On-Demand Water Heaters: Efficient and Versatile Solutions
On-demand, or instant, water heaters are compact appliances that provide hot water exactly when needed. Unlike traditional water heaters, most models lack a storage tank, heating only the water required. Simply turn on the faucet, and hot water is instantly available—it’s that straightforward.
These units are significantly smaller than conventional water heaters, primarily because they don’t require a tank. This eliminates the need for extensive pipework, making them ideal for sinks or basins located away from typical plumbing areas, such as kitchens or bathrooms. They’re also perfect for heating hot tubs, which are often situated far from standard plumbing. Additionally, on-demand water heaters can be used in kitchens, bathrooms, and laundries, depending on your needs.
From Point-of-Use to Whole-House Solutions
Originally designed for point-of-use applications, tankless water heaters have evolved. Today, an increasing number of models can supply hot water for an entire house. While the water is still available “on demand,” it may not always be at the exact point of use, offering greater flexibility for larger households.
Basic instant water heaters use either an electric heating element or a gas burner. More advanced low-mass water heaters employ cutting-edge technology to deliver significantly higher volumes of hot water. These high-tech, typically gas-fired units feature electronic ignition and power exhaust systems. They can also connect to an external storage tank, enhancing their versatility compared to traditional models.
Advanced Technology for Efficiency
Electric Tankless Water Heaters
Stiebel Eltron, available through GO Tankless (www.gotankless.com), produces leading-edge tankless water heaters popular in North America. Equipped with sensors and microprocessors, their units automatically adjust water flow, pressure, and temperature. The company claims these heaters can reduce water heating costs by up to 50%, making them an eco-friendly choice.
When a Stiebel Eltron tankless water heater is activated by turning on a faucet, the flow sensor detects water movement, triggering the heating elements. Once the faucet is turned off, the unit shuts down, immediately stopping energy consumption. Built to high German engineering standards, these heaters feature durable aluminum cases and copper heating chambers.
Bosch (www.boschhotwater.net) offers two electric tankless water heaters under the PowerStar brand, designed for North American homes. The larger model delivers 3.7 gallons per minute at 105°F, suitable for two sinks simultaneously, a shower, or a bathtub. Alternatively, it provides 3 gallons per minute at 115°F for two sinks or a dishwasher. The smaller model supplies 2.3 gallons per minute at 105°F for a shower, bathtub, or washing machine, or 2 gallons at 115°F for a sink or dishwasher. However, the smaller model is not recommended in regions where groundwater temperatures fall below 60°F, excluding most of Canada and northern U.S. states. Bosch also manufactures an Italian-designed mini-tank point-of-use water heater with a glass-lined tank.
Gas-Powered Tankless Water Heaters
Gas-fired instant water heaters typically offer higher flow rates than electric models, though not all support multiple appliances simultaneously. Installing multiple units can ensure hot water availability for tasks like showering while running a dishwasher or washing machine, often proving more cost-effective than a single unit.
However, gas-fired units with constant pilot lights can waste energy. Operating costs for pilot lights vary, so check with the manufacturer before purchasing. Some models feature intermittent ignition devices that don’t run continuously, or you can manually turn off and relight the pilot light as needed for true “instant” functionality.
Union Gas produces natural gas tankless water heaters. When a faucet is turned on, a flow switch activates the burner, rapidly heating the water to the desired temperature. Once the faucet is turned off, the unit stops heating, conserving energy.
Bosch also manufactures ENERGY STAR-certified gas tankless water heaters capable of supporting at least two hot-water appliances simultaneously. These units are larger than their electric counterparts and feature electronic ignition for efficiency.
Takagi (www.takagi.com), a well-established Japanese company in the North American market for over 15 years, produces gas-powered water heaters with water flow sensors. These sensors trigger automatic ignition, heating water through coils in a heat exchanger in a fraction of a minute. When the faucet is turned off, the unit shuts down instantly.
Energy Savings with Tankless Water Heaters
Still skeptical about tankless water heaters? The U.S. Department of Energy states: “Demand (tankless or instantaneous) 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.”
Cost Considerations
High-quality on-demand water heaters typically cost more upfront than conventional tank storage models. However, their lower energy and operating costs make them a worthwhile long-term investment. For households seeking efficiency, versatility, and cost savings, tankless water heaters are an excellent option to consider.
