Monthly Archives: February 2011

Energy Efficient House

Energy Efficient House: Design Recommendations

An energy efficient house which offers a recognised standard of energy and comfort, will have the following important features incorporated into its design:

  • It is correctly orientated to the sun (southern hemisphere locations require a northern orientation)
  • The window glass area and window placement have been scientifically calculated
  • Walls and floors are made from a mass material that is suitable to the climate of the area
  • Insulation is correctly placed and of the exact R rating for optimum effect
  • There is adequate natural ventilation, related correct window and door placement
Energy efficient house image

Energy Efficient House by Ecotect Architects

House Orientation

The majority of blocks in a housing estate should encourage houses of a rectangular shape with long axis close to east-west. Generally, the ratio of long to short axis must be more than 1.5. This will afford maximum privacy and cost efficiency. In cold climates the proportion will be longer but in hot climates for an energy efficient house result the shape will be more of a square than a rectangle.

Window Placement

In the southern hemisphere the living area should face north and have the largest window area. Conversely the northern hemisphere, living areas should face south. For the purpose of clarity, in this article we will presume the location of the energy efficient house is in the southern hemisphere. Windows should be shaded in summer but be free of shading in winter. The shading type can be adjustable or permanent – such as eaves, awnings and shutters.

North Walls

North facing glass should be clear. Avoid tinted glass in temperate climates. Fixed shading should have a specifically calculated overhang. When calculating the area of glazing to the north it is wise to restrict it to no more than 35% of the effective floor area in temperate climates. In colder or warmer climates the ratio is adjusted accordingly. For an energy efficient house to work well in all seasons, pergolas with deciduous plants or creepers, or shutters and awnings which are adjustable are preferable to a system of permanent shading. It is important to allow winter sun to enter the energy efficient house, therefore permanent shading should be avoided.

East-West Walls

In order to restrict the sun access, windows in the east and west walls should be minimised – or shaded to prevent the sun from entering. Shade structures are not useful for the east and west walls. The area of glazing should be restricted to less than 5% of the total floor area for both of these walls combined, with the western wall to account for no more than 2% of the total floor area. Allowances may be given if the other elevations use more than the minimum amount of recommended shading. The allowances will be calculated by a specialist in energy efficient house design. There are specific maximum co-efficients of shading which must be included in the calculation. Variations will be made for each climate.

Shading

Climbing deciduous creepers, deciduous trees and plants are recommended to shade east and west windows. Adjustable shade controls and tinted glass is also recomended for windows in the east and west walls.

South Walls

It is not required that windows in the south facing walls are shaded – if shading is used it should be limited in order to maximise winter sun benefits. The east, west and south facing glass areas should be restricted to a maximum of 15% of the floor area. Shading these areas will not allow this restriction to be lifted in a temperate or a cold climate zone. It may be found by using a computerised thermal analysis, that reflective or tinted glass may be used on south facing windows.

Stabilising Internal Temperatures

It is important to use the right materials in the construction of an energy efficient house – these materials differ from climate to climate. In a temperate climate, materials which absorb and store heat well, such as brick, rammed earth, rammed limestone and concrete, will provide stable air temperatures, especially in the hotter seasons. Construction should be on a concrete slab. Hard surface flooring materials, which absorb heat, are recommended specifically for north facing rooms. Coverings such as tiles, slate or polished concrete will continue to work over a 24-hour period. In extreme weather conditions, doors and windows should be kept closed.

Insulation

In a temperate climate the roof insulation should be a minimum of R1.5. and if perimeter walls are of light weight they must have insulation with an R value of at least 1.0. Under extreme climate conditions these rates may increase to over R4.

Ventilation

To keep an energy efficient house naturally ventilated, the natural breeze patterns of the area must be considered. Windows and doors in the sleeping and living areas must be placed to capture the natural flow of air. Doors to the exterior of the house or rooms with high-flow fixed ventilation like bathrooms and toilets should be weather stripped. To prevent heat loss in winter, chimneys should be provided with a damper.

Hot Water System

The hot water system should be either gas or gas boosted solar. During long periods without adequate sunshine, the gas boosting will be required to maintain a steady supply of hot water. By combining these guidelines and working with energy efficient professionals, your energy efficient house will be cost-effective to run and work to the highest standards of comfort and energy efficiency.

Energy Efficient House Design Manual

Energy Efficient House Design Manual

By combining these guidelines, reading energy efficient house design manuals and working with energy efficient professionals, your energy efficient house will be cost-effective to run and work to the highest standards of comfort and energy efficiency.

Energising South East Asia Conference | Renewable Energy Investments

The  Energising South East Asia Conference and Exhibition will  be the largest sustainable energy expo ever held in Western Australia and is shaping up to be the largest expo to showcase renewable energy and energy efficiency ever held in Australia.

Energising SEA | Renewable Energy Investments image

Energising SEA | Renewable Energy Investments

Around the world, growth in renewable energy investments are now greater than any other form of energy source.

Global renewable energy investments are around $US160 billion and this burgeoning of global effort in green energy is underwriting interest in the Energising South East Asia conference
Asia continues to be the fastest growing market in clean tech, with renewable energy investments now in excess of  $US40 billion. For example, China alone now has 42.3 GW of wind power, and has surpassed the US in terms of total installed capacity of wind.

Australia is lagging behind the world in both renewable energy investments and carbon pricing, as highlighted this week by Prof Ross Garnaut in his first update of the Garnaut Climate Change Review. But interest is strong – as it should be in the nation with the world’s best renewable energy resources.

Recent reports suggest Australia has the potential to produce some of the world’s cheapest renewable energy, and to meet all its energy demands by 2050.

Energising South East Asia Conference :   DETAILS

Prof Ray Wills
CEO
Sustainable Energy Association of Australia
ceo@seaaus.com.au
Mobile +61 (0)  430 365 607

Passive Solar Homes Design Creates 300,000 New Jobs

Designs of passive solar homes, incorporating advances in recycling building materials from demolition, water and waste water design should be the focus of progress in our search for answers to reduce our domestic energy consumption.  New advances in solar water heating, grid connected photovoltaic systems and the integration of other renewable energy systems should be incorporated  into the built environment.

Passive Solar Homes to Create Opportunities

Solar Passive House Image - solar Umbrella

Passive Solar Homes with Solar Umbrella

Passive solar homes, adapted to become energy and water efficient such as this house shown with a solar umbrella, could create 300,000 new jobs in the building industry – this growth would take place over 20 years and be in key industry areas.

The growth in new jobs will only take place if we are serious about reducing greenhouse gas emissions and introducing policies and practices to ensure we only construct and reconstruct energy and water efficient homes.

Australia’s built environment constitutes 33 per cent of greenhouse gas emissions and this figure increases to 40 per cent when infrastructure and embodied energy are taken into account.

These amounts could  be reduced if energy consumed in existing homes is reduced by between 30 and 50 per cent and by 80 per cent in all new homes. This is why passive solar homes are the only realistic solution to our residential built environment energy problems.  However not all designers and architects specialise in energy efficient design and a ‘near enough is good enough’ attitude will not bring the best results in reducing energy consumption. Contact passive solar homes specialists for the best advice and outcome and ask them for proof of their expertise before you enter any contracts.

Retro-Fitting Existing Homes

Of the 7.5 million houses in Australia we know most need to be retrofitted to become more  energy and water efficient. Many of these will eventually need to be replaced with new state-of-the-art passive solar homes because it will be too costly to retrofit them.

Homes to be demolished will have to be carefully recycled and this will entail the introduction of procedures and policies to ensure wastage is kept to a minimum.

Building Codes Needed For Recycling Existing Homes

National building codes and other relevant legislation in Australia do not require home owners and builders to comply with energy and water efficiency principles when demolishing, retrofitting or renovating homes.
Legislation is lagging and up until now lay people and industry groups have led the way in the instigation of innovative and necessary change.

The idea of adapting a home to become more energy and water efficient is normally decided by home owners, who place pressure on designers and builders to trial new methods.

Once these techniques have been found to be effective, builders adopt them into mainstream practice and political parties follow by introducing them into legislation.

This means the general public and industry professionals will continue to lead the way in the push for important change, but this may not be enough if we are to significantly reduce greenhouse gas emissions to mitigate the impact of climate change.

Demand For Passive Solar Homes

Many people in Australia want to live in passive solar homes and work in buildings that have been designed and built to comply with energy efficient and climate sensible principles.

While it’s good news people that people  want to live in energy efficient homes, there are barriers to these lifestyle changes which include money, industry know-how and legislative amendments. This is because the cost to retrofit a property may initially be outside a home owner’s budget despite the investment eventually being offset in energy savings while also reducing each of the occupants’ carbon footprints.

Legislation Lags Consumer Demands

Industry know-how and current legislation are also not at the level desired by consumers.   In the interim, young people, tradespeople, homes designers and architects could extend their skills’ levels by enrolling in sustainability courses  and placing pressure on landlords and employers to implement climate sensible and energy efficient principles in the rental market and the workplace.

However retrofitting and building new passive solar homes by home owners is probably the most likely and definitely the most effective response to our domestic over-consumption of energy.

 

Image: Courtesy Wikipedia