Tag Archives: energy efficient buildings

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.

Solar Energy and the Built Environment

Solar energy  passive design considerations have not yet become mainstream building industry practice  in Australia, despite its many positive advances in the built environment.

In my opinion, conservative forces in the building industry are still going out of their way to stifle progress by lobbying government for negligible changes to the building code compliance system and even pushing to water down the debate,  so that the long established building industry approach to land subdivision and the building of  packaged  ‘project’ homes remains largely unchanged.

Built Environment Solar Passive Design Saves 80-90% Energy

The Built Environment solar passive house South Beach Image

Built Environment South Beach House

Image: 2010  Residence located at South Beach, Western Australia Designed by Ecotect-Architects

This design is passive solar with solar water heating, photovoltaic and water conservation technologies which will save 80 – 90% energy and up to 60% water usage, when compared to the average luxury home or “Mac-Mansion”!  A 2005 award-winning solar passive house also designed by Ecotect-Architects is featured in the Swanbourne Centre blog.

The image shows the western façade with the north solar collection façade running down the block to create maximum privacy. (Note: for buildings in the northern hemisphere the aspect would be to the south rather than north.)

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Watch Out for Fraudulent Sustainability Builders: Expert Warns Home Owners

December 2009

Jacinta Goerke
Journalist

AN AUSTRALIAN sustainability expert is warning consumers to watch out for designers, architects and builders claiming to be sustainability specialists.

The warning was issued today following a rise in the number of people appointing unqualified sustainability practitioners to design and build their homes and offices.

LEED-certified homes

LEED-certified homes

Leading Australian eco architect and adjunct professor at Murdoch University Mr Garry Baverstock said he was aware of the sudden increase in the amount of unqualified people claiming to be ‘sustainability’ experts.

“Sustainability is the new buzz word and there is a growing number of drafts people, architects and builders claiming to be ‘experts’ when they are neither qualified nor experienced in this area,” said Mr Baverstock.

“I’m worried it will all come to a head in a few years when people realise their homes and offices don’t comply with sustainability principles and will label ‘sustainable buildings’ a joke.

“This is such an important issue because the built environment in developed nations such as Australia accounts for between 40 and 50 per cent of greenhouse gas emissions so our buildings need to comply with the best possible sustainability and energy efficiency rating systems,” said Mr Baverstock.

Mr Baverstock said it was not easy to design and build top rating energy efficient buildings because specialist expertise and coordination was required.

He said many practitioners were telling people they were sustainability experts just to win jobs.

“I believe this fraudulent behaviour must be stopped and for practitioners to return to university to complete post-graduate studies in environmental science and sustainability,” he said.

“These courses provide students with knowledge and skills over and above what they would have learnt in their undergraduate architectural and engineering degrees,” he said.

Mr Baverstock said tips for people looking to appoint sustainability experts included requesting copies of practitioners’ qualifications in sustainable design/environmental architecture; number and types of awards won for green building designs; addresses of past projects over the last ten years; client testimonials; and the names of energy rating systems used.

Commercial business owners should contact the Green Building Council of Australia (GBCA) to see if their proposed architects and builders are registered with them.

Image-
Name: Northside green homes
Source: http://commons.wikimedia.org/wiki/File:Northside-green-homes.jpg
Image released to public domain

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