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Energy efficient home window frames


The most energy efficient window frames are made from materials that won't transfer heat and cold, such as timber, uPVC or combination frames. The type of window frames you choose can help you:



Windows consist of glazing and framing. Both components contribute to the overall performance of the window, called a U-value. U-values measure the amount of heat passing through a glazed unit in watts; the lower the U-value, the more energy efficient your window is. In your home, you should aim to use windows with low U-values because they will be more effective at keeping out unwanted heat and cold. Low U-values can improve your comfort levels and reduce your energy costs. Our uValues can be downlaoded here.

Timber frames

Timber window frames are highly energy efficient as they do not conduct heat. They perform extremely well when combined with double glazing, but do require more maintenance than either aluminium or uPVC frames. 

uPVC frames

Another efficient frame type used with double-glazed windows is uPVC, or un-plasticised Polyvinyl Chloride. uPVC frames have been used in Europe and the United States for many years, as they perform in a similar manner to timber frames but are more durable and require little maintenance.

Combination frames

Aluminium window frames that combine aluminium and timber are more efficient than thermally broken aluminium frames. These frames usually combine low maintenance aluminium as the external component and timber, which acts as an insulator, as the internal component of the frame.

Aluminium frames

Aluminium is a popular choice for window frames because it's light, strong and requires little maintenance. Unfortunately, it isn't the most energy efficient choice. Because aluminium is a good conductor, you can lose a great deal of heat through the frames in winter and gain unwanted heat in the same way during summer. This could impact the comfort of your home, the cost of your energy bills and the overall performance of double-glazed windows.

To reduce heat loss during winter and heat gain during summer through aluminium window frames, be sure to install a thermal break. A thermal break is an insulating material placed between the interior and the exterior elements of the window frame, which will minimise the transfer of heat and cold through the frame.

uValue Range:

  • Traditional timber 1.8 - 2.5

  • BINQ's Archetto series 1.0 - 1.5

  • BINQ's Azione series 1.5 - 1.8

  • uPVC 1.0 - 1.8

  • Aluminium 3.0 - 4.0

  • Thermally broken aluminium 2.5 - 3.0


A well-managed timber source is arguably the most enviromentally friendly building production available.


Timber is the ultimate renewable. Trees capture and store carbon and are renewable, recyclable and biodegradable. When we choose sustainably and responsibly harvested timber over other materials, we reduce our dependence on fossil fuels and their consequent carbon emissions.


Timber can be used to increase a buildings ‘life cycle assessment’, has minimal embodied energy and the ability to change appearance by re-painting/staining as trends change – there is no better product!

Timber by-products can be used for carbon neutral energy sources or fertilizers and (providing that we replace what we harvest) is the only truly sustainable building material we have. Aluminium, steel, concrete & plastic are not produced from renewable sources.


Of course, many of these environmental factors are well known, but here is some practical information you may not be aware of.

  • While many people would consider ‘re growth forestry’ as being ‘plantation’, reality is that they are not plantations because plantations are grown in a mono-culture where habitat once was. Re growth forestry’s purpose is to balance habitat and timber production in perpetuity – a task that plantations or mono-cultures cannot do. A task that agro-forestry aims to meet.

  • Sustainable timber helps beat climate change. According to the IPCC, “a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre or energy from the forest, will generate the largest sustained mitigation benefit”. Source.

  • The forest and wood products industry in Australia has one of the best circular economies available. Source.

  • United Nations define sustainability as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Source.

  • Swapping timber for concrete and steel in construction (whether large or small buildings) will greatly reduce carbon emissions caused by the building industry. SourceConstruction material pyramid

  • When constructing a window, choosing timber instead of aluminium creates a lower ‘U’ value which translates into a more energy efficient and comfortable home. In fact, the humble single glazed timber window naturally performs better than an aluminium window of the same kind. It takes the incorporation of an expensive ‘thermal break’ to create a similar U-Value in an aluminium window. Source.

  • A hardwood timber window with a protective coating will have the greatest life cycle assessment of any type of window. Refer to this comparative life cycle assessment of window systems. This information translates to other building materials too – such as wall claddings, stairs, floors and structural components.

  • Hardwood has a great Life Cycle Analysis which results in one of the best Environmental Product Declarations possible. Use this to obtain more Green Star credits.

  • Wood is ‘better than carbon neutral’ because of stored carbon during photosynthesis. A working hardwood forest is better for the climate than the alternative Carbon Stocks and Flows in Native Hardwood

  • Timber is a carbon-storing building material. Source.

  • Timber is good for our mental health and well-being. Source.

  • The by-products of sustainable timber can be used as carbon neutral energy alternatives to fossil fuels. Source.

  • Sustainable timber can have a positive impact on Green Star ratings. Source.

  • “Australian developers and builders do not have to choose between saving money and protecting the environment. Instead, they can take advantage of the latest in sustainable material and design innovations [MASSLAM] that will reduce emissions without incurring higher costs. Its a win for the environment and the building sector”. Source.

  • Our timber suppliers are proudly third party audited for Australian Forest Standard (AFS), the Programme for the Endorsement of Forest Certification Schemes (PEFC), the Environmental Management System ISO14001. Source. You can view ASH’s Environmental Policy here.

  • In Australia, 6 out of 10,000 trees are harvested each year. Source

We've completed many case studies on why timber is the most sustainable

Pile of Logs

victorian ash

80% of the timber we use to manufacture our timber products is Victorian Ash sourced from local suppliers where the timber is grown locally.

Only 6% of Victoria’s total forest area is both suitable and allocated for harvesting and regeneration on an 80 year cycle. Less than 0.05% of the forest area is harvested each year (yes, that decimal point is in the right place). It is then regenerated. Not only that, but 100% of each log we receive is used by utilising off-cuts to make finger jointed products and using the sawdust as a carbon neutral green energy solution to power our suppliers kilns.


On a holistic level, our Victorian Ash is one of the best options once you include carbon sequestration, life cycle analysis, harvesting and regeneration. Here are some of the facts.


  • 100% of our timber is sourced from regrowth forests.

  • 100% is regrown.

  • Before harvesting, all flora, fauna, silvicultural, historical and cultural aspects are surveyed, plotted and allowed for. Source.

  • The harvesting process is scientifically designed to mimic natural growth pattern of Victorian Ash species to ensure regeneration occurs within an organic cycle. Source.

  • Less than 0.05% of the forest area is harvested each year on an 80 year rotation. (Yes, that decimal point is in the right place). It is then regenerated. Source.

  • Only 6% of Victoria’s total forest area is both suitable and allocated for harvesting and regeneration on an 80 year cycle. These areas are scattered throughout the state to minimize and spread impact. Habitat trees are protected with protection zones varying in size depending on the animals requirements. 70% of the Victorian ash forests are in National Parks and reserves. Source.

  • The seed mix of each harvest is collected and re-planted in place of harvest to maintain diversity. Source.

  • Around 200,000 seeds are sown per hectare during aerial seeding. Source.

  • 100% of each log we receive is used. E.g. Off-cuts are finger jointed to make structural timber and sawdust used as a green energy solution to power our suppliers kilns. Source.

  • Up to 50% of the weight of kiln dried Victorian Ash is actually stored carbon (320kg per cubic metre approximately). This is far more helpful for life-cycle assessment and embodied energy considerations than other building materials or soft woods. Source.

Learn more about the different window material options by visiting the case study and white paper area of our website.


Our uPVC profile supplier, Aluplast, are certified according to ISO 50001. Aluplast has been able to significantly cut their energy consumption by introducing a new, highly-efficient compressed-air screw compressor, streamlining the energy consumption of production lines and applying a range of other measures. This means that the production facilities we source from  now have the lowest energy consumption figures in Europe.

Designed with recycling in mind

PVC can be recycled up to seven times without any compromises in terms of material quality.


Aluplast began thinking about recycling a long, long time ago. They not only helped to drive towards the creation of Rewindo – an association dedicated to window recycling where uPVC window fabricators make a voluntary commitment to sustainable business – they have also invested heavily in recycling facilities for their Karlsruhe site. When they start developing their innovative products, they factor in recycling right from the outset. Take the energeto® windows, for instance: all of their materials can be separated with ease and then recycled. 

The raw materials used for our window profiles are based on a calcium-zinc chemical stabiliser that is strictly lead-free. With this eco-friendly stabiliser and our involvement in “VINYL 2010” (which implies the use of recycled materials in our plastic profiles. among other things), aluplast offers window systems that can be fabricated and recycled in an ecologically sound way. 

The Aluplast profiles come with up to 80% recycled content and there is an established program betwen window fabricators and Aluplast that allow us to package up all of our offcuts to return to Aluplast whom in turn recycle the material. There is also an inititive for a program for end of life windows that will allow windows many years in to the future to be recyled, rather than disposed of through general waste.

EPD: Certified eco footprint

Our uPVC products come with EPDs, the European Environmental Product Declaration in accordance with ISO 14025 and EN 15804, which carefully document the eco footprint of our plastic windows over an average product lifecycle of 50 years.

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