How Your Water Heater Works – Part 2: Tankless Water Heaters
Tankless water heaters are an interesting alternative to the traditional storage tank water heaters we discussed in our last blog post. Also known as instantaneous or on-demand water heaters, tankless systems heat water as you need it, rather than storing hot water for later use.
The first question many people ask is whether a tankless water heater can keep up with heavy demand, such as someone taking a shower while the dishwasher is running. Tankless water heaters come in different capacities, and a larger system can heat more water at once than a smaller system can. Beyond that, a gas-fired tankless system generally has an adjustable flame, and the flame size increases in response to a surge in hot water demand.
Energy Star explains how the tankless system works: “When a hot water tap is turned on in the home, cold water is drawn into the water heater. A flow sensor activates the gas burner, which warms the heat exchanger. Incoming cold water encircles the heat exchanger and leaves the heater at its set-point temperature. Combustion gases safely exit through a dedicated, sealed vent system.”
The U.S. Department of Energy (DOE) says a tankless water heater can be less expensive to operate than a storage tank system. “Tankless water heaters provide hot water only as it is needed. They don’t produce the standby energy losses associated with storage water heaters, which can save you money.”
The DOE notes that tankless water heaters typically provide hot water at a rate of 2 to 5 gallons per minute. “Gas-fired tankless water heaters produce higher flow rates than electric ones,” according to DOE.
For homes that use 41 gallons or less of hot water daily, on-demand water heaters can be 24 percent to 34 percent more energy efficient than conventional storage tank water heaters. “They can be 8 percent to 14 percent more energy efficient for homes that use a lot of hot water—around 86 gallons per day,” DOE writes. “You can achieve even greater energy savings of 27 percent to 50 percent if you install a demand water heater at each hot water outlet.”
The initial cost of a tankless water heater is greater than that of a conventional storage water heater, but tankless water heaters will typically last longer and have lower operating and energy costs, which could offset its higher purchase price, according to DOE. “Most tankless water heaters have a life expectancy of more than 20 years. They also have easily replaceable parts that extend their life by many more years,” DOE writes. “In contrast, storage water heaters last 10 to 15 years.”
To inquire about a new hot water heater, please contact us today. We’ll be happy to answer all your questions.