Can be gas or electric powered. The heater is a large steel tank that always keeps the water stored at a certain temperature, usually 65 degress, by a thermostat. It provides full mains pressure and will deliver hot water to the tap faster than all other heaters. Recommend servicing every 5 years to check/replace the anode & relief valves. The storage heaters are often large in size and will require adequate space if installed down side of house or internally.

Average life expectancy is 10-14 years for gas & 8-12 years for electric.

These heaters are common in units or smaller houses. They are smaller in size than the storage heater and are installed up on the wall. They only deliver low water pressure, approx 10 litres per minute. They require servicing every 5 years.

Average life expectancy 20-25 years.

These heaters have grown in popularity over last 10 years. They are slightly smaller than the instantaneous heaters & are fixed up on the wall. They require a power point for ignition. Depending on model they can provide mains pressure and can deliver hot water reasonably fast to the tap. They do require a specific sized gas supply pipe so are not often suitable for emergency replacements. Good for installing down the side of house as are small in size. Can be expensive to repair once they reach the 8-10 year mark.

Average life expectancy 10-20 years.

Relatively new on the market. These heaters are similar in size and shape to storage tank, (slightly bigger). They only require an electrical supply and have very low running costs, similar to that of refrigerator. They provide full mains pressure and maintain a stored tank of water at a certain temperature (60 degrees) with a thermostat. Will need servicing every 5 years to check/replace the anode & relief valves. Initial purchase price is high compared to other heaters.

Average life expectancy 8-12 years.

Solar heater depending on whether electric or gas boosted will deliver near mains pressure hot water. Cheaper running costs but higher installation costs than all other other heaters.

Average life expectancy 20 years.

These heaters are common in multi level units and office blocks where gas is not available. Most require a 3 phase power supply. Pressure is low, often 10 litres a minute. These heaters are very small and can fit under a cupboard but have a high breakdown rate and often need repairs every few years or so.

Average life expectancy depending on brand, 5-15 years.