An average household can use around a quarter of its total energy on heating water, so it’s important to use an efficient system that suits your needs. Reducing the amount of hot water you use and using a more efficient hot water system are great ways to reduce your energy costs and your impact on the environment.
Types of hot water systems
There are two basic types of hot water systems:
- Storage water heaters heat and store water in an insulated tank for use when it's needed.
- Instantaneous systems (or continuous flow systems) only heat water when it’s needed and don’t use a storage tank.
Energy used for hot water systems
Hot water systems can use a variety of energy sources to heat water:
- solar energy
- natural gas or LPG (liquefied petroleum gas)
- electricity
- wood or coal.
There are two different types of electric hot water systems: the modern energy efficient heat pump systems and the traditional element-based systems which are being phased out from 2010.
If you are building or renovating, check with your builder, supplier or local council about requirements for hot water systems. Minimum energy performance standards apply to hot water heaters and other household appliances.
Choosing a hot water system
The best type of hot water system for your home will depend on your situation. Think about:
- the number of people in your home, how much hot water you use and how you use it
- existing energy sources - for example, is natural gas available in your area or is there good sunshine for a solar system?
- your climate
- how much space and access you have to locate a system
- your budget along with the purchase and operating costs of the systems
- your existing system.
When you are comparing different systems and costs, take into consideration the long term savings you could make on energy bills with a more efficient hot water system. Do some research and talk to suppliers or installers for advice on which system would be best for you. Also consider the warranty offered.
You might be eligible for rebates or other assistance to help with the cost of installing a new hot water system.
Different types of hot water systems include:
Getting the most out of a hot water system
Before you select and install a new hot water system, it makes sense to see if you can reduce your water usage. If you can find ways to save water, you could save money by buying a smaller system than you would have otherwise needed.
The way a hot water system is designed and installed can have a significant impact on its efficiency. About 30 per cent of the energy used to heat water in a storage system is wasted due to heat loss from the tank and associated pipe work. Speak to your installer, designer or builder to make sure you get the best result.
- Estimate your hot water needs accurately to make sure your system is the right size for your household. If storage tanks are too small for the number of people in the house, hot water can run out. If the tank is too large, operating costs will be higher.
- Choose the right system for your needs and climate.
- Position is important. For example, positioning your solar system to face north and avoiding shade will help it to operate at peak performance. Electric heat pump systems are best placed in a warm, ventilated location to operate effectively.
- Protect hot water systems from outside temperatures when necessary. For example, in cold and temperate climates solar hot water systems are likely to need protection from frost. Insulate hot water pipes, including plastic pipes. This is known as ‘lagging’.
- Keep hot water pipes as short as possible to minimise heat loss. In new or renovated homes locate wet areas like bathrooms and laundries close together if possible.
Plan ahead
Hot water systems can fail suddenly leaving you without hot water and the need to make a decision quickly about a replacement. By planning ahead you can avoid installing a system that’s not right for your needs just because you need hot water in a hurry.
- If you have an older storage system, say more than five years old, have the tank inspected so necessary replacements can be anticipated. Hot water systems may last much longer than this but it’s good to be prepared.
- You can do some research on hot water systems in advance. If you need to make a decision quickly, this will make the process quicker and easier and help make sure you get the best system for your needs.
Once traditional element-based electric hot water systems are phased out, your range of choices for a replacement system will be different.
Small-scale Technology Certificates (STCs)
If you install a solar hot water or heat pump hot water system at home, you could be eligible to receive renewable power incentives in the form of Small-scale Technology Certificates (STCs). An STC is a measure of renewable energy which can be traded for cash or a discount on the purchase price of a hot water system.
Phasing out of hot water systems
Around half of Australian households currently use conventional electric hot water systems to heat water in their homes. These water heaters produce at least 3 times the greenhouse gases of low emission alternatives.
The Australian Government is working with the state and territory governments to phase out these systems across the country (except in Tasmania). Restrictions are currently in place for new detached, terraced and town houses across the country and for some existing houses in South Australia and Queensland. The phase-out will extend to all houses during 2012. For more details see Phase-out of greenhouse intensive hot water systems.
The phase-out also includes off-peak electric water heaters as they use the same amount of energy and have equally high greenhouse gas emissions as peak or day rate electric hot water systems. In fact, many off-peak systems are less efficient as they tend to be larger to cope with only being heated during the off-peak time period.
This means that if you have one of these electric systems, when you need to replace it you will have to consider other options - solar, heat pump or high efficiency gas. You will not have to purchase a low-emission hot water system until your current one needs to be replaced.
Electricity costs and tariffs
Electricity tariffs (charges) will have an effect on how much you pay for your water heating. It is important to discuss your tariff options with your installer before installation so you understand how different tariffs will affect your running costs and your system’s performance. It’s even more important to find out about tariffs if you have a boosting system for your heat pump or solar hot water service.
If you have an existing electric storage hot water system, switching to an off-peak tariff can save you money on your energy bill. With an off-peak storage hot water system, your water is only heated during the off-peak time period when energy prices are cheaper.
However, it’s important to be aware that off-peak systems don’t use less energy or produce less greenhouse gas emissions just because they’re only heating water during off-peak periods. In fact, many off-peak systems can use more energy overall as they tend to be larger to store hot water for use whenever it’s needed.
Find out more about electricity costs and tariffs (see link under ‘Step three: Take action’) or contact your local electricity provider.
