The smaller a home’s footprint, the easier it is to achieve high energy efficiency.
Building or renovating your home is a chance to make your life significantly more sustainable right from the outset – aspect, insulation, windows and building materials can all have a substantial impact on your home’s environmental footprint. Designing these features well will set you up for a life with lower energy bills and more comfortable living spaces. And, as always, the smaller a home’s footprint, the easier it is to achieve high energy efficiency.
The following is taken from Your Home and should be provided to your draftsperson or architect early in the design phase to discuss options for your new home.
- Use high levels of well-insulated thermal mass.
- Use north-facing, high thermal mass living areas with passive solar access.
- Select a site exposed to cooling breezes, and design to exclude adverse winds while allowing for cross-ventilation and night purging.
- Design to capture cool air drainage on still nights (cool air flows in similar patterns to water as surface temperatures drop due to night sky radiation).
- Limit external wall area.
- Choose compact floor plans with central, closable stack ventilation shafts or solar chimneys.
- 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.
- Double glaze living areas and consider using it in bedrooms.
- For north-facing windows select high SHGC glazing and passive shading.
- For east and west façades select low SHGC coatings (e.g. low-e).
- South-facing glass should have low U-value and high visible light transmittance.
- Thermally improved or insulated frames (timber or PVC) are important.
- Passive solar shading to northerly windows is critical.
- Shade all east and west glass in summer.
- Consider adjustable shading to allow variable solar access in spring and autumn.
- Refer to Insulation for appropriate insulation levels in each climate zone and recommended minimum insulation levels.
- Use bulk and reflective insulation in ceilings, and bulk or reflective insulation in walls.
- 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 effectively 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 more extreme regions.
- Check typical heating and cooling requirements in the local area to determine appropriate passive heating levels (consult your local thermal performance expert).
- Prefer high thermal mass construction.
- Use earth coupled slabs.
- Choose light coloured roof materials