When building a new passive home or even an extension that meets the Passive House Criteria it is important to factor in the climate where the house is being built. This is called designing by climate and is a key criterion for meeting Passive Home Certification standards. So what does designing for climate mean?

It means the following:

• The house design takes the local climate into consideration. 
• House planning has a thermal comfort focus (not too hot or cold). 
• The home does not require additional heating or cooling.
• The house design considers projected climate changes. 
• Passive house design principles such as energy-efficient practices are implemented.

What Are Passive Home Principles?

Water, air, vapour, and thermal control layers play a critical role in passive home building. Creating a well-insulated, airtight envelope that, combined with proper insulation, and efficient ventilation reduces energy consumption, maintains air quality, and ensures comfort and durability. These strategies promote long-term cost savings and a healthier living environment.
To learn more about The 4 control layers click here.

Australian Climate Zones

Identifying the climate zone is critical to house planning –  Cool regions such as Launceston require different strategies than tropical regions such as Darwin.

Australia has eight climate zones, defined by the National Construction Code (NCC), each with different home-building requirements. There are 69 regional subzones, defined by the NatHERS. The climate zones cover vast and significantly varied areas, so regional subzones are important for planning.

When researching, consider temperature ranges, including frequency and severity of heatwaves, humidity ranges, and winds – The Australian Bureau provides an all-inclusive graphical representation of this.

You can gain an overview of your climate by comparing seasonal energy bills, consulting an architect, designer, or local energy authority, or referring to meteorological records.

WUFI software can be used during the house planning process to optimise thermal performance in a Passive Home. WUFI does a hydrothermal (heat and moisture) analysis of buildings. During the initial design phase, WUFI is used to model wall and roof build-ups using local climate data which enables the Passive builder to make informed design and material decisions that will greatly reduce the likelihood of moisture-related problems i.e. mould.

To learn more about climate change in Australia click here.

Image Source: yourhome.gov.au

Why Is Designing For Climate Important?

To guarantee that all designs, specifications, calculations, and other paperwork adhere to the Passive House standard, they are all examined. This ideally happens even before a building permit application is submitted. This is followed by a short report that would highlight any issues which could affect the certification process.

This allows the passive house team the opportunity to address issues early on. The final design is assessed after improvements are implemented, and if the plan passes the assessment, construction can start. 

The post-construction documentation is reviewed once the project is completed. If the final project fails to meet any of the requirements a report detailing the shortcomings will then be issued. The project can be resubmitted for assessment provided the shortcomings can be resolved. 

If Passive House Certification criteria are met, the building owner will receive the following:

• A certificate
• A supplementary booklet with documentation of the energy balance calculation
• A plaque (optional)

Image Source: climatechangeinaustralia.gov.au

NSWClimate Zone: Warm Humid Summer, Mild Winter

Your regional climate determines the most effective design strategies for your home. Taking the NSW climate into consideration these are the key points that you need to take into consideration during the design and construction of your passive home or passive house extension.

The below information is taken from the Australian government’s website on Passive Design for Climate. You can find the source here.

Climate characteristics:

• Distinct summer and winter seasons.
• Moderate to low day–night (diurnal) temperature ranges.
• High humidity with a definite dry season during winter.

Design objectives:

• The main aim is to eliminate the need for seasonal temperature control.

Design considerations:

• House planning should take into consideration exposure to breezes and cross-ventilation.
• For home building consider narrow floor plans and design openings to encourage the movement of breezes.
• Locate sleeping spaces in lower levels and use low or no thermal mass to prevent radiant heat at bedtime. 
• Consider screened and shaded outdoor living areas and sleep-out spaces.

Windows and shading:

• With home building avoid overuse of glazing.
• Use low SHGC glazing and low U-value glazing with thermally broken frames in regions with cooler winters or hotter summers.
• Use windows such as louvre or casement which are 100% openable.
• Shade all east- and west-facing walls and glass.
• Shade south-facing walls in buildings that are north of the tropic of Capricorn.
• In more southerly and inland regions use passive shaded north-facing glass.

Insulation:

• Meet or exceed the minimum insulation levels for the region.
• Avoid installing bulk insulation in ceilings and walls unless winter heating is used.
• In areas where no winter heating is required, use multiple layers of reflective foil for a one-way valve effect.
• Insulate internal wall surfaces.
• Use highly breathable reflective vapour barriers in walls and add bulk insulation to air-conditioned rooms.
• Line open ventilated spaces with reflective foil insulation and design to remove condensation.
• Use roof spaces to provide heat flow buffer zones by ventilating in summer and sealing in winter.

Heating and cooling:

• Avoid auxiliary heating.
• Consult your local thermal performance expert to determine appropriate passive heating levels.
• Use high-energy-rated cooling appliances.
• Include the use of ceiling fans.

Construction systems:

• Use lightweight wall construction where day–night temperature ranges are low, and add thermal mass where these ranges exceed 6°C.
• Where summer ground temperatures exceed 19°C at a depth of 3 metres, use elevated lightweight floors. Consider using earth-coupled slabs in areas where deep-ground summer temperatures are less than 19°C.
• Choose light-coloured roof and wall materials for home building.

To learn more about Passive Houses in Different Climates from Passipedia click here.