Moving into all electric flat with storage heaters and THTC, any tips during the pre-move??

me1000uk

Hi All, 
I appreciate there are so many THTC threads and whatnot as I've tried to go through them but it does seem like there is a fair degree of variability in individual setups. As a result I'm hoping someone will be kind enough to provide some tips in relation to my current predicament The questions themselves are relatively simple I hope but will provide whatever info I can below to set the context as a small detail may change the advice.
The small flat has 2 storage heaters (inside front door and in the living room) and a hot water system (not sure the terminology) but it says on it 'Direct combination, 40L Cold/144L Hot, maximum length of immersion heaters 400mm'. There's also a sign on it saying it's not been tested as system has been drained. (presumably prior to sale of flat). There's also a black thing the size of a smoke alarm on the side, with a wire coming out which I presume is an element as it says 3kw on it. this is in its own cupboard in the corridor. (Note it's a top floor flat with a loft).

I spoke to an energy saving advice line and the recommended I switch to Economy 7 as it's the first thing anyone should do on THTC which apparently isn't something worth sticking to. I checked the rates and whilst economy 7 and the benefits will be cheaper there is some mystery involved without actually testing the waters to see the practical effects/usage.

As I'm going to get some work done on the flat in advance, it's obviously a good time for any changes if need be, but I've never had this done before hence the questions.
Really appreciate any help during this ridiculously stressful time for many. The storage heaters are old manual Dimplex ones, and have 2 switches (presumably one would be a day switch which I don't know why considering it doesn't appear to have any other function except store/release manually, as from googling it seems some have a convection function)

Note we're a family with 2 young children.
1) If I switch to Economy 7, will the hot water and storage heating automatically be switched on/off with the off-peak supply, or do I need to manually do it daily. My friend lives in a nearby flat with a similar setup and he leaves the heaters on and the THTC kicks in at set times (and his storage heaters have only 1 wall switch). Other threads indicate there may be some work required, but they could be different setups to mine. If there already are 2 meters and 1 is cheap, then is it simply a case of the meter switching engineer installing the cheap bits into the off-peak and the regular wiring into the peak? My nightmare scenario would be switching to Economy 7 and charging any heating/hot water to day bits.
2) Is electric shower the best scenario? Hot/cold water comes out fine in neighbouring properties so I think should be fine, but I've seen electric showers where it trickles out if turned to hot. Is that likely a faulty shower as I've in the past used standard mixer showers due to the hot water supply being building-wide. Electric showers are a new experience. Would a mixer shower drain the hot water far too quickly in this scenario.
3) is there any work required that may save me headache in the future? like is there servicing required for the heating or hot water? There will be a new bathroom installed so should I ask them to check/commission anything?

Really appreciate any tips. Crazy time to move but at the time of purchase the world was a bit more normal and things have naturally got delayed by months.

molerat

1) The timing all depends on how your system is wired up.  You should have a separate or split consumer unit supplied purely by the off peak output from the meter.  There is a thread on here where the idiot meter installer did not connect up the off peak at all, leaving the customer with no heating or hot water, and deliberately hiding the spare consumer tail because he had the wrong type of E7 meter with him ! There should not be any need for wiring changes but it is always handy to have an electrician or someone who knows to look at how it is wired.

2) Depends on the type of tank.  If a large well insulated tank, usually about 6ft tall, then you should be able to have a pumped mixer shower without fear of running out with the option of topping up the top of the tank on peak.  If a normal tank then likely an electric shower will be best suited.

3) Again depends on the hot water system.  Nothing for the heaters - fix them when they break and give them a good hoovering every now and then - but sealed hot water systems should have an annual service.

The second switch on the heater is usually for a fan assist, you can often have that wired to a wall mounted stat or manual control.  What heating is in the bedrooms ?

me1000uk

molerat said:

1) The timing all depends on how your system is wired up.  You should have a separate or split consumer unit supplied purely by the off peak output from the meter.  There is a thread on here where the idiot meter installer did not connect up the off peak at all, leaving the customer with no heating or hot water, and deliberately hiding the spare consumer tail because he had the wrong type of E7 meter with him ! There should not be any need for wiring changes but it is always handy to have an electrician or someone who knows to look at how it is wired.

2) Depends on the type of tank.  If a large well insulated tank, usually about 6ft tall, then you should be able to have a pumped mixer shower without fear of running out with the option of topping up the top of the tank on peak.  If a normal tank then likely an electric shower will be best suited.

3) Again depends on the hot water system.  Nothing for the heaters - fix them when they break and give them a good hoovering every now and then - but sealed hot water systems should have an annual service.

The second switch on the heater is usually for a fan assist, you can often have that wired to a wall mounted stat or manual control.  What heating is in the bedrooms ?

Hi there. Thanks a lot for the response. Gives me some hope that I'm on the right track. From the sounds of things Economy 7 is the way to go and I can later switch supplier from the legacy. The energy advice line and the supplier both seem confident that there is no way the storage heaters will take day rates unless I use the wrong switch. They seem keen enough to get rid of the thtc as they are a specialised team and it takes an effort to find the right expert on them. I presume economy 7 has 2 methods of connection. So the standard meter will be connected to the standard rate and the other heating meter will be connected to the off-peak rate, so I assume supply should be maintained provided no mess up from their side. The old meter is a prepaid one anyway so has to be changed and I have the choice of thtc or economy 7.

I will check with the bathroom fitters or separate electrician or plumber to see what service can be done to the water tank. As mentioned it said 144L hot on it so I assume that's the capacity. With a couple of showers that would be drained very quickly so Electric I guess makes sense from what you say. Electric showers seem to trickle on hot, but I guess what I've seen must be old or something as surely no-one would get an electric shower if it doesn't provide an acceptable flow.

In terms of bedrooms they seem standard panel heaters but unlikely to get too much use as whilst a 2-bed, the flat itself is small so will get plenty of heat from the storage heaters.
No idea if the second switch on the wall provides a fan or not I guess I'll be in for a surprise to see what happens or if it works, my friend doesn't have a second switch. I have also been told by the advice line that replacing the storage and panel heaters with modern equivalents with better timing etc generally isn't a major decoration job so it can be done at a later date without too much inconvenience if needed. 

As a side note, on economy 7 would the washing machine be charged at night rates during the night period as presumably it would be wired into the day rates. Would make sure to get a washing machine with a timer if I can utilise night rates.

Thanks again.

Gerry1

Everything is charged at the lower rate overnight on E7 however it's wired.  You need a meter with a 5th port that can be used to switch the dedicated circuits that supply the E7 NSHs  and the immersion heater (the lower one if there are two).  They may also need a 24h circuit if they have a convector bolted on for an expensive top up in the evening, which is likely because the THTC hours were designed for NSHs that by today's standards were badly insulated and under dimensioned.  You may wish to consider adding another NSH (possibly second hand) or upgrading to clever modern ones which don't waste so much heat overnight and have a fan to blow out heat only when needed.

If there's only one immersion heater then it's probably on a 24h circuit, probably with a local timer and perhaps a boost switch that can be used in emergency to get a dollop of expensive hot water if you've messed up or been away.  It's very important to understand how the immersion heater(s) work because it will be cripplingly expensive if you're heating water at peak E7 rates (which are even higher than single rate)..  An instantaneous electric shower should be avoided for this reason.

Silly question: is it absolutely impossible to get mains gas?

me1000uk

Gerry1 said:

Everything is charged at the lower rate overnight on E7 however it's wired.  You need a meter with a 5th port that can be used to switch the dedicated circuits that supply the E7 NSHs  and the immersion heater (the lower one if there are two).  They may also need a 24h circuit if they have a convector bolted on for an expensive top up in the evening, which is likely because the THTC hours were designed for NSHs that by today's standards were badly insulated and under dimensioned.  You may wish to consider adding another NSH (possibly second hand) or upgrading to clever modern ones which don't waste so much heat overnight and have a fan to blow out heat only when needed.

If there's only one immersion heater then it's probably on a 24h circuit, probably with a local timer and perhaps a boost switch that can be used in emergency to get a dollop of expensive hot water if you've messed up or been away.  It's very important to understand how the immersion heater(s) work because it will be cripplingly expensive if you're heating water at peak E7 rates (which are even higher than single rate)..  An instantaneous electric shower should be avoided for this reason.

Silly question: is it absolutely impossible to get mains gas?

Hi there, thanks for the response. The flat is completely electric I'm afraid so no real option of gas. In terms of getting another storage heater it will probably be an option budget-wise in a few months so will look into it.
In terms of the tech side it sounds confusing for a layman like me. The flats themselves aren't mega old, (mid 90s) so I am hoping the wiring isn't something too unusual. From your advice I guess I need to work out what the immersion heater is doing, There is some kind of timer on the kitchen wall which I have no idea what it does and I presume is connected to the hot water. It says electrisaver on it and a boost button which ties in to what you're saying. From what I can tell on the tank it appears to have one element. I'm not sure if that's just wired to the THTC meter always at the cheap rate (which may be the case).

I will need to sort out the electricity in the next couple of weeks (change meters/activate supply) but the flat may not be used until early 2021 so now I guess is the time for adjustments. It still seems like Economy 7 is the way to go provided I don't do accidental day usage.

I don't think I have much option but to use an electric shower. It seems the building and neighbours all have them as if I'm using the tank it'll run out of hot water soon.
So I guess another question to add to my list when the meter guys come is the hot water and will it get switched on during the day. I presume an electrician wouldn't have much trouble installing something to regulate that.

jbuchanangb

Among all this don't forget that as soon as you have the keys to the place, you have to contact the current electricity supplier and open an account with them on standard terms, whatever they are, for the existing configuration. Photo the meter(s) and provide the readings. Whatever else you do you have to start from that baseline.

me1000uk

jbuchanangb said:

Among all this don't forget that as soon as you have the keys to the place, you have to contact the current electricity supplier and open an account with them on standard terms, whatever they are, for the existing configuration. Photo the meter(s) and provide the readings. Whatever else you do you have to start from that baseline.

Yep thanks I already had that discussion with them as due to the pandemic things got delayed and they wanted to charge me for the existing prepay meter but we reached a point where they'll wipe the charge and start from scratch with the new meter that they install so that is the one positive!

Gerry1

The immersion heater timer can be used on a 24h supply so that it mimics the cheap rate period for E7.  But you must be absolutely certain about this - look at the meter on wall and see exactly when it switches over.  Don't forget that some areas have a two hour gap in the cheap rate, e.g. 2230 - 0030 and 0230 - 0730 GMT.   There's often a local timer than can give you a daytime boost of up to two hours,  use it only in emergency.  Beware mechanical timers that can go out of kilter after a power cut.  It's a bit of a bodge - a separate E7 circuit switched by the meter is much better and avoids the risk of bill shock from a wonky or wrongly set timer.

If there's a conventional switch (possibly labelled Boost) for a second immersion heater, leave it permanently off for the same reason.  Using hot water at daytime rates will bankrupt you !

You may be able to find a conventional NSH via Freecycle or Freegle.

me1000uk

Gerry1 said:

The immersion heater timer can be used on a 24h supply so that it mimics the cheap rate period for E7.  But you must be absolutely certain about this - look at the meter on wall and see exactly when it switches over.  Don't forget that some areas have a two hour gap in the cheap rate, e.g. 2230 - 0030 and 0230 - 0730 GMT.   There's often a local timer than can give you a daytime boost of up to two hours,  use it only in emergency.  Beware mechanical timers that can go out of kilter after a power cut.  It's a bit of a bodge - a separate E7 circuit switched by the meter is much better and avoids the risk of bill shock from a wonky or wrongly set timer.

If there's a conventional switch (possibly labelled Boost) for a second immersion heater, leave it permanently off for the same reason.  Using hot water at daytime rates will bankrupt you !

You may be able to find a conventional NSH via Freecycle or Freegle.

Thanks, when the electricity gets switched on and whatnot I'll keep an eye out. Will also contact the number on the tank to see if the manufacturer/installer has any info. Probably best to service it as it's been drained for a while! Will check with the bathroom fitters and plumbers if they can advise too.

me1000uk

So with the electricity supplier failing to make the appointment in changing the meter I still have some leeway.
Having spent time in my friend's flat with a similar looking setup, it appears their Panel heaters are hooked into the off-peak circuit as well as when the panel heaters were switched on, the cheap meter was going up with a spinning disc at the bottom.
I suspect the water and potentially electric shower is hooked up to this too but need to find a way to work this out because the peak meter only goes up by around 4-5 in a day and the off-peak around 30 which sounds like massive amounts of heating and probably showers all going off the 'cheap' meter.
At 15/19p for the THTC rates it's not comparable with E7 price-wise which is something like 11/18p, until you realise that an E7 usage pattern may well have half your usage at 18p and the THTC has 85 percent of your usage at 15p.


I think going to E7 may mess me up in this scenario against the advice of the energy helpline and even the supplier, but obviously as a layman I could be missing something obvious.

Should I stay with THTC and see if scottish power or edf can offer a complex meter tariff (form browsing online it may be possible)?

Is it right in thinking that on both economy 7 and THTC the storage heaters and immersion heaters are inefficient because why would you want your tank to start heating at 0100 when in theory you could start heating at 0500 or something, especially if there's a lunchtime switch on from the supplier during winter for THTC. There seems to be a lot of redundant heating overnight?
Are timer's the solution in this case and do they last years or are they invitations to failure.
Maybe I'm missing something obvious. I wonder if an electrician can work this out quickly or it's hidden in the wiring somewhat and more money for just confirming the obvious. I think I've aged a couple of years just thinking about this because once I've moved in with the kids the last thing I want is having to do complex wiring in a freshly decorated home. It's now or never really.

qwert10

Hi I used to have storage heaters for years and loved them but I did have an open fire to top up.
There are energy deals where you get either free or really cheap energy at night worth a look but but rate dearer in day. Also you will save on gas standing daily charge.
The older storage heaters are more reliable than new ones mine had bricks inside and were second hand and in 20 years never went wrong.sure yours are newer.
Anyway you can save by checking out the exact timing of the cheap rates (varies by area and supplier) and heating hot water at night as mentioned and showering before the higher rate kicks in. (easier in summer cheap rate kicked out at 8 or 8.30 am).Also I used to iron early morning once a week and cook a joint etc. You can also use washer/dryer/bread-maker then etc
Also used to recharge everything overnight.
I would beware with the panel heaters as can be very dear to run. Also keeping doors shut is essential as once the heat has come out during the day you won't have any more.
Hope it goes well,