Energy Efficient Water Heaters

Energy Efficient Water Heaters
Water heating accounts to about 15 percent of the total household energy use. Let's take a look at some of the popular energy efficient water heaters that help in saving money.
Water heaters are appliances used for constant hot water supply. A heating source is used in these appliances 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 the heater.

Types of Heaters

Based on the technology used, there are many varieties that are considered energy efficient. These consume 10-50 percent less power than the standard old models. Some of them are mentioned below.

Conventional Storage
These are very popular and most widely used. In these, hot water is stored in reservoirs or tanks. The amount of water stored depends on the size of the reservoir. However, usually a tank holds more than 20 gallons of hot water. The source of fuel in these can be electricity, oil, propane, and natural gas.

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 and as soon as it is released, cold water enters the tank and hence, the tank is always full. One major disadvantage of storage tanks is the wastage of electricity, as water is continuously heated even though it may not be used frequently. This is called standby heat loss. One can opt for heavily insulated reservoirs in order to reduce the standby heat loss.

As the name suggests, such heaters don't have reservoirs. These function on demand basis. Hence, they are also known as demand water heaters. There are mainly two types in these based on the fuel usage: gas-powered and electric.

In these, 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. Since water is not stored, the chances of rust and corrosion are minimized, which is why they have a longer lifespan than the conventional storage units. Another advantage is that there is no standby water loss, which helps save approximately 15 percent more electricity.

Heat Pump
These are more common in warm climatic areas. In these, electricity is used to transfer heat from one place to another, instead of directly heating the water. This way, the surrounding air is transferred to heat the water stored in the tank. They should be installed in locations where the temperature is between 40 °F to 90 ºF, and enough space (at least 1000 cubic feet) should be maintained around the units. They do not operate efficiently in cold conditions.

These are also known as solar domestic hot water systems and are the most cost-effective units available in the market. One can use these irrespective of the climate. In these, there are solar collectors for heating water. The heated water is then stored in tanks. These use sunlight as the fuel, which is why they are more cost-effective as compared to others. However, the benefits and feasibility of using them depends on the location, direction of roof, and the size of the family.

It is a fact that high efficiency water heaters save energy, but the actual amount saved depends on the size of the heater and fuel options. Among the many options for fuel, natural gas is the best. In case, installing a power-saving heater is not possible, one can save energy by taking certain precautions such as conserving hot water and setting the temperature to a medium level (120 °F). Another effective way is to insulate the tank and hot water pipe.
Solar Water Heater on the Roof of a House
Electric water heater
Gas-fired boiler
HVAC heating
Storage tanks