The energy outcomes you achieve in your home will be influenced at many stages during your project, and will require input from designers, builders and suppliers of systems as the project evolves.
Key stages and methods for incorporating energy in your project are listed below. Your priorities and objectives around energy, and the amount of certainty you want to have in achieving those objectives, will help determine which you use.
1. Define your priorities and set objectives
Your energy objectives should be included in the design brief as early as possible and then regularly checked throughout the design process so they are not forgotten along the way. Embedding them in the core of the project right from the beginning can result in a more integrated and cost-effective outcome.
2. Estimate your energy use
An energy profile of your house is a detailed breakdown of the systems and appliances that use energy. It analyses how much they use and how often they are used to estimate annual energy consumption and its dollar value.
A baseline energy profile can be created early in the design process, incorporating a set of assumptions. As the design evolves the profile and assumptions can be regularly refined, with the end result being a detailed energy budget for the home to help select the right systems and appliances to meet your objectives.
3. Decide if a rating tool or certification is right for you
If you’ve decided to use a rating tool, its objectives and strategies will also need to be incorporated early in the design process, as it could dictate the way the design is approached. Some tools will provide specific guidance on the aspects required to meet objectives, others will set targets and it will be up to you and your design team to find the best way to meet them.
In addition to reducing your energy use, it is likely that achieving your energy targets will require consideration of the quality of the building envelope and passive design. How far you go will depend on the stringency of the objectives and targets set by the tool you select.
4. Prioritise and test design
Finding ways to make the most of the surrounding environment will be cost-effective and will have a great impact on future energy use. Passive solar is a key element of good design. As part of their training, architects and some architectural designers are familiar with the principles of passive solar. If energy efficiency is sought, engaging a professional with experience on passive solar design is key. Passive solar strategies such as including eaves and shading devices on the north, east and west, narrower building shapes, and increased thermal mass can have a significant impact on a project’s energy use, especially with regard to the energy required for heating and cooling.
The passive performance of your project can be verified using energy modelling. A good energy model simulates the house’s performance and can inform decision making from the early design stages, helping identify:
- the effect different design options will have on the energy required to heat or cool your home to achieve desired temperature ranges.
- the effect of different options for placing or orientating your home on the site by showing how shading from surrounding buildings, contours, vegetation and self-shading will affect passive solar heating and summer overheating.
- the effect different glazing and insulation options will have on letting heat into your home and retaining it.
5. Use systems and products to optimise the design
Understanding your expected energy use through energy profiling and modelling allows you to optimise the design and then select the systems and products that will help achieve your objectives for energy performance. They should be considered together, as they will all contribute to your home’s overall energy use.
Energy efficiency can be achieved through small improvements such as selecting efficient lighting and appliances and larger gains by choosing efficient systems for ventilation, space and water heating. The effort taken to understand your expected energy use will pay dividends here, as it will help in selecting systems of the right size, ensuring you don’t over-invest.
When evaluating options it is important to consider not only the initial investment but also their long-term cost (see the Lifecycle Costs article for more detail). Some systems will also have design implications. For example, when using PV panels, the correct area, pitch and orientation will need to be considered within the project’s roof space.
Some objectives may also require systems that generate energy. PV panels are currently the most popular form of self-generation, and the cost of a solar power system has fallen dramatically in recent years. There are other systems to consider such as small wind turbines and micro-hydro systems. Your ability to use any of these systems will depend on the natural resources available on site, including access to sunlight for solar energy.
Systems and products to discuss with your architect or designer include:
- Lighting
- Appliances and whiteware
- Water pumping
- Ventilation
- Heating and cooling
- Energy generation
6. Build well
In addition to the quality of the design and selection of the right products and systems, the quality of your home’s construction will also affect the performance of the building. Testing systems during construction will ensure they perform to the standards they were designed to, and prevent them from becoming an obstacle to achieving objectives.
Ensuring that elements such as wall insulation are properly installed will also contribute to achieving energy objectives as heat loss will be minimised, reducing the energy required to heat the house and keep it warm.
7. Use your home intelligently
How you live in your house will also play an important role in achieving objectives and keeping energy usage at estimated levels. An energy-efficient home can still waste energy if the occupants don’t pay attention to the energy they use. Simple actions will have big impacts in the long run, for example:
- turning off appliances at the wall
- turning heated towel rails off during the day
- turning heat pumps or gas fires on only when you are in the room
- choosing to dry your clothes outside instead of using a dryer.
The following section describes the options available for understanding both how your home is performing and the impact your behaviour is having on its performance.