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  • FIRST POST
    dr_winston
    Should I turn the power to my combi boiler off? (Have searched)
    • #1
    • 4th Jun 13, 3:52 PM
    Should I turn the power to my combi boiler off? (Have searched) 4th Jun 13 at 3:52 PM
    Hi, basically my flatmates have been arguing over this since we moved in six months ago. One says that the boiler should only be turned on when we need hot water (shower/ bath/ washing up) and for heating (in winter, obviously it's not needed now).

    Whereas the other says to just leave the hot water function on and all the time for when we need it as.

    So does leaving the hot water, and therefore the power to the boiler, on waste electricity and gas? and would only turning it on save us much?

    Cheers ; )
Page 1
  • DragonQ
    • #2
    • 4th Jun 13, 4:06 PM
    • #2
    • 4th Jun 13, 4:06 PM
    So does leaving the hot water, and therefore the power to the boiler, on waste electricity and gas?
    Originally posted by dr_winston
    In terms of gas, no. The whole point is that hot water is only created when you turn the tap on (both the positive and negative of having a combi boiler). As for the electricity, I can't imagine the boiler using much in "standby" mode. Even if it used 5 W you're talking 5 per year.
  • Wywth
    • #3
    • 4th Jun 13, 4:09 PM
    • #3
    • 4th Jun 13, 4:09 PM
    Hi, basically my flatmates have been arguing over this since we moved in six months ago. One says that the boiler should only be turned on when we need hot water (shower/ bath/ washing up) and for heating (in winter, obviously it's not needed now).

    Whereas the other says to just leave the hot water function on and all the time for when we need it as.

    So does leaving the hot water, and therefore the power to the boiler, on waste electricity and gas? and would only turning it on save us much?

    Cheers ; )
    Originally posted by dr_winston
    With a combi boiler, when there is a request for hot water i.e. by someone turning on a hot tap, water is heated by the combi boiler which then flows through to the relevant tap.

    You won't save much by turning the electricity suppy off when the boiler is not needed.
  • molerat
    • #4
    • 4th Jun 13, 4:16 PM
    • #4
    • 4th Jun 13, 4:16 PM
    The miniscule amount you will save is far outweighed by not getting into a freezing cold shower and having to run through the flat stark naked and dripping wet to turn the boiler on
    www.helpforheroes.org.uk/donations.html
    • Andy_WSM
    • By Andy_WSM 4th Jun 13, 6:07 PM
    • 1,989 Posts
    • 4,411 Thanks
    Andy_WSM
    • #5
    • 4th Jun 13, 6:07 PM
    • #5
    • 4th Jun 13, 6:07 PM
    Also if you keep turning it on & off at the mains it is only a question of time before you blow the main PCB which will cost hundreds of s to replace. Your few pence a day electricity saving will look rather pitiful then!
  • Nada666
    • #6
    • 4th Jun 13, 9:04 PM
    • #6
    • 4th Jun 13, 9:04 PM
    As you have flatmates (there are at least three of you) then it is certainly not worthwhile. For a single person it can make sense to switch it off - a comb-boiler can easily cost as much for electricity as it does for gas and make up one-third of the electricity bill.
  • rogerblack
    • #7
    • 4th Jun 13, 10:26 PM
    • #7
    • 4th Jun 13, 10:26 PM
    However!!!
    Do read the manual, and ensure there is not a reservoir of water, kept hot with electricity. This can use significant amounts of power, and can usually be switched off somehow without turning off the boiler.
  • DragonQ
    • #8
    • 4th Jun 13, 11:25 PM
    • #8
    • 4th Jun 13, 11:25 PM
    As you have flatmates (there are at least three of you) then it is certainly not worthwhile. For a single person it can make sense to switch it off - a comb-boiler can easily cost as much for electricity as it does for gas and make up one-third of the electricity bill.
    Originally posted by Nada666
    Oh yeah? Might use my power meter to see how much mine uses.

    EDIT: Heh, my earlier estimate was bang on. 4.6 W, so under 5 per year.
    Last edited by DragonQ; 04-06-2013 at 11:28 PM.
  • Wywth
    • #9
    • 5th Jun 13, 10:30 AM
    • #9
    • 5th Jun 13, 10:30 AM
    Oh yeah? Might use my power meter to see how much mine uses.

    EDIT: Heh, my earlier estimate was bang on. 4.6 W, so under 5 per year.
    Originally posted by DragonQ
    What type of power meter did you use to get that result in 3 minutes?

    Boilers are normally hard wired i.e. not plugged in via a 13A socket.
    I've just looked at my boiler (which is not a combi boiler) and there is no access to the power cable at all (without removing any covers)
    There's an on/off switch on the wall, and presumably the cable travels from that, behind the wall, to the back of the boiler.
  • Nada666
    Oh yeah? Might use my power meter to see how much mine uses.

    EDIT: Heh, my earlier estimate was bang on. 4.6 W, so under 5 per year.
    Originally posted by DragonQ
    Well done. Shrug. Your boiler (claims) to only use 0.77 kWh per week. My one uses more than 6 kWh. Either I have a carp boiler or your instaneous reading is misleading. Even if your reading is reliable not everyone will have a boiler that efficient. As I said it is only significant for single people - more than one person using hot water (and paying the bill) it makes little sense to switch it off. But more than 300 kWh per year is easily one third or one quarter of an annual bill for a single person.
  • mjmal51
    Well done. Shrug. Your boiler (claims) to only use 0.77 kWh per week. My one uses more than 6 kWh. Either I have a carp boiler or your instaneous reading is misleading. Even if your reading is reliable not everyone will have a boiler that efficient. As I said it is only significant for single people - more than one person using hot water (and paying the bill) it makes little sense to switch it off. But more than 300 kWh per year is easily one third or one quarter of an annual bill for a single person.
    Originally posted by Nada666
    Something wrong there? Are you measuring the electricity used in winter and therefore the power consumed by the pump for central heating?
    When in hot water only mode the only power is to keep the boiler in standby - negligible. Won't matter if a single person or 10 people in the house.
  • Nada666
    Something wrong there? Are you measuring the electricity used in winter and therefore the power consumed by the pump for central heating?
    When in hot water only mode the only power is to keep the boiler in standby - negligible. Won't matter if a single person or 10 people in the house.
    Originally posted by mjmal51
    I'm pretty sure the boiler uses that. It's an ancient Ferroli Optima 800. On hot water only left on 24 hours a day I end up using an extra six or seven kWh per week. Is this a fault? On reflection 35 W on average does seem very high - a laptop can almost run on that so 35 W should really be its peak, not average, wattage.

    (Could it be just the circuit boards? - cf ridiculous battery consumption of digital radios compared to analogue)
    Last edited by Nada666; 05-06-2013 at 3:36 PM.
  • mjmal51
    I'm pretty sure the boiler uses that. It's an ancient Ferroli Optima 800. On hot water only left on 24 hours a day I end up using an extra six or seven kWh per week. Is this a fault? On reflection 35 W on average does seem very high - a laptop can almost run on that so 35 W should really be its peak, not average, wattage.

    (Could it be just the circuit boards? - cf ridiculous battery consumption of digital radios compared to analogue)
    Originally posted by Nada666
    The pcb on the combi boiler only needs enough power to stay live, even if you run the hot water taps 24 hours a day, the power consumed by the boiler won't really be different to running the taps for 5 mins/day.
    As was stated earlier turning the power off/on to the boiler several times a day is a good way to blow the pcb and end up with a bill for a few hundred pounds.
    A C rated freezer uses about the same as the amount you are quoting of 7kwh/week
    Last edited by mjmal51; 05-06-2013 at 3:50 PM.
  • DragonQ
    What type of power meter did you use to get that result in 3 minutes?

    Boilers are normally hard wired i.e. not plugged in via a 13A socket.
    I've just looked at my boiler (which is not a combi boiler) and there is no access to the power cable at all (without removing any covers)
    There's an on/off switch on the wall, and presumably the cable travels from that, behind the wall, to the back of the boiler.
    Originally posted by Wywth
    Yeah mine is just in a normal 13 A socket so I used my free plug power checker thingy that I got via MSE ages ago . It was a constant 4.6 W for about a minute so I'm sure it's accurate for idle. Obviously when heating water it'll change.

    It's also brand new so I'm not surprised it has low idle power usage. Probably only worth turning it off if I'm away for a few days (or longer) during the summer.

    Well done. Shrug. Your boiler (claims) to only use 0.77 kWh per week. My one uses more than 6 kWh. Either I have a carp boiler or your instaneous reading is misleading. Even if your reading is reliable not everyone will have a boiler that efficient. As I said it is only significant for single people - more than one person using hot water (and paying the bill) it makes little sense to switch it off. But more than 300 kWh per year is easily one third or one quarter of an annual bill for a single person.
    Originally posted by Nada666
    Well I didn't just plug it in a read off the number, I left it for a minute or so and it was constant. How old is your boiler?

    I've actually been checking my appliances that are on all day to find out where the power is going (since I'm using ~150 W when not at home). So far I've accounted for 75 W and the only things I haven't checked are my server (have to wait until for a convenient time since I'll have to turn it off to plug it into the power checker) and the washing machine (can't see where it's plugged in so can't check it).

    Sadly, I can't really economise on most of that 150 W. I can reduce it by about 5 W but that's about it. It means that all of my "expensive kWh" are taken up by my constantly-on items.
  • southcoastrgi
    As you have flatmates (there are at least three of you) then it is certainly not worthwhile. For a single person it can make sense to switch it off - a comb-boiler can easily cost as much for electricity as it does for gas and make up one-third of the electricity bill.
    Originally posted by Nada666
    Well done. Shrug. Your boiler (claims) to only use 0.77 kWh per week. My one uses more than 6 kWh. Either I have a carp boiler or your instaneous reading is misleading. Even if your reading is reliable not everyone will have a boiler that efficient. As I said it is only significant for single people - more than one person using hot water (and paying the bill) it makes little sense to switch it off. But more than 300 kWh per year is easily one third or one quarter of an annual bill for a single person.
    Originally posted by Nada666
    I'm only here while I wait for Corrie to start.

    You get no BS from me & if I think you are wrong I WILL tell you.
  • ahar
    So far I've accounted for 75 W and the only things I haven't checked are my server (have to wait until for a convenient time since I'll have to turn it off to plug it into the power checker) and the washing machine (can't see where it's plugged in so can't check it).

    Sadly, I can't really economise on most of that 150 W. I can reduce it by about 5 W but that's about it. It means that all of my "expensive kWh" are taken up by my constantly-on items.
    The server could be taking up a significant chunk of that 75w, depending on what you've got running. I seen people quote around 50w idle for a HP micro server with 4 disks, and even my ARM based qnap NAS pulls 25-30w when idle.
  • Nada666
    Originally posted by southcoastrgi
    What is it that is amusing?
  • DragonQ
    The server could be taking up a significant chunk of that 75w, depending on what you've got running. I seen people quote around 50w idle for a HP micro server with 4 disks, and even my ARM based qnap NAS pulls 25-30w when idle.
    Originally posted by ahar
    Yes, I fully expect it to. It used to run at 39 W when idle with an AMD E-350 setup but since then I have upgraded the hardware to be more capable so the idle power usage should be higher. It has 8 HDDs and an SSD but the HDDs are spun down unless needed and so use minimal power.

    I doubt the washing machine uses much, considering that's brand new too.
  • southcoastrgi
    What is it that is amusing?
    Originally posted by Nada666
    because your figures are way out, the boiler will use hardly any electric & the pump around 50w, so all told about the same as a light bulb so hardly a 3rd of your total electric bill
    I'm only here while I wait for Corrie to start.

    You get no BS from me & if I think you are wrong I WILL tell you.
  • Nada666
    because your figures are way out, the boiler will use hardly any electric & the pump around 50w, so all told about the same as a light bulb so hardly a 3rd of your total electric bill
    Originally posted by southcoastrgi
    50W is four to six light bulbs, not one.

    I have checked over the years for other daemons and really have not identified any. I switch everything off except the boiler and leave for a few days - meter increments by less than a kWh per day. Switch the boiler off too - no change.

    As far as I can see there are boilers today rated at 14W standby - an A rating seems to be 10W and less (may be wrong there) (though most achieve 5W or less). If boilers sold today use 14W it doesn't seem impossible that a boiler made seventeen years ago would use 35W. Electricity was a lot cheaper then.

    6 or 7 kWh is a third or more of my electricity useage - I only use 14 to 18 kWh per week excluding that.
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