Enter your details and we’ll send the guide right to your inbox!
Page 5 of 9
Heating water consumes the second greatest amount of energy in the average household (after heating and cooling). Understanding your water consumption habits is therefore a key component of any energy-saving strategy. Knowing what the right system for your home is can greatly reduce your energy consumption, and minimise water wastage.
The most effective measure you can take to curb your home’s need for water heating is to use less hot water! Ultimately, the less water your system must heat up, the less energy your water heater consumes. There are various concrete measures you can take to help reduce your hot water consumption.
Check your shower
Is your hot water system healthy and efficient?
Normally, homeowners only upgrade their water heating system after their old one breaks down. Plan for the future so when the time comes to get a new system, you know the type that is most appropriate for you.
Understanding the different types of water heating will allow you to be smarter about your energy efficiency. Choose the right system based on:
Continuous flow systems heat up water as it flows in, meaning they are not affected by the heat loss from the storage of hot water. These systems use electricity or gas to heat up water as it passes through the pipe, so you can’t run out of hot water unless the source of electricity or gas is cut off.
The unit itself is small and discrete compared to storage systems. Depending on the number of the hot water outlets in the home, you will need to get the appropriately sized system;, otherwise you might not have sufficient hot water.
Older systems take a couple of seconds before the hot water reaches the outlet, but newer systems have designs that allow water to come out instantly hot. Some systems also allow you to set the water temperature so it doesn’t require dilution with cold water due to being overheated - nor does it come out too cold.
Storage systems come in the form of a unit and a storage tank. The unit heats up the water and stores it until it needs to be used. These systems suffer from standby heat loss, but can readily provide hot water and meet greater demand when needed.
Keep in mind that tanks need consistent maintenance, as they can suffer from corrosion and ‘scaling’, which is the build-up of mineral deposits from water with high mineral content.
Electric vs Gas Systems
Compared to continuous systems, storage systems using gas or electricity consume more energy, as they must continuously reheat the water after the heat is lost from the tank.This translates into more operational costs down the track. This can be minimized with better insulated tanks and pipes, and more efficient systems.
Electric systems take around 1 to 2 hours to heat up hot water, depending on the system. Gas systems take about half this time. Electric systems may be subject to different electricity rates. Some electricity retailers offer cheaper rates if they are able to control when the system will turn on. This usually means that your tank will be set to run during the night, when there is less stress on the grid. These ‘off-peak’ systems generally require larger tanks, as the hot water has to last through the whole day.
Heat pumps work in the same way as a refrigerator, but in the opposite direction, so that heat is extracted from the air and put back inside. The system comes with a compressor unit and a tank, but these can usually be combined; they also often have a booster systems in case the temperature is too cold or demand is high.
These systems are very efficient when compared to electrical/gas storage systems, but require an ideal climate and well-ventilated spot. Heat pumps don’t generally work well in cold regions, instead running best in moderate climates. They can also be situated near compressors of air conditioners to make use of the warm air being expelled out of the home.
This system is a good alternative when solar isn’t suitable for your house, and the only energy source available is electricity.
Solar thermal hot water comes with the solar unit and a booster element. Water is heated using solar energy during the day and hot water is maintained by the element during periods of less sunshine, or when the water temperature is not quite warm enough. The system runs better in sunny locations, and may not operate effectively or at all in some colder and less sunny climates. A well-run system will pay for itself over the long run, as running costs are comparatively low, despite the more expensive upfront cost.
Heating water with solar PV
Solar PV systems can be retrofitted or installed new with a device called a hot water diverter, which effectively channels ‘excess’ solar electricity (i.e. solar output in excess of household demand) into the element of a hot water tank. In doing so, a hot water diverter can improve the returns on not only the hot water system but also the solar PV system. Sophisticated diverter units (or regular hot water units coupled with a smart energy management system) may also be capable of taking advantage of cheaper, off-peak or controlled load rates in addition to solar energy.
In the next chapter, learn about reducing energy consumption in other aspects of your household.Back to Contents