For details of using the 'Draw hole' tool, please refer to the Draw window tool.
Holes are used for two purposes:
1. As an air flow path between a zone and an other zone or outside (in much the same way that Vents are used). Holes cannot be controlled - they simply represent a constant air flow path in the fabric.
Holes positioned on external walls only have an effect on Simulation calculations when the Natural ventilation building model option is set to Calculated. They have no effect on Heating and Cooling Design calculations. Holes positioned on internal partition walls are used to mix the air between the two adjacent zones when the Scheduled Natural ventilation building model option is set. They also provide an air flow path when the Calculated option is set. You can find information on the way Mixing works by looking at the Vent Operation help topic.
2. For merging zones together. Note that the Merge zones connected by holes option must be selected for this to work.
Tip: It is possible to draw large holes in surfaces to give the effect of the surface having being removed. This can be a useful technique for creating atrium-type spaces, connecting gable roof blocks to the main roof block and generally merging zones in different blocks.
Note: Holes transmit solar radiation.
You can draw holes in internal and external horizontal surfaces to model the flow of air between storeys or to outside, but you should be aware when using the Calculated natural ventilation option that Large horizontal openings are only modelled approximately.