Design for climate

What is design for climate?

Design for climate means that a home is designed or modified to:

• suit the climate it is built in
• keep the occupants thermally comfortable (that is, they do not feel too hot or too cold)
• use minimal heating or cooling.

The design should also consider projected changes to the climate.

Australian climate zones

The climate for your region will determine the most effective design strategies for your home – a cool region such as Launceston will require different strategies from a tropical region such as Darwin.

Identifying your climate zone is the first step to designing for climate.

Australia has 8 climate zones, defined by the National Construction Code (NCC). Each climate zone has different design and construction requirements. There are also 69 regional subzones, defined by the NatHERS, which are determined by local geographic features including wind patterns and height above sea level. Given Australia’s geographic size, the 8 climate zones cover vast areas and may contain significant variations within them, so looking at the characteristics of your regional subzone might provide the most useful information.

You can gain a more detailed idea of your local climate by comparing your summer and winter energy bills, consulting an architect or designer, asking your local energy authority, or referring to local meteorological records. If you are doing your own local climate research, you should look at:

• temperature ranges, both seasonal and day–night (diurnal)
• extreme temperatures, especially the frequency and severity of heatwaves
• humidity ranges
• direction of cooling breezes, hot winds, cold winds, wet winds (for example, the Australian Bureau of Meteorology provides a graphical representation of wind direction, strength, and frequency for each region in Australia
• seasonal characteristics, including extremes in summer and winter
• impact of local geographic features on climatic conditions (for example, the effect of local mountain ranges on winds).

NatHERS software uses computer simulations to assess the potential thermal comfort of Australian homes on a scale of 0 to 10 stars – the more stars, the less heating or cooling energy required to keep the occupants comfortable. The software produces computer simulations that assess how well your building suits your climate zone. NatHERS software can be used during the design process to help optimise a home’s thermal performance.

Thermal comfort

To achieve thermal comfort in your climate zone, it can be useful to understand what thermal comfort means for humans.

Humans are sensitive to heat and cold, and are comfortable within a very narrow range of thermal conditions. Our body temperature is about 37°C and our bodies constantly produce heat, which is lost to the environment. To stay comfortable, we must lose heat at the same rate it is produced, and gain heat at the same rate it is lost. The following diagram shows the various ways our bodies achieve this.

Source: Steve Szokolay

Physiological and psychological comfort

Human thermal comfort has 2 components: physiological and psychological. Both needs must be met before we feel truly comfortable.

The main factors influencing both physiological and psychological human comfort are:

• temperature
• humidity
• air movement
• exposure to heat sources
• exposure to cool surfaces.

Careful design and technology choices can result in a building that delivers physiological comfort – that is, it addresses all the physical factors necessary for comfort. However, the same building might not meet our psychological comfort needs.

Important triggers for psychological discomfort are air movement, radiation and conduction. They trigger innate self-preservation responses that can override our ability to perceive physical comfort. For example, we can feel cold in a room that is a comfortable 22°C if there is a cold window nearby. Conversely, we can feel warm at 0°C if we are well insulated with warm clothing and standing in the sun.

Acclimatisation is a critical component of psychological comfort. If we are used to an environment, it will feel comfortable. This can affect our heating and cooling needs. For example, the increasing presence of air-conditioning in homes may be shifting expectations and perceptions of comfort so that we expect homes to be cool during summer.

Losing body heat

We lose body heat in 3 ways: evaporation, radiation and conduction.

Our most effective cooling method is the evaporation of perspiration. Evaporation rates are influenced by air movement. Generally, a breeze of 0.5 metres per second is equivalent to a 3°C reduction in temperature. High humidity levels reduce evaporation rates, which is why humid environments can feel hotter.

We also lose heat by radiating heat through the air to surfaces that are cooler than our body temperature, such as tiled concrete floors cooled by night breezes or earth coupling. Radiation can be very important to our psychological perception of comfort.

Conduction is when heat is lost through direct body contact with cooler surfaces, such as when you go for a swim or walk on a tiled floor. Conduction is a particularly important component of psychological comfort.

Gaining body heat

We gain body heat in 3 ways: shivering, radiation and conduction.

When the heat produced by our bodies is not enough to maintain our body temperature, we shiver. This generates body heat and also triggers psychological warning mechanisms. We usually respond to these warnings by putting on more clothes or sheltering from wind and draughts.

We can also gain heat through radiation from a heat source, such as a heater or sun through a window. As with cooling, radiation is very important to our perception of comfort.

The final source of heat gain is conduction through direct body contact with a heated surface, such as a heated floor. Heated floors also provide radiant heat and raise air temperatures through conduction and convection.

Why is design for climate important?

Approximately 40% of household energy is used for heating and cooling. This could be cut to almost zero in new houses through effective, climate-appropriate design. And although reducing or eliminating the need for heating and cooling in existing homes is more of a challenge, significant reductions in energy use can still be achieved through simple changes.

Designing for a changing climate

Designing for a changing climate is also important. Climate change may alter the characteristics of each climate zone during the lifespan of homes currently being built or renovated. Considering the potential changes to the climate will help to ensure that your home remains comfortable and resilient to weather extremes and holds its value over time.

To build a comfortable and resilient home for the future, think beyond your current climate to consider how it might be in 10, 20 or 50 years from now.

You can find more information about projected changes in the climate for your local area at the Australian Government’s Climate change in Australia. This site includes a tool to identify locations that currently have a climate similar to what your predicted future local climate may be. These can help you to understand what conditions may be like in your location in the future.

Climate change potential impacts and responses

Potential climate change impacts	Possible responses
Increased temperatures Increased frequency of heatwaves	Incorporating passive cooling principles in design Building a ‘cool retreat’ – a part of the building that can provide comfort during heatwaves
Low rainfall	Designing in ways to harvest water and reduce water use
Bushfires	Using shutters, sprinklers, fire-resistant materials and roof design that minimises the risk of catching embers
Severe thunderstorms and high-intensity rainfall events	Using metal roofing that is resistant to impact (for example, hail) and adequate window protection Ensuring gutters and drainage systems can withstand a 1-in-100-year rainfall event
Cyclones and extreme wind	Using structures and building materials designed to cope with heavy winds and cyclones
Flooding Sea level rise and storm surge	Not building in flood- or surge-prone areas Raising floors and using water-resistant building materials

This section provides an overview of key design objectives and responses to creating thermally comfortable homes in each main climate zone in Australia. These should be customised to your individual site, locality and design brief. Confirm the best strategy for your climate by using NatHERS software.

Source: Australian Building Codes Board

Zone and description

 1 Hot humid summer, warm winter

 2 Warm humid summer, mild winter

 3 Hot dry summer, warm winter

 4 Hot dry summer, cool winter

 5 Warm temperate

 6 Mild temperate

 7 Cool temperate

8 Alpine

Climate zone 1: Hot humid summer, warm winter

 

Climate characteristics

• Moderate to high temperatures year round
• Low to moderate temperature variation between seasons
• Low day–night (diurnal) temperature range
• High humidity year round, though there is a mild dry season during winter

Design objectives

The main aim in this zone is to achieve effective cooling in a humid climate.

Your building design and cooling method need to work together. There are 3 main design approaches; the approach should be chosen at the beginning of the design process, because it can be difficult to change this in the future.

You can choose a design that is:

• free running - these homes are cooled using air movement from fans, whirlybird ventilators, stack ventilation and cross-ventilation. These buildings should not be air-conditioned without substantial alteration (for example, reducing the size of openings, adding bulk insulation around the areas to be conditioned, careful detailing to prevent condensation)
• conditioned - these homes must be well insulated and able to be made airtight while the air-conditioning is running. Both inward and outward condensation issues should be addressed
• hybrid - these homes have air-conditioned, insulated core rooms in the centre of the house (for example, a TV room), surrounded by free-running spaces.

Homes using conditioned and hybrid design approaches should be designed to provide sleeping comfort without air-conditioning, so you can choose to switch the conditioning off at night.

Design considerations

• Orientate the building to take advantage of cooling breezes, and position landscaping and outbuildings to funnel breezes over, under and through the building.
• Make sure your design maximises night-time sleeping comfort. Locate sleeping spaces in lower levels. Use low or no thermal mass in sleeping spaces to prevent radiant heat. Consider sleep-out spaces.
• Install ceiling fans in all rooms.
• Use passive cooling measures; ventilate roof spaces well with fans or whirlybirds and design for condensation removal
• Locate cooking areas and heat-generating appliances (for example, fridges) on external walls and away from sleeping areas.
• Provide shaded outdoor living areas.
• Locate pools and spas on the northern side of the building where they will be shaded in the hot humid season and warmed during the dry season.
• Use light colours on roofs and walls.
• Maximise planted areas in landscapes.

In free-running buildings

• Use high or raked ceilings to promote convective air movement.
• Encourage natural air flow through the home with large, high level openings (for example, shaded openable clerestory windows, roof vents or ridge vents).
• Funnel cool breezes through the building using larger openings on the leeward side (the side that is sheltered from the wind) and smaller openings on the windward side (facing the wind).
• Use only 100% openable windows (for example, louvre or casement).
• Maximise external wall areas (plans with 1-room depth are ideal) to encourage cross-ventilation.
• Elevate the building to permit air flow beneath floors.
• Install ceiling fans or whole-of-house fans that are positioned centrally (for example, in the roof or in a hallway).

In conditioned buildings

• Use internal thermal mass walls surrounding conditioned central cores for radiant cooling of adjoining unconditioned sleeping spaces.
• Avoid overuse of glazing.
• Use the highest energy rated air-conditioning appliances. Install smart control systems and a variable output speed compressor to maximise efficiency (refer to Heating and cooling).
• Condition only critical rooms rather than the entire house.
• Design air-conditioned spaces to be sealed off, preventing loss of cooling when running.
• Design to accommodate both inward and outward condensation (wherever humid warm air meets a cooler surface).
• Provide ceiling fans in conditioned spaces.
• Shade the outdoor unit of the air-conditioner. Locate the unit where its hot air output will be directed away from the house.

Windows and shading

• Shade all windows and walls, including those that are south facing. Include extended eaves where possible or vertical shading where not.
• Use glazing with low U value and low solar heat gain coefficient (SHGC) and thermally broken window frames to avoid heat gain or cooling loss.
• Shade the home, especially windows, and outdoor spaces with planting and shade structures.
• Consider shading the whole building with a fly roof.

Insulation

• Ensure insulation is appropriate for the climate and installed correctly.
• Avoid bulk insulation to ceilings and walls, except in conditioned spaces.
• Insulate internal wall surfaces well from any external thermal mass.
• Insulate elevated floors with reflective, closed-cell bulk insulation to resist upward heat flow and condensation.
• Use multiple layers of reflective roof and ceiling insulation to create a 1-way valve effect, allowing indoor heat to be released without letting outside heat in.

Construction systems

• Use lightweight (low-mass) construction materials. Innovative hybrid design solutions with some high-mass construction may also be appropriate, especially in areas of high cyclone risk.
• Use light-coloured reflective roof and external wall materials.
• Design and build for cyclonic conditions.

Climate zone 2: Warm humid summer, mild winter

 

Climate characteristics

• Distinct summer and winter seasons; hot to very hot summers and mild winters
• Moderate to low day–night (diurnal) temperature range, which can vary significantly between regions (for example, inland to coastal)
• High humidity with a definite dry season during winter

Design objectives

The main aims in this zone are to eliminate the need for heating in winter and reduce the need for cooling in summer, in a humid climate.

Design considerations

• Orientate the building for exposure to cooling breezes and design for cross-ventilation.
• Use narrow floor plans and design openings to encourage movement of breezes through and with the building.
• Make sure your design maximises night-time sleeping comfort. Locate sleeping spaces in lower levels. Use low or no thermal mass in sleeping spaces to prevent radiant heat at bed-time. Consider sleep-out spaces.
• Provide screened and shaded outdoor living areas.

Windows and shading

• Avoid overuse of glazing.
• Use low SHGC glazing in all cases and low U value glazing with thermally broken frames in regions with cooler winters or hotter summers.
• Use 100% openable windows such as louvre or casement.
• Shade all east- and west-facing walls and glass year round
• Shade south-facing walls in buildings that are north of the tropic of Capricorn.
• In more southerly and inland regions heating requirements increase, so use appropriate levels of passive shaded north-facing glass.

Insulation

• Meet or exceed recommended minimum insulation levels for the climate region. Avoid installing bulk insulation in ceilings and walls unless winter heating is used (refer to Insulation).
• In areas where no winter heating is required, use multiple layers of reflective foil in ceiling and roof spaces to create a 1-way valve effect.
• Insulate internal wall surfaces from any external thermal mass.
• Use highly breathable reflective vapour barriers in walls and add bulk insulation to rooms that are air-conditioned.
• Line open ventilated spaces with reflective foil insulation and design to remove condensation.
• Use roof spaces to provide heat flow buffer zones by ventilating them in summer and sealing them in winter with fans or ‘smart’ ventilators (refer to Passive cooling).

Heating and cooling

• Avoid installing auxiliary heating.
• Check typical heating requirements in the local area to determine appropriate passive heating levels (consult your local thermal performance expert).
• Use high-energy-rated cooling appliances in selected rooms.
• Include ceiling fans in all living and sleeping spaces.

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 all areas where deep ground temperatures are less than 19°C in summer.
• Choose light-coloured roof and wall materials.

Climate zone 3: Hot dry summer, warm winter

 

Climate characteristics

• Distinct summer and winter seasons; hot to very hot summers and cool winters
• Distinct wet and dry seasons
• Significant day–night (diurnal) temperature range
• Low rainfall
• Low to moderate humidity

Design objectives

The main aims for this zone are to reduce the need for cooling in summer. This is relatively straightforward and cost effective because the zone has low humidity and high day–night temperature ranges.

Design considerations

• Use high levels of well-insulated thermal mass.
• Choose a site that has good exposure to cooling breezes; design for cross-ventilation and night purging.
• Use north-facing, high thermal mass living areas with passive solar access.
• Limit the external wall area.
• Consider compact floor plans with central, closable stack ventilation shafts.
• Consider mechanical ventilation of ceiling spaces to ensure high-level flows of cooler (south-side) air in summer and a complete seal in winter.
• Provide screened, shaded outdoor living areas that allow winter sun penetration.
• Use garden ponds and water features to provide evaporative cooling, preferably within screened, shaded outdoor living areas.

Windows and shading

• Avoid overuse of glazing.
• Use low U value glazing in all cases.
• Use low SHGC glazing in regions with hot summers and mild winters.
• Use double glazing in regions with cooler winters.
• Shade all east- and west-facing glass in summer.
• Shade south-facing glass in buildings that are north of the tropic of Capricorn.

Insulation

• Use bulk and reflective insulation in ceilings, and bulk or reflective insulation in walls. Meet or exceed recommended minimum insulation levels for the climate region.
• Include external insulation to all thermal mass.
• Insulate under concrete slabs if using in-slab heating.
• Insulate elevated floors (lightweight or concrete).
• Ensure all spaces are air sealed.

Heating and cooling

• Use evaporative cooling and passive solar heating in living areas.
• Provide ceiling fans in all living and sleeping spaces.
• In regions with more extreme conditions, consider active solar heating and reverse night cooling connected to in-slab hydronic systems.
• Check typical heating and cooling requirements in the local area to determine appropriate passive heating levels (consult your local thermal performance expert).

Construction systems

• Use high thermal mass construction.
• Where summer ground temperatures exceed 19°C at a depth of 3 metres, use insulated concrete slabs or insulated elevated lightweight floors with high thermal mass walls.
• Consider using earth-coupled slabs in all areas where deep ground temperatures are less than 19°C in summer.
• Choose light-coloured roof materials.

Climate zone 4: Hot dry summer, cool winter

 

Climate characteristics

• Distinct summer and winter seasons; very hot summers with hot, dry winds and cool winters with cold dry winds
• High day–night (diurnal) temperature range
• Low rainfall
• Low humidity all year round

Design objectives

The main aims in this zone are to reduce the need for cooling in summer and heating in winter. Well-designed passive solar heating and cooling are equally important. High thermal mass solutions are particularly effective. Active solar heating and cooling systems are well suited to sunny winters and clear summer night skies, and will also provide flexible thermal comfort solutions for a changing climate.

Design considerations

• Choose a site exposed to cooling breezes, and design to exclude adverse winds while allowing for cross-ventilation and night purging.
• Use north-facing, high thermal mass living areas with passive solar.
• Use appropriate glass-to-mass ratios.
• Design to draw cool air from the surrounding environment on still nights (when surface temperatures drop due to night sky radiation, cool air flows in similar patterns to water).
• Limit the external wall area.
• Choose compact floor plans with central, closable stack ventilation shafts.
• Consider central courtyards with evaporative cooling water features to allow night cooling with wind protection.
• Use mechanical ventilation in ceiling spaces to ensure high level flows of cooler (south-side) air in summer and a complete seal in winter.
• Provide screened, shaded outdoor living areas that allow winter sun penetration.
• Use garden ponds and water features outside windows to provide evaporative cooling.

Windows and shading

• Avoid overuse of glazing.
• Use different glazing types for each façade; low U value glazing is essential in all cases.
  – Use double glazing in living areas and consider in bedrooms.
  – For north-facing windows, choose high SHGC glazing.
  – For east- and west-facing windows, choose low SHGC coatings (for example, low-e).
  – South-facing glass should have low U value and high visible light transmittance.
• Use thermally improved or insulated frames (for example, uPVC or timber).
• Include passive solar shading to north-facing windows.
• Shade all east- and west-facing glass in summer.
• Consider adjustable shading to allow variable solar access in spring and autumn.

Insulation

• Use bulk and reflective insulation in ceilings, and bulk or reflective insulation in walls. Meet or exceed recommended minimum insulation levels for the climate region.
• Provide external insulation to all thermal mass.
• Insulate under concrete slabs if using in-slab heating.
• Insulate elevated floors (concrete or lightweight).
• Ensure all spaces are air sealed.

Heating and cooling

• Use evaporative cooling and passive solar heating in living areas.
• Provide ceiling fans in all living and sleeping spaces.
• Consider active solar heating and reverse night cooling connected to in-slab hydronic systems in regions with more extreme conditions.
• Check typical heating and cooling requirements in the local area to determine appropriate passive heating levels (consult your local thermal performance expert).

Construction systems

• Consider high thermal mass construction.
• Use earth-coupled slabs.
• Choose light-coloured roof materials.

Climate zone 5: Warm temperate

 

Climate characteristics

• Four distinct seasons: summer and winter can exceed human comfort range; spring and autumn are ideal for human comfort
• Hot to very hot summers with low to moderate humidity
• Mild winters with low humidity
• Moderate day–night (diurnal) temperature range near coast to high diurnal range inland

Design objectives

The main aims in this zone are to reduce the need for cooling in summer and heating in winter. This zone offers the most cost-effective opportunities to achieve energy-efficient outcomes. With careful design, 7–9 star rated houses can be achieved in this climate with minimal heating and cooling use.

Although this zone has some overall climate characteristics common to all regions, it also has a greater range of climatic conditions between regions. For this reason, pay careful attention to the 69 subzones in NatHERS to decide the best design responses for your site. You can compare the following recommendations with those in adjoining zones (4 or 6) that may match your climate more closely.

Design considerations

• Analyse your site to identify conditions that require specific design adjustments.
• Use passive solar heating and cooling for all subzones.
• If access to adequate sunlight is not available for passive solar heating, consider using lightweight building frames that respond quickly and efficiently to minimal auxiliary heating.
• Use composite thermal mass, such as a ground slab with low-mass wall construction
• Use roof spaces as a thermal buffer zone by ventilating them in summer and sealing them in winter.

Windows and shading

• Avoid overuse of glazing.
• Carefully size and orientate windows, as this will often yield ideal results with less expensive glazing options.
• Use passive solar shading on north-facing windows.
• Shade all east- and west-facing glass in summer.
• Consider adjustable shading to allow variable solar access in spring and autumn.

Insulation

• Use bulk and reflective insulation in ceilings, and bulk or reflective insulation in walls. Meet or exceed recommended minimum insulation levels for the climate region.
• Insulate under concrete slabs if using in-slab heating.
• Provide external insulation to all thermal mass.
• Insulate elevated floors (concrete and lightweight).
• Ensure all spaces are air sealed.

Heating and cooling

• Avoid auxiliary heating and cooling.
• Include ceiling fans in all living and sleeping spaces.

Construction systems

• Consider composite thermal mass construction.
• Consider earth-coupled slabs.
• Choose low-embodied-energy walls, roofing and finishes.
• Choose light-coloured roof materials.

Climate zone 6: Mild temperate

 

Climate characteristics

• Four distinct seasons: summer and winter exceed human comfort range; spring and autumn are ideal for human comfort
• Hot to very hot summers, moderate humidity
• Mild to cool winters with low humidity
• Low day–night (diurnal) temperature range near coast, high range inland

Design objectives

The main aims in this zone are to reduce the need for cooling in summer and heating in winter. This zone offers good cost-effective opportunities to achieve energy-efficient outcomes.

There is some variation in climate between regions in this zone – analyse your site to determine whether heating or cooling is the main need.

Design considerations

• Minimise solar and ambient heat gains with shading and insulation.
• Use cross-ventilation for cooling. Use convective ventilation and heat circulation.
• Use passive solar heating where solar access is available.
• Minimise external wall areas (especially east- and west-facing).
• Use appropriate glass-to-mass ratios.
• Where solar access is unavailable, lightweight solutions that respond quickly and efficiently to minimal heating are a viable alternative.
• Use roof spaces to create a thermal buffer zone to summer heat gain (ventilated) and winter heat loss (sealed). Use thermostat-controlled fans or closable ventilators.

Windows and shading

• Avoid overuse of glazing.
• Carefully size and orientate windows as this will often yield ideal results with less expensive glazing options.
• Use high SHGC and low U value glazing.
• Consider double glazing in regions with higher heating needs.
• Use insulating blinds or snug-fitting curtains with pelmets.
• Use passive solar shading on north-facing windows.
• Minimise and shade all east- and west-facing glass in summer.
• Consider adjustable shading to allow variable solar access in spring and autumn.

Insulation

• Use bulk and reflective insulation in ceilings, and bulk or reflective insulation in walls. Meet or exceed recommended minimum insulation levels for the climate region.
• Insulate all thermal mass externally.
• Insulate under concrete slabs if using in-slab heating.
• Insulate elevated floors (concrete and lightweight).
• Calculate thermal lag in high thermal mass walls such as rammed earth or mud brick to determine appropriate insulation levels.
• Seal thoroughly against draughts and include entry airlocks.

Heating and cooling

• Avoid auxiliary heating or cooling. • Include ceiling fans in all living and sleeping spaces.

Construction systems

• Consider composite thermal mass construction.
• Consider earth-coupled slabs.
• High thermal mass walls can be used with appropriate glass-to-mass ratios.
• Choose low-embodied-energy walls, roofing and finishes.
• Choose light-coloured roof materials.

Climate zone 7: Cool temperate

 

Climate characteristics

• Four distinct seasons: summer and winter exceed human comfort range
• Hot dry summers (increasing with climate change)
• Cold to very cold winters with majority of rainfall (decreasing with climate change)
• Highly variable spring and autumn conditions (increasing with climate change)
• High day–night (diurnal) temperature range
• Low humidity

Design objectives

The main aim in this zone is to reduce the need for heating in winter, but also achieve thermal comfort in summer. Designs with large north-facing windows and double glazing, together with appropriate thermal mass, are recommended to increase solar gain.

Design considerations

• Apply best-practice passive solar design principles where solar access is available.
• Site new homes for solar access, exposure to cooling breezes and protection from cold winds.
• Maximise the use of north-facing walls and glazing.
• Use appropriate glass-to-mass ratios.
• Locate living areas on the north side of the home, with bedrooms and service areas (bathrooms, laundry and garages) on the south.
• Minimise external wall areas, especially east and west.
• Avoid high ceilings and provide airlocks between lower and upper floors.
• Design for controllable (zoned) convective air movement throughout the house to distribute heat while minimising draughts and temperature stratification.
• Where passive solar access is unavailable, minimise all glass areas and limit thermal mass except where exposed to heating sources.
• Design furniture layouts to minimise exposure to convection draughts.
• Ventilate roof spaces in summer and seal them in winter (use automated fans or closable roof ventilators).

Windows and shading

• Avoid overuse of glazing.
• Carefully size and orientate windows.
• Use high SHGC, low U value double glazing.
• Use thermally improved or insulating frames (for example, uPVC or timber).
• Design and detail to prevent window condensation.
• Include passive solar shading to north-facing windows.
• Use insulating blinds or heavy curtains with sealed pelmets. Consider double curtains or tight-fitting airtight blinds behind curtains.
• Minimise and shade all east- and west-facing glass in summer.
• Consider using adjustable shading to some west-facing glass areas to boost afternoon solar heat gains in winter and allow variable solar access in spring and autumn.

Insulation

• Bulk insulate all walls, ceilings and exposed floors. Meet or exceed recommended minimum insulation levels for the climate region.
• For walls, use bulk insulation with highly breathable sarking or multiple layers of reflective foil insulation, with detailed design to reduce the risk of condensation.
• Insulate all thermal mass externally (including rammed earth and mud brick).
• Use reflective foil insulation in roofs and high levels of bulk insulation in ceilings.
• Insulate all elevated floors (concrete and lightweight).
• Insulate slab edges.
• Insulate under concrete slabs if using in-slab heating.
• Include airlocks to entries.
• Air seal all spaces.

Heating and cooling

• Install energy-efficient auxiliary heating (for example, well-designed active solar energy systems with substantial heat storage capacity or an efficient heat pump (ground, water or air source).
• Avoid wood heating in urban areas.
• Avoid auxiliary cooling; use good cross or closable ventilation and ceiling fans in living and sleeping spaces instead.

Construction systems

• Use earth-coupled slabs, except where earth temperatures at a depth of 3 metres are below 16°C in winter. Insulate under the slab or use insulated, lightweight floors in these regions.
• Use low thermal mass walls on sites with no solar access.
• Use lightweight wall construction where diurnal temperature ranges are low and increase thermal mass and solar exposed glass as they increase above 6°C.
• Choose light-coloured roof materials.

Climate zone 8: Alpine

 

Climate characteristics

• Four distinct seasons: winter exceeds human comfort range and will likely continue to do so under climate change
• Warm to hot, dry summers
• Cold to very cold winters with high rainfall and some snow
• Highly variable spring and autumn conditions
• High day–night (diurnal) temperature range
• Low humidity

Design objectives

The main aim in this zone is to achieve effective heating. A high level of thermal performance is required to keep energy use low. Because heating is a major cost in these climates, the additional cost of 10-star thermal design is quickly recouped.

Design considerations

• Apply best-practice passive solar design principles where solar access is available.
• Avoid building on sites without good access to sunlight. Site new homes for optimum access to sunlight and protection from cold winds.
• Maximise north-facing walls and use double glazing.
• Locate living areas on the north side of the home, with bedrooms and service areas (bathrooms, laundry and garages) on the south.
• Consider multilevel designs that allow sunlight into all rooms while maintaining a compact form.
• Minimise external wall areas, especially east and west.
• Use the highest glass-to-mass ratios.
• Ensure the interior is airtight and consider a heat-recovery ventilation system.
• Avoid high ceilings and provide airlocks between lower and upper floors.
• Design for controllable (zoned) convective air movement throughout the house to distribute heat while minimising draughts and temperature stratification.
• Design furniture layouts to minimise exposure to convection draughts and maximise exposure to radiant heat.
• Seal roof spaces.

Windows and shading

• Avoid overuse of glazing. Careful sizing and orientation of windows is essential.
• Use high SHGC, lowest U value double glazing.
• Use thermally improved or insulated frames (for example, uPVC or timber).
• Design and detail for high levels of window condensation.
• Use heavy curtains with sealed pelmets or insulating blinds. Consider double drapes or insulating blinds behind curtains.
• Minimise all east- and west-facing glass and shade it in.
• Consider using adjustable shading on west-facing glass areas to boost afternoon solar heat gains and allow variable solar access in spring and autumn.
• Avoid east-facing glazing where morning fog limits winter solar gains.

Insulation

• Bulk insulate all walls, ceilings and exposed floors. Meet or exceed recommended minimum insulation levels for the climate region.
• Consider using 150mm or 200mm deep studs to achieve higher rating wall insulation.
• Use additional layers of insulation fixed to frames to reduce thermal bridging.
• Detail and specify insulation provisions carefully and supervise installation.
• Externally insulate all thermal mass to high levels, especially rammed earth and mud brick.
• Use the highest levels of bulk insulation in ceilings.
• Line the underside of roofing material with downward-facing, closed cell, foil-coated bulk insulation to avoid loss of R value (thermal resistance) through compression.
• Insulate all elevated floors (concrete and lightweight) to the highest level.
• Insulate slab edges and under concrete slabs.
• Include airlocks to entries.
• Ensure all spaces are air sealed.

Heating and cooling

• Install energy-efficient auxiliary heating, such as well-designed active solar energy systems with substantial heat storage capacity or an efficient heat pump (ground or water source).
• Avoid wood heating in urban areas.
• Consider highly insulated first-floor bedrooms that are heated by convection and conduction from ground floor heating.

Construction systems

• Insulate under slabs or use highly insulated, lightweight floors.
• Use highly insulated, low thermal mass walls in rooms with no exposure to direct sunlight.
• Choose dark-coloured roof and wall materials.

• Australian Greenhouse Office (2005). Global warming: cool it! A home guide to reducing energy costs and greenhouse gases, Australian Government Department of the Environment and Heritage, Canberra.
• Baggs S, Baggs J, Baggs D (1991). Australian earth-covered and green roof building, Interactive Publications, Carindale, Queensland.
• Cairns Regional Council, Cairns style design guide. 
• Cement Concrete & Aggregates Australia, Energy efficiency in building regulations and the use of concrete in housing [PDF]. 
• CSIRO (Commonwealth Scientific and Industrial Research Organisation) and BOM (Bureau of Meteorology) (2015) Climate change in Australia: technical report.
• Energy Rating.
• Hollo N (2011). Warm house cool house: inspirational designs for low-energy housing, 2nd edn, Choice Books, Sydney.
• Hyde R (2013). Climate responsive design. A study of buildings in moderate and hot humid climates, Spon Press, London.  
• Nationwide House Energy Rating Scheme (NatHERS).
• Queensland Department of Public Works, Designing for Queensland’s climate [PDF].
• Renew.
• Sanctuary magazine.
• Seeley International, Climate design wizard.
• Sustainability Victoria (2020), Energy smart housing manual. 
• Window Energy Rating System (WERS), How to select windows.
• Wrigley D (2010). Making your home sustainable: a guide to retrofitting, rev. edn, Scribe Publications, Brunswick, Vic.

Learn more

• Read Passive heating and Passive cooling for tips on designing your home to work well in winter and summer
• Review Insulation for more ideas on how to slow heat transfer through your home
• Explore the Materials section for ideas on methods and materials for new home construction

Authors

Original author: Chris Reardon

Contributing author: Paul Downton

Updated: Chris Reardon 2013, Caitlin McGee 2020