    • Yes
    • Renewable energy used:
    • Solar PV grid connect
    • Size of PV system:
    • 5kW
    • Average Daily Energy Consumption:
    • Minus 4kWh (i.e. 4kWh more produced than consumed per person)
    • Total cost of home when constructed:
    • $219,000
    • Cost estimate of sustainable home/features:
    • $30,000
    • Estimate of annual savings:
    • $2000
    • House Size
    • 135m2 plus 57m2
    • BAL Rating
    • BAL – 12.5: Ember attack with heat up to 12.5kW/m2
    • Roof
    • Metal (Colorbond)
    • Wall Materials
    • Lightweight construction (timber frame)
      Metal (Galvanised)
    • Window and Door Types
    • Awning
      Double glazing
      Low-e, films
      Retrofit Double Glazing
    • Universal design accessability
    • Adaptive design
    • Universal Design Features
    • 80cm minimum door opening width
      Minimum 110cm wide hallways
      No Corner cupboards
      Strong fittings like towel rails that can be used as hand rails
    • Number of bedrooms
    • 3
    • Number of bathrooms
    • 2
    • Garden / Outdoors
    • Composting
      Edible garden
      Water wise plants
    • Waste Reduction Practices:
    • Compost all food scraps
      Swap with friends and neighbours
      Waste free/reduced construction site
    • Healthy home features
    • Airtight house design
      Automated ventilation system
      Cross flow ventilation
      Low VOC paints/sealer/varnish
      Natural light and ventilation

    • Healthy Home
    • Entire north wall is a thermostatically controlled solar air heater that pumps fresh warm air to the bedrooms on the south side
Mittagong NSW 2575
    • Housing Type:
    • Standalone House
    • Project Type:
    • Retrofit/addition
    • Builder
    • Jane Lemann (Owner Builder)
    • Designer
    • Andy Lemann

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