Openings refer to several types of Wall Openings including Windows, Doors (including Opaque Louvres) & Permanent Openings within the Hero Model. Their properties are different depending on their type.


Windows are used to represent all non-opaque Openings, this includes standard Windows as well as the Glazed portion of a Glazed Doors unless the glazing portion is <25% of the Opening’s Area (as per NatHERS Technical Note guidance).

 NatHERS Technical Note 8.1 Glazed Doors

“Fully or partially glazed hinged doors and sliding doors are considered to be windows in NatHERS software tools. Only the glazed portion of a partially glazed door is to be modelled as a window. The remaining component of the partially glazed door is to be modelled as a solid door. If the glazing component is less than 25% of the door, the door may be modelled as a solid door.”

Internal Windows

Note Internal Windows (i.e. Window on a Wall between Zones) can be modelled within Hero however an Information Alert will be raised notifying the User that no Solar Gains are simulated between those Zones within Chenath. I.e. Internal Windows do not transit Light or Solar Gains between them. Their modelling impacts will be limited to conductive heat transfer losses/gains.


Doors are used to represent Opaque Openings including standard Doors but also Opaque Louvres.

Doors can only be used on External or Internal Walls and cannot be used on Neighbouring Adjacency Type Walls (such as between two Dwellings or between a Dwelling & a Class 2 Common Area)

Permanent Openings

A Permanent Opening is used to model a permanent connection between two Zones such as an Open Hallway between a Kitchen Zone and a Hallway Zone.

Permanent Openings can only be used on Internal Walls between two Zones of the same Dwelling

Openings & Screens, Eave & Wing-Walls

All Openings on External Walls have the Screen, Eaves & Wing-Walls of their Parent Walls applied to them automatically within Simulation.

Openings on Floating Walls

Openings can be added to Floating Walls as per standard Walls.

Openings with the Visual-View


Openings are created using the Opening Draw Mode


You can Select an Opening either within the Visual View or the Data-Grid.

Openings also share the common context-menu actions of Select Parent (which will select the Parent Wall of the Opening) which can also be called by (blue star) Double Left-Clicking the Opening.

The Send to Back feature can also be very useful for Openings particularly when multiple Openings are aligned over the top of one another, so that you can select the desired Opening. Select the Opening on top and choose the (blue star) Right-Click Context Menu -> Send To Back feature and the previously selected Opening on top will now be below any other Openings. You can now select the Opening on top.

Deleting Openings

Openings can be deleted by:

  • selecting the Opening within the Visual-View or Data-Grid and pressing ⌨ Delete; or

  • by using the (blue star) Right-Click Context-menu Delete action within the Visual View

Moving Openings

Openings can be moved in the Visual View by selecting them and then (blue star) Dragging them into their position.

You can also (blue star) Drag the corner Points of an Opening to extend or shrink the Width of the Opening.

Openings cannot extend outside the Width of their Parent Walls and in these situations, Hero will block any attempts to move further.


Openings can be split using the Split & Merge Drawing Mode

Windows can be Split to model different Specifications for different portions of a Window such as Splitting a Window into it’s Fixed & Awning portions so that the Fixed & Awning Window portions can have a Fixed & Awning Type Window Specification applied to them from the Window Library.

This can also make it easier for Users, Window Manufacturers & Builders to evaluate & select the appropriate Window Suites to use for the project.

Openings within the Data-Grid



Edited Within


The Name of the Opening.

The Opening’s Name is numerically incremented during creation (e.g. from W01 to W02 to W03) and so it can be useful to create Openings based on their Window Schedule tag (if available) so you do not need to rename the Openings.

Opening Data-Grid Name Column


The Type of the Opening: Window, Door or Permanent

Type Column


Windows & Doors only

The Specification of the Window or Door.

Window Specification

The available Window Specifications within the Opening Data-Grid Specification Column is based on the Window Library Selected Windows List.

Door Specification

There a variety of Door Specifications available within Hero including standard timber, insulated, metal & insulated metal Doors as well as two Opaque Louvres specifications.

 NatHERS Technical Note Guidance on Window Specification

8.2 “When modelling windows or glazed doors, assessors must use either:
• The Australian Fenestration Rating Council (AFRC) custom window codes corresponding to the windows specified on the design documentation; or
• Default windows.”

8.3 “If a custom window is specified on the design documentation that is not available in the NatHERS custom window library, assessors must model:
• a default window with the specified opening type; or
• an available custom window that meets all of the following parameters:
- identical opening type (e.g. fixed, awning, casement, sliding) to the window specified on the documentation; and
- a total window system U-value equal to, or greater than, the window specified on the documentation (e.g. if the U-value of the specified custom window is 3.0, the modelled window selected could be 3.5); and
- a total window system Solar Heat Gain Coefficient (SHGC) +/-5% of the window specified on the documentation.”

8.4 “When using default windows, clear glass must be used in lieu of obscure glass (for instance, in a bathroom or WC).”

8.5 “In the absence of obscure glass in the custom windows library, assessors must model either:
• The clear window from the same range of custom windows that are being used (i.e. the same supplier, same frame type and frame material); or
• A default clear window.”

Specification Column


The Orientation of the Opening (i.e. it’s normal direction or direction it is facing)

Not Editable


The Width of the Opening (in mm)

Visual View & Width Column

Left Offset

The Distance from the Left Edge of the Parent Wall to the Left Edge of the Opening (in mm)

Visual View & Left Offset Column (hidden by Default)

Total Height

The Total Height of the Opening (in mm). (I.e. Head Height - Sill Height)

Total Height Column

Head Height

The Head/Top Height of the Opening (in mm) above the Level’s Reference Height

Head Height Column

Sill Height

The Sill/Bottom Height of the Opening (in mm) above the Level’s Reference Height

Sill Height Column (hidden by Default)

Opening Style

Windows Only

The Opening Style of the Window (e.g. Casement, Louvre, Awning etc). Changing the Opening Style will typically update the Openable Percentage of the Window

Opening Style Column

Openable Percentage

The Percentage of the Opening’s Area that is Openable for Ventilation as per NatHERS Technical Note Guidance

 NatHERS Technical Note Guidance on Openable %

8.6: “When using custom windows, assessors must use the manufacturer’s ventilation charts to determine the openable percentage of the window and/or door. If this information is not available, apply the provisional opening percentage in Table 5. These reflect the area of window that can open and deducts a percentage for the window frame.”

8.7 “When using default windows, assessors must apply the provisional opening percentage figures in Table 5. These reflect the area of window that can open and deducts a percentage for the window frame.”

8.8 “Assessors must use their judgement in applying opening percentages to default or custom windows that have complex opening arrangements and/or are made of different window types.”

8.9 “Assessors must adjust opening percentages to windows with restricted opening safety requirements and no complying security screen. If the restricted opening percentage is not specified on the design documentation, assessors must use the provisional opening percentage of 10% for all window types.”

Openable Column


External Windows & Doors only

Whether the Window or Door has Weatherstripping or Draught-proofing specified to signficantly reduce air-leakage.

Weatherstripped Column

Insect Screen

External Windows & Doors only

Whether the Window or Door is fitted within fixed Insect Screens.

Insect Screens within a Chenath Simulation reduce Ventilation rates through Openings but do not effect modelled Solar Heat Gains or Heat Transfer.

Insect Screen Column

Frame External Colour

External Windows & Doors only

The External Colour (and Solar Absorptance) of the Window or Door Frame

External Colour Column

Internal Shade

Windows only

The Internal Shade device for the Window as specified & noted on the Plans, and it’s effective R-Value, Solar Transmittance (ST) & Solar Absorptance (SA)

Internal Shade Column

External Shade

Windows only

The External Shade device for the Window as specified & noted on the Plans, and it’s effective Shading Coefficient (SC)

External Shade Column

Window Library

The Window Library holds the complete library of all Window Specifications available for NatHERS Simulation. The Selected Windows list within the Library is what is presented to Users within the Opening Data-Grid’s Specification column.

Further Information: Window Library

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