Heating on all night 2

Discussion in 'Plumbers' Talk' started by The Dormouse, Jan 15, 2009.

  1. The Dormouse

    The Dormouse New Member

    PRIMERASPORT first placed this question on Dec 30th - ‘Someone told me that over a 24 hour period, you will hardly use any more gas by leaving your central heating on low all night in the cold weather as opposed to switching it on every morning and having to heat the water from stone cold...is he talking **?’

    However the thread descended into chaos without providing a definite answer.

    I searched the forum & found my original topic on this subject under the name (deliberately controversial) ‘Central heating timers are a waste of time’ on 7/11/03. All the replies were supportive, probably because they had already tried keeping their heat on all night without being deterred by reactionaries .

    These are all the postings I could find from members who had tested the setting, found it satisfactory & not a waste of energy. Of course many more users would not be forum members or have reported their experiences.

    susie 9/11/03.
    diyaster 9/11/03
    Pugley 9/11/03
    ADSL Nation 10/11/03
    plumberandgas.com 10/11/03
    dewaltdisney 30/6/04
    graceland 2/1/09
    Refurb Bob 10/1/09

    Total of members including myself reporting
    satisfactory results & no increase in energy use; Nine

    Number of members having tested the setting
    with unsatisfactory results and/or energy wastage; Zero.

    I leave it to the questioner to judge whether all the satisfied users reporting to the Screwfix forum are fools or liars, as implied by a few detractors.
  2. Dick Puller

    Dick Puller New Member

  3. HOTDOG ø

    HOTDOG ø Active Member

    Get a life dormouse!
  4. sinewave

    sinewave Screwfix Select

    I'm with ya Dormouse!

    You get the same results with an Inverter driven Air-conditioning system.

    Ours has been on 24Hrs/day since last September!
  5. HOTDOG ø

    HOTDOG ø Active Member

    What make is yours Sine? Toshiba?
  6. sinewave

    sinewave Screwfix Select

    Mitsubishi Electric.
  7. devil's advocate

    devil's advocate New Member

    T'Dormouse, I recognise a few usernames in your list above and know them (well, as far as I can through the cyber-ether) to be very credible peeps - dwd, diyaster, etc.

    I wonder how many of them, however, have tested your hypothesis in anything approaching a truly scientific method? Ie, by removing - or taking into account - all other variables that could affect the results?

    That'll be none, of course, 'cos it would be far too complex.

    So don't you come spouting your indignant 'judgment' on here...

    If a house is reasonably well insulated, there's a good chance that the amount of additional (yep, I said 'additional') gas used will be minimal, and will be well worth it for the increased comfort offered.

    However - and T'Dormouse, you ain't a fool by any means - you simply cannot have additional heat for a longer period for nothing. Really, the argument doesn't have to progress further than that. You would have to rewrite the laws of physics otherwise.

    It should help to understand what's involved here by using the 'cup of tea' analogy - it, and the house, are both heated to the temp required, and can then be either kept at that temp ad infinitum, or just re-heated up to temp as and when required.

    Keeping it at temp is more convenient and more 'comforting' to us.

    But uses more energy.

    (I suspect that, if you ASK the peeps listed in your OP above whether they BELIEVE that NO additional gas is used when running 24hrs as opposed to 12/12 cycles, they will answer "Well, not really...")
  8. Captain Leaky

    Captain Leaky New Member

    How noisy is it Sine?
  9. sinewave

    sinewave Screwfix Select

    39-45 dba between low & high fan speed. :)
  10. towser

    towser New Member

    I think it is very logical that the less the heating is on, then the lower the temp difference on average between in and out so lower total heat loss. However I was also trying to think why there could be very little difference in fuel cost when heating is permanently on. I am making a WILD GUESS and have NO FIGURES to prove anything but here goes.
    Cold air holds LESS water vapour than hot. Heating the air will cause moisture to be evaporated into the air. In order for moisture to evaporate there is a LATENT HEAT required to be added to it. If the air is maintained at the warmer temperature all the time there would be less heat required (other than air changes) for the evaporation of water than when heating from cold. PERHAPS THIS IS WHERE THE ANSWER MIGHT BE??
  11. imran_

    imran_ New Member

    Speak up man!!!
  12. The Dormouse

    The Dormouse New Member

    T'Dormouse, you ain't a fool by any means - you simply cannot have additional heat for a longer period for nothing.

    With respect DA (as they say when handing out an insult!) the point is that more heat is not used for an additional period. The existing amount of heat becomes differently distributed, that's why simple analogies don't work.

    Anyway I was hoping to hear from the questioner, but he's probably lost the will to live by now.
  13. devil's advocate

    devil's advocate New Member

    "more heat is not used for an additional period. The existing amount of heat becomes differently distributed... "

    Semantics, T'Dormouse. Calling it something else doesn't change it...

    Towser, that's a valid point to raise and, believe me, if someone provides evidence that I'm wrong on this I WILL come on here and humbly concede.

    I think you'll find, however, that any extra energy required in getting the additional moisture to evaporate by heating up from cold, will STILL be less than the energy used CONSTANTLY in HOLDING this additional vapour in the heated air.

    I guess the energy required for the whole heating/cooling process in a house will involve some being used for the purpose you mention, but it's no different from the energy being used for the heating of the walls, ceilings, air, etc.
  14. HOTDOG ø

    HOTDOG ø Active Member

    Right, let's keep it simple let's say for arguments sake that during the colder months the ambient outdoor temperature is a 6C.

    For the purpose of a house we can assume everything to be at uniform temperature as would be the case at steady state.

    The driving force for temperature change is the difference between the two bodies. The higher the difference the higher the rate of transfer.

    Based on this a home at a constant 18C loses more energy to a 6C surrounding (outdoor temperature) than a home that is say 18C for 2hrs on the morning and perhaps 4hrs on an evening.

    During the times between the temperature of the home is either reducing or increasing based on the timer settings.

    At these times the loss of heat from the home is less than would be the case for a home at constant high temperature, therefore you save money on your fuel bill.

    If you really want to save money then spend your efforts on reducing heat loss from your home as this directly reduces heat loss (waste) from your home....hope that makes sense....
  15. The Dormouse

    The Dormouse New Member

    Even simpler, try it and see. It's much easier and more certain than using powers of intellect.
  16. G Brown

    G Brown New Member

    Don't be silly old man! My heating is scarcely on 6 hours a day and my gas bills are lovely and small.
  17. ecm

    ecm New Member

    Dormouse, have you not done the calcs yet, like I suggested on the last post of the original thread?

    Then you can put this to bed for once and all (after turning the heating off, of course).
  18. The Dormouse

    The Dormouse New Member

    Sorry ecm but that's a bit too subtle for me.

    Why should I want to prove that it costs more to leave the heating on or perform calculations, when I already have real experimntal results that prove that it doesn't?.

    And what calculations?, those that have been predetermined by someone to produce the 'right' result?.
  19. G Brown.

    G Brown. New Member

    "So don't you come spouting your indignant 'judgment' on here..."

    You have a nerve DA, that is all that you do. pot, kettle, black. ;)
  20. devil's advocate

    devil's advocate New Member

    (Yeah, but all my spouting is justified. :p)

    T'Dormouse, when you - and the others you have listed - recorded your gas consumption measurements, did you take into account all the other variables - ambient temp, cost of gas, other sources of heat, amount of daily sunshine (huge difference), adjustments to rads in other rooms, etc. etc. etc?

    If 'yes', then publish your results and become rich and famous.

    If 'no', then please, please stop. Really, stop.

    What you are claiming simply cannot be the case. It is - literally - physically impossible.

    It is simply disingenuous to then tell those of us who have looked at this in a rational way to simply ignore the 'intellect' or accepted scientific practice, and just go and 'try it and see'.

    You ought to be ashamed (I'm only half kidding there :()

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