Considerations

When buying a hot water system, it is important that you choose one that fits your needs.  Do not focus solely on the purchase price – also consider how much it will cost to run over its total lifetime.  If possible, look for an energy efficient system.  Also look at things such as how easy the system will be to install, how easy it is to run and maintain, and what kind of warranty is offered.

It is a good idea to ensure that the system is located as close as possible to all of the major areas in the home to use hot water – the bathroom, the kitchen and the laundry.  If you cannot find a suitable central location, then install as closely to the kitchen as possible.  This will help to minimize the lengths of pipe, keeping the cost of installation lower and preventing heat loss from the pipes.  It will also help to reduce the amount of time that you have to wait for hot water to come through from the taps, minimizing water wastage.  Finally, make sure that the hot water system is sheltered in order to prevent heat loss from the tank itself.

Types of Hot Water Systems

The two main types of hot water systems that are available are storage water heaters and continuous flow (or instantaneous) water heaters.  Both of these systems are suitable for the average household.  Storage water heaters heat the water, which is then stored in an insulated tank for use throughout the day.  They are most economical when run on solar energy, natural gas, or off-peak electricity.  However, you can also run them on LPG, peak electricity and solid fuels.  If you have a mains pressure system, the hot water will come through at the same pressure as the cold water does, meaning that more than one hot water tap can be turned on at the same time without any loss of pressure.  Constant pressure systems deliver the hot water at a lower pressure than mains pressure systems and are normally located in the roof space of a home.  The amount of pressure depends on the vertical height between the tank and the point of use.

Continuous flow or instantaneous water heaters heat the water, as it required, removing the necessity for a storage tank.  This also means that it is impossible to run out of hot water.  Because they are significantly smaller than storage water heaters, they can be installed internally or externally on a wall or in a cupboard.  These heaters are connected to the mains water supply and deliver heated water at a slightly reduced pressure than cold water.  Adequate amounts of hot water can be delivered to one or two points within the home at one time and some units have electronic controls to deliver precise temperature control.  However, it is vital that these hot water systems are correctly sized according to how they will be used.  Continuous flow heaters operate the most economically on natural gas but they can also use LPG or general tariff electricity.