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 are modelled using perfectly clear glass plus in some cases an airflow path. When positioned on external walls holes only generate airflow in Simulation calculations when the Natural ventilation building model option is set to Calculated. External holes have no effect on airflow in Heating and Cooling Design calculations but will create an additional heat flow path categorised in the heat balance as 'Glazing'. 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 and for Heating and Cooling design calculations. 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 are modelled as windows with perfectly clear glazing and so they transmit solar radiation as well as presenting an air flow path.
More information on Drawing holes can be found in the Basic Drawing Tools 7 Tutorial