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Star ratings and variations

Find out how to achieve the optimal star rating for your climate with a number of window and upgrade options.A NatHERS energy rating star certificate

Star rating

The design was targeted at achieving NatHERS 7 stars in a temperate Australian climate such as Sydney or Perth. On testing it also achieved 7 stars in all state and territory capital cities as well as Cairns, with the use of improved glazing products in some locations.

A 7 star rating is achievable with basic inexpensive materials such as aluminium windows and single glazing when the right design principles are applied—such as passive design and appropriate use of insulation and material selection.

Orientation, choice of windows and any modifications to the design will all have a powerful impact on the design.

For example, use of specific energy efficient products such as double glazing and window frames that contain a thermal break, can lead to even better efficiency outcomes.

New dwellings in cool and temperate climates or anywhere near a busy road or railway line should always consider the benefits of double glazing for both thermal and sound improvements.

Orientation is also key. The design works in cool and temperate climates where you can orient living areas to be north facing. In tropical areas it is more important to have the appropriate shading and to be able to pick up cooling breezes.

When using these plans, it is important to check the impact of your block’s particular shape on the orientation of the design with a NatHERS energy rater. Note that the design will not suit blocks that do not have north to the boundary side of the lot.

Modifications to the design, for example the inclusion of downlights for lighting can result in the house failing to achieve a 7 star rating. Downlights, even with LED luminaires, require a hole in your ceiling insulation and will therefore reduce the rating and should be avoided for ceilings which open into roof spaces.

Design for climate is an important component. The specifications for each climate should be read carefully. If you are considering changing any of the specifications you should consult an expert to determine the impact of those changes on your building’s energy rating.

The range of star ratings achieved for each climate zone are shown in Table 1.

The lower star rating demonstrates the performance using the base construction and windows. To achieve a base rating, the design was initially simulated using single glazed aluminum framed windows (with the exception of Cairns and Darwin where Low Solar gain low e glazing was used as the base rating).

The higher star rating has been obtained by changing to a higher performing window frame and glazing systems, and by fine tuning various aspects of the construction. The NatHERS climate zone is used by ratings software to assess your home's efficiency.

The NatHERS star rating is based on the level of heating or cooling expected to be needed to maintain thermal comfort in different climate zones. The rating software takes into account all aspects of the building’s design, rather than basing this on any one single material selection or design parameter. For more information visit the NatHERS website, or watch the Explaining NatHERS YouTube video.

City Base rating Maximum rating Climate zone NatHERS climate zone

Table 1: Star rating ranges achievable for each city

Adelaide 6.8 8.4 Warm temperate 16
Brisbane 6.3 8.4 Warm humid summer, mild winter 10
Cairns 6.4 7.4 Hot humid summer, warm winter 32
Canberra 7.0 8.4 Cool temperate 24
Darwin 6.0 7.0 Hot humid summer, warm winter 01
Hobart 6.6 8.1 Cool temperate 26
Melbourne 6.2 8.1 Mild temperate 62
Perth 7.1 8.1 Warm temperate 13
Sydney 7.1 9.0 Warm temperate 17

The 7 star rating involved using a concrete slab on the ground floor with the addition of waffle-pod construction for colder climate areas. The amount of thermal mass in the internal walls, and the selection of window systems, was carefully tailored according to suitability and availability in the various climate areas.

Reverse-brick veneer was used on some internal walls to improve the amount of internal, vertical thermal mass. See Brickwork and blockwork for more details on this construction type and why it is well suited to many Australian climatic regions.

Full details are shown in Table 2 which lists the building specifications and details for each climate zone.

Table 2: Specifications and ratings for each city
City Rating Floor variation1 Roof colour2
Window frames Window glazing Ceiling insulation Wall insulation3
Adelaide 7.2 - Surfmist® Aluminium Hi solar Gain Low e single glazing R4.1 R2.5
Brisbane 7.0 - Surfmist® Aluminium Low Solar Gain low e R3.5 R1.0
Cairns 7.0 - Classic Cream® Timber Low Solar Gain low e R3.5 R2.5
Canberra 7.0 300 mm waffle pods Surfmist® Aluminium Single glazing R4.1 R2.5
Darwin 7.0 - Surfmist® Timber Low Solar Gain low e + outdoor living R3.5 R1.0
Hobart 7.0 300 mm waffle pods Windspray® Timber Hi solar Gain Low e single glazing R4.1 R2.5
Melbourne 7.0 300 mm waffle pods Windspray® Timber Hi solar Gain Low e single glazing R4.1 R2.5
Perth 7.0 - Classic Cream® Aluminium Single glazing R3.5 R1.5
Sydney 7.1 - Surfmist® Aluminium Single tinted glazing R3.5 R1.5
Note 1: Floor is burnished concrete slab on ground, unless variation is specified.Finish for all areas is ceramic tiles in wet areas.
Note 2: Roof material is Colorbond®.
Note 3: Internal walls adjacent to the garage must be insulated at the same rating as external walls.

Window and upgrade options

All new housing (and home extensions) should consider higher performing window frame and glazing systems to improve the energy efficiency, comfort and resilience of their design. Although more expensive than standard single clear glazing, retrofitting improved glazing after the house is built is always more costly than including it as part of the build.

It’s worth noting that poor window choice can severely impact on the heating and cooling loads of a building. Up to 40% of a home’s heating energy can be lost and up to 87% of its heat gained through windows. Improving windows’ thermal performance reduces energy costs and greenhouse gas emissions.

So while in all but Cairns and Darwin a  NatHERS 7 star rating can be achieved with single glazing due to the combination of highly energy efficient design features showcased in the house plans, allowing for improved glazing as part of your build will allow you to maximise the benefits of the energy efficient design. This will impact on your comfort levels and energy savings for the life of your home— making it worth the investment. 

Window and glazing options for the Design For Place plans are available for each climate zone. You should review the options relevant to your climate and location and then select the option to achieve your desired rating.

The following explanatory notes outline how the ratings were achieved and a short description of product specifications. To better understand the impact of windows and glazing on your home’s comfort and performance, see Glazing.

  • A base energy rating was achieved using single glazed aluminum framed windows - with the exception of Cairns and Darwin where Low Solar Gain low e glazing was used to achieve base rating. Further simulations were then undertaken using various combinations of higher performing window systems for the following climate zones: Melbourne, Hobart, Adelaide, Sydney, Perth, Brisbane, Darwin and Cairns.
  • ‘Hi solar Gain Low e single glazing’ is a product that allows solar gains in cool climate areas and the improved results of using this type of glass can be seen in the Melbourne where this product as a single pane in a timber frame takes the design to 7 star.
  • ‘Low solar Gain Low e single glazing product’ restricts the amount of solar gain and improves the result in sub-tropical and tropical areas.
  • Temperate areas like Sydney and Perth can gain by using either of the glass types— Hi solar gain Low e single glazing or Low solar gain Low e single glazing– one would provide winter benefits and the other a summer one, see the results below to gauge the impact.

Adelaide

NatHERS Climate Zone 16

To achieve a base rating the design was initially simulated using single glazed aluminium framed windows, further simulations were then undertaken using various combinations of higher performing window systems. For details of all the materials and finishes view the full specifications

Table 3: Adelaide - base rating and upgrade options
Suggested upgrades Star rating
Base rating: Single glazing, aluminium framed 6.8
Hi solar Gain Low e single glazing, aluminium frame 7.2
Single glazing, timber framed 7.3
Hi solar Gain Low e single glazing, timber framed 7.6
Air fill double glazing, aluminum framed 7.6
Argon fill double glazing, aluminium framed 7.7
Air fill double glazing, timber framed 8.3
Argon fill double glazing, timber framed 8.4

Brisbane

NatHERS Climate Zone 10

To achieve a base rating the design was initially simulated using single glazed aluminium framed windows. Further simulations were undertaken using a higher performing window system, and demonstrating the benefit of adding ceiling fans in this climate zone.For details of all the materials and finishes view the full specifications.

Table 4: Brisbane - base rating and upgrade options
Suggested upgrades Star rating
Base rating: Single glazing, aluminium framed 6.3
Single tint glazing, aluminium framed 6.3
Low Solar Gain low e, aluminium framed 7.0
Single tint glazing, aluminium framed plus 5 ceiling fans 7.9
Single glazing, aluminium framed plus 5 ceiling fans 8.1
Low Solar Gain low e, aluminium framed plus 5 ceiling fans 8.4

Cairns

NatHERS Climate Zone 32

To achieve a base rating, the design was initially simulated using single glazed aluminium framed windows. With this climate zone ceiling fans are included. The following upgrades were simulated:

  1. Higher performance glazing
  2. Applying R1.0 external insulation to the concrete block walls
  3. The addition of a 3 metre deep outdoor living area adjacent to the dining/living room
  4. The use of timber window frames in lieu of aluminium frames

Note Timber window frames can be changed to Fibreglass or uPVC window as they all have similar performance values.

For details of all the materials and finishes view the full specifications.

Table 5: Cairns - base rating and upgrade options
Suggested upgrades Star rating
Single glazing, aluminium framed + outdoor living 6.1
Single tint glazing, aluminium framed + R1.0 external insulation to concrete block walls 6.1
Base rating: Low Solar Gain low e, aluminium framed 6.4
Single tint glazing, aluminium framed + outdoor living 6.4
Low Solar Gain low e, aluminium framed + R1.0 external insulation to concrete block walls 6.9
Low Solar Gain low e, aluminium framed + outdoor living 6.9
Low Solar Gain low e, timber framed 7.0
Low Solar Gain low e, timber framed + outdoor living 7.4
Low Solar Gain low e, timber framed + R1.0 external insulation to concrete block walls 7.5

Canberra

NatHERS Climate Zone 24

To achieve a base rating the design was initially simulated using single glazed aluminium framed windows, further simulations were then undertaken using various combinations of higher performing window systems. For the north facing eaves the projection is 900 mm. For details of all the materials and finishes view the full specifications.

Table 6: Canberra - base rating and upgrade options
Suggested upgrades Star rating
Base rating: Single glazing, aluminium framed 7.0
Hi solar Gain Low e single glazing, aluminium frame 7.2
Single glazing, timber framed 7.3
Air fill double glazing, aluminum framed 7.6
Argon fill double glazing, aluminium framed 7.8
Air fill double glazing, timber framed 8.2
Argon fill double glazing, timber framed 8.4

Darwin

NatHERS Climate Zone 01

To achieve a base rating, the design has been rotated 180° and initially simulated using Low Solar Gain Low e glazed aluminium framed windows; with this climate zone ceiling fans are included. The following upgrades were then simulated:

  1. Higher performance glazing
  2. The addition of a 3 metre deep outdoor living area adjacent to the dining/living room
  3. Heavy mass uninsulated concrete block walls in lieu of the insulated concrete block walls

Note Timber window frames can be changed to fibreglass or uPVC window as they all have similar performance values.

For details of all the materials and finishes view the full specifications.

Table 7: Darwin - base rating and upgrade options
Suggested upgrades Star rating
Single tint glazing, aluminium framed, no insulation to 190 mm concrete block walls c/w light colour render. 5.6
Single tint glazing, aluminium framed + 190 mm concrete block with R1.0 external insulation and 140 concrete block for internal walls 5.9
Single tint glazing, aluminium framed + outdoor living 6.0
Low Solar Gain low e, aluminium framed, no insulation to 190 mm concrete block walls. 6.1
Base rating: Low Solar Gain low e, aluminium framed 6.2
Low Solar Gain low e, aluminium framed + outdoor living 6.4
Low Solar Gain low e, aluminium framed + 190 mm concrete block with  R1.0 external insulation and 140 concrete block for internal walls 6.4
Low Solar Gain low e, timber framed 6.8
Low Solar Gain low e, timber framed, no insulation to 190 mm concrete block walls. 6.9
Low Solar Gain low e, timber framed + outdoor living 7.0
Low Solar Gain low e, timber framed + 190 mm concrete block with R1.0 external insulation and 140 concrete block for internal walls 7.0

Hobart

NatHERS Climate Zone 26

To achieve a base rating the design was initially simulated using single glazed aluminium framed windows. Further simulations were undertaken using various combinations of higher performing window systems. Additional simulations were undertaken with a 1000 mm eave projection to the north. For details of all the materials and finishes view the full specifications.

Table 8: Hobart - base rating and upgrade options
Suggested upgrades Star rating
Base rating: Single glazing, aluminium framed 6.6
Hi solar Gain Low e single glazing, aluminium frame 6.9
Single glazing, timber framed 6.9
Hi solar Gain Low e single glazing, timber frame 7.0
Single glazing, timber framed, 1000 mm eaves to North 7.1
Hi solar Gain Low e single glazing, aluminium frame. 1000 mm eaves to North 7.1
Air fill double glazing, aluminum framed 7.3
Argon fill double glazing, aluminium framed 7.4
Air fill double glazing, timber framed 7.9
Argon fill double glazing, timber framed 8.1

Melbourne

NatHERS Climate Zone 62

To achieve a base rating, the design was initially simulated using single glazed aluminium framed windows. Further simulations were then undertaken using various combinations of higher performing window systems. For details of all the materials and finishes view the full specifications.

Table 9: Melbourne - base rating and upgrade options
Suggested upgrades Star rating
Base rating: Single glazing, aluminium framed 6.2
Hi solar Gain Low e single glazing, aluminium frame 6.6
Single glazing, timber framed 6.6
Hi solar Gain Low e single glazing, timber frame 6.8
Hi solar Gain Low e single glazing, timber frame. 1000 mm eave to North 7.0
Air fill double glazing, aluminum framed 7.1
Argon fill double glazing, aluminium framed 7.3
Air fill double glazing, timber framed 7.8
Argon fill double glazing, timber framed 8.1

Perth

NatHERS Climate Zone 13

To achieve a base rating, the design was initially simulated using single glazed aluminium framed windows, then further simulations were undertaken using a higher performing window system in this climate zone. Further simulations have been made to show the results using both uninsulated. Cavity Brick (high mass), and Cavity Brick with R0.14 insulation with a reflective foil (hybrid foil product) facing 1 air gap, in lieu of the Reverse Brick Veneer walls. For details of all the materials and finishes view the full specifications.

Table 10: Perth - base rating and upgrade options
Suggested upgrades Star rating
Single glazing, aluminium framed, uninsulated high mass walls 7.0
Base rating: Single glazing, aluminium framed 7.1
Single glazing, aluminium framed, insulated high mass walls 7.3
Low Solar Gain low e, aluminium framed 7.4
Hi Solar Gain low e, aluminium framed, uninsulated high mass wall 7.6
Hi Solar Gain low e, aluminium framed 7.7
Hi Solar Gain low e, aluminium framed, insulated high mass walls 7.8
Hi Solar Gain low e, timber framed, insulated high mass walls 8.1

Sydney

NatHERS Climate Zone 17

To achieve a base rating, the design was initially simulated using single glazed aluminium framed windows, then further simulations were undertaken using a higher performing window system demonstrating the benefit of adding ceiling fans in this climate zone. Note: Timber window frames can be changed to Fibreglass or uPVC as they all have similar performance values. For details of all the materials and finishes view the full specifications.

Table 11: Sydney - base rating and upgrade options
Suggested upgrades Star rating
Single tinted glazing, aluminium frame 7.1
Base rating: Single glazing, aluminium framed 7.6
Low Solar Gain low e, aluminum framed 7.7
Hi Solar Gain low e, aluminum framed 7.9
Single glazing, aluminium framed plus 5 ceiling fans 8.4
Low Solar Gain low e, timber framed 8.4
Hi Solar Gain low e, aluminium framed plus 5 ceiling fans 8.6
High Solar Gain low e, timber framed plus 5 ceiling fans 8.9
Low Solar Gain low e, timber framed plus 5 ceiling fans 9.0

Please note the Design For Place house plans and content are only available on this website and are not featured in the Your Home book.