Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

BTU Question

I have read several of Dan's books as well as other literature and I was hoping to clarify something; the definition of <strong><span style="text-decoration:underline;">BTU</span>. </strong>Most of the definitions reference a BTU being the amount of heat necessary to raise 1 pound of water by 1 degree Fahrenheit. I understand this but others reference a time, that being one minute; "the amount of heat necessary to raise 1 pound of water by 1 degree in 1 minute".  Which is the correct answer? Thanks in advance for your help. 


  • Paul Fredricks_3Paul Fredricks_3 Posts: 1,549Member
    I don't think

    there is a time associated with BTU's. When a piece of equipment has a BTU rating, "per hour" is implied.
  • DanHolohanDanHolohan Posts: 14,871Member, Moderator, Administrator
    British Thermal Unit

    It's the amount of heat needed to raise one pound of water one degree Fahrenheit. Btu has nothing to do with time. There's another term, Btuh, which is Btus per hour and that combines the heat input with time. 
    Retired and loving it.
  • MikeyBMikeyB Posts: 696Member

    I read in the Operators Engineer's Exam (posted in teh library) that a BTU "is that heat required to raise water at 39 degrees F. one degree per minute"
  • Jamie HallJamie Hall Posts: 12,114Member
    Dan's right,

    the OE exam wrong.  BTU is a measure of energy, and has nothing to do with time.  As soon as time gets into the act, you're talking power, not energy.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Mark EathertonMark Eatherton Posts: 5,843Member
    I've seen it stated...

    that it is roughly the equivalent of a wooden kitchen stick match....

    Don't think you could keep a stick match burning for a minute.

    Also remember something about two Englishmen drinking at a pub, and determining that it was the amount of energy necessary to raise one PINT of beer, one degree fahrenheit. Or SOMETHING to that effect.

    Maybe they were playing with matches :-)

    Maybe it should be called an ITU (Irish Thermal Unit) ??

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • MikeyloveMikeylove Posts: 3Member
    That BTU thing again

    I really appreciate everyone's help and quick responses and I believe I am closer to fully understanding the concept. I have one last thing to add, I was recently watching a video on Taco's site, it was a video by John Barba called "Universal Hydronics Formula" and he stated several times BTU per minute. How does that correlate to our discussion? Thanks again guys.
  • DanHolohanDanHolohan Posts: 14,871Member, Moderator, Administrator
    Here's the source:

    Note how the first Btu was the amount of heat needed to raise one cubic foot of water one degree Fahrenheit.  Mr. Tredgold made it up. We got to change it once he was dead.

    May you can make this stuff up!
    Retired and loving it.
  • MikeyloveMikeylove Posts: 3Member
    Thank you

    Thank you very much
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!