Modelling eaves and adding a node to accurately reflect different eave / alfresco widths within the same external wall.

The eaves widths are determined by the distance between the external wall and the roof line.  The eaves width must be drawn accurately when modelling the shading of windows and/or walls.  BERS works out the length of the eave so no additional data entry is required unless there are 2 different eave widths within the same wall.

Example 1 - using the building elements summary page, check eaves have been modelled as per the plans.  The "External Wall" button will allow you to check eave widths but not offsets.  In this example most of the walls have a 500mm eaves with a few of the walls with a 100mm eaves, based on modelling as per the NatHERS Tech Note 10.3

Example 2 - where there are 2 different eave widths within the same wall a node needs to be added so that the software can recognise the different shading widths.  Add a node to the wall featuring the 2 different eave widths, and add 1mm to the new wall within the existing wall so that the different eave widths can be recognised.  This means the zone which originally had 10 external walls, now has 11 external walls.

Sometimes adding a node after the glazing has been modelled will result in a glazing glitch.  If this happens, delete the glazing, add the node (change the wall height of the new zone by 1mm) and then re-model the glazing.  New added wall = total 11 external walls for this zone.

BERS Pro is working on a solution to this glazing node glitch.

Without the additional node modelled, the software would incorrectly automatically select the widest eave width and calculate the heating and cooling loads based on the entire wall being shaded by a 3.5m shading device / eaves.  With no additional node modelled the zone only shows a total of 10 external walls, as opposed to 11.

Please Note: an eaves can only be modelled in the same way as a zone.  The eave line needs to connect with the staring eave node to complete the eave modelling.  Recommend always starting your eaves line in the top most right hand corner of the design so that it is easier to re-connect with the first node.