How do twin and single element water heaters differ?
BOTH single and twin element water heaters have the same recovery capability as they use the same sized elements. Normally, both elements do not operate together. The difference is in the Automatic Recovery of a Twin. A Single Element Water Heater will have a boost button at the meterboard, often incorporated into electronic meters. Twin Element water heaters have a top element with a thermostat setting which is set 10 – 15 degrees lower than the bottom element thermostat. Because hotter water floats on top of cooler water, the top element will not energise until the water temperature at the top thermostat has dropped substantially. This will only be as a result of high levels of hot water use because the top thermostat is located within the top 50 Litres of the heater. No boost button is required as the boost is Automatic. The top thermostat will switch off the top element allowing the bottom element to heat at the Off-Peak Tariff.
