Sustainable, energy-efficient and space-saving features
As the popularity of Green homebuilding continues to rise in the industry, more and more builders are choosing to incorporate components that are energy-efficient. Much of this is driven by demand from increasingly savvy consumers who want these features as a way of saving money, in both the short and the long term.
For hot water heating, tankless water heaters are one of the most energy-efficient options available on the market. “As part of the high consumer demand for Green products, tankless water heaters are a key benefit,” says Butch Aikens, tankless resource manager with Rheem Manufacturing, a company that makes energy-efficient gas tankless water heaters. “Unfortunately, many builders are still thinking in terms of cost instead of their home’s value in the eyes of the consumer. Although tankless water heaters have higher initial prices, they also have more longevity. On average, a hot water tank will last around 12 years, while a tankless water heater will last around 20 years. Consumers like that.”
Tankless water heaters are an important component of a home’s overall energy-efficiency portfolio and can help builders earn points toward LEED or other Green certifications. In addition to these benefits, tankless water heaters are one way for builders to differentiate their products, says Gregg Johnson, EVP and chief operating officer for SKYE International Inc., a maker of high-quality, stainless steel electric tankless water heaters.
This can be especially important in a challenging market. “It can be a great value proposition to show potential homebuyers the energy savings from having a tankless water heater,” Johnson says. “Considering that an average mortgage payment on account of a tankless water heater investment is $8, and the monthly savings on water heating is $25 to $30, these units are cash flow positive from day one.”
Builder Jeffrey Dinkle, president and founder of Atlanta-based Eco Custom Homes, has been installing tankless water heaters exclusively in his homes for the past seven years. “With tankless water heaters, homeowners will never run out of hot water,” Dinkle says. “Normally, two 75-gallon hot water tanks would serve a larger custom-built home. But after a shower and a Jacuzzi bath there would be no hot water left. During holidays with a house full of guests this could be even more problematic. As for the energy usage with hot water tanks, it is pointless keeping 150 gallons of water warm all day for the whole year.”
Space efficiency is another consideration. “A conventional large tank takes up over 25 square feet, which makes it expensive to house,” Dinkle says. “Tankless water heaters take up very little space and can be mounted outside if needed. We have been specifying these systems in container home (ISBU) projects we have been working on, because of the space requirements.”
According to Johnson, in contrast to traditional hot water tanks, a tankless water heater does not require the same dedicated space or minimum clearances and thus does not typically cause a negative impact in the design of a home.
“For example, in order to accommodate a large water heater in the garage, it often requires that useable square footage be taken away from more visible areas of the house such as the dining room or the closet,” Johnson says. “Tankless water heaters can be mounted on the wall and therefore have little or no effect on a home’s design layout. This allows for more flexibility.”
For installing tankless water heaters, Aikens says it’s important to size each unit based on the number of baths in a home. This can even be fine-tuned, he says, whether the home has fixtures or body sprays that are water-efficient. For gas tankless water heaters, proper fuel sizing is a key consideration. “The fuel system must be sized to the tankless water heater’s maximum capacity,” Aikens says. “By doing so, you are ensuring that the unit is operating at peak efficiency. This is a critical step, because an undersized fuel system will lead to underperformance.”
For correctly sizing tankless water heaters for an intended water temperature, builders and contractors should be aware of the required temperature rise that is required, says Bill Riley, sales and marketing specialist with Stiebel Eltron, a company that manufactures compact and efficient Tempra tankless electric water heaters. “The difference between the temperature of the incoming water and the desired target temperature—which is usually 110 degrees—dictates the amount of gallons a unit can process,” Riley says.
According to Riley, in addition to monthly energy savings of up to 40 percent on the hot water portion of a utility bill, tankless water heaters also contribute to a home’s water efficiency. “If a homeowner wants to access cooler water, a hot water tank system needs to draw in and use cold water to lower the temperature,” Riley says. “However, a tankless water heater can produce any desired water temperature without having to use additional water. In this regard, they are a water-saving feature.”
But in addition to their many benefits, Dinkle says there are also concerns that builders should be aware of. “One of the biggest issues with the gas models is that they won’t turn on under half-gallon-per-minute flow rate,” Dinkle says. “As such, they need to be equipped with a ¾-inch high-pressure gas line. It’s also important to install the optional condensate drip line on the vent pipes because water vapor can shorten the life span of the units, in some cases. But given the life-cycle costing as
well as the space and energy savings, I
think they are a win-win.”
Visit link: by Jeff Gunderson, Builder News Mag
Tankless water heaters evolve