Category Archives: Energy Efficiency

How to: Change the Climate Data to reference one of the climatic zones of South Africa

The first step before changing the climate data is to set the Project Location. This is important considering that choosing one of the climatic zones of South Africa would not help you to locate the project correctly.

To do this you can access the Project Location from Energy Model Review > Environment Settings…

With the Project Location window open you can then enter a Latitude: and Longitude: Please note: this can be entered as “decimal degrees” or “degrees, minutes, seconds” by clicking on the arrow pointing to the right.


You can verify the coordinates that you have entered by clicking on the button “Show in Google Maps…”

Once you have done this you can click on “OK” to close the Project Location window. You should then see Environment Settings window once again. Now click on button “Climate Data”


Now click on the option: Use ASHRAE IWEC, TMY, WTEC2 file and then click on the “Browse…” button


You can now select one of the 6 climatic zone files. This can be accessed by downloading as per my previous blog. Then click on “Open” to close this window. The climatic data referenced will now be shown. In this example I choose Durban. Please note: that this data would not be as accurate as the climate data downloaded from the Strusoft Climate Server which would be related to the exact location. Whereas the Durban.epw file covers East London to Richards Bay?


You can now close the Climate Data window by clicking on “OK”.





Climatic zones of South Africa & Energy Analysis using ArchiCAD 16

A new feature of ArchiCAD 16 Energy Evaluation is  the ability to choose the Climatic Data for your project location. Previously you were limited to a single  source for this data, namely: “Download from StruSoft Climate Server”. This option is still there but now you can also choose: “Use ASHRAE IWEC, TMY, WTEC2 file”. I received the current 6 “official” climatic zone weather files that have the file extension EPW from Agrément South Africa. You can download these files from my Dropbox link – Click here!

You can also get your own free Dropbox account by joining and installing Dropbox by – clicking here

Join us, Graphisoft SA at Green Building/ Sustainability Week

Graphisoft SA will be again participating in the The Green Building Conference and Exhibition for a second year in a row. Join us on 27th July for a workshop from 9h30-10h30. This will be a practical workshop illustrating the application of SANS 204 using ArchiCAD 16 with its built-in Energy Evaluation functionality. As you are aware, this year energy efficiency in buildings standard SANS 204 became mandatory. Or come visit us at our stand where you can learn more about the integrated Energy Evaluation functionality.

The Green Building Conference and Exhibition 2012 is happening alongside various other Sustainability Conferences, at Sustainability Week in Sandton Convention Centre.
Green Building 2012 will again feature several innovations in its programme and market offerings:

The programme will be separated into clearly defined ½ day modules, each featuring international and local experts and concluding with a facilitated panel discussion with the speakers from that module.

Modules are structured so as to be attractive to all stakeholders, but will allow people to choose not to attend all sessions without losing any coherence, and CPD credits will also be structured accordingly.

Window-to-floor area ratio calculation in 4 easy steps (SANS 10400-XA & 2)

First some background: New legislation in South Africa dictates that it is necessary to determine the window-to-floor area. This ‘regulation’ is applicable to many other countries, not just South Africa. (LEED in USA, Green Building – various countries, Energy Star etc…)

“SANS 10400- XA 4.4.4 Fenestration Buildings with up to 15 % fenestration area to nett floor area per storey comply with the minimum energy performance requirements. Buildings with a fenestration area to nett floor area per storey that exceeds 15 % shall comply with the requirements for fenestration in accordance with SANS 204.”

This window-to-floor area ratio balances energy, first cost, and indoor environmental quality. This will prevent solar gain from overheating the living space. Having too little glazing misses out on free solar energy – but too much glazing can result in excessive heat gain in the summer and unnecessary heat loss in the winter.

From a purely economic viewpoint, lower window area ratios lower the first cost to purchase. Window-to-floor area ratios above 15% for standard construction require increased envelope performance ratings and mechanical equipment efficiencies.

While energy use increases with window area, the penalty is not significant when high performance windows (double or triple glazed) are used. But of course the first cost to purchase for these are much, much more higher.

How to:

I am aware that there are “fenestration calculators” available (there is even one for purchase?) But these still require the user to manually count the windows (Yes, 1, 2, 3, 4….etc) together with their relevant height x width.  In-fact this method is daft and pales in comparison to the speed and ease that this is possible to achieve using ArchiCAD.

In this example I used the standard “ArchiCAD 15 Template” (INT English). The example building is a 2 story office building. Ground Floor = 260m2 and First Floor = 260m2. Therefore 260 x 15% = 39m2

Place a zone stamp on the floor plan to establish the total floor area per story (this can be done with one click)

How to do this in 4 easy steps:

In the Navigator – Project Map > Schedules > Element double click on “Window list” to open it.

Click on “Scheme Settings…”

Under Criteria / Window List – click on “Add” and change criteria to “Story” (this will filter the window schedule by story) Just remember to change this to “1”. Later on you can also duplicate the Scheme – Window List and “Rename” it to Window List Ratio Ground Floor and Window List Ratio First Floor for example.

Under Fields / Window List Copy – find the field “W/D opening surface on the reveal side”. Related to each selected schedule field, 3 buttons are available at the right to fine-tune sorting criteria. Choose  display a “sum” to add a schedule cell that will contain the sum total for all items of this field.

Click on “OK” to close the Scheme Settings window. You will then see the total square meter displayed for all the windows for the story selected.

Summary: As per the result (which only takes a minute to set up) one can clearly see that in this example both the Ground & First floor fenestration do not exceed the 15% per floor area ratio. Of course the windows can be modified and optimized, individually or globally, and the resultant ratio established by a simple click on Window List to recalculate the result in seconds.