The Australian Window Association has issued an Industry Alert about the “Incorrect Use of Glass Only Values for Glazing Energy Performance Ratings”. In summary, the National Construction Code defines glazing as “glass plus frames” for Energy Efficiency purposes. Modelling glass-only U-values & SHGC contravenes AS2047, the NCC and the Australian Consumer Act.
To avoid confusion, at Anderson Energy Efficiency we ALWAYS model glass plus frames. When we use the term “glazing” that refers to glass + frames (total system), and when we use the term “glass” that is glass-only (no frame or frame-less). In fact, there is no alternative possible in NatHERS software – frames are mandatory in the glazing modelled.
To clarify the reading of our NCC Section J Energy Efficiency Reports, the glass-only properties are listed in our NCC Section J compliance reports. This is because the Energy Efficiency Assessment is usually performed well before the selection of the glazing supplier. Back in 2005, Energy Efficiency requirements were introduced in the Building Code of Australia Volume 1 and ever since then it’s been our practice to model glass in generic Aluminium frames with no thermal breaks for Commercial building energy assessments, unless otherwise specified. This is for both the Proposed and Reference Buildings in Verification Method JV3. Consequently, the frames “cancel out” in the relative Annual Energy Consumption calculation. Therefore, changing the frame performance will make virtually no difference to our compliance results.
The short version – we fully comply with the advice issued in this alert and this has been our standard operating practice ever since Energy Efficiency was introduced to the Code.
At Anderson Energy Efficiency we guarantee to find a Building Solution for your project. Any changes in the building needed for compliance include lowest-cost options and are subject to client approval before the Report is produced. You can trust Anderson Energy Efficiency to provide the professional, quality result your project deserves. Contact us for a competitive fee proposal!