As commercial buildings increasingly transition away from traditional storage-based hot-water systems to modern tankless water-heating systems, there’s likely to be some lingering confusion over how to make the switch. In a column for Plumbing & Mechanical Engineer, Brian Fenske, director of commercial business at tankless manufacturer Navien, says fear of the unknown keeps some designers from eliminating storage tanks from their systems — despite the ability of tankless water heaters to eliminate tanks and increase water-heating efficiency.

“In my past experiences and involvement with the tankless industry, I’ve discovered the two reasons storage tanks are most often applied to tankless domestic hot water systems,” Fenske writes. “One, the confusion of the tankless being and acting like a boiler, and two, the inability or lack of confidence to let go of the often-unneeded storage tanks. Let’s face it, those old habits die hard, and those insecurities are all nestled into our designer’s minds.”

There are some legitimate reasons to incorporate storage into a domestic hot-water system, he says, including space, high-demand dump loads, and insufficient gas Btu service. But by eliminating storage entirely, designers can offer the best, most-efficient hot-water systems. Fenske goes on to offer helpful design criteria for selecting and designing tankless hot-water systems. For more insight, download our Ultimate Guide to Commercial Tankless Water Heating.

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Top photo: A bank of 10 Navien NPE Tankless Water Heaters constructed with Navien Ready-Link racks and manifold systems at the University of New Mexico’s University Stadium.