Dowell ThermaLine™ awning window
Energy Performance data comparison chart

Dowell ThermaLine™

Selecting the right energy efficient windows and doors for your home can be a daunting task. To assist you in your decision making process, our energy performance comparison chart, clearly shows the products performance properties, based on Dowells awning window product range.

The glass fiber compound makes the thermal barrier strip durable, but most of all it matches the thermal barrier strip’s Linear Thermal Expansion Co-Efficient (LTEC) with that of the aluminum’s.


Please note; There have been instances where window companies quote just the glass U value. This does-not represent the true performance of the window which must include the frame in the calculation of the window U-value. Dowell uses the ‘Uw’ in describing the performance of its windows in-line with the Australian Standard to assist specifiers and consumers to make informed factually based decisions. Reference source; Window Energy Rating Scheme, 2014 WERS Certified Products Directory - AFRC (Manufacturer Dowell), [online] Available: (13 November 2014)





Dowell ThermaLine™ Thermally Broken Aluminium windows and doors Energy performance product data as rated by WERS.

Dowell ThermaLine™

The Window Energy Rating Scheme (WERS) rates whole of window product energy efficiency performance and is managed by the Australian Window Association (AWA).


WERS is independent of any one manufacturer and acts as a fair, rigorous and credible system for testing performance claims. WERS-rated windows must meet all relevant Australian standards. The scheme forms part of the quality assurance that smart manufacturers offer their customers. It is all about certified performance.

  • WERS enables windows to be rated and labeled for their annual energy impact on a whole house, in any climate of Australia. A New Zealand variant of WERS, the ‘Window Efficiency Rating Scheme’, is also available. To participate in WERS, window makers must obtain energy ratings for their products from a rating organisation that is accredited by the Australian Fenestration Rating Council (AFRC).


Reference source; Window Energy Rating Scheme, 2014 WERS Certified Products Directory - AFRC (Manufacturer Dowell), [online] Available: (13 November 2014)


Key to ratings table: Glazing ID = Glass Type & Thickness / Space & Gas Fill: UW = Whole-window U-value (Uw): SHGC = Whole-window solar heat gain coefficient (SHGCw): TVW = Whole-window visible transmittance (Tvis): AI = Air infiltration rate (L/s.m2) at positive (inward) pressure difference of 75 Pa.

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