Water heaters are heating appliances used for heating water, in either a business or domestic context. Choosing the right kind of water heater can be extremely important, as the cost of hot water is one of the largest contributors to the size of household bills. The ideal water heater will strike a balance between cost, output and energy efficiency. To this end, numerous variations of water heater are available. Hot waters heaters differ in regards to their fuel type, size and energy-efficiency.
Gas Water Heaters
The most commonly seen kind of water heater is the conventional water storage heater. This type of water heater is fuelled by either gas (natural gas, propane or fuel oil) or electricity. In the case of a standard gas water heater, a gas burner sits beneath a reservoir of water. This gas burner heats the water in the storage tank depending on the settings on the mounted thermostat. If the water in the tank is too cold, the gas burner is triggered and the water is heated. This water is then released from the tank when a hot water tap is turned elsewhere in the building.
Electric Water Heaters
Gas water heaters of this kind are similar to electric water heaters, which use electric elements instead of a gas burner to heat the water. Whether a gas water heater or electric water heater, the system is not as energy-efficient as other options due to the fact that water is heated even when hot water is not needed.
Solar Water Heaters
Other kinds of hot water heater are available that are more energy-efficient, such as solar water heaters. A solar water heater is different from a gas water heater of electric water heater in that it uses energy from the Sun to generate heat. Cold water is pumped from an internal tank through an array of solar collectors, which will have been heated by the sun. This process heats the water, which is then stored in a tank until it is required. The lid of the storage tank is closed when the Sun goes down, minimising heat loss.
Instantaneous Water Heater
A further variation of water heater that is even more energy efficient is the instantaneous water heater. Instant hot water heaters are designed to only heat water when it is needed, rather than storing it in a tank. When the hot tap is turned on, water is pumped through an electric or gas-powered heating system which heats the water directly. This type of water heater must be fitted close to the tap from where the hot water is desired. Under sink water heaters therefore generally fall into this category of water heater. They are often employed in outside bathrooms or hot tubs, and can be useful if the existing water heater system does not allow more than one appliance to be used simultaneously, such as the sink and the shower.
Portable Water Heater
A second variety of tank-less water heater is the portable water heater. This kind of heater is small and is generally suitable for outdoor locations, possessing its own water container and variable controls. They are generally propane powered and can be charged up as they are needed.