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    Calculating BTU and choosing radiators and capcula


    I am currently researching radiators and trying to calculate BTU to ensure I choose the right size and type. I am COMPLETELY new to this process as well as working with tradespeople.

    I am doing something wrong, because the numbers I get sound way off - over 9000 BTU for a small bedroom. I have read on a few radiator selling sites that the best way to choose a radiator is to get a plumber in who will calculate the BTU more precisely and help choose the right radiator. As professionals, would you say that’s correct? Is helping choose the right radiators part of service you offer? Or is more a heating engineers’ territory? Many thanks in advance!

    Asked by Dovile on 29th Sep 2021
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    Best Answer

    Manchester Gas Services

    "In order to calculate the size of the radiator required we calculate the Mu value of a room ( this is the amount of heat lost through windows, walls, floor, and ceiling.)
    From this, we can calculate how much heat is required to overcome this loss and heat room.
    As a rule of thumb, the bigger the better as long as the radiator does not look ridiculously large."

    Answered on 28th Oct 2021 - Member since Mar 2016 - report
    Aaf electrical service

    "If you pay £50 I am sure a qualified plumber like myself will give BTU calculations in writing."

    Answered on 29th Sep 2021 - Member since Feb 2020 - report
    Mark Harrison

    "If you calculate height x width x length, that will give you the room size, then input those measurements into the website thus giving you the correct size radiator."

    Answered on 29th Sep 2021 - Member since Nov 2020 - report
    TopLine Plumbing & Heating

    "Just use a website with a BTU calculator. (I think B&Q has one). All you need to do is input the measurements of the room and answer I few questions on the room and you will get your answer.

    Changing radiator or sizing radiator is well within a plumber's scope of work."

    Answered on 29th Sep 2021 - Member since Mar 2021 - report
    C B Plumbing

    "Hi, no you are right a plumber should have enough knowledge to calculate the BTU for a room, have you taken off the heat loss factor of the outside wall, inner wall, window wall, door to outside, these are all to be considered when doing the BTU."

    Answered on 29th Sep 2021 - Member since Jan 2020 - report
    Harrow Plumbing & Harrow Homes maintenance

    "Hi, yes, if you measure height x width x length and then put it into google on heating radiator sizing it will give you the correct BTU.

    Hope this helps."

    Answered on 29th Sep 2021 - Member since Sep 2021 - report

    "When understanding the heat that a radiator can produce, I would always insulate, so that if you are using a radiator with less than 5000 BTU then the insulation is sometimes more important than a rad with a high BTU, and keeps you comfy."

    Answered on 8th Oct 2021 - Member since Jan 2020 - report
    Green Home Power and Heating

    "This is a heating engineers job, "plumbers" can fit radiators but 80% of the time that's all they do and don't even know about the rest of the job.. They may leave airlocks in the system if it's gravity-fed or fail to add inhibitor and fail to flush out the acidic flux or properly calculate the BTU requirements or balance the system. A heating engineer will do the work in a manner that is kind to the boiler and does not leave a timebomb behind. However, if you are informed enough you can make it work, most importantly add inhibitor AFTER THE SYSTEM IS PROOVED AND FLUSHED."

    Answered on 6th Dec 2021 - Member since Nov 2021 - report

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