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Sustainable Homes

An All Electric Home is more Sustainable
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Making Plans to Electrify
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PowerPoint presentation - a personal example
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IS YOUR HOME A “LEAKY BUCKET”?

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If your home is cold in winter and hot in summer, then you probably live in an older house (pre-2010) with a poor energy rating (below 2.5 stars). Australian homes are often called “leaky buckets”. This is a reference to “air leakage”. So how do we fix it?

 

A new home should have a 7 Star NATHERS (National Australian home energy rating scheme) energy rating. Achieving this in an existing home is not impossible. But there is  confusion about what to do, where to start and costs are major barriers.  

 

Air flow (leakage) is measured as the number of air changes per hour. For “leaky buckets” this means 25 to 30 air changes/hour. By comparison, a certified passive house (10 stars) would have an air leakage of less than 0.6 air changes/hour.

 

The air flowing through is stealing the warm air you have paid to heat in winter and the cool air you have paid for in summer. Where is it all escaping? We are commonly told to seal up gaps around our doors and windows, but what we don’t hear about is sealing up the openings in our ceilings and walls. Below are the common findings:

 

  1. Ventilation fans; in bathrooms, laundry, toilets and kitchen ceilings extract air into the roof space which is open to the outside.

  2. Permanent openings in ceilings; are open to the roof space. These were needed because gas heaters produce carbon monoxide gases and need to exhaust to the outside. 

  3. Walls Vents; designed to allow air to flow through the external wall cavity. 

  4. Toilet windows with permanent openings; (with fly screens) at the top.

  5. Halogen or incandescent ceiling light fittings with holes for air flow (cooling).

 

Reducing air flow means closing the openings (air leaks) referred to above. If you are a DIYer, you may be able to deal with Items 2, 3 and 4. Ceiling and wall openings can be plastered over or filled, sanded and painted. Ceiling openings can be covered in the roof space and then insulated. Toilet window openings can be closed over with wood glued in place with silicon or similar sealer. 

 

Ventilation fans, Item 1, require the fitting of a damper or hinged flap, either on the vent fan outlet or inside ducting that is connected to the fan. Dampers open when the fan is on and close when off.

 

Single fans in your bathrooms etc. can be exchanged for new fans with a damper. If they use a power socket in the roof space, then this is a DIY task.

 

Item 5, recessed or flush fitting down lights, should be replaced with sealed LED’s that allow insulation to lay over them. If they use a power socket in the roof space, this may be a DIY task.

 

Beyond the above, you will need an Electrician or other suitably qualified tradesmen.  

 

PLEASE NOTE. This advice is general in nature, and you should always consult with a licensed tradesman.

If you use gas heaters inside your home, you cannot seal up ceiling and wall vents.

WA SUSTAINABLE HOME RENOVATION PROJECT

 

This information is an example of how it is possible to upgrade an older double brick West Australian home. The converted home, originally built in 2006, has now received a NATHERS 7.9-star energy rating. The home is now more energy efficient than new build which would have a 7-star rating. The home is more sustainable, cheaper to run and more comfortable to live in. 

 

This home is single story, double garage, 3beds, 2bath, 2cars, TV lounge and a study space. The house footprint is 250sqm, built on a level 450 sqm subdivided block. The front faces north and has narrow access down the east and west sides to an enclosed back yard. Built on a concrete slab with double brick walls (50mm empty cavity), the roof has no eaves and dark grey cement tiles (with no sarking or insulation). The windows were originally black aluminium, with 5mm clear glass (tinted to the front). The house had approximately 120 sqm of poorly installed R2.5 ceiling insulation. Gas was connected to supply gas heating points, a 900mm gas cooktop and a freestanding gas hot water storage tank. There are two reverse cycle A/C units. There were no trees or shade to the front or rear of the property.

 

Project outcomes.

  • Improved energy efficiency with a 7.9-star energy rating.

  • Gas appliances removed and changed to electric appliances.

  • Roof top solar energy, requiring less than 5% of electricity from the grid.

  • Cheaper to run, with no gas bills and currently has a credit with Synergy.

  • The home is more comfortable in summer and winter.

  • A greener outlook to the front and rear.

  • Reduced fuel costs (petrol) by approximately 75%.

  • Reduced air pollution.

  • Lower carbon footprint.

 

Renovations since 2021.

  • Installed over 100sqm of additional R4 insulation to ceilings.

  • Installed a 240litre heat pump hot water storage tank. 

  • Installed a 9kW (12 panels to east and 8 to west), 5kW inverter solar system.

  • Installed a 13.7KW Tesla Powerwall 2, home battery system.

  • Installed a 900mm induction cooktop.

  • Replaced all windows and doors (except front entry doors) with UPVC double glazed windows and doors (6.6mm ECO glass, Argon filled).

  • Installed an automated ventilation system to transfer warm or cool ‘filtered air’ to the house from the roof space.

  • Reduced airflow through the home by closing 2 (400x400) ceiling vents. Installed new dampers into all vents from the bathrooms and the range hood. Sealed door frames.

  • Installed ceiling fans to all bedrooms, the TV lounge, family room and the undercover outdoor area.

  • Installed ECO bead insulation to all external double brick wall cavities. 

  • Replaced roller blinds with new plantation shutters, honeycomb blinds, Sheers blinds and curtains.

  • Replaced all halogen downlights with LEDs.

  • Replaced all ceiling lights with LED downlights.

  • Installed 2 powered fans in the roof space.

  • Installed a shade sail over front driveway.

  • Insulated the garage door with 25mm foil board, sealed the entry doorframes.

  • Temporary (DIY made) shade sails installed (during summer) over 8 windows to east and west.

  • Front garden:  Two Jacaranda trees planted on the margin strip (free from Melville city council). A Peppermint tree to our front lawn to provide shade.

  • Rear garden: Built a pergola (with shade cloth), planted a Peppermint tree and an artificial pear tree, a Jasmin wall, a lillypilly hedge. Border with native plants. Compost bin.

 

Energy efficiency/sustainability measures.

  • A small EV (180km range) used for local travel, charged from excess solar using a standard 10Amp socket.

  • The timber floors have been re-finished in a low VOC water-based varnish.

  • Home appliances all have high energy efficiency and low water use ratings. The home only uses one 500lt fridge freezer.

  • Follows the Melville City FOGO waste system, collect miscellaneous items of waste e.g. bottle tops, scrap metals, for delivery to local recycling programs.

  • Walk to the local shops and use public transport to the city and Fremantle.

 

Sustainability improvements to do.

  • Replace the front entry doors with UPVC double glazed units.

  • Install permanent shade/pergola roofs in way of temporary ones.

  • Upgrade the old reverse cycle A/C units as they fail.

  • Convert front margin strip to a native garden.

  • Reduce water usage.

What’s possible for your home?
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Home Electrification Calculator
rewiringaustralia.org/go-electric/calculator

EV Savings Calculator
rewiringaustralia.org/go-electric/ev-savings-calculator

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