Inside a NatHERS Assessment, Part 6: Shading, Orientation and the First Star Rating

Inside a NatHERS Assessment · Part 6 of 7

The home is almost fully modelled (Part 5). Two of the biggest influences on comfort remain – shading and orientation – and then the assessor runs the first simulation.

Shading: eaves, wing walls and screens

Shading controls how much summer and winter sun reaches the windows and walls. The assessor adds three kinds:

• Horizontal shading (eaves) drawn along the external walls.
• Perpendicular vertical shading (wing walls) from the dwelling, porch, fences and neighbours.
• Vertical shading (screens) from the dwelling, porch, fences, trees and neighbours.

Crucially, shading from the surroundings – fences, trees and neighbouring buildings – is included, because real sites are not modelled in isolation.

Calculating north

Orientation is set by entering the north offset in degrees (90 degrees for this example). Orientation is one of the most powerful and lowest-cost factors in thermal performance: the same house rotated on its block can gain or lose stars.

The first result

With everything entered, the assessor runs the simulation and reviews the energy loads using diagnostic reports and a heat-map view to see where the home gains and loses heat. The worked example lands at 6.5 stars on this first pass – close, but short of the 7-star minimum for a new home under the National Construction Code. In the final part, we look at how to close that gap.

References and resources

This series follows the worked example known as NatHERS Example 3. The official documents below are the authoritative sources. We host backup copies for convenience, but the versions on nathers.gov.au are definitive.

• Modelling guidance (the steps this series follows): nathers.gov.au | local copy
• Example 3 architectural drawings (the plans referred to throughout): nathers.gov.au | local copy
• Example NatHERS certificate samples (what the assessment produces): nathers.gov.au | local copy
• A guide to the NatHERS Certificate: nathers.gov.au | local copy
• NatHERS Assessor Handbook (the full handbook, all chapters): nathers.gov.au | local copy
• NatHERS guidance note: nathers.gov.au | local copy

Always use the latest version. NatHERS documents are updated from time to time. We do not guarantee that the versions referenced or backed up here are the most current. Always confirm the latest release on the NatHERS website before relying on them.

Disclaimer. This series is for education only. Its purpose is to simplify and explain the official notes where they may not be clear. It is not a substitute for the original documents or for accredited assessor training. If anything is unclear or you have a question, refer to the original document and contact your college or registered training organisation (RTO), or the NatHERS team.

Next – Part 7: From 6.5 to 7 Stars →