The U.S. Department of Energy issued a final rule notice amending the minimum efficiency standards for residential boilers, which will go into effect Jan. 15, 2021.

The revised national minimum annual fuel utilization efficiency requirements and new maximum standby and off-mode electrical consumption standards in the final rule are:

  • Gas hot water boilers — 84% AFUE, 9 W (standby and off-mode).
  • Gas steam boilers — 82% AFUE, 8 W (standby and off-mode).
  • Oil hot water boilers — 86% AFUE, 11 W (standby and off-mode).
  • Oil steam boilers — 85%AFUE, 11 W (standby and off-mode).
  • Electric boilers — AFUE N/A, 8 W (standby and off-mode).

Read more about standards for residential boilers at