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Discuss BTU's at delta T65 and T50 in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. pacarter11

    pacarter11 New Member

    Hi Guys,
    Need some help. I have calculated online the BTUs for the rads (calculator used T65) then when purchasing I was looking at the T65 radiator calculations...
    But I have since noticed, Europe uses T50 as standard. What calculation would I use to convert the T65 BTU needed to the new T50 (I presume I would need to increase the number).

    Or would it stay the same and I would just need to choose rad BTU's at T50?
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Flow plus return temp

    Divide by two

    Minus your room temp





    Mins let’s say 18

    Gives you a delta t of 39.5

    Delta t of 50 you would need your flow and return around 75-65

    Which if you have a condensing boiler is bad

    TBH I would work off a delta t of 40
  3. John.g

    John.g Active Member

    Output of a 50 deg rad is (50/60)^1.3. I , can't work this out in my present location but very easily done on a spreadsheet . You can also and easier look it up in a radiator temperature correction table.
  4. John.g

    John.g Active Member

    Slightly misread your post so if the calculation was based @ T65 then the correction factor to run @T50 is 1.41, (65/50)^1.3.
    IF it had been based @T60 then the correction factor to run @T50 is 1.27, (60/50)^1.3.

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  1. BTU at Delta T65

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