Tank Vs. Tankless Water Heater

Water heater is used for warming water for household purposes. It is one of the basic appliances installed in every home. Since heating water contributes to maximum electricity consumption, it is always better to analyze the energy efficiency and size, while installing a new water heater. Speaking about the energy efficient water heaters, the fuel and type of water heater are taken into consideration.

The performance of water heaters varies even with the same fuel type. For example, electric pump water heaters are more efficient in comparison to the traditional electric storage water heaters. In general, there are two types of water heaters based on the configuration, namely, tank water heaters and tankless ones. Let's take a look at the differences between the two.

In a tank or storage water heater, the heating system is installed in a special insulated tank. Cold water is supplied to the tank through an inlet pipe and is heated according to the set temperature. The heated water is stored in the same tank until it is withdrawn. In case of a tankless water heater, there is no storage of hot water. The cold water is heated directly after passing heating coils installed in the unit.

Regarding energy efficiency, tank water heater consumes more electricity to operate than the tankless type. As hot water is heated and stored constantly in the tank water heater, energy consumption is high. In tank water heater, cold water is supplied in the tank as soon as hot water is drawn off. Thus, the reservoir is always full with hot water, even if it is not required. This way energy is wasted in a tank water heater, which is called standby heat loss.

As the amount of hot water availability in a tank water heater depends on the size of the reservoir, there are chances of insufficient or excess hot water. Whereas in a tankless heater, hot water can be withdrawn constantly. Since hot water is supplied on the demand basis, tankless type is also referred to as demand or instant water heater.

Tank water heaters are available with fuel types - electric, natural gas and liquid propane. As compared to electric tank model, gas and liquid propane heaters are more energy efficient. The primary fuel types used in case of tankless water heater are electric and natural gas.

While purchasing a tank water heater, the size of the tank is the major criteria for selection. A smaller size tank water heater may not be sufficient to provide the required hot water, while an extra large size may result in energy wastage. Hence, depending upon the hot water requirement and family size, correct size tank water should be installed. Since there is no storage tank in tankless water heater, size is not an issue while selecting the tankless type.

One word of advice for tank water heater is to insulate the tank properly so as to reduce standby heat loss and chances of corrosion and rust. Otherwise continuous water storage lead to corrosion of the tank and lowers the lifespan of water heater. In tankless water heater, sediment filter in the water inlet pipe and regular flushing of the heat exchanger are necessary to prevent cracking.