RightSpec® Sizing Guide

Your Complete Water Heater Sizing Source

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Welcome to RightSpec®

Niles' RightSpec® is the most comprehensive and intuitive sizing program available, and the all-new design makes it easier to use from virtually anywhere. There is no sign-up required or program to download. Feel the confidence of specifying Niles products right the first time with RightSpec®!


It is the responsibility of the application engineer or installing contractor to properly design the plumbing layout and correctly size all components within. This includes, but is not limited to: water heaters, storage tanks, expansion tanks, mixing valves, piping, pumps, etc. In no event does Niles make any warranty, expressed or implied, regarding the design and installation of the plumbing system, or its components, except for the limited manufacturer’s warranty provided with the water heater(s) and/or storage tank(s).