NatHERS Design Factors
House orientation shapes how a home receives sun, shade, heat and daylight. In NatHERS, this can directly influence the heating and cooling demand of the design.
House orientation affects NatHERS ratings because it changes how sunlight reaches the home throughout the day and across the seasons. Good orientation can support useful winter sun, controlled summer shading and more stable indoor temperatures. Poor orientation can increase heat gain, heat loss or reliance on mechanical heating and cooling.
Orientation describes how a home is positioned in relation to the sun, wind and site. In NatHERS, orientation is important because each façade receives different solar exposure throughout the day and year.
A room facing north, east, south or west will not behave the same way. The direction of windows, the location of living areas, the depth of shading and the shape of the building can all influence how much heating and cooling the home may need.
This is why orientation is one of the earliest design decisions that can affect the NatHERS pathway. Once the home is fixed on the site, many later performance decisions need to respond to that starting point.
A NatHERS assessment estimates how much heating and cooling a home may need to stay comfortable in its local climate. Orientation influences that result because it affects when and where solar heat enters the home.
Well oriented homes can use sunlight more strategically. In many climates, this means allowing useful winter sun into living spaces while preventing excessive summer heat gain through shading and glazing design.
Poor orientation does not always mean a home will fail NatHERS, but it can make the pathway harder. More pressure may be placed on glazing performance, shading, insulation, roof colour, ventilation strategy and construction details.
Orientation is one of the few thermal performance decisions that cannot easily be upgraded later.
Once the home is placed on the site, the NatHERS pathway has to work with that decision.
Different orientations create different thermal conditions. In many Australian climates, north facing living areas can be helpful because they can receive useful winter sun and can often be shaded more easily in summer with well designed eaves.
East facing windows receive morning sun. West facing windows receive afternoon sun, which can be harder to control and may create cooling pressure in warmer climates. South facing windows often receive less direct sun, but they can still influence heat loss, daylight and comfort.
These are general principles, not fixed rules. The best orientation strategy depends on the climate zone, site constraints, neighbouring buildings, landscape, room layout and the overall design intent.
• Direction of living areas and bedrooms
• Window size and placement on each façade
• Solar exposure through different seasons
• Shading from eaves, awnings, balconies and neighbouring structures
• Internal zoning and room use
• Local climate and heating or cooling priorities
Orientation and windows are closely linked. A window’s thermal impact depends heavily on which direction it faces, how large it is, what glazing is specified and how well it is shaded.
A generous north facing window with suitable shading can behave very differently from an unshaded west facing window of the same size. NatHERS modelling recognises these differences because the timing and intensity of solar exposure changes by orientation.
For a deeper explanation, see our guide to how window design affects NatHERS ratings.
Good orientation is not only about getting sunlight into the home. It is also about controlling when sunlight should be kept out. Without suitable shading, solar access can quickly become unwanted heat gain.
This is especially important for east and west facing glazing, where low angle sun can be difficult to manage. External shading, façade depth, balconies, screens and landscape elements can all help reduce summer heat gain.
The strongest NatHERS outcomes usually come from orientation and shading working together, rather than treating shading as a late addition after the home has already been designed.
Orientation can also affect whether thermal mass is useful. If winter sun reaches an exposed concrete floor or masonry surface, that material may store warmth and release it later. If summer sun reaches the same surface without control, it may store unwanted heat.
For thermal mass to support NatHERS performance, it needs to be coordinated with solar access, shading, glazing and climate. Orientation helps determine whether the mass receives useful heat or becomes a source of overheating.
For more detail, see our guide to thermal mass and NatHERS performance.
• Large west facing glazing without enough external shading
• Living areas placed where they receive poor solar access in cooler climates
• Bedrooms or upper levels exposed to strong afternoon heat
• Shading that does not match the orientation of the window
• Copying a design from one site to another without checking climate and orientation
Poor orientation can often be managed, but it may require more careful design decisions. If the home cannot be ideally oriented because of site constraints, the NatHERS pathway may depend more heavily on glazing performance, shading, insulation, roof colour and layout.
For example, a home with unavoidable west exposure may need stronger external shading, reduced glazing area or improved glass performance. A home with limited northern exposure may need a different approach to insulation, daylight, thermal mass and heating demand.
The key is to identify the pressure points early. NatHERS modelling can help show whether orientation is a major issue and which design changes are likely to be most effective.
For many new residential projects, orientation can affect whether the home reaches the required NatHERS star rating. This is especially important for projects targeting or required to achieve a 7 Star Rating.
In NSW, orientation related thermal performance can also affect BASIX outcomes where NatHERS modelling supports the thermal pathway. If the building orientation, window arrangement or shading changes after assessment, the documentation may need to be reviewed.
Orientation also sits beside Whole of Home considerations, because stronger thermal design can reduce heating and cooling demand before systems and appliances are considered.
Good orientation should respond to the specific site and NatHERS climate zone. A strategy that suits a cool temperate climate may not suit a hot humid region, and a coastal site may behave differently from an inland site.
Project teams should consider where living spaces are placed, how windows are distributed, where heat is likely to enter and whether shading is integrated into the design. These decisions can make the NatHERS pathway easier or harder long before specifications are selected.
The aim is not always perfect orientation. Many sites are constrained. The aim is to understand the orientation clearly enough to design around it intelligently.
Certified Energy provides NatHERS assessments for new homes, townhouses and multi residential projects across Australia. Our team can model the proposed design and help identify how orientation is influencing the rating.
Where needed, we can help project teams understand how the rating is affected by solar access, glazing, shading, insulation, roof colour, thermal mass, floor construction and climate zone. We can also help connect the assessment with related requirements such as NatHERS, BASIX, 7 Star Rating and Whole of Home.
For a broader explanation of the rating framework, visit our NatHERS Knowledge Hub.
Yes. House orientation can affect a NatHERS rating because it influences solar access, heat gain, shading, daylight and how much heating or cooling the home may need.
What is the best orientation for a home in Australia?The best orientation depends on the climate, site and design. In many Australian climates, north facing living areas with appropriate shading can support passive solar performance, but the strategy should be tested for the specific project.
Are west facing windows bad for NatHERS?West facing windows are not automatically bad, but they often need careful shading and glazing because afternoon sun can create heat gain and cooling demand in many climates.
Can poor orientation be fixed in NatHERS?Poor orientation can often be managed through glazing, shading, insulation, roof colour, layout and construction choices, but it may make the NatHERS pathway more difficult.
When should orientation be considered?Orientation should be considered as early as possible, ideally before the home layout and window strategy are locked in. It is much harder to correct later than many specification items.