I saw that my Natural Gas provider stated I could receive a benefit if I had one or installed one, so I was wondering what it was.

1 Answer 1


In this context a boiler is more-or-less the same thing as a tankless/on-demand/instant water heater. From what I can gather the term 'boiler' is used instead of one of those other terms based on characteristics of the unit or the usage. Heaters with higher BTU (or kW) ratings, or designed for higher duty cycles, or used as a heat source in a space heating or space heating plus domestic water heating application are often called boilers.

AFUE is annual fuel utilization efficiency. It is a measure of heat output (in the heated water) vs heat input (heat capacity of the fuel gas being burned). Higher AFUE is more efficient.

  • 1
    i.e. "94+" is presumably equal to or greater than 94% efficient - as opposed to 80-85% for typical boilers.
    – Ecnerwal
    Sep 25, 2020 at 20:19
  • The gas companies give rebates for higher efficiency and so do the electric companies the new heat pump units are slow recovery but if you vent them outside in the winter and inside in the summer they really do make a difference power wise but I don’t expect them to last as long as straight resistance rods.+
    – Ed Beal
    Sep 25, 2020 at 21:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.