Achieving the sustainability outcomes you aspire to in your home requires them to be considered throughout the entire process – from the earliest stages of design to the completion and everyday use of your home.
The level of involvement you want to have in decision making is up to you, but it is important to remember that someone needs to be considering sustainability throughout the project. The process of ‘getting there’ can be divided in to the following five steps:
The process of ‘getting there’ can be divided in to the following five steps:
1. Define your priorities and set objectives
The previous section discussed the importance of defining the type, scope and time of impact that matters to you. This will be essential when setting the objectives and quantifiable targets that will guide the design of your new home.
2. Decide if a rating tool or certification is right for you
Certification schemes can simplify the process of setting objectives and targets by providing guidance and standards created and tested by experts. There are various schemes on the market, with different approaches and structure. It is key to research and understand the alternatives before committing to one, as your choice will have great impacts on your project’s outcomes.
If you decide to use a rating tool or certification scheme, its objectives and strategies will need to be incorporated into your Design Brief early in the process, as they might dictate the way the design is approached.
3. Prioritise and test design
When starting a new house project or a major renovation, your sustainability outcomes should be incorporated right from the design stage.
Amongst other things, design that aims to work with nature and like nature can: - capture the sun’s energy for heating and wind for cooling
- retain the sun’s warmth using window placement and thermal mass
- establish a respectful relationship with neighbours and the street, creating stronger communities and allowing equal access to natural resources
- allow you to be partially independent from the city water supply by providing adequate catchment areas for rainwater and sufficient space to store it
- reduce the amount of waste sent to landfill by designing to standard sizes and considering materials that have been used before
- harness energy from the sun for generation of electricity or heating of water by providing adequately oriented and pitched roof space.
Creative thinking can open up infinite possibilities of what can be done. Sustainable design can achieve synergies between the project’s form, its function, the natural resources in the surroundings, and the different elements of the building. For example, to achieve some level of independence from the national grid, design should consider the optimal orientation and roof pitch to allow for photovoltaic (PV) solar panels to be installed, and this will be done ideally in a way that seems effortless and blends in with the rest of the house.
The initial stages of design can be the most cost-effective for incorporating strategies that will improve the performance of your home and allow you to achieve your objectives. Good design doesn’t necessarily cost more; it understands the surrounding environment and how to make the most of existing resources. The ‘Concept and
Preliminary Design’ section of our residential design process expands on design considerations when developing your project. As the project moves forward, testing your design will allow you to verify that your sustainability objectives and targets are being met. Thermal models of your house will allow you to estimate internal temperatures and energy usage. Targets around water can also be tested with specialised tools.
4. Use systems and products to optimise the design
As the design progresses, the impact and performance of your home can be enhanced by the systems that go into it. Selecting the right ones to use should be dictated by your objectives, and your decision making should advance holistically, taking into account how systems interact with each other. For example, surplus energy generated by PV panels can be used to heat up the hot water cylinder, rather than exporting it to an electricity retailer who may only pay a low rate for it.
There is a perception that systems with higher performance are more expensive, but sometimes a careful evaluation of the options will reveal that more sustainable alternatives are available without any extra costs, or that a larger initial investment can be recouped via reduced operating costs. Such is the case with heating systems, for example. Although a plug-in heater may seem like an economic solution, its electricity use can be up to three times higher than that of a heat pump. Provisioning for the installation of a heat pump early can result in a lower long-term cost for heating.
The fittings and materials in your home also have an impact on its performance and the outcomes you experience. An efficient showerhead, for example, has the potential to reduce both your water use and – because it reduces your use of hot water – the energy required for water heating. And if the impact of the materials you use is important to you, it will be important to consider their lifecycle impact – impacts in their manufacture, use and disposal. For example, when choosing insulation, there are products made from recycled content that are fully recyclable at the end of their lives. These two ways of considering what goes in your home are detailed in the
6. Use your home intelligently
Achieving your sustainability objectives can involve making small changes in how you use your home, such as:
- turning off the lights and appliances when leaving a room
- using the dishwasher and washing machine only when they are full
- setting the thermostat in your hot water cylinder to 60°C.
- composting your food scraps
- adding mulch to your garden to reduce evaporation and therefore the amount of water your plants will need.
These changes to your behaviour will help your house operate more efficiently and could be essential to achieving your objectives over time. See the Ministry for the Environment’s ‘25 Easy Steps towards Sustainability’ for more ideas.