The tankless water heater was originally introduced in the United States approximately 15 years ago by the Japanese company Takagi. Since then, on-demand systems have become the most advanced heating units in the world, and manufacturers like Rheem, Eternal and other major brands have followed suit in delivering hot showers and baths to American homes the environmentally friendly way.
While traditional boiler systems continually draw energy to maintain desirable water temperatures to ensure there is a supply ready when needed, demand type systems deliver as the name indicates: on demand – and only then. This means that instead of wasting energy virtually 24 hours a day on maintaining a reservoir, on-demand systems lie dormant until the moment the “hot” tap is turned on at the sink.
Because of this lack of continuous use of energy, the tankless water heater is generally more energy efficient than traditional storage systems and have the added advantage of saving homeowners money with reduced energy bills. According to the Department of Energy, the average household can see a reduction of approximately 30 percent in related heating expenses, and more than $100 in savings in overall energy costs annually by using on-demand systems. The federal government also offers tax credits and rebates on qualifying EnergyStar rated units.
Although the acquisition cost of a demand type unit is generally higher than that of a traditional storage system, energy efficiency and reduced operating costs quickly offset the purchase price. On-demand systems usually outlive boilers, which have an estimated life span of 10-15 years. With proper maintenance, demand units can last as long as 20 years and more, with easily replaceable parts that can extend the systems life expectancy even further.
In addition, while boilers only contain limited amounts of supply, often making simultaneous or back-to-back showers impossible, or at least frustratingly cool and uncomfortable, a tankless water heater can deliver an unlimited amount of hot water for average use because there is no storage unit to be drained. For large families or excessive simultaneous use, however, the installation of multiple inter-connected units is recommended. Separate units can also be installed for high-demand appliances such as Jacuzzi tubs, washing machines or dishwashers.
A tankless water heater works by drawing cold fluid into the unit through a pipe, then warming it through either a gas burner or an electric element. There is no wait time for output, and most units produce 2-5 gallons per minute. Gas-operated units typically deliver higher flow rates than their electric counterparts. Solar energy can also be utilized to operate on-demand systems and, vice versa, on-demand units can also function as a booster to solar domestic hot water systems.
Several considerations are important in the selection of the optimal on-demand system, including energy source and fuel availability, flow preferences, demand, square footage and the location of bathrooms and appliances. The advice from professional installers and a careful review of manufacturers’ specifications will be helpful in choosing the right unit.
On-demand units are available for just about any budget. The purchase price of a tankless water heater starts as low as $150 and can reach as high as $3,500 for top models. They are a great example of energy savings strategies. Installation by a qualified plumbing and heating contractor is highly recommended. Prospective buyers are encouraged to check references and insist on cost estimates in writing when selecting an installation professional.