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The next step in energy rating: the international ETTV method vs. BCA Section-J glazing calculator

conference contribution
posted on 2015-01-01, 00:00 authored by Mehran Oraee Namzadi, Mark LutherMark Luther
The most important prevention in minimizing energy transfer in commercial buildings is the treatment of glazing in the building facade. In a commercial building, while the impacts of roof, walls and floors on the overall heating and cooling loads of the building have low effects, glazing is likely to be the most important factor. This paper investigates the BCA Section-J glazing calculator and the ETTV (Envelope Thermal Transfer Value) methods and tries to look for differences as well as similarities in calculation of building envelopes energy performance. For this investigation, a hypothetical high-rise commercial building in Melbourne, Australia is considered when evaluating the energy performance of the envelope through these two methods. Both methods consider the U-Value of glass and wall materials as well as Solar Heat Gain Coefficient (SHGC) and Shading Coefficient (SC) of the glass. Findings in this research project indicate differences and significant discrepancies between the BCA Section-J and ETTV methods in evaluating the energy performance of commercial building façades. Issues of calculation weaknesses are identified with the lack of air leakage and infiltration of a particular façade design or window to wall ratio (WWR). Suggestions have been made where improvement to the overall energy calculation through facades of a commercial building is needed.



Architectural Science Association. International Conference (49th : 2015 : Melbourne, Vic.)


423 - 433


University of Melbourne


Melbourne, Vic.

Place of publication

Melbourne, Vic.

Start date


End date






Publication classification

E Conference publication; E1 Full written paper - refereed

Copyright notice

2015, University of Melbourne


R Crawford, A Stephan

Title of proceedings

ASA2015: Living and learning: research for a better built environment : Proceedings of the 49th International conference of the Architectural Science Association