Increasing Energy Efficiency | Off-Grid Energy Australia
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Increasing Energy Efficiency

Efficient house design and smart appliance choice are the most effective methods for reducing the electricity requirements of your new home. Simple concepts such as passive design, good insulation and natural lighting are great ways to reduce the heating, cooling and lighting electricity demand while also improving comfort levels. We can help you to choose efficient appliances – and identify ones to avoid.

Off-Grid Energy Australia consultants are trained in efficient house and passive design concepts and can provide you with recommendations how to reduce your energy requirements during the consultation phase. We see many homes requiring little or no heating or cooling thanks to the implementation of simple and smart design concepts.

Contact us today on 1300 334 839 or email

Passive Design


Summer Cooling

Ventilation & Air Flow

Winter Warmth

Insulation & Thermal Mass

Lighting & TVs

Kitchen Appliances

Laundry Appliances

Swimming Pools, Spas, Pumps

Passive Design

Passively designed houses take advantage of the climate and surrounds to provide a consistent, comfortable temperature inside the house with no ‘mechanical’ heating or cooling. A well designed passive house should be able to remain within 18°C and 28°C throughout the year in most locations.

Passive design ideas and techniques can be used in any house construction type and in any climate area of Australia. It is very important to consider these techniques when first planning your home as they are more easily incorporated during construction, rather than imposing them on an already built structure.

Passive design features may include:

  • considering the orientation and placement of the house on the site
  • heavily insulating ceiling and walls
  • using the winter sun and thermal mass to heat the house
  • shading the house from the sun in summer
  • using natural airflow and ventilation to help cool the house especially at night
  • making sure all doors and windows are adequately sealed

  • Internal Planning

    The internal layout of your home will also help reduce heating and cooling requirements. The main consideration you should have in mind is allowing in the maximum amount of winter sun, and minimal amount of summer sun, into the high use areas of the house. The Northern aspect of the house will be the most comfortable area to be in meaning that all the daytime living areas should be placed on this side of the house. Areas such as bedrooms that require less heating can be placed on the Southerly side of the house, and any ‘utility’ rooms can be placed on the hottest, Western sides of the house.

    These utility areas should be located close together in the house to minimize the amount of heat lost from hot water piping.

    To help keep warm in winter and cool in summer stay in the highly used areas, these rooms may need to be ‘zoned’ together and be able to be separated from other areas of the house (i.e. with doors or corridors). Smaller floor plans, reducing open plan living, and reducing ceiling height (max 2.7m) can also help with this.


    By orientating your home correctly on your site, you can improve how well the passive heating and cooling works. In most cases, the best orientation for a house is with the rooms used the most facing the North (with large windows is appropriate) and minimal windows on the East and West facings. If there is no additional shading around the house, it is best to have the longest alignment of the house within 15° east or west of north.


    The design of the landscape around your house will also play a part in your passive design. Trees can protect the house from summer heat and allow the winter sun into the house. Vegetation can provide essential wind breaks or even channel the breezes into the home to help cool it down. Of course it is always best to use water wise, native, indigenous and edible plants where possible to get the most out of your garden.

    Please be careful not to plant trees in a position where they will shade any solar panels (photovoltaic or solar hot water) and reduce system performance.


    Your house should be designed with appropriate eaves, louvers, awnings, shade sails or vegetation. Deciduous trees planted on the Northern side of the house will provide shading in summer, and drop their leaves in winter to provide extra heat and light in winter. Considering the mature height and width of a tree or shrub can make a dramatic difference to the amount of heat that enters the house.

    Pergolas, vines, or angled louvers can also be used for shading windows and any outdoor entertaining areas.

    Angled louvers are very effective in removing high angled summer sun, and allowing low angled winter sun to enter through.

    Shading Tips

  • Fit external blinds or awnings to more effectively block out morning and afternoon rays.
  • Ensure internal windows are fitted with lined curtains, or close fitting blinds, to reduce heat entry.
  • Double glaze your windows. This is highly effective for heat prevention and loss.
  • Secondary glazing (double-sided heat intensive membrane) is a low-cost way to protect glass.
  • Close curtains or blinds on days of extreme heat or cold.
  • Summer Cooling

    An Australian summer can rapidly turn your home into an oven if the home is not designed or orientated with this in mind. A mixture of shading from veranda’s or vegetation, and insulation will minimize the heat entering the house in summer. Any heat that does enter the house can be removed by adequate ventilation. Courtyards and landscaping can help redirect natural breezes into your house and maximize air flow through the house.

    By limiting the number of windows on the East and West sides of your house, you can limit the amount of strong summer sun that enters into the house.

    By using light colored roofing materials, excess solar heat can be reflected away from your house and prevents it building up in the roof cavity and passing through to the rooms below. In new builds use a high roof pitch to reduce summer heat gain through the roof and ceiling; in winter higher pitched roof surfaces can be used to collect more solar hot water and solar electricity typically when you need to collect it most.

    Where possible don’t install cool air ducts in a ceiling; this is inefficient because much heat that will leak into the ducting.

    Air Conditioning

  • Use thru wall or ducted evaporative cooling with thermostat and humidity sensor functions if you have a suitable water supply and typically do not have excessive humidity in the cooling season.
  • Keep your air conditioning set at 25°C or higher in cooling mode.
  • Don’t use a reverse cycle air conditioner for heating when powered by a standalone power system (poor energy resource / load match).
  • Use ceiling fans instead of an air conditioner.
  • Use the exhaust fans in your kitchen and bathrooms to briefly expel hot air overnight.
  • Do the cooking and ironing in the cooler part of the day.
  • Ventilation & Air Flow

    Designing your home to make the most of natural air flows is a simple way to reduce the temperature in your home. Having air flow through the house can draw in cooler air, push out high level warm air, and assists the natural cooling mechanisms used by the body.

    The most effective way of creating this air flow is with cross ventilation. This is when windows are positioned in the house to allow for air to flow naturally from one side of the house to the other. Natural ventilation should be designed so warm air trapped at ceiling level can be easily expelled through high open window outlets.

    Ventilation will also help to cool any thermal mass materials used in the house (see section on thermal mass below). Ceiling fans can increase air flow and may be used instead of air conditioning in some cases.

    Ventilation Tips

  • Draw cool air in on the shaded sides of buildings and create natural air flow throughout your home.
  • Cross ventilation – allowing cool air in from shaded areas while clearing hot air out of opposite areas.
  • Open windows at night when the temperature has dropped to assist with clearing out hot air.

  • Zoning and Draught-Proofing Tips

  • Closing doors to create different zones in your home.
  • Installing draught excluders or weather-strips at the base of doors and between the door and its frame.
  • Using plants, other buildings and fences as wind breaks to shelter your home from intense heat or cold.
  • Installing doorways at the top and/or base of stairwells.
  • Installing swing doors instead of sliding doors so less cool air can escape.
  • Remember to keep sliding doors closed.
  • Use automatic door closers for swing and sliding doors.
  • Replacing louver windows to avoid draughts and air leakage.

  • Winter Warmth

    In order to warm your home in winter, you will need to allow the sun to warm the floors and walls (thermal mass) during the day and release the heat back into the room at night. To increase the amount of heat absorbed by the floors and walls, keep them free of carpets and other insulating materials; dark coloured low sheen surfaces are the best heat absorbers. You can increase the amount of sun entering your home in winter by designing your main living areas on the Northern side of the house, and providing adequate windows that are shaded in summer but not in winter. Deciduous trees drop their leaves in winter, letting in the sun to warm the home.

    It is important to ensure that heat is kept in the building during winter by using high R value insulation, glazing, sealing off any draughts and ‘zoning’ your home to keep heat in the rooms that are used the most.

    Heat is stored more easily by materials with high thermal mass (below), such as bricks, concrete, rammed earth, and stone inside the house.

    Solar thermal ‘Heat Shifters’ or Wood burner ad on heat shifters are a simple duct and fan system that can help distribute warm air from one of these heat sources throughout the home, they can also help even out uncomfortable temperature statification between and ceiling and floor levels.

    Water Heating Tips

  • Take shorter showers.
  • Fit a water efficient showerhead.
  • Wash your clothes in cold water.
  • Choose an energy efficient washing machine.
  • Replace electric hot water units with a solar thermal unit, or gas fired unit.
  • Only wash clothes or dishes when the machine is full.
  • Make sure hot water pipes and tanks are well insulated

  • Heating Tips

  • Turn your heating down a few degrees.
  • Fit thick and close fitting curtains.
  • Make sure you have a high R value insulation installed in walls and ceiling.
  • Insulation

    Insulating your house provides a barrier to heat flow both into and out of your house. Most homes will include ceiling insulation as standard but to ensure a complete barrier, it is recommended that you install wall insulation as well. To further insulate your windows and help control the heat flow in summer and winter, you can use heavy curtains or blinds with sealed pelmets. Always install high R value insulation rather than standard insulation.

    Thermal Mass

    This refers to a heavyweight material’s ability to store thermal (heat) energy. Solid materials such as brick, masonry, rammed earth, concrete or stone, can provide sufficient thermal mass to absorb, store and re-release thermal energy if placed in the appropriate areas.This ‘evens-out’ the internal temperature on the house between day and night or from day to day.

    It is important to consider where to place the thermal mass, which thermal mass products to use for each climate zone, and the amount of thermal mass product to use for each area of the home. Thermal mass should be positioned where it will be directly exposed to the most heat in winter.

    Thermal mass materials will absorb heat from the winter sun during the day, and release it back into the room at night. In summer, thermal mass will cool down via ventilation overnight, allowing it to absorb and remove the heat from the room during the day.
    Thermal mass materials will absorb heat from the winter sun during the day, and release it back into the room at night. In summer, thermal mass will cool down via ventilation overnight, allowing it to absorb and remove the heat from the room during the day.


    Switching to energy efficient lighting is one of the easiest and quickest ways to reduce your energy use. The most efficient option for home lighting is now LED lamps and fixtures (Light Emiting Diode); Compact fluorescent lamp lighting (CFL) is nearly as efficient as LED but they contain toxic murcury. Both lamp types use much less energy to produce the same amount of light as incandescent globe including. Especially LED’s and but also CFL’s will also last a lot longer than incandescent globes.

    Note: Halogen lamps are also incandesent; they have similar low efficiency.

    Clever use of mirrors, windows, light reflective surfaces and light colored furnishings can reduce the need for extra lighting. Being creative and thoughtful about your lighting choices can reduce your requirement for artificial lighting and create sensational effects.

    Lighting Tips

  • Switch to energy efficient light globes.
  • Switch off lights not in use.
  • Use timers or sensor switches to limit run time.

  • Televisions

    Here are the typical efficiencies for types of televisions, listed from best (1) to the worst (5) for the same size screen.

  • 1. Full LED screen
  • 2. LED backlit LCD
  • 3. Fluorescent backlit LCD screen
  • 4. CRT screen
  • 5. Plasma screen
  • Note: LED = Light Emitting Diode; LCD = Liquid Crystal Display; CRT = Cathode Ray Tube


    Older dishwashers are less efficient than hand washing, so if you do need a dishwasher, purchase an up-to-date water and energy-efficient model. When choosing a new dishwasher make sure to compare the EnergyRating and water rating, and look for models with economy cycle options. Make sure your dishwasher choice is sized correctly. Buying a full sized dishwasher (generally holding 12-14 table place settings) and filling it once a day may be a better option than doing many washes in a smaller dishwasher. If possible connect your dishwasher to a tempered solar hot water supply to reduce heating energy use.

    Fridges & Freezers

    Fridges and freezers, especially older models, are huge users of energy in the home.

    Use the EnergyRating to compare different fridges and freezers, and find the most efficient model for your needs. Correctly sizing your fridge is important as you don’t want to be cooling empty shelves, but you do want to have enough room to fit in all your food. Keep in mind top loading freezers typically use less energy than front loading freezers and cyclic defrost fridges typically use less energy that auto defrost fridges.

    Make sure that your fridge will have enough space around the top, back and sides for ventilation where it will be positioned in the house.

    Refrigeration Tips

  • Switch off the second fridge when not in use for long periods or if it is old have it recycled.
  • Ensure fridge coils are clean and in a cool, well ventilated location to disperse excess heat.
  • Ensure door seals are kept clean and seal well.
  • Locate fridges and freezers in cool spots, away from direct sun and other heat sources such as stoves or in hot sheds.
  • Suggested operating temp: fridge = 3 to 5°C, fresh food compartment = 4°C to 5°C, freezer = -15°C to -18°C.
  • Never put hot food into the fridge – let it cool down first.
  • Try to open the fridge door as little as possible.
  • Washing Machines

    Always choose a front load washing machine over a top loader, as they as generally more energy and water efficient.

    Choosing an appropriate sized washing machine is important and you may also like to consider buying a machine that does both large and small washes. Make sure the washing machine has a cold water cycle, an economy cycle and ‘load sensing’ as this will give you more energy efficient options for washing.

    Clothes Dryers

    Clothes dryers use a lot of energy, try to avoid using a clothes dryer; arrange an undercover drying area if possible for damp weather drying. Use the EnergyRating website to find the most efficient models if you have to use a dryer. Gas-fired or heat pump clothes dryers may be more expensive to buy initially but they are cheaper to run making them a better option if a clothes dryer is needed.

    Swimming Pools, Spas & Pumps

    Swimming pools and spas can be very high users of energy and water. Make sure to correctly size your pool or spa so that it meets your needs and you are aware of the energy and water required for its use.

    To prevent evaporation and heat loss, cover the pool with a fitted pool cover or a cover that traps the sun’s heat and heats the water passively. If you do need to heat your pool or spa, choose solar heating rather than gas or electricity.

    To help reduce your pool/spas’ energy requirement, ensure that pool plumbing has larger diameter pipes and has as few corners as possible, and make sure your pool pump is correctly sized for your needs. Timers and multi-speed pumps can also help with reducing energy usage.