UDRH update: DHW distance

REM v15.0 and later includes a new DHW Efficiencies page. The Plumbing Design section of this page provides a field to input the distance (ft) from the farthest water fixture to the DHW appliance. This input is problematic for several reasons:

  • Due to the page's formatting it appears to be related to recirculation systems, increasing the chances of incorrect inputs. 
  • Measuring and collecting this distance is not on most Raters' to-do list. Because there is no "auto-calculate" button available (coming in 15.4), there is no reasonable method for inputting a standard distance (see Addendum A to ANSI-RESNET Std 301). 
  • The potential for inflated Program savings exists in homes that are submitted with very low distances inputted. 

The updated UDRH, available on the Rater Field Guide page, now sets the reference home's DHW distance equal to the rated home. This eliminates the potential for improper savings.