Hot water systems in [state]

Hot water is important, for the comfort and convenience we've come to expect and also from an energy standpoint. Heating water can account for 15% or more of a household's total energy budget. It's good to know some basic information about hot water systems, because you don't want to keep using a hot water system that's inefficient or ready to fail. Here are some important details about different types of hot water systems.

Tank-type water heaters are most common. A tank-type water heater utilizes natural gas, propane, electricity or fuel oil to heat water. Today's ENERGY STAR®-rated tank-type water heaters come with tank insulation to reduce standby heat loss as the water in the tank "waits" to get used. When water temperature inside the tank drops to 115degrees (F) or so, the heating element will turn on automatically to bring the water back up to the right temperature. This heating cycle repeats whether you are using hot water or not.

Heat pump water heaters can be super-efficient. Some heat pump HVAC systems are designed to heat water for washing while also providing whole-house heating and air conditioning. Another type of heat pump water heater utilizes a compact air-source heat pump on top of the water tank to heat the water. In both cases, this type of hot water system is super-efficient compared to tank-type water heaters that rely on gas, oil or electric resistance heat.

Tankless water heaters save energy by eliminating standby losses. True to its name, a tankless water heater has no ability to store hot water in an insulated tank. Instead, water is heated as it passes through a heat exchanger. Most residential tankless water heaters use natural gas or propane as the heat source. Because gas is consumed only when a hot water tap is turned on, tankless water heaters can be less expensive to operate than tank-type water heaters. However, they can be twice as expensive as a tank-type water heater to install, so it will take time for this hot water system to pay for itself in energy savings.

Indirect water heaters are efficient in wintertime. An indirect water heater relies on your whole-house heating system to heat the water you use for washing. In the winter, when your heating system is operating to keep the house warm, an indirect water heating system provides domestic hot water for free. But this energy savings is lost during hot weather, when the heating system has to operate in order to heat water. Indirect water heating systems make more economic sense in cold climates.

A solar hot water system can cut water heating costs by 80%. If your house or your property has good solar exposure, you may want to consider a "solar thermal" system that relies on a renewable resource (the sun) to heat your water. Solar hot water systems have been used in the U.S. for over a century, so this technology is well-established. Water or an antifreeze solution is heated in a solar collector that can be mounted on the ground or on the roof of a building. Hot water is stored in an insulated tank that has a backup heat source that's used when solar energy isn't available. In best-case scenarios, solar thermal systems have been able to reduce water-heating expenses by 80%.