There are two types of Hot Water Systems: 1) storage systems and 2) continuous flow (instantaneous) systems.
Storage systems heat the water in a tank, which is then available for use throughout the day. Storage tanks are used on most electric, gas, solar and heat pump hot water systems.
The tanks are insulated to reduce the heat loss over time and to reduce the consumption of energy needed to continually reheat the water.
There are both mild steel and stainless steel tank options available. The stainless steel tanks are more expensive to buy, however they last longer and typically don’t require as much maintenance.
Storage systems are more economical when they are run on solar energy, natural gas or off-peak electricity (where available).
Capacity of the system does not need to equal the volume of hot water consumed each day. (See System Sizes)
Also known as an “Instantaneous System”, this system heats the water as it is required, therefore eliminating the need for a storage tank. The benefit of these systems is that the house will never run out of hot water.
This can be beneficial if you consume a lot of water or have a large family or large number of people drawing off the same system.
These systems are typically cheaper to run as they don’t have to continually keep the water heated and don’t suffer the heat loss associated with storage.
Most continuous flow systems run off of gas, however there are electric versions available.
The size (or flow rate) that you would require, depends on the amount of hot water outlets that you have in the home and how many of them that would be used at one time. Your local supplier will be able to help you work out what size system you need.
For an average two-bathroom home, the size required will be in the vicinity of 24 L/min.