Energy Efficient Water Heaters

Water heaters are appliances that are used for constant hot water supply. In a water heater, a heating source is used to raise the temperature of normal water. Since hot water is needed for many domestic activities, water heating is the most energy consuming activity in every house. Keeping this in mind, one needs to take proper care while installing a water heater.

Some Energy Efficient Water Heaters

Based on the technology used, there are many varieties of energy efficient water heaters. These water heaters consume 10-50 percent less energy than the standard old models. Some of the popularly opted high efficiency water heaters available in the market are mentioned below.

Conventional Storage Water Heaters
Storage water heaters are popular water heaters, in which hot water is stored in reservoirs or tanks. The amount of hot water stored depends on the size of the reservoir. However, it is usual that a tank holds more than 20 gallons of hot water. Sources of fuel in a storage water heater include electricity, oil, propane and natural gas.

In a storage water heater, a gas burner under the tank heats the water that comes in from the cold water inlet pipe. There is a hot water tap on the top of the tank for releasing hot water. As soon as hot water is released, cold water enters the tank and hence, the tank is always full. One major disadvantage of storage tanks is waste of energy, as water is continuously heated even though it may not be used frequently. This loss of energy is also known as standby heat loss. One can opt for heavily insulated reservoirs, in order to reduce standby heat loss.

Tankless Water Heaters
As the name suggests, tankless water heaters don't have reservoirs to store hot water, instead these systems function on demand basis. Hence, tankless water heaters are also known as demand water heaters. Under these systems, there are two types based on the fuel usage, namely, gas-powered and electric.

In tankless water heaters, cold water passes through a heating unit (gas burner or electric system) and water is heated instantly. As hot water is released, cold water travels to the unit via pipes, thus tankless water heaters have the advantage of constant hot water supply. Since water is not stored, chances of rust and corrosion are minimized and ultimately, they have a longer lifespan than the storage heaters. Another advantage of tankless water heaters is that there is no standby water loss, thus saving energy to about 15 percent.

Heat Pump Water Heaters
Heat pump water heaters are more common in warm climate areas. In heat pump water heaters, electricity is used to transfer heat from one place to another, instead of directly heating the water. This way, energy from the surrounding air is transferred to heat the water stored in tanks. There are certain conditions for efficient use of heat pump water heaters. They should be installed in locations, where the temperature is between 40 ºF - 90 ºF, and also enough space (at least 1000 cubic feet) should be maintained around the heater. Since, heat pump water heaters do not operate efficiently in cold climate, many people don't prefer them.

Solar Water Heaters
Solar water heaters, also known as solar domestic hot water systems, are the most efficient water heaters available in the market. One can use a solar water heater, irrespective of the climate. In solar water heaters, there are solar collectors for heating water. The heated water is then stored in storage tanks. Since, sunlight is used as fuel in solar water heaters, they are more cost-effective as compared to other water heaters. However, the benefits and feasibility of using solar water heaters depend on the location, direction of roof and the size of the family.

Though, it is a fact that high efficiency water heaters save energy, the actual amount of saved energy depends on the size of the water heater and fuel options. Among the many options of fuel used in water heaters, natural gas is the most efficient. In case, installing an energy efficient water heater is not possible, one can save energy by taking certain precautions such as conserving hot water, and setting the water heater temperature to a medium level (120°F). Another effective way of saving energy is by insulating the tank and hot water pipe.