Home Performance
Passive design and NatHERS are closely connected. Passive design shapes how a home responds to climate, while NatHERS helps assess how that response affects thermal performance.
Passive design uses the home’s orientation, glazing, shading, insulation, thermal mass, air movement and building fabric to improve comfort with less mechanical heating and cooling. NatHERS models how the home is expected to perform thermally in its local climate. When passive design is resolved well, it can support a stronger NatHERS rating and a more comfortable home.
Passive design is about making the building itself do more of the comfort work. Instead of relying mainly on heating and cooling equipment, the home is shaped to respond intelligently to sun, shade, wind, heat, cold and seasonal change.
This can include placing living areas where they receive useful daylight and winter sun, protecting windows from unwanted summer heat, insulating the building fabric, reducing draughts and using materials that suit the climate.
Passive design is not one feature. It is the coordination of many design decisions so the home is naturally more comfortable.
NatHERS assesses how much heating and cooling energy a home may need to maintain comfortable indoor conditions in its local climate. Many passive design decisions directly influence this result.
For example, a home with well placed windows, effective shading, suitable insulation and a climate responsive layout may need less heating and cooling than a home with large exposed glazing, weak insulation or poor solar control.
This is why passive design can be one of the most effective ways to improve a NatHERS rating without relying only on late product upgrades.
NatHERS does not reward sustainability language.
It responds to the actual thermal behaviour of the home: how the design handles heat, cold, sun, shade and building fabric performance.
Orientation is one of the foundation decisions in passive design. It affects how the home receives sun throughout the day and across the seasons. It also influences which rooms are exposed to heat, light, shade and cooling breezes.
Good orientation can help a home make use of winter sun while reducing unwanted summer heat. Challenging orientation can still be managed, but it may require more careful glazing, shading, insulation and material choices.
For more detail, see our guide to why house orientation matters for NatHERS.
Windows are central to passive design because they affect daylight, views, solar gain, heat loss and ventilation. The aim is not simply to add more glass, but to place and specify windows so they support comfort in the relevant climate.
A well designed window strategy considers orientation, frame type, glazing performance, window area, shading and the way each room is used. The same window may perform differently depending on which façade it sits on and what climate zone it is in.
For more detail, see our guide to how window design affects NatHERS ratings.
• Orientation and room layout
• Window size, location, frame type and glazing performance
• External shading and solar heat control
• Ceiling, roof, wall and floor insulation
• Thermal mass, floor construction and exposed materials
• Air leakage control, ventilation strategy and climate response
Shading is one of the clearest links between passive design and NatHERS. External shading can reduce unwanted solar heat gain before it enters the home, which can improve summer comfort and reduce cooling demand.
Good shading is not generic. It needs to respond to orientation and climate. A north facing window, west facing window and east facing window may each need different shading strategies to perform well.
For more detail, see our guide to shading and solar heat gain.
Insulation supports passive performance by slowing heat transfer through the roof, ceiling, walls and floors. It helps the home retain warmth in cooler weather and resist unwanted heat gain in warmer weather.
The effectiveness of insulation depends on where it is installed, how it is detailed and how it works with glazing, shading, air leakage and climate. More insulation is not always the only answer, but well resolved insulation is a key part of the building fabric.
For more detail, see our guide to how insulation affects NatHERS ratings.
Passive design is not the same as doing nothing.
It is active design thinking, applied early, so the home needs less correction from mechanical systems later.
Thermal mass can support passive design when it is used in the right climate and coordinated with solar access and shading. Materials such as concrete, masonry and tile can absorb, store and release heat over time.
Thermal mass can help stabilise indoor temperatures, but only when it is managed well. If it receives too much unwanted summer sun, it can store heat that works against comfort. If it receives useful winter sun, it can help support warmth.
For more detail, see our guide to thermal mass and NatHERS performance.
Passive design often includes planned air movement. Cross ventilation, operable windows and layout can help occupants use natural air movement when outdoor conditions are suitable.
This should not be confused with uncontrolled air leakage. Planned ventilation can support comfort. Draughts and gaps can undermine comfort by making the home harder to heat or cool.
For more detail, see our guide to air leakage and home performance.
Passive design is always climate specific. A strategy that works well in a cool climate may not suit a hot humid climate. A home in a hot dry inland location may need a different response from a coastal home with milder temperatures and breezes.
This is why NatHERS uses local climate data when assessing thermal performance. The home is not assessed as a generic design. It is assessed in relation to where it will actually be built.
For more detail, see our guide to why climate zones matter in home design.
Early design decisions can shape orientation, layout, window placement and shading.
Later decisions can still improve performance, but they may rely more on product upgrades.
The strongest NatHERS outcomes usually come from combining good design with suitable specifications.
Passive design can help a home meet the thermal performance pathway required for residential energy compliance. For many new homes, this may connect with 7 Star Rating, Whole of Home and state based pathways such as BASIX in NSW.
A home that is passively well resolved may need fewer late adjustments during NatHERS assessment because the design already responds well to climate and comfort.
The compliance benefit is practical: better passive design can make the pathway clearer, while also improving how the home is likely to feel.
Australian homes need passive design strategies that respond to their specific location. Hot, cold, humid, dry, coastal, inland and alpine conditions all create different comfort priorities.
The best passive design is usually quiet and integrated. It appears as well placed windows, considered shading, suitable insulation, stable indoor conditions, appropriate thermal mass and a building fabric that supports comfort without needing constant correction.
NatHERS helps test whether those design decisions are working together as intended.
Certified Energy provides NatHERS assessments for new homes, townhouses and multi residential projects across Australia. Our team can model the home and help identify how passive design decisions are influencing the rating.
Where needed, we can help project teams understand the effect of orientation, glazing, shading, insulation, thermal mass, roof colour, floor construction, air leakage assumptions and climate zone. We can also help connect NatHERS with related requirements such as NatHERS, BASIX, 7 Star Rating and Whole of Home.
For the broader assessment framework, visit our NatHERS Knowledge Hub.
Passive design can affect NatHERS by reducing the heating and cooling energy a home is predicted to need. Orientation, shading, glazing, insulation, thermal mass and climate response can all influence the rating.
Is passive design the same as NatHERS?No. Passive design is a design approach that uses climate, sun, shade, insulation and building fabric to improve comfort. NatHERS is an assessment method that models thermal performance and provides a star rating.
Can passive design help a home reach 7 Stars?Yes. Passive design can help support a stronger NatHERS rating, including 7 Star outcomes, by reducing heating and cooling demand through better design rather than relying only on product upgrades.
Does passive design mean no air conditioning?Not necessarily. Passive design aims to reduce heating and cooling demand. A home may still use mechanical systems, but the building fabric should reduce how much correction is needed.
When should passive design be considered?Passive design should be considered as early as possible, before orientation, layout, window placement, shading, roof form and construction details are locked in.