Building or renovating a home can be one of the most challenging and rewarding experiences in a person's life. The results will be with you for years, and perhaps a lifetime, so getting it right from the beginning is very important. The following is a list of things to consider when designing, renovating or making small improvements to your sustainable home
‘Passive design’ is design that takes advantage of the climate to maintain a comfortable temperature range in the home. Passive design reduces or eliminates the need for auxiliary heating or cooling, which accounts for about 40% (or much more in some climates) of energy use in the average Australian home.
The most economical time to achieve good passive design in a home is when initially designing and building it. However, substantial renovations to an existing home can also offer a cost effective opportunity to upgrade thermal comfort — even small upgrades can deliver significant improvements.
A passively designed home makes the most of natural heating and cooling methods to keep its occupants comfortable year-round. Orientation, spatial zoning, thermal mass, ventilation, insulation, shading and glazing are the seven core components of passive design,
Design for your Climate
Passive design strategies vary with climate. The best mix of passive design strategies also varies depending on the particular attributes of your site.
Good passive design ensures that the occupants remain thermally comfortable with minimal auxiliary heating or cooling in the climate where they are built. Each of the eight main climate zones in Australia has its own climatic characteristics that determine the most appropriate design objectives and design responses. Identifying your own climate zone and gaining an understanding of the principles of thermal comfort helps you make informed design choices for your home. The Nationwide House Energy Rating Scheme (NatHERS), with its star classifications, is an additional and useful resource.
For instance, lightweight and ventilated in hot, dry climates , and well-insulated with good solar access in cool climates. In tropical and hot, dry climates, orientate the house to exclude the sun year-round and to maximise cross-ventilation. In all other climates, your aim should be to minimise summer sun and maximise winter sun, which basically means a northern orientation. Couple your passive solar design with thermal mass (materials such as concrete that absorb heat energy, or a ‘proxy’ such as a phase change material) to retain the warmth of winter sunlight and/or the cool of summer shade .
Good orientation also improves solar access to panels for solar photovoltaic (solar power ) and solar hot water.
Australians have some of the biggest houses in the world. Yet the smaller a home, the easier it is to achieve higher energy efficiency standards, and the lower the upfront and ongoing costs
Active heating and or cooling is necessary in most Australian homes but before you buy a heater or air conditioner ,first, consider how you can improve your home to make it more comfortable. Australian homes are traditionally ‘leaky’ and draughts can be responsible for 15- 25 per cent of heat loss – a similar amount of cool air when you use air conditioning. Sealing your home against air leaks is one of the simplest upgrades you can undertake to increase your comfort while reducing energy bills and greenhouse gas emissions. The more extreme your climate, the more beneficial sealing is, with the exception of naturally ventilated homes in the tropics. Seal any leaks, use curtains and blinds, make the most of the sun’s heat and shading to moderate your home’s climate, and insulate. If you need air-conditioning, make sure you also have ceiling fans, which significantly increase its efficiency.
Glazed windows and doors bring in light and fresh air and offer views that connect interior living spaces with the outdoors. However, they can be a major source of unwanted heat gain in summer and heat loss in winter. Up to 40% of a home’s heating energy can be lost and up to 87% of its heat gained through glazing. These thermal performance problems can be largely overcome by selecting the right glazing systems for your orientation and climate, and considering the size and location of window openings in your design.
Shading of your house and outdoor spaces reduces summer temperatures, improves comfort and saves energy. Direct sun can generate the same heat as a single bar radiator over each square metre of a surface. Effective shading — which can include eaves, window awnings, shutters, pergolas and plantings — can block up to 90% of this heat. Shading of glass to reduce unwanted heat gain is critical, as unprotected glass is often the greatest source of heat gain in a house. However, poorly designed fixed shading can block winter sun. By calculating sun angles for your location, and considering climate and house orientation, you can use shading to maximise thermal comfort. Adjustable shading is therefore more effective.
One of the most effective ways to save money on energy bills and make your home more comfortable is to insulate. Insulation acts as a barrier, preventing heat passing in and out of a house. By reducing this heat flow you can more easily maintain a comfortable temperature inside, regardless of the temperature outside. In winter, once your home has been heated to a comfortable level, it will stay that way with less energy input than an uninsulated home. In summer, an insulated home will take longer to heat up, requiring less energy for active cooling. Insulation is not just limited to the roof – you should also insulate your walls and floor for maximum energy efficiency. Insulation can also help with weatherproofing and soundproofing. Climatic conditions determine the appropriate level of insulation as well as the most appropriate type to choose — bulk, reflective or composite. The most economical time to install insulation is during construction.
Lighting makes up about 11 per cent of the energy consumed in a typical home, about the same as refrigeration. Households can reduce energy use for lighting by 50 per cent or more by making smart lighting choices and using more efficient technology. Spending a little time and effort to get the lighting right in your house can save you money on energy bills and make rooms more comfortable and enjoyable.
For instance using LED lighting is much cheaper to run than compact flurescent or Halogen , which is why new lighting installation under the Basix require LED lighting to be installed .
An inefficient appliance can mean a lot of wasted energy as well as more heat in your home – which can be a problem in summer or in hotter climates.When looking for an appliance, try to select the most efficient one that meets your needs and budget.
Consider solar power (photovoltaic panels) and wind turbines to reduce energy bills.
One of the most difficult tasks households face is to try and reduce their demand for water. The National Water Efficiency Labelling Standard (WELS) scheme requires certain products sold in Australia to be registered, rated and labelled for their water efficiency. Look for WELS label as a guide for choosing, bathroom, laundry and kitchen fixtures, as well as washing machines and dishwashers.
use a minimum 3 or 4 WELS star-rated shower heads, toilets and water fixtures. Collect roof rainwater for use in the laundry, toilets as well as in the garden. Use drought tolerant plants in your landscaping plans.
'Passive ' homes need 'active users of the home. You need to be tuned into your home – its needs and yours – to make the most of passive solar design. Open and close blinds, doors and windows to let sunlight and breezes (and cross ventilation) in or keep them out. Remaining engaged can help lessen your environmental impact and ensure your home is performing as well as it can, all the time.