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About hot water
An average household can use around 25% 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.
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.
Hot water systems can use a variety of energy sources to heat water:
- solar energy
- natural gas or LPG (liquefied petroleum gas)
- wood or coal.
It's important to note that there are two types of electric hot water systems: the modern energy-efficient heat pump systems and the traditional element-based systems.
If you’re building or renovating, check with your builder, supplier or local council about requirements for hot water systems. Minimum energy performance standards apply to some water heaters and other household appliances.
The best type of hot water system for your home will depend on your situation.
- the number of people in your home, how much hot water you use and how you use it
- existing energy sources—for example, availability of natural gas in your area or 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’re 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.
By installing a low-emission water heater, your household will save energy, reduce greenhouse gas emissions and may be financially better off over the life of the system. You might be eligible for rebates or other assistance to help with the cost of installing a new hot water system.
A number of low-emission alternatives to electric water heaters are available. You can choose from options including:
Around 50% 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 and are generally less efficient and more expensive to run. However, there may be some situations, such as having limited space, where conventional electric hot water systems may be suitable.
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% 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, system 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. For example, heat pumps work best in warm climates.
- 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. 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.
Hot water systems can fail suddenly, leaving you without hot water and with 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.
If you install a solar 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 solar or heat pump hot water system.
Electricity tariffs (charges) will have an impact 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 (see heading titled 'Avoiding the peak: stop your bills climbing') 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 system.
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, which is generally at night.
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.
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Did you know?
About 30% of the energy used to heat water in a storage system is wasted due to heat loss from the tank and associated pipe work.
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