Should An Immersion Heater Be Turned On All Day?

Discussion in 'Plumbers' Talk' started by Sebastian Nagy, Aug 30, 2022.

  1. Sebastian Nagy

    Sebastian Nagy New Member

    Hi all, I have recently moved into a flat that runs on electric only and I have an immersion heater. The heater turns on and off during the day, I presume it has a temperature sensor of some sort. The heater is using up quite a lot of electricity during the day. Im only at home in the evening.
    The water within the tank is literally only used for the bathroom tap and the kitchen tap. It’s only me that lives in the flat. Would it be okay to have it switched off during the day and only turned on when needed? Or can a timer be fitted? Not too sure what’s most efficient and if it’s good/safe to turn it on and off constantly. Thank you.
     
  2. andy48

    andy48 Screwfix Select

    To give a full answer we would need more information, in particular whether the hot water cylinder has one or two immersion heaters, and whether you are on an Economy 7 type electricity tariff. As an interim answer:
    1. If you have only 1 immersion heater, a timer could save you money, which given the current rising costs, could be quite a bit.
    2. If you have 2 immersions:
    2a. The lower one will be on the economy tariff if you have one, which means electricity only goes to it during fixed hours, and generally might as well be left permanently on.
    2b. The upper one will be for "top ups", and you may well want to leave it permanently off.
    2c. The lower one will heat the whole cylinder, the upper only about the top third of the cylinder.
     
  3. Cliff Rees

    Cliff Rees Active Member

    Do not forget whichevr way you choose to operate it, efficient thermal insulation to the cylinder and nearby hot pipework is essential
     
    qwas123 likes this.
  4. Crowsfoot

    Crowsfoot Screwfix Select




    The coming energy crisis means all the economical savings (being based on "save a bit" from a "you have to be able to spend it first) are now out of the window (as very few will be able to afford to spend it in the first place).
    The days of having readily available stored water at constant temperature via a thermostat could will be over.
    It could well work out cheaper to just switch the IH on and off manually.
     
    Kingscurate and rogerk101 like this.
  5. robertpstubbs

    robertpstubbs Screwfix Select

    There will probably be a temperature setting inside the cover over the immersion element. You could consider reducing the temperature. Note there are live terminals inside the cover so you should turn the heater power off to be safe when opening it.

    5BE4B384-4448-4825-9582-119CF13DEED5.jpeg
     
  6. just pumps

    just pumps Screwfix Select

    I suspect the saving in cost would be minimal unless the stat is sky high to start with.
     
  7. robertpstubbs

    robertpstubbs Screwfix Select

    I would expect that the cost of maintaining each additional degree of temperature would increase progressively or even exponentially.
     
    Abbadon2001 likes this.
  8. just pumps

    just pumps Screwfix Select

    That goes without saying after all you dont get nowt for nowt.
     
  9. ejenner

    ejenner Active Member

    We run ours at night. It does come on again after the kids bedtime just in case the Mrs wants a bath. But to be honest... our electricity bills are sky-high and always have been... so I'm not sure I can really recommend the right approach.

    My theory with my setup is that it's on a thermostat so should only turn on when the water gets below a certain temperature. So theoretically it could be left on all the time... however... my fear is if it's pointlessly turning on and off all day it could be heating the water in short bursts throughout the day and just wasting a load of electricity in the process. I find having it set to about 60-70 degrees, turning it off at 6am when the cheap electricity ends, it is still warm enough for the kids bath at around 6pm in the evening.

    I think a combination boiler would be a much better solution though. That way it only runs on demand. We're on oil heating so I have to keep an eye on the tank level and can't just run the oil boiler all the time without the possibility of the tank running out unexpectedly at a time when it isn't convenient to spend £1000 topping it up.
     
  10. AnotherTopJob

    AnotherTopJob Screwfix Select

    When we had a hot water cylinder we boosted it twice a day - an hour at about 6 in the morning, and again at about 4.
    That worked well for family of 4.
     
  11. Severntrent

    Severntrent Screwfix Select

    Or in Yorkshire owt for nowt
     
  12. robertpstubbs

    robertpstubbs Screwfix Select

    If you don’t need the convenience of hot water on tap, just boil a bit in a kettle when you need it. It will work out cheaper.

    You could install some sort of point-of-use water heating / tap but there is a high up-front cost.

    If you have enough dishes and cutlery then running a dishwasher every week or two is a cost effective way of heating water.
     
  13. just pumps

    just pumps Screwfix Select

    :D
    Little sister lives there and has picked up some of their sayings, makes me laugh some of them.
     
  14. Tilt

    Tilt Screwfix Select

    Pointless keeping water hot if it is not going to be used IMO.
    Just one person in the house / flat, then just heat it as and when required.

    Maybe consider a water heater in the kitchen, fitted with a timer (maybe a Timeguard NTT03) and set it to suit your needs.
     
  15. chesterw

    chesterw Well-Known Member

    We only turn ours ON on Christmas day, because that's bath day
     
    Denis6482, rogerk101 and Kingscurate like this.

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