The average household uses 64 gallons of water each day. According to the U.S. Energy Information Administration, with water heating the second largest household consumer of energy.
A good solution being adopted by many homeowners is a tankless water heater (also known as a demand or instantaneous water heater), which saves on space and energy.
Tankless water heaters provide hot water only when it is required. They do not include a storage tank, which uses energy continuously to heat the water even when it’s not being used. That means you’re not wasting energy heating water when you don’t need it.
Here’s how a tankless water heater works: When a hot water faucet is turned on, cold water is carried through pipes and circulated through a series of coils called a heat exchanger. The water is directly heated by an electric element or a gas burner that heats the water only as long as there is demand.
Gas-fired on-demand water heaters produce higher flow rates than the electric ones. Residential gas tankless water heaters have energy outputs from 120,000 BTU to a high of 199,000 BTU. Stiebel Eltron’ says their largest residential electric tankless water heater is 125,000 BTU. The downside to this is that high BTU output gas tankless water heaters are physically larger than electric tankless, plus they require big (and expensive) gas supply lines, and may require more expensive venting. The tankless unit turns off once the hot water faucet is turned off.
Tankless units typically provide hot water at a rate of two to five gallons per minute, depending on the model and the temperature of the groundwater. If demand for hot water will be required simultaneously for several different uses, such as multiple showerheads, dishwashers, and washing machines, two or more units may be required. Some units provide enough hot water only for a tub or washing machine at one time; others can supply enough for multiple simultaneous needs. Tankless water heaters generally cost more than a typical 40-gallon water heater, but usually have longer warranties, last longer (20 years compared to 10-15 years for tank water heaters), and allow the homeowner to save money on energy. According to energy.gov, “For homes that use 41 gallons or less of hot water daily, demand water heaters can be 24% to 34% more energy efficient than conventional storage tank water heaters.” Energy savings vary depending on the efficiency rating of the unit and the cost of energy in the area.
Many of the companies that produce these heaters have special features available in some of their models. Stiebel Eltron (electric units)has a patent on their Advanced Flow Control™, which automatically slightly reduces flow when demand is high. Some of Rheem’s (gas and electric units)Prestige models have EcoNet® Smart Technology available which provides Wi-Fi connectivity and added features that offer system protection, control and monetary savings. Users can download the EcoNet App at the App Store or Google Play, as well as sync to Nest® and Wink® systems for a fully integrated smart home. EcoSmart tankless electric water heaters have proprietary self-modulating technology, which insures that only the energy needed for each water-heating instance is used. This capability is important in that it makes their water heaters safe in as much as the water will never be too hot or too cold. When considering purchasing a water heater the homeowner needs to consider the size of the heater that will be required, installation costs, the type of fuel (gas, electric or propane) and the actual size and bulkiness of the heater itself. The other issues are the flow rate of the unit and the noise level it might make.
Rinnai (natural gas and propane) offers Amazon Alexa integration with its products allowing users to ask Alexa to start circulation or tell Alexa they want to take a shower, and the tankless water heater will spring into action. They also integrate with Google Home allowing users to control their tankless unit’s temperature as well as recirculation. They can tell the unit to set temperature to 1a particular degree or just that they need hot water. The Control-R™ 2.0 mobile app with smart home integration features more than 20 available voice commands to activate the recirculation system, select a favorite temperature and has built-in timers and schedules allowing for multiple on/off recirculation periods throughout the day.
For additional information about tankless water heaters, visit the Department of Energy’s Efficiency and Renewable Energy website .