Myths and misconceptions, poor standards and slow industry are some of the reasons why Australia is lagging the world, having inefficient residential and commercial buildings.

Residential and commercial buildings account for almost half of all annual worldwide energy consumption and greenhouse gases[1].

In fact, the Australian Academy of Science states that in maintaining our standard of living, each Australian produces enough carbon dioxide (CO2) to replace the column of atmosphere above one square metre of land, every year.

Furthermore, the average Australian house will produce enough CO2 to entirely replace the atmosphere above it with greenhouse gas. There is no way our current levels of energy use and greenhouse gas emissions can be sustained[2].

Designing and building energy efficient residential and commercial buildings is a priority for Australia. It is vital that the building and construction industry moves to higher star rating buildings that deliver better energy and thermal efficiency and comfort. Overseas, the move to energy efficient building happened over 30years ago. The US and Europe have long been driving sustainable construction through government initiatives, industry building codes and standards. However, the Australian building sector has been slow at ensuring all factors of construction are contributing to energy efficiency and greenhouse gas emissions reduction.

Energy and thermally efficient buildings significantly reduce the energy required for heating and cooling.

Double glazed windows have long been a popular choice across Europe and the US as a key solution for thermal and energy efficiency. According to Richard Walker, president and CEO of the American Architectural Manufacturers Association, double glazed windows accounted for over 55 per cent of all new and replacement windows in the US in 2012. In Australia, it is estimated that the double glazed window market is less than five per cent, even though we have a similar climate to the parts of the US.

Double Glazed Exterior of 1 Bligh Street, Sydney

Double glazed exterior of 1 Bligh Street, Sydney

Closer to home, New Zealand has introduced double glazing in residential windows into its NZ Building Code (Clause H1 Energy Efficiency).

“Because the Building Code is a performance-based rather than a prescriptive code, the use of double glazing cannot be made a mandatory requirement, but its use is recommended as the most cost effective solution to reduce heat loss through windows and the likelihood of condensation forming on the glass,” said BRANZ sustainability scientist John Burgess[3].

Residential windows in Australia typically perform very poorly in terms of thermal efficiency. Windows are the single most important source of heat loss from an insulated building – an unprotected single pane of ordinary glass loses almost 10 times more heat than the same area of insulated wall.

There has long been a misconception in Australia that double glazing is only for cold climates to keep the cold outside, but double glazing is also just as effective in keeping the heat of an Australian summer out.

In fact, standard glazed windows contribute to 87 per cent of the summer heat gain in a typical Australian insulated home[4]. Using double glazing can result in significant savings of 40 per cent off energy bills for heating and cooling[5].

Unfortunately, there is a lack of common understanding in the Australian market of the benefits of double glazed windows for occupier comfort and lower cost bills.

Lachlan Austin, marketing manager for CSR Viridian, was recently reported as saying that “Over 85 per cent of windows going into Australian homes are single glazed. Window fabricators view double glazing as a premium product and market it as a ‘Lexus’ even though on a global standard it is a ‘Camry’”[6]

Double glaze windows using PVC profiles

Double glaze windows using PVC profiles

In addition, most windows here (double and single) are aluminium, which is a poor insulator and provides little if any improvement to the thermal efficiency of a home.

Australian standards for new buildings are insufficient in weighting sustainable practice. They focus upon certain materials while overlooking thermal efficiency and its impact upon the overall building envelope. 6-star energy ratings for new homes have long been the minimum standard in many countries, whereas they have only been recently mandated in some Australian states.

Australians will continue to miss out on low bills, low greenhouse emissions and comfortable homes and buildings for as long as we continue to ignore the facts about thermal efficiency. It is time for industry standards, building codes and government policies to focus effectively on energy and thermal efficiency.


  • I think a large percentage of the industry would provide these answers to the headline is "Because clients aren't asking for it" or "It costs to much". I hear this way to many times from designers and builders. Every building, from commercial towers to single dwellings, should be highly energy efficient and should also use sustainable building materials and products inside and out. The building industry needs to practice sustainability as matter of course, day in day out. That's the only route to a responsible industry. Sustainable building is not just for the top end of town. The industry and associated suppliers need to get together on this and sort it out once and for all otherwise we keep floundering in the sustainable mud. We owe it to our community to produce healthy building stock.

  • Hi Sophi, excellent article, wise words! As double and triple glazed window manufacturers (timber) we have been trying to educate the market here in Australia for 25 years. Great to have reinforcement! Cheers, Edith

  • In Queensland we have a new performance method to control heat in buildings both residential and commercial. It is called opening it up, open a window and allow passive heat controls and natural ventilation to reduce energy use and green house gases. Our buildings are designed to "Leak like sieves", which is appropriate in the subtropics. In high rise residential, often balconies provide shade in the best developments. Double glazing and thermal separation are excellent for Southern Australian conditions, however entirely different measures are required at the &quot.

  • This surprises me because I know Australia has a very effective Green Building Council and an Energy Efficiency Council. I campaigned strongly for greater Government recognition of the importance of Energy Efficiency a few years ago and thought the message had been understood. Now I'm based in Singapore and find that Government agencies and business gets the message and the public private partnership seems to be working. Of course more could be done, but it is obvious here – and in other Asian countries – that energy efficiency helps companies/buildings/businesses save money at the same time as saving energy.

  • With respect, NCC Section J is fairly demanding and looks at facade direction, surface area of glazing, then the important combination of frame and glass and uses Window Glazing Calculator to optimise each and every project.
    Double glazing in hot climates holds heat in after the a/c stops and needs extra pulldown the next morning at the worst peak time. Aluminium frames that are not decoupled should be barred. New breed Low E glass can be close to double glazing in a single more economical unit.

  • The price of land and housing is very high – increasing property values are people's main concern. People think that having a house that might require some thought to manage temperatures, lighting costs etc might reduce the profitability of the investment.
    The idea of saving money through having a more energy efficient house does not seem to be of interest to home owners. The attitude is that water comes from the tap as needed, hot or cold, the air conditioning keeps us cool, the heating keeps us warm. To have a home that is energy efficient due to care in its construction is not a common goal. Perhaps the costs of gas and electricity need to be come even more expensive to spark a desire for energy efficiency in Australia

  • Australia is still debating how to keep energy prices low rather than how to reduce energy consumption!

  • why do 6 star rated buildings have their lights on all night?. Why is it ok to use way over J6 IF GREEN POWER is used?
    Energy efficient buildings are not efficient it is all a furphy to make people feel good

  • After reading all the comments , Good article Sophi you have stirred the possum . The main problem is ,the building industry is made up of a large group of builders who fight amongst them selves to do the least for the least amount of money to the lowest standard & the client wants to pay as little as possible . Then there is the BS like , Just open a window , multi glazing is for cold climates , use brick or concrete on the exterior of the building . To top it off, why is a lot of professionals in the building industry blind , deaf & dumb when it comes to understanding ICF & how it really works . what is ICF ? Insulated Concrete Form . As builders in Australia we must stop building houses as we have in the past & just add some bandaids to fix the problems ,It does not work, we need a whole new approach .With ICF we are held back to 8 to 10 stars by inferior windows & Doors & it is the standards that need to change .

  • After living in Central Queensland for 12 months and being sourounded by an explosion of development I feel I can comment on this subject. I also have an engineering background an architectural qualification. The domestic construction I observed in CQ was extremely poor but not only from an energy efficiency perspective. Insulation was completely omitted or only consisted of a thin layer directly under the roofing to prevent direct heat contact from steel roofing. Foil sheet on was was considered wall insulation (outlawed in NZ decades ago), plumbing water supply pipe work only clipped onto framing sporadically on the outside of framing in the brick veneer drainage cavity. Thermal envelopes serve to maintain an internal environment wether this requires heating or cooling.
    But energy is so low cost due to all the coal fired power stations so where is the insentive for improvement?

  • There is a perception that its 'expensive' to design energy efficient buildings, statutory requirements are too lax in this area, energy costs too cheap, and a paradigm shift is still required at all levels of the design, technical, local govt, utility providers, construction, procurement, and facility management process to think differently so that our buildings are as efficient as possible. All too often there is no time in the design process to research what's needed, to properly weigh up the upfront costs against ongoing costs, and in the end it becomes all too hard and better the devil you know…….

    • marisa. You are correct. It is very easy to make a building energy efficient with no capital outlay and no government assance required. I see too much government funding been given out for projects that do no more than waste energy.

  • For me, it's about accountability. Nobody is worried about Section J of the BCA because they won't get in trouble if they get it wrong. It's like speeding along a road and there is no police force to book you for it. Would you adhere to the speed limit? No! Even if a cop stopped you and said "Did you know you were speeding?" and you say "No." and then the cop says 'Well, yeah you were, so don't do it again. On your way." Would you change your behaviour? Of course not. It's only because cops give us massive fines, with a serious risk of losing our licences, that we have changed our driving behaviour over the last 2-3 decades. Until we have 'cops' booking people for not producing energy efficient buildings (especially with the risk of losing our licences!), no one is going to bother to change what they've always done. And as we go into the second decade of Section J, we can clearly see that this is true!

    • well said. J6 the BCA Nabers are all garbage.
      When people brag about a Nabers 6 star rated building but leave every light on 24/7 who is fooling who about been sustainable. And the government are also stupid for funding all this.
      I saw a bunning shop get 250,000 or around that to upgrade lighting. What did the do. Kept all the hogh bays and added T5 high bays no fittings came out. So what was saved ZERO
      but the government felt good and promotes the fact they gave bunning money.
      Once again big companiez that can afford to do things themselves getting funding to waste energy.

  • Great comments above… 2 comments of concern though in relation to the article….

    1. “It is estimated that the double glazed window market is less than five per cent (in Australia)”… not sure where that is from as it does not reflect what i am seeing!

    2. “Using double glazing can result in significant savings of 40 per cent off energy bills for heating and cooling” …. the source (Woods Products Victoria) actual states” A significant saving of 40% off energy bills to heat and cool all residential and commercial buildings can be made if appropriate glazing is installed”. By misquoting the term “appropriate glazing” in replacement for “double glazing”, this article creates a very real misconceptions that double glazing is as effective across Australia as you move away equatorial regions….it simple is not!

    • Darren you are quite correct. I think everyone knows this sustainable issue and star rating in all a con job to keep people employed that thaught all this up.
      To reduce power consumption is very easy and people would know that lighting, HVAC&R are the biggest users of power. As tou quite rightly say why dont you see more double glazing. All costs could be offset by energy saving and all these funds that are given out is not required. This will save the government millions of wasted dollars.
      They always looking at cutting funds to areas that need it such as the blind and disabled. But willing to hand out lots of money to crap.

  • Interesting comments! A few from my experience. We designed and built a passive house following the International Passive House Standard which models the design to predict a maximum energy use per sqm per annum. (see facebook page superpodhome) In Australian terms it is an 8.7 star house but the energy efficiencies are just not measured on the Nathers scale. This house is so good it needs NO heating and NO cooling in Melbourne.
    There is no risk of us leaving the heater on all winter because we don't have one.
    As for windows we got triple glazed and boy was that hard to get here!
    Thermally efficient window frames are also almost impossible to get here. Overseas they are 10 – 20 years ahead of us.
    One big difference is that there is little proper testing and data of the performance of building products here. Some companies assert certain figures but have no spec sheets to back it up. You can't buy those products and hope to comply with the Passive House Standard.
    Yes we need to change our laws, our perceptions, and our practices. In the meantime, people can still choose to voluntarily build better buildings (pending legal change which might be 10+ years away).

  • There are a number of reasons in my opinion. Here's one:

    Building services & energy engineers are usually involved far too late in the design process. Good design takes a bit of time. Integrated, first-principles lean design is the best way to design buildings that are both cost-effective to build, operate & maintain, & be energy efficient. McDonalds menu star rating systems aren't the best way – it's just an easy way to market it, unfortunately it often ends up as just a green-washing exercise.

    Integrated design can't happen unless all design disciplines are involved from the start & are given equal status. You won't see Toyota designers come up with a beautiful, heavy, expensive vehicle design & then say to the engineers "just make an engine to fit in there somewhere & make it cheap", or "We've come in over budget but we need to keep the body & interior as-is, Can we use a 1980's engine design to save money". It just wouldn't happen – yet it happens all the time with buildings.

  • Whilst I agree that it is worthy of consideration on any new build, there are also glazing films which are also great at significantly reducing glass surface heat transference.

    As for those building's you see with the lights on, they are often either being cleaned or are 24hr operations by the tenant.

    Many buildings start out with intelligent lighting controls, etc. only to have these disrupted and disabled by tenancy fitout. Same thing with supplementary A/C controls not integrated into the base build so that they oppose each other.

    Every building has unique features and these need to be addressed by appropriate design and installation at every change to structure, equipment, layout, occupation, furniture & fittings.

  • I will put forward a different view point – maybe it is just a lack of education, if you don't know the how and why, and no one can prove to you that you will actually benefit from it, then you are right to be sceptical about it.
    Energy efficiency can be designed and verified in the building design process, quite easily and cost effectively. There are software products and design strategies that can be used within the current design timelines and fees that will result in savings in both the short and long term.
    I have witnessed the use of the BCA section J analysis software by Darren O'Dea. It does a very good job, very quickly at highlighting design changes that will result in the best energy efficiency from the design.
    Sefaira is also a software package I have used to demonstrate the impacts of design changes that impact energy efficiency, while allowing optimising the building for daylighting and views.
    IES-VE does a very good job and if used by an experienced operator can provide answers quickly and cost effectively at the very start of a project, determining the best orientation of a building to achieve energy efficiency.
    My point is the tools and capabilities exist, the efficiency of the operators and understanding architectural intent are the areas where we need to improve so that providing these services and analysis of buildings becomes the norm.
    Education of the benefits of having building physicists work within the architectural design environment is key to achieving the long term outcomes we are all striving for.

  • Though double glazed windows will, in the long term, provide lower bills, low greenhouse emissions and comfortable homes and buildings, we cannot ignore the fact that replacing the typical single glazed window would mean a cost so expensive, not only with the glass itself but with appropriate frame needed as well. Unless our building code mandates it, I am sure many will continue to ignore the facts about thermal efficiency, which will be so helpful both for the extreme heat of summer and the coldness of winter. When industry standards, building codes, and government policies focus effectively on energy and thermal efficiency in building construction, maybe a less expensive double glazed glass will be available in the market and attract more users to choose them.