Central heating automation does it really work?

Discussion in 'Home Automation' started by ericmark, 30 Oct 2018.

  1. ericmark

    ericmark

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    Last year I had two electronic heads for the TRV which seemed to work well, there were some Hick-ups to start with, tried adding pennies as spacers and all sorts, but it seemed to settle down, and when room set to 20°C it went to 20°C.

    So I decided to expand now 4 electronic heads and they are not doing well, it may be the valves have not been opening and closing for years and now working again it will take some time to settle down, or it could be not cold enough yet for heating to run for long enough, or even faulty valves. It took some time for first two to settle down, I thought it was my fiddling with settings, but could just as likely been time needed to settle down.

    I don't worry if under temperature, likely simply boiler not running, however it does seem they are often over temperature as well, this to my mind should not happen, although once hot a radiator is still going to be heating a room of course.

    If the valves are faulty, then one has to ask were the electronic heads really required? Could I have changed valves and even with mechanical heads all would have worked?

    In the old days of fires in the rooms, we would feel cold, light the fire and the room temperature would raise to some silly level but we would not realise how hot until we left the room and returned, central heating did two huge things, one because combustion air drawn from outside it stopped the drafts, and two it stopped the rooms over heating, although it took some careful adjustment of the lock shield valve to balance rooms.

    Theory was when the TRV came out, the wall thermostat moved from living room to coolest room on ground floor with no independent heating and no outside door, often there was not such a room, so hall was closest compromise. We were told in theory you didn't actually need a wall thermostat, anti-cycle software was fitted into the boiler and by the time of year this could not cope it was time to turn boiler off. So TRV in every room and boiler used return water temperature to work out how much to modulate the output.

    However to save needing to manually turn off the boiler, often a wall thermostat was fitted and the TRV turned full on in that room.

    Then came the smart control idea, never quite worked out why you need to adjust temperature? all it needs is to be able to switch it on remotely before you return home, so on/off is all that is required, however the so called smart feature seems to have been included in TRV's and wall thermostats not just a simple on/off switch.

    So yes I can use my phone to turn down all radiators before I leave, then turn them back up before I start on my return. But question is does the house actually cool enough in 10 hours to actually save much energy? Or does a boiler running flat out to reheat house become less efficient to one which has modulated so you end up using exactly the same amount of energy?

    And once cooled and reheated how long before heat is stable? In old houses without thermal insulation added yes loads of heat wasted, but once double glazed, cavity wall, and loft insulation added, I find in 10 hours the house has only cooled between 2 and 4°C so one I could have just waited until I got home and flicked the switch on the programmer, as not cool enough to worry about, or two just left it running as so little heat lost, specially as once switched off, and back on again, some rooms over shoot, and some lag behind so it takes two or three hours to settle, in fact for rooms which have over shot the setting, we open a window to cool them down again, so no real gain.

    So is there really any point in all these Smart controls?
     
  2. Mottie

    Mottie

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    Short answer, no. It’s all ballcocks although I did consider it before I decided that I don’t really need to control the heating in my house when I’m not there. If I come home early and it’s not warmed up, I can always keep my coat on or wait ten minutes but at the end of the day, we’re not going to freeze to death are we?
     
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  4. bernardgreen

    bernardgreen

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    I agree with Motman.

    We could if the automation system decides it doesn't want humans sharing it's house......
     
  5. foxhole

    foxhole

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    Temp is never stable , it moves a few degrees either side of the set temp depending on various variables like how often doors are open , shut , left open etc etc.
     
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  7. ericmark

    ericmark

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    TRV-report1.jpg Having decided the system was useless, I came to get a screen shot and it was spot one. I thought last year it was working well, so this year added two more electronic TRV heads, however after fitting my wife's bed room was regularly over temperature, mine under temperature the living room over temperature only the hall seemed to always be spot on. As to if there was rubbish floating around the system, the software needed to bed in, or just needed to get colder don't know, but today as you can see it's spot on.

    But set the temperature down over night, and it drops so slow I wonder if it is worth it. OK it can heat a room up quickly but without opening a window or door with the insulation in this house it takes ages to fall, winter is a real problem with sun low in the sky, it hits the bay window and you can see the thermometer move. To be fair the electronic TRV reacts a lot faster and has stopped the room hitting 28°C when the sun comes out. Still common to hit 24°C but a clear improvement.

    So yes the eTRV does control the room better than the mechanical wax type. But as to geofencing, still in 10 hours house will cool maybe 4°C in heart of winter, I would love to be able to measure how much energy it saves, but I think it will take many years for the eTRV to pay for them selves, OK it makes the temperature more constant, with less overheating, so more comfortable, but some how don't think it saves money.
     
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