Economy 7 and energy usage concerns in new flat

WiserMiser

Leave both the cupboard switches on and leave the Horstmann slide switch on Manual Boost.  Then the lower heater will give a tankful of hot water which should last the day, and the upper heater won't be switched on automatically by the Horstmann.  You can tweak the lower heater's start time so that it's not heating up before midnight and leaking a little bit of heat unnecessarily in the small hours.  Set it to switch off shortly before the end of the cheap rate period.

After that it should happily run without needing much attention (well, until the meter is replaced or GMT returns).  Just press the Boost button on the Horstmann if the water occasionally runs cool before the end of the evening.

The icing on the cake would be to replace the switched outlets in the cupboard with ones which have an indicator light, then you'll be in absolutely no doubt what's live and when.  New switched outlet boxes aren't expensive.

It's not as bad as it sounds.  You just have to remember that the Horstmann is totally dumb, it has no absolutely idea what the real cheap rate times are, it'll unthinkingly keep doing exactly what it's been told to do, warts and all.  That's great, but the onus is on you to get it right.  However, now that you understand the system better, it should be quite straightforward.  Just check it from time to time, especially after the clocks change.

The thin wire is probably a temperature probe next to the tank and connected to a thermostat via the thin wire.

Simelthwate

Scot_39 said:

Thanks @WiserMiser

I didn't realise that off peak LED was just programmed time.

https://www.tlc-direct.co.uk/Technical/DataSheets/Horstmann/EL7_U.PDF

I read to much into the difference between programmed times and the "cheap period" you should program them inside.  As that implies the installer might only have set for a fraction of the period or periods. And added 2+2 together - as in simple systems like mine - the one main element is just connected to off peak restricted supply.  

(Actually I used to have a boost button - that operated one of the contactors on my old RTS switch / meter - for HW output only (separate from te ain NSH output) - haven't had or needed boost since on spit off peak E10 - as it is het 3x per day)

Sorry @Simelthwate

No need to apologise at all. I appreciate you trying to get to the bottom of this.
Yes, it seems the off-peak LED just matches programmed time, not the actual off-peak period. What a palaver.

Simelthwate

WiserMiser said:

Regarding E.On Next, you need to get them to rebill at the correct rates, night being the cheap rate.  Unfortunately there's nothing you can do if the Horstmann was switching the immersion heater on at the wrong time, that's water under the bridge and sadly it's your problem not theirs.

However, you should ask for compo from E.On Next for the serious overcharging: it should never have been allowed to happen.  Ask for £100 politely but firmly, and consider accepting £50.  Or £150 and settle for £100 if you're bold !  Go to the Ombudsman if they don't play ball.

Unfortunately you'll have to check the times and re-program the Horstmann again after the meter has been changed because the new E7 times won't be exactly the same.  The only way to be sure will be to check the new meter's display, you mustn't rely on what you are told or read because it'll be an expensive mistake forever if you get it wrong.

I see that the Horstmann programming error is my problem not EOn's, but please could you explain the compensation aspect to me a bit more? What is it that they would be compensating us for? The bill shows three times as much billed at 15.625p (295.7kWh) than at 32.143p (93.7 kWh). If they should have charged 295.7kWh @ 32.143p instead of 15.625p then they have undercharged if anything. I feel like I am completely misunderstanding the situation.

Thanks, I will remember to reprogramme the Horstmann once the meter is changed. I definitely do not want to make an expensive mistake. 

Simelthwate

WiserMiser said:

Scot_39 said:

As the post by @WiserMiser has pointed out - I think we were both mistakenly interpreting off peak LED as literally off peak from meter.

(The same way some posters here ask if the NSH or immersion spur has a LED on the switch to indicate wires live)

It's always a good idea to have an easily visible indicator on a storage heater supply so that you know when the night rate is available and you can use high power appliances more cheaply.  It also allows any unexpected changes in the times to be spotted, very important if using local timers.

Scot_39 said:

I'll leave it between you and your sister if you want to narrow down the rate timings - and if so - via the meter cabinet - or in home via a live wire connector - or listening for the NSH charging to save such trips - around c23:30 or c0730 c0830 would seem obvious test points..

It's essential to know the exact switching times if you're using local timers like the Horstmann.  You can check over a few evenings if you don't want to keep staring at the meter.  Having established the exact start time, you can then check almost seven hours later.  If it switches back after exactly seven hours then it's 'job done'.  If not, it's probably a 'split shift' cheap rate, so it would need checking almost nine hours after the cheap rate starts.

The best solution is to feed the immersion heater and the NSHs from circuits switched by the meter, then heating up anything at peak rate will be impossible unless the boost button is used.  However, that does require wiring changes and potential redecoration, which is why some people settle for the 'cheap but fiddly and risky' local timer solution.

Thanks. There aren't any indicator lights on the storage heater supply at present so I will try to get these installed if new storage heaters are put in. 

Right then, I will find out the exact start time and check approx 7 hours later. I hope that'll be the end of it.

I will certainly investigate the option to have the immersion heater and NSHs switched by the meter. My mum is planning to redo some of the rooms and probably get new NSHs so depending on the cost of the wiring changes, some potential redecoration will be fine.

WiserMiser

Simelthwate said:

WiserMiser said:

Regarding E.On Next, you need to get them to rebill at the correct rates, night being the cheap rate.  Unfortunately there's nothing you can do if the Horstmann was switching the immersion heater on at the wrong time, that's water under the bridge and sadly it's your problem not theirs.

However, you should ask for compo from E.On Next for the serious overcharging: it should never have been allowed to happen.  Ask for £100 politely but firmly, and consider accepting £50.  Or £150 and settle for £100 if you're bold !  Go to the Ombudsman if they don't play ball.

Unfortunately you'll have to check the times and re-program the Horstmann again after the meter has been changed because the new E7 times won't be exactly the same.  The only way to be sure will be to check the new meter's display, you mustn't rely on what you are told or read because it'll be an expensive mistake forever if you get it wrong.

I see that the Horstmann programming error is my problem not EOn's, but please could you explain the compensation aspect to me a bit more? What is it that they would be compensating us for? The bill shows three times as much billed at 15.625p (295.7kWh) than at 32.143p (93.7 kWh). If they should have charged 295.7kWh @ 32.143p instead of 15.625p then they have undercharged if anything. I feel like I am completely misunderstanding the situation.

Thanks, I will remember to reprogramme the Horstmann once the meter is changed. I definitely do not want to make an expensive mistake. 

They seem to be making a very basic mistake that would result in serious overcharging.  Even if initially in your favour, that would only be temporary and you'd be disadvantaged forever.  If so, there's really no excuse because it's so obvious, the whole point of E7 is that the night rate is always lower to allow heat to be stored, full stop.

Wait until the problem has been resolved and then request compo if, as seems highly likely, there's simply no excuse for having made such a mistake: it has wasted your time,  caused worry and would have resulted in ongoing financial losses.

You may well find that compo is offered automatically.

WiserMiser

Simelthwate said:

WiserMiser said:

Scot_39 said:

As the post by @WiserMiser has pointed out - I think we were both mistakenly interpreting off peak LED as literally off peak from meter.

(The same way some posters here ask if the NSH or immersion spur has a LED on the switch to indicate wires live)

It's always a good idea to have an easily visible indicator on a storage heater supply so that you know when the night rate is available and you can use high power appliances more cheaply.  It also allows any unexpected changes in the times to be spotted, very important if using local timers.

Scot_39 said:

I'll leave it between you and your sister if you want to narrow down the rate timings - and if so - via the meter cabinet - or in home via a live wire connector - or listening for the NSH charging to save such trips - around c23:30 or c0730 c0830 would seem obvious test points..

It's essential to know the exact switching times if you're using local timers like the Horstmann.  You can check over a few evenings if you don't want to keep staring at the meter.  Having established the exact start time, you can then check almost seven hours later.  If it switches back after exactly seven hours then it's 'job done'.  If not, it's probably a 'split shift' cheap rate, so it would need checking almost nine hours after the cheap rate starts.

The best solution is to feed the immersion heater and the NSHs from circuits switched by the meter, then heating up anything at peak rate will be impossible unless the boost button is used.  However, that does require wiring changes and potential redecoration, which is why some people settle for the 'cheap but fiddly and risky' local timer solution.

Thanks. There aren't any indicator lights on the storage heater supply at present so I will try to get these installed if new storage heaters are put in.

I will certainly investigate the option to have the immersion heater and NSHs switched by the meter. My mum is planning to redo some of the rooms and probably get new NSHs so depending on the cost of the wiring changes, some potential redecoration will be fine.

To eliminate the risk of charging at peak rate, each High Heat Retention NSH will need a 24/7 supply for the control system plus an overnight E7 supply switched by the meter.  Some HHR NSHs have a built-in instant boost heater to allow daytime top ups (a bit like the Horstmann button).  Make sure the new heaters are not programmed to allow this to happen automatically, and if in doubt about the heater size get the larger version.

You don't want to end up with some that are too small and keep needing expensive top ups during a big freeze.  Just like the Horstmann, best to understand the system and program it yourself rather than rely on the defaults or what the installer decides.

Simelthwate

Scot_39 said:

1) Off peak times

Beware - their are many meter set-ups that do not use the standard regional timings - like 00:30 to 07:30 (which would be GMT anyway - so 01:30 to 08:30 B/DST )

So Firstly beware of anyone telling you what your E7 times are, not all in some regions - use the same times.

Whilst 7 hours in a solid block - other variants - like 2+2+5 or even 3+4 splits are possible.

I'd probably trust the offpeak light on the switch more than a casual enquiry with customer services given what looks like an older digital install with external timer control.

If you cannot hear anything - at the tank - once hot the water can often be heard bubbling off the element in older tanks - you could try turning on one of the NSH - again you might hear the heater as heats / expands or at a push - you could check the imp flash rate on the meter if suitable access at that time possible (not easy in some flats)  - 3kW for a typical immerion heater on the meter should be a real flash rate frequency changer.

Other options include a live wire detector from a DIY store - or non contact pen / meter if electrically savy.  (DO any of the NSH fused spur switches or HW timer feed switch - have a little led on them ?)

Anyway - 

If you post your region / distributor ID code and  MTC from their bill MPAN(s)

https://www.ssen.co.uk/our-services/service-information/what-is-a-mpan/

or

https://en.wikipedia.org/wiki/Meter_Point_Administration_Number

Their are a couple of knowledgible people who may be able to track down precise timing information - using something called SSC codes and the associated TPR timings - from the region and MTC.

2) Meter

Secondly cannot see your meter clearly - but looks like an older digital generation that needs an external time switch - to set the use of peak/off peak rate - and to actually switch the restricted supply for the NSH / HW immersion heater. 

You can see their is only one live output tail on the meter itself - which will be live 24/7.

If you visit again could you take a clearer piciture or give us the meter type - looks maybe like an Ampy 5235D or similar earlier / later variant.  (May even have been under Landis+Gyr brand - who rebadged ampy models after buyout)

And try to follow the thin grey wire - and supply a photo - if safe to do so - as in the case of the Ampy - that would be the meter's external rate selection input - often from an RTS or electromechanical time switch (which can drift hideously in any case with say power outages as age).  

Which assuming you do have a restricted off peak only feed to heaters and HW tank - as some of the labels on the CU indicate - would also be driving a seperate meter tail to flat CU.

3) Shower + HW

WAter is something many overlook in larger properties - but in smaller modern efficient design flats - or for those like me who avoid higher room temps to save money at current rates - HW can be a significant share of mix.

 

Showering can consume a lot of electricity - and with e7 timing - that may or may not be at your mums peak rate.

A 10m wash under 9kW shower - 1.5kWh - 52p at 35p/kWh. At off peak a lower 23p etc.

Women sometimes with hair care even longer.

And if your mums elderly / infirm - my mum when really started to lose mobility - could often be 20 minutes plus some days  - so upto 3 kWh.

It might very well be worth staying large tank - if the pressure good enough to drive a plumbed in - thermostatic valve controlled mixer shower - instead of the electric so can shower using water mix with the hot charged consistently at off-peak rate?

I am a lowish user and a low temp setting heater - so my HW is in itself about a third annual consumption - almost enough to make E7 viable vs single rate.

1) Off peak times - I think we have covered this in our later posts

3) Shower + HW - showering will be at peak time. My sister has cut down on the number of showers due to the cost but with long hair it does take 20+ minutes per shower. I think my mum is similar but has more frequent showers.

They currently have 9.5kWh showers but one of the reasons it takes my sister so long to have a shower is because to have the shower at a reasonable temperature requires lowering the pressure and the area the shower head covers is small so it takes a long time to even get her hair wet and to then rinse out the shampoo. I don't know if a bigger shower head would help. I feel like it may cover more of her head at once but with a weaker spray. Because most of the body is not covered with hot water at any point, like it was with a good shower at my mum's last property, they are also cold when having a shower. I think they will be too cold to have a shower in winter. I have used it once and I was cold even when it was 25 degres outside. 

Mum had a couple of companies round to quote for new heating and hot water. They both suggested a storage heater in the hall and lounge and a panel heater or electric radiator (e.g. Rointe) in each bedroom and the kitchen. For the 2 bathrooms (one ensuite), one said a heated towel rail in each and one said a downflow heater in each.
For the water, one suggested a Sunamp Thermino which heats up off-peak and the other suggested a pressurised cylinder that could feed one shower and the sinks, and keep the other shower electric. They both quoted about £8k inc installation which is obviously a massive expenditure and not one that could ever be recouped financially in terms of reduced electricity costs vs old, inefficient equipment. But it would hopefully improve quality of life having more controllable NSH than 30+ year old ones. We would still need to resolve the issues with the electric showers being inadequate.

I do wonder whether these companies are massively overcharging or £8k is reasonable. They are largeish, national companies (not Fischer) that specialise in electric heating, rather than say a local electrician who may be able to do it a lot cheaper if we bought the radiators/NSH ourselves and they just installed them. I would be a bit concerned that they wouldn't have the expertise to set up the NSH/water heater properly and we'd end up being charged peak rates to charge them up. This may be a completely unfounded worry, but looking online there don't seem to be many electricians in the area that mention electric heating as one of their services. Hence the enquiries with the national companies.

The majority of the flats in my mum's block have had the old NSH removed and have had electric radiators installed instead. They say it's a lot cheaper, although I'm not sure how. Quite a few have had the immersion tank removed/disabled and had undersink water heaters installed in the kitchen and bathrooms instead. None of the ones I've spoken to have a Sunamp Thermino.

Scot_39 said:

Ofgem do produce TDCVs for electric - the mid one now 3900 kWh pa - so just under 11kWh per day including winter - I used to be over the old one 4200 (with 1+1 part time way over) single - below new 3900 kWh - but only by running low temperatures (14/15, 15/16 max 17 living room).

But if a decent chunk of the 12 kWh current is say showers at peak times - changing that alone might swing the balance for you to stay on E7 even in summer

4 kWh for HW is not high - for 2 - even for casual use - the tank itself will lose 1-2 kWh depending on size - a waste in summer - additional heat for flat in winter.

 

If recently purchased - given your considering HHRs type improvement s etc - what did the EPC say - for heating energy use ?

If they havent been their long - their might be data as a very rough guide from previous users - at swithc sites like 

https://energy.comparethemarket.com/home

It's accurate for me - but others say not so much - try your mums flat - or a similar one in same block etc.

But its rough - I use about half the energy my neighbour does - every degree - 2 vs 1 occupant  etc etc.

Does the TDCV you mention of 11kWh/day include heating and hot water or just heating? My mum is already at 15-16kWh/day without heating so even with reduced showers they will be massively over this when they start using the heating. 

The EPC was done earlier this year and it improved from a D to a C with the only thing changing being the use of low-energy lighting. They have changed Electric Storage Heaters from 'Poor' to 'Average' even though the original ones are still installed.


The only suggested step they have given to improve the energy rating is to install a gas condensing boiler which is just not possible. No mention of getting HHR storage heaters or any improvement to water heater. They are suggesting an average household would spend £1025 on heating, hot water and lighting which includes 4740 kwH/year on heating and 1931 kwH/year on hot water (5.3kWh/day). I don't know whether the latter assumes showers use water from the immersion tank or not. 

Unfortunately the comparison sites don't show the correct annual usage as the flat was unoccupied for quite a few months so they show a very low estimate.

Looking at other flats, the flat opposite is the most similar to mum's in terms of size, same floor, and having an immersion heater (don't know about heating) but it's occupied by 1 man who goes away quite a bit - he's on E7 with 77% night rate and and uses 7500kWh/year. Some others are 5000 kwH with 82% night rate, 2500 with 93% night rate, 5250 with 13% night rate, 3300 single rate, 3700 with 71% night rate (Single lady who had NSH removed and put electric radiators in last year. She doesn't use immersion but boils kettle to wash up and assume washes hands in cold water). Aside from the flat opposite, I don't know which flats are actually on an E7 tariff even though a night rate % is given for them.

Mum is already on 780kwH from 30 Apr to 20 Jun so approx 5582kwH/year and that's without heating which I imagine will add minimum 5000kWh (based on EPC report) but probably a lot more, so way over the highest of the other flats.

Scot_39 said:

5) Meter old - upgrade due ?

A meter upgrade to smets2 - might be needed - in any case - if meter roughly as expected.

But when it comes to tariff flexibility

You need to remember that heer old NSH likely rely on meter (on smart that would be called ALCS) - with the meter controlled restricted time switched supply matching tariff times - to keep them only charging at off peak - and even if upgrade it probably better to dual wire and keep the charging meter controlled - unless find a compelling tariff / reason not to.

With old NSH tariffs like Cosy or other TOU will generally not offer the same ALCS functionality to reflect the reduced period rates (but you can program newer HHR NSH ones to charge to match if found a really good option - Dimplexd Qs upto 4 periods a day - Elnur ECombi HHRs only 2 iirc).

And if do get one and in a good signal area / location assuming a communal cubpoard - not all are - with older heaters - a switch to Snug Octopus might be a good option for the first winter whilst get a benchmark (before spending £1000+install on larger top end new HHR NSH) - as keeps a cheap 6 hr overnight charge window - but adds a 1 hr boost in afternoon -  to keep old heaters heat lasting better into evening / night time. 

When I got a quote -  it was c30% cheaper off peak than their E7 (9p on snug off peak in my region (EM) vs your mums EOn is 15p - but maybe regional - and even the peak rate was c10% lower than their E7) They couldnt do my meter in their viewable window at the time - might try in autumn after RTS fuss died down if still here.

As we have discussed, I will arrange upgrade from RTS to smets2. Last night I was trying to understand this ACLS and saw a lot of people complaining that their energy provider hadn't set it up properly and they were being charged peak-rate at times that should have been off-peak. Also people having an inapopropriate meter installed or being wired incorrectly. I am nervous about another thing going wrong given the problems we've already had with the immersion being programmed incorrectly and EOn charging the wrong day/night rates. We haven't tried the NSH yet but it looks like once switched on at the wall there is no way to control what time they come on. So again, having the meter set up correctly so that these charge up on off-peak only is very important

Do you know what I can say to EOn to get them to ensure that they send the right person who knows what they are doing when changing from an RTS to a smart meter with E7 tariff so that the right meter is installed and it is set up correctly inc the ACLS?

Thanks for the info about new HHR NSH. They look a lot more flexible in terms of traiffs and controllability. 
   
Based on what you know about the wiring/consumer unit/immersion/NSH setup in the flat, do you think Snug Octopus would be compatible with it once we get a smets2 meter? It sounds good and seems to be 9p off-peak in my mum's area too.

Simelthwate

Robin9 said:

Can we talk about the hot water tank - often located in the airing cupboard.

There will be two electrical supplies to this  - one connected to the top of the tank, the second to the bottom.  The one at the top should be switched off -  this is the daytime booster and should rarely be used as it uses the higher rate. The bottom should be on -  this uses the nightime rates.   

If this is a modern tank with a cream/white jacket it will be well insulated and barley warm to the touch.  The older copper ones used to be fitted with a loose jacket.

Thank you. I showed some pictures of the tank yesterday. It does have a cream jacket. Thankfully we have not used the daytime booster yet.

Simelthwate

@QrizB Thanks. I employed your suggestion of turning the 'Water Heater Day' supply off. I will leave it off to prevent any accidental usage of the Boost.
I also used the video to determine which rate was active so this was very useful.

QrizB

A quick note on instantaneous electric showers.

The outlet temperature depends on the incoming water temperature, the power of the shower and the flow rate.

It takes 4.2 Joules of energy to raise 1ml of water by 1 degree C. With a 9.5kW shower, you're applying 9500 Joules per second.

In summertime, the incoming water might be 15 degrees C. To get a tolerable 37 C shower, you need to raise that water by 22 C. 9500 Joules is enough energy to raise 103ml of water by 22 C, so your shower flow rate will be 103 ml per second - that's 6.2 litres per minute.

In wintertime, the incoming water might only be at 5 C and you need to raise it by 32 C. Now you can only heat 71ml per second and your flow rate is 4.2 litres per minute.

By comparison, a gas combi boiler might be rated at 24kW and under the same conditions can supply 15.5 litres per minute in the summer or 10.7 litres per minute in the winter.

A pumped shower drawing hot water from your hot water tank would be able to match the performance of a combi boiler and would be my suggestion if you wanted a higher flow shower. I would have thought you would get a plumber to install a pumped shower for £1000 or less. (Note this will only reduce your electricity bills if you're heating the water in the tank on the overnight cheap rate.)