Tankless Heaters: Always Full

Europe and Asia have been using tankless water heaters for several decades, but in the United States tankless just now catching on? Why is that? Do Americans enjoy long, hot showers that eventually turn cold? Is our society so prosperous that lowering energy bills is not a concern? Regardless of the reason, the tankless revolution has arrived and it promises to be the wave of the future.

According to the American Gas Association, approximately 9.5 million water heaters are sold annually. Of those sales, the split between gas and electric is 50/50, with 80 percent as replacement water heaters and 20 percent for new construction.

With the building industry’s green renaissance in full swing, there’s a built-in demand for tankless, both gas and electric, due to water and energy savings they deliver. And when increased space and endless hot water are factored in, tankless is virtually unbeatable.

“The reason for the rapid growth in tankless water heater sales is because consumers are embracing the concept of saving energy, water and other resources. For years, energy has been relatively inexpensive in the United States and most consumers have not felt the need to save energy and water,” says Fred Huggins, vice president of sales and marketing for Noble Innovations. “However, that’s changing as gas and electricity prices rise and as consumers become more green conscious. The success of the LEED for Homes program and introduction of NAHB’s new National Green Building Program are major indicators of how green American consumers and businesses are becoming.”

“In comparison to electric tank style heaters, the homeowner will save 15 to 20 percent on the water heating portion of their electric bills,” says Bill Riley, sales and marketing specialist for Stiebel Eltron. “As you know, tank-style heaters must continually heat and reheat water throughout the day to higher than necessary temperatures due to heat dissipation through the wall of the tank. This results in stand-by losses of 15 to 20 percent of the kilowatt-hours used.”

Stiebel Eltron is adding a Tempra upgrade and a new Tempra Plus model this year. These will include an upgraded basic model that will be capable of heating water to 140 degrees F, among other enhancements. Additionally, Stiebel Eltron will present the Tempra Plus models that will automatically limit the water flow rate in case the unit is not able to maintain the set-point temperature.

“Tankless water heaters are a great solution for many remodeling projects for several reasons,” says Nina Knight, Rinnai America Corp. marketing communications coordinator. “First, their compact size allows them to be installed in a small area.

Second, they are great for providing hot water for shower towers and large garden tubs that would require large or multiple tanks.”

Rinnai recently launched its hydronic air handler, which was designed specifically to work with the company’s tankless water heater. The air handler uses the hot water from the tankless unit to heat the user’s home. The main benefit of this product is that only gas and venting for the tankless unit is required, whereas two gas lines and two vent penetrations are needed when using a water heater and furnace. Rinnai’s air handler also has a built-in domestic priority system so if the domestic load combined with the heating load is too high, the air handler will stop running until the domestic load eases.

“If you heat too much hot water, even with a tankless water heater, it will no longer give you the savings in fossil fuel usage which many environmentalists are looking for,” cautions Bob Hitchner, director of tankless sales for Rheem Water Heating.

“But the environmentally conscious consumer also sees a lot to like in the tankless water heater. This is because they are indeed extremely energy efficient when used to heat the water for an average home.”

An Endless Flow from a Small Source

“Most everyone has, one time or other, run out of hot water with their tank water heater,” says Hitchner. “When that happens, they have to wait a long time until the water heater is filled with hot water. It is all or nothing with a tank water heater. In the case of tankless, you never actually run out of hot water, but you may not have as much as you want. In this case, the pressure in your shower might drop until someone else ends their shower, for example. But the water will always be hot.”

This year, Rheem will launch a new whole-home tankless water heater that is very compact in size. The unit is called the 66 Series heater, and it will be a 180,000-Btu heater which is concentrically vented using 3- by 5-in. venting. This heater will modulate down to just 11,000 Btu. The 66 Series promises to be ideal for those looking for an easy-to-install, concentrically vented whole home tankless water heater.

“The most popular advantage of tankless water heaters is that you will never run out of hot water,” Daichi Nakagawa, Noritz marketing manager. “This is because tankless water heaters heat water on-demand and that means no storage or shortage of hot water. Imagine the luxury of always having hot showers or filling up a Jacuzzi hot tub and still having an endless supply of hot water for the rest of your household needs. It’s about time your home had equal supply of hot and cold water.”

Noritz’s new N-084MC features condensing technology that yields 93 percent energy efficiency vs. the 60 percent yield of a typical tank water heater. This will dramatically decrease production of carbon dioxide, and thereby help reduce the emission of greenhouse gases. These heaters come with stainless steel casings for enhanced aesthetics. The main component of this new technology is the super heat exchanger, which is actually two heat exchangers fused into one. The primary heat exchanger is made of copper and the secondary is stainless steel.

With the Paradigm electric tankless from Skye, water passes through the heating element so water is heated to over 100 degrees F in less than five seconds. The Paradigm is designed to be a drop-in tank replacement and is robust enough for nearly any residential or light commercial application. The unit promises a 99.8 percent efficiency rating for energy efficiency and virtually no maintenance.

Another plus is that tankless is aesthetically unobtrusive. “Compared to traditional water heaters, one of the most obvious differences is its small size, “ says Nakagawa. “Our tankless water heaters come in models that mount on the wall, inside or outside. This eliminates the bulky tank that requires much more space.”

“Our largest Tempra 36 model is only about 22 in. wide, the Tempra 24 about 15 in. wide, both about 15 in. high and 5 in. deep,” says Stiebel Elton’s Riley. “Compared with the bulky traditional tanks, this can provide a great deal of space saving and present various mounting alternatives. Point-of-use units are even smaller, with our Mini measuring 6 1/2 in. high by 7 1/2 in. wide and 3 1/2 in. deep.”

The Bosch Aquastar 2700 ES gas tankless water heaters feature space-saving design for limitless installation possibilities.

The product delivers over 7 gpm, enough to run two to three applications at the same time. The 2700 ES features an electric ignition and is available for either natural gas or liquid propane. A wireless remote is available for quick starting and easy temperature control.


Typically, on-demand water heaters may require a little more maintenance than standard water heaters due mainly to the presence of mineral buildup. Depending on the structure of the unit, regular demineralization may be required to remove mineral sediment.

In most installations, the all stainless steel Viridian “truly tankless” water heater from Noble Innovations requires no periodic demineralization because the unit continuously flushes and rinses itself thanks to the company’s patented Jalix technology. For the utmost efficiency and low maintenance, the product’s elements are 24 ft. long, which is more than twice as long as other brands. Given their extra length, the elements only need to get about half as hot as other models, which cuts down on minerals being extracted from the water. Being “truly tankless,” Viridian water heaters have no place for sediment to accumulate. Their low-maintenance design eliminates the need for water filters and their standard 3/4-in. plumbing connections virtually eliminate water pressure drop.

“In 2003, gas tankless sales were approximately 50,000 units; however, in 2006 gas tankless sales exceeded 250,000 units,” says Fred Huggins. “However, due to performance and product perception issues, electric tankless water heaters have not seen this kind of growth. We believe, though, that given Viridian’s demonstrable high-end product quality, exceptional performance and low-maintenance design, the brand will do very well. Over the past eight months, Viridian electric tankless water heaters have been introduced to thousands of builders, architects, plumbers, distributors and other building industry professionals at various product trade shows and their acceptance has been tremendous.”

Installation Considerations

Manufacturers offer some words of caution and advice for going tankless. “The installer needs to clearly understand the electric panel’s capacity and existing power demands,” explains Huggins, “and that the home’s electrical wiring or the gas line infrastructure can be modified as required. Homeowners and installers need to do their research before they buy a tankless water heater, whether from their plumber, builder or retail location.”

“Please make sure the gas meter and gas line are properly sized to handle a tankless gas water heater,” cautions Kevin Ruppelt, general manager of home water products for General Electric. “You may contact your local gas company to help with sizing and upgrading gas lines and meters. In many cases the original gas line and meter will be sufficient.”

He adds, “When installing any type of gas product, it is important that a properly trained installer is used. GE offers a DVD on GE tankless gas water heater installations and provides a detailed installation manual as well. GE recommends the installer view the video and installation instructions and use a properly informed installer/plumber that meets with local codes.”

The new line of GE tankless gas water heaters, available in both indoor and outdoor models, is designed to fit in small spaces. The units can be equipped with an optional remote controller that allows the user to monitor and adjust hot water temperature in the bathroom, kitchen, laundry room or any other room. Outdoor units are equipped with ceramic heaters that prevent them from freezing at temperatures as low as –30 degrees F. These heaters are available in two sizes — 7.5-gpm and 9.4-gpm flow — indoor and outdoor.

“A remodeler must take into account the current setup in the house as well as the number of hot water applications,” adds Nakagawa. “The current location of the heater in relationship to the most commonly used applications should be taken into account when choosing where the heater should be installed. A tankless heater installed closer to the hot water application will decrease the use of water because the hot water will reach the application sooner.”

Noritz only distributes through wholesalers so that only qualified installers can install the company’s product. Noritz trains installers so that they will know how to size, install and repair if necessary. The company’s Noritz University is a collection of training classes offered at all Noritz branches. Classes range from an introduction to tankless water heaters to more in-depth commercial multisystem installation and troubleshooting seminars. Noritz University also offers courses on how to market and sell tankless to consumers. Groups of all sizes and skill level can attend Noritz University.

Paloma’s digital tankless gas water heaters are available in the 7.4 Series, 5.3 Series and 4.2 Series, depending on the project and customer needs. All of the company’s digital tankless models are equipped with a detachable remote controller.

The main controller can be installed in a kitchen or laundry room and used to set the right temperature. Optional bath controllers override any others to increase scald-prevention safety. The digital remote controllers require some additional wiring.

If the plumber or remodeler installing a tankless unit chooses hard piping, they must be cautious when sweating pipes close to the heater so that the casing is not damaged in the process. After installation, the filter should be checked for any debris caught in the line from materials like solder or Teflon tape, as this can obstruct the water flow and affect minimum water flow activation rates.

“Once you know which model you need, check with your electrician to make sure the size of the electric service is sufficient,” says Bill Riley. “In some cases, the size of the electrical service has to be increased to accommodate the additional load that is created by the electric tankless unit.

“Further, the homeowner or remodeler can actually tailor the usage points to maximize the output of hot water,” adds Riley.

“This can be done by using newer, low-low shower heads and aerators on all the faucets. These can still provide the homeowner with acceptable flow rates. There really is no need to have a 2.2-gpm aerator on the kitchen sink.”

“When it comes to water heating, tankless is the way of the future,” predicts Riley. “For very little additional investment, you can get substantial energy savings. In this age of rapidly rising energy costs, there is a big need to find technologies that give you a lot of “bang for the buck,” which provides good savings and little added initial investment.”