Can someone help me with peak and off peak immersion on a hot water cylinder please?
Posted by checkthisgram@reddit | AskUK | View on Reddit | 49 comments
Recently moved into a 1 bed flat, by my self and my electricity bill came through as £90, which shocked me, I’ve spent the last few days trying to see what has caused this, I have a cylinder with 2 immersions, off peak on bottom and peak on top, I never use the peak but yesterday I drained all the hot water out of the cylinder and turned the off peak switch on at 1pm, by 5pm the cylinder is full of incredibly hot water, I’m not sure why, I thought off peak was night only.
I don’t want this to be running 24/7
Ambitious-Health-132@reddit
Did you figure this out? I've just moved into an apaartment and just got my first bill which was £157?? We have electric heating and an immersion heater, never had either before. I'm very confused. How do you make it so it just reheats at night or something? I can't pay almost £200 for electricity alone in a 1 bed flat..
checkthisgram@reddit (OP)
It was only the first month that was £90 odd, I was turning the immmersion on when needed and left my bedroom radiator on at night times.
I’m lucky to have an off peak emmersion heater so I just leave that on 24/7 and I haven’t turned my heating on since and now it’s £33 a month.
The biggest was definitely the heating, electric rads / storage heaters are the worst
Ambitious-Health-132@reddit
I haven't got a clue how to check anything with our immersion heater. It's just a big blue tank that says Economy 7 on it, there's no dials or anything. Just a box on the wall with 4 buttons (adv,prog,BST,time).
Do you know anything about them? :') I'm flabbergasted by this bill we've received
checkthisgram@reddit (OP)
So economy 7 means you get 7 hours of off peak electricity (night time) so anything electric you use is cheaper during that time, you’ll want to check exactly what hours they are, and use the time switch to set your immersion on for them so it heats up on a cheaper price over night, you’d be surprised how long that water in the tank will stay hot for
RippedSlo0th@reddit
Sounds like your off peak heater is wired into the normal circuit.
checkthisgram@reddit (OP)
How can I find this out?
RippedSlo0th@reddit
I have no idea without seeing the set up.
Classic_Mammoth_9379@reddit
The “on peak” heating element is at the top, so it will heat just the top half of the water - which you might want if you need water when electric is expensive. Conversely the “off peak” element is at the bottom so heats all the water.
How your electricity is charged and how your timer works is entirely separate to that. Are you even on an economy 7 tariff?
checkthisgram@reddit (OP)
I think I am, but what I’m concerned at, is why is my water being heated during peak times
Classic_Mammoth_9379@reddit
Based on what you said, it’s because you turned it on at 1pm. What I’m trying to say is that the naming of the elements is based on their intending use, it doesn’t mean they only work at specific times, unless your timer/control system does that. If you manually turn it on, then it’s on.
checkthisgram@reddit (OP)
So it’s not a switch that will only heat it on off peak hours?
u7N269eEYxJw@reddit
I owned a small flat with Economy 7, it had storage heaters that were on at the wall but only heated overnight during the Economy 7 period.
The hot water system was the same as yours, the lower element was on all the time but only heated overnight during the Economy 7 period. There should be a thermostat on the tank that controls the tank temperature, this will stop the element from overheating the water.
The top element was manually switched on and off as needed, I never switched it on, the overnight heating was enough to heat the entire tank.
Have a look here on the Octopus energy site, it should help you identify your meter and see what energy you are using and whether you are on an economy 7 tariff.
https://octopus.energy/help-and-faqs/articles/how-do-i-read-my-meter/
The app should show you your usage too, I have an economy 7 meter but chose to pay a flat rate across both bands as the daytime unit cost is a lot more expensive, working from home consumed more peak rate electricity and was cheaper on the flat rate. Depending on your meter and how Octopus have set it up, you may be able to see hourly usage. You may see higher usage after 1:00 pm or whenever your off-peak is set to start.
Give Octopus a call, they are very helpful.
You can check to see whether your hot water turns on and off correctly, turn off the top element and listen for the water heating, it’s no different to a kettle. Then listen at the start of off=peak, you should hear the tank starting to heat. I know the off-peak may be 1:00 am, but you only need to do this once. In the morning it should be quiet as the power is off at the meter, you shouldn’t hear anything all day, even if you do use the water.
That should save the cost of an electrician coming out at least. The only other possibility is that the thermostat on the tank has failed, this will look like a small box cut into the tank cladding, or that it is set above 60°. Hopefully everything works out and you should start to see a reduction in your electricity bills.
checkthisgram@reddit (OP)
Thank you, I’m very grateful. I’ll have a look into this
Classic_Mammoth_9379@reddit
I’m just someone on the internet that has never seen the system and only has your words to go on… but the evidence you relayed suggests that is the case. Seems unlikely a physical switch would know what time of day it is.
Candid-Bike-9165@reddit
Typically the meter switches the eco7 devices on itself the user shouldn't have to be up a 1am to switch on their hot water
Classic_Mammoth_9379@reddit
I am expecting there to be some device in the flow that CAN be used to control the supply on a timer, just isn't clear from the context that this is the case here, especially given the behaviour described i.e. if this was on a separate circuit controlled by the meter, then flicking the switch at 1pm wouldn't have turned the heat on immediately.
Candid-Bike-9165@reddit
I think you're mixing up eco10 and 7 with 10 only some electricity was metered on the cheap rate
With 7 all electricity used during off peak hours is charged at off peak hours
as OP has a duel immersion with peak and off peak his was originally set up with a switched off peak circuit which is switched on by the meter
Classic_Mammoth_9379@reddit
True, I was more saying that I don't believe there is a requirement to have a second switched circuit these days, you can still have a dual tariff meter but only one always-on circult if you want. I certianly agree that with the immersion and storage heaters, there must be some way to have them only operate off peak, but there are a lot of options. And most immersions I've seen have controls that allow them to be directly powered outside of timer/external controls.
checkthisgram@reddit (OP)
Thank you for your input
Basic-Pangolin553@reddit
Because you turned it on. You had it on for like 4 hours too, thats gonna use a lot of electric. Get yourself a count back timer switch for the on-peak switch so its never on for longer than an hour or so.
checkthisgram@reddit (OP)
So it’s not a switch that will only heat it on off peak hours?
Basic-Pangolin553@reddit
Nope. They will both work any time you switch them on, but the logic is that the on peak element takes less time to reach it's temperature and cut off, so uses less electricity when electricity is at its most expensive. The off peak element has to heat the whole tank so it will take ages to reach its cut off temperature, and will use way more electricity to do so, so you only want to use that at night when electricity is cheaper
Jumpy_Imagination208@reddit
Mine stays on all of the time, between 8pm and 2pm it heats up (just the setting on it, nothing I can change). When I need extra hot water, I press the peak button, I never have the peak button on for more than an hour/ hour and a half.
I try to remember to do any charging after 8pm. Although sometimes I think about waiting until 8pm to run the washing machine, I also live in a flat and don’t want to run it too late.
My bill is circa £70 each month- electricity is my only form of energy (ie no gas).
checkthisgram@reddit (OP)
For some reason my hot water seems to be heating up 24/7. Not sure what to do.
How do you heat your home, I have panel heaters but they seem to cost a lot so I’ve just chose to be cold instead
Alternative-Bee2962@reddit
Do you have storage heaters in your flat? If so are you on an economy 7 tariff?
checkthisgram@reddit (OP)
Yes I have storage heaters
Alternative-Bee2962@reddit
Have you checked that you are on an economy 7 tariff, because if you are just on a normal one that could explain why your hot water is on 24/7 and technically your water should only heat when your off peak electricity kicks in overnight when it would be on the cheaper price and is set to come on using the off peak and you should have a second power supply that runs on the peak electricity so you can override the hot water if you need to heat the tank in the day.
But all electric is expensive and my previous place was economy 7 and my electric throughout the winter for a one bedroom flat was about £170 a month and that was heating my water overnight and two storage heaters plus your normal electricity use for everything else.
checkthisgram@reddit (OP)
£170 is not promising at all, very depressing.
I’ll have to ask around if we are economy 7 unless there’s an easy way to find out?
Alternative-Bee2962@reddit
Look at your tariff on your suppliers account. You should be able to see when you log into your account and will be under tariff details. If it's economy 7 you will have a peak and off peak tariff price.
Do you have two fuse/circuit boards where your electric meter is? If so one will be an off peak board and it will have your storage heaters and water tank and the other one will be all your plug sockets, lights, override for your water tank and cooker for your peak electricity.
If you have this set up and you are not on an economy 7 tariff you need to change your tariff to economy 7 and it should sort out your water heater problem and it will only turn on when your off peak electricity runs when it's just turned on at the off peak power switch (normally midnight to 7am and this will be cheaper electric then what you pay throughout the day) and this is what your storage heaters will use to heat up over night. I hope this helps and makes sense
Jumpy_Imagination208@reddit
I’m really fortunate in that I don’t really have to heat my home that much… it’s EPC rated B. I have electric heaters (not storage ones. Ones that you just turn on for an hour or so when needed…I’ve never had to use the timer programme for them as I’ve never consistently needed heating on at the same time each day).
My issue is more how to I keep it cool in the summer… it’s unbearable at times- I have all the windows open, fans running and plenty of ice in the freezer.
checkthisgram@reddit (OP)
Thank you for your responses
EvidenceWorth4671@reddit
I wonder if you might have an old Radio Tele-Switch (RTS) unit attached to your meter which no longer switches it between high and low rates?
checkthisgram@reddit (OP)
It’s only a 4 year old flat so I don’t think that’s the case
Candid-Bike-9165@reddit
Just a thought try turning on the boost or on peak switch a previous person might have swapped which switch goes to which element you can hear the water heating after a moment also thevswitches should have lights
Other than that yes the eco7 devices shouldn't be coming on during peak hours
You should have two electricity circuits in your flat your meter should switch on the eco7 devices at the correct time itself using that second circuit
I would get ahold of your electricity supplier as theyre responsible for the meter I expect the wrong one has been fitted for eco7
HealthyWhereas3982@reddit
I have off peak/peak timings. My storage heaters are on a seperate E7 timing circuit, and only come on off peak. I have two off peak blocks a day rather than just overnight.
My immersion heater will work whenever I turn it on. I have a timer, and programme it to come on during my off peak hours for 45mins or so. I can also 'boost' it if I need to. Have you got some sort of timer you can programme?
Also, make sure your tank has good insulation round it to keep the stored water hotter for longer.
Ideally, you need to establish what your off peak hours are, and use as much electric as you can during those hours.
checkthisgram@reddit (OP)
I don’t have a timer fitted, which I thought was quite odd when I moved in
HealthyWhereas3982@reddit
Well that sounds like an expensive pain in the arse! Are you renting or owning?
Asking because you could ask your landlord/lady if they know the solution?
If you own the flat, and you have the budget, maybe get an electrician or ask advice about getting a timer fitted. Or if you're up at 7am and your off peak goes off at 8 (for example), put the immersion on then?
Tbh, if it's just for washing up it's cheaper to boil a kettle.
checkthisgram@reddit (OP)
I own the place. I know a sparky who might be able to help, I just didn’t know that an off peak switch would run at on peak hours. Jusy one of them things where if you don’t know, you won’t know
Thanks for your help
HealthyWhereas3982@reddit
No probs, I've grown up with E7 so it's ingrained. Basically, off peak hours will be x times, e.g. 1am-8am depending on your supplier and region.
Whatever you have on at those times will be charged at off peak rates (usually half peak). During peak hours, you'll get whacked with peak rate cost. The immersion heater isn't tied to the off-peak circuit like storage heaters are, so when you use it, you'll pay whatever rate you are on at the time. You just have to know your off peak hours :-) Good luck!
adrianm758@reddit
When my meter was changed for a smart meter I was told economy 7 would no longer work.
HealthyWhereas3982@reddit
I succumbed to getting a smart meter and my E7 still works. I had a long 'discussion' with 'customer services' to get my two blocks of off peak (3-7am and 1.30-4.30pm) reinstated, as they automatically put me on 1-8am overnight. I mostly wfh so the pm session is amazing. It was actually sorted out ok in the end! Might be worth having a word with them about your E7.
Nun-Taken@reddit
Have you signed up to an off-peak tariff? Something like Economy 7.
checkthisgram@reddit (OP)
I have a smart meter in an apartment block with octopus, that’s all I know
Nun-Taken@reddit
A good start would be to look at a bill or the app and establish your tariff. How do you heat the place?
checkthisgram@reddit (OP)
I don’t, as they’re storage heaters, and I’m not paying that price
Candid-Bike-9165@reddit
Mine cost 1-1.50 a night although given your immersion problems your eco7 isnt working
flaninacupboard2@reddit
Hopefully there is a timer circuit attached to your off peak heater, something that looks like a mechanical clock. Send us a picture.
checkthisgram@reddit (OP)
All it says is eco, I will get hold of a picture
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