More flexible electric heaters

QrizB

MalthouseMark said:

QrizB said:

The "average" dual-fuel property (with gas for heating) only uses 2700kwh of electricity a year for everything, which makes me think your estimate of almost 4000 is on the high side.

A bit like the energy cap reports only talk about dual-fuel scenarios. I struggle to find details for electric only homes.

There's a separate energy cap for multi-rate metered homes, which is what essentially all electric-only ones are. Yours was one when you had E7.

Here's Ofgem's latest revision to the TDCVs:

https://www.ofgem.gov.uk/decision/decision-typical-domestic-consumption-values-2023

The multi-rate-metered electricity-only homes are "Profile Class 2". You might think the numbers are low but that's because most electricity-only properties are 1- and 2-bed flats; larger homes that are off the gas grid typically have oil, LPG or biomass heating (or more recently, heat pumps).

MalthouseMark said:

But include my baking habit, and my wife’s baking habit and it may not be that far off. Certainly not near an 80/20 split.

If you're saying you use very little hot water, you might be right. But water heating is usually the biggest single contributor to energy use after space heating.

Gerry1

GDB2222 said:

MalthouseMark said:

Typhoon2000 said:

Economy 7 historically had two circuit. Everything plugged in to the 1st circuit will be normal rate during the day and cheaper during the E7 hours. The second circuit only switches on during the E7 hours allowing you to use storage heaters without having to use a programmer to switch them on at the appropriate time. You have never needed to use the second timed circuit to benefit from E7, you could plug your heater into the main circuit and use a timer.

That's what I seem to remember - two circuits. The Rointe heaters (i.e. "non storage heaters") were fitted into the E7 circuit years ago, before we came, as it is a higher rated circuit capable of running heaters. But they were not running at night so it was costing lots.

The supplier moved us to a single rate and put both circuits into the one supply box to save money (i.e. not doing things at "day rate" instead moving to a comparatively lower "one rate all day or night") However the radiators are fixed in position and plugged into that old E7 night-time circuit. Oh and several of those were single sockets in the past but were swapped to double sockets to so we now use them for other things. In other words if we went to E7 again all the "non storage heaters" would be plugged in to the wrong circuit (which, whilst it is a circuit rated for the higher load of a bunch of heaters, is intended to be used at night) and things plugged in to the double sockets would not work unless it was the E7 night period and that circuit were activated.

Or that's how I see it. I could be completely wrong as what the electricians actually did is not stuff I understand properly. However there's more than enough potential for it to be an utter mess with things we rely on not powered on.

As a simple example the PC that I'm typing this on is plugged into a double socket. The other plug has a radiator fixed to the wall by the desk... that would therefore be an E7 circuit. It would end up only being "on" during the night and therefore would the PC work?! I really don't know!!! I would have expected power to be able to allow a genuine storage heater to work during the day (i.e. run its program).

The whole thing confuses the heck out of me. Which is another reason I'm sceptical about any switch back to E7.

Modern night storage heaters don’t need a separate circuit, so you are okay. The electricity to them stays on 24/7, but they only switch themselves on during the cheap times. So, you don’t need to alter your wiring, as you just wire the storage heaters in place of your existing heaters. 

At least, that’s how I understand it, but it would be great for an expert to confirm.

@GDB2222 Yes, you can use Dimplex Quantums in this way (and probably others) but it can be a high risk bodge because it's quite difficult to find out your E7 switching times.  Ask your energy supplier and you risk getting a call centre agent who doesn’t realise that suppliers don't set the times (it's your DNO); the agent may quote default figures that don't match your meter's actual times.  Even if they do understand the subtleties, they may prefer to fob you off so they can close down your call quickly and boost the number of calls they've answered.

If you use HHR NSHs in this way it's critically important to study the manuals and to program them yourself rather than relying on the default settings or whatever the electrician recommends: he's unlikely to be there around midnight and at breakfast time to see precisely when the meter changes over.  He may think the E7 times are 0030 - 0730 but not realise that in some regions peak rate kicks back in for two hours, probably while your NSMs are still charging.  If your meter's times turn out to be 2230 - 0030 and 0230 - 0730 then the first two hours will always be charged at peak day rate (even higher than the single rate).  The bills will rocket, but he'll remain none the wiser because he won't be paying them.

GDB2222

Gerry1 said:

GDB2222 said:

MalthouseMark said:

Typhoon2000 said:

Economy 7 historically had two circuit. Everything plugged in to the 1st circuit will be normal rate during the day and cheaper during the E7 hours. The second circuit only switches on during the E7 hours allowing you to use storage heaters without having to use a programmer to switch them on at the appropriate time. You have never needed to use the second timed circuit to benefit from E7, you could plug your heater into the main circuit and use a timer.

That's what I seem to remember - two circuits. The Rointe heaters (i.e. "non storage heaters") were fitted into the E7 circuit years ago, before we came, as it is a higher rated circuit capable of running heaters. But they were not running at night so it was costing lots.

The supplier moved us to a single rate and put both circuits into the one supply box to save money (i.e. not doing things at "day rate" instead moving to a comparatively lower "one rate all day or night") However the radiators are fixed in position and plugged into that old E7 night-time circuit. Oh and several of those were single sockets in the past but were swapped to double sockets to so we now use them for other things. In other words if we went to E7 again all the "non storage heaters" would be plugged in to the wrong circuit (which, whilst it is a circuit rated for the higher load of a bunch of heaters, is intended to be used at night) and things plugged in to the double sockets would not work unless it was the E7 night period and that circuit were activated.

Or that's how I see it. I could be completely wrong as what the electricians actually did is not stuff I understand properly. However there's more than enough potential for it to be an utter mess with things we rely on not powered on.

As a simple example the PC that I'm typing this on is plugged into a double socket. The other plug has a radiator fixed to the wall by the desk... that would therefore be an E7 circuit. It would end up only being "on" during the night and therefore would the PC work?! I really don't know!!! I would have expected power to be able to allow a genuine storage heater to work during the day (i.e. run its program).

The whole thing confuses the heck out of me. Which is another reason I'm sceptical about any switch back to E7.

Modern night storage heaters don’t need a separate circuit, so you are okay. The electricity to them stays on 24/7, but they only switch themselves on during the cheap times. So, you don’t need to alter your wiring, as you just wire the storage heaters in place of your existing heaters. 

At least, that’s how I understand it, but it would be great for an expert to confirm.

@GDB2222 Yes, you can use Dimplex Quantums in this way (and probably others) but it can be a high risk bodge because it's quite difficult to find out your E7 switching times.  Ask your energy supplier and you risk getting a call centre agent who doesn’t realise that suppliers don't set the times (it's your DNO); the agent may quote default figures that don't match your meter's actual times.  Even if they do understand the subtleties, they may prefer to fob you off so they can close down your call quickly and boost the number of calls they've answered.

If you use HHR NSHs in this way it's critically important to study the manuals and to program them yourself rather than relying on the default settings or whatever the electrician recommends: he's unlikely to be there around midnight and at breakfast time to see precisely when the meter changes over.  He may think the E7 times are 0030 - 0730 but not realise that in some regions peak rate kicks back in for two hours, probably while your NSMs are still charging.  If your meter's times turn out to be 2230 - 0030 and 0230 - 0730 then the first two hours will always be charged at peak day rate (even higher than the single rate).  The bills will rocket, but he'll remain none the wiser because he won't be paying them.

Does the peak rate kicking back in from 0030 to 0230  reflect the success energy companies have had in persuading customers to start using night time electricity? So, lots of customers have their cars and heating starting to charge from just after midnight.

I noticed that the OP has been using an E7 tariff of around 6p off peak and 34p peak. I am surprised how high the peak rate figure is. Is that something he can get down a bit? 

MalthouseMark

@QrizB, that's an interesting document and table. Thanks for that. Every time the cap goes up I see information about "typical consumption" in the media and it all relates to a gas/electric home not a fully electric one. I did look on Ofgem's site for stuff about the cap as it relates to "fully electric" houses and hadn't found it so thank you for that link. Most useful.

With the water heating comment you made earlier - we really use hot water for a few showers. Our dishwasher heats water as does the washing machine but those are the main uses of water in the home for us on a daily basis. Sure we'd save a little by heating the tank at night on an E7 rate but not as much as might initially be suspected. Most of the water heating in the immersion tank is "topping up" already reasonably hot water rather than heating a tank full of cold.

That 90% of properties in "Profile Class 2" are Economy 7 is interesting and I can see how some properties having multiple meters would drag the TDCV figures down. That said with us at 10,000 kWh in an old house compared to the revised TDCV of 6,700 for a high use scenario I'm not surprised at our use.

Just below the table you clipped in is this one


Showing the typical Profile Class 2 split - which if you look back to my own estimation of 56/44 I don't feel I'm too far off in analysis of my own home.

MalthouseMark

GDB2222 said:

I noticed that the OP has been using an E7 tariff of around 6p off peak and 34p peak. I am surprised how high the peak rate figure is. Is that something he can get down a bit? 

I'm using the E7 tariff off our supplier's website for comparison to my existing non-E7 tariff when doing calculations. (I am definitely not on E7 right now 😉). There may well be better E7 options for peak out there. I simply picked the closest option from my existing supplier for ease.

GDB2222

I checked the E7 tariff that I pay:

It's 27.9p peak and 11.6p off-peak.

It might be worth doing your figures again using those rates, just for comparison purposes.

Scot_39

MalthouseMark said:

@Gerry1 yes, I am aware that whoever put them in fifteen years ago wasn’t “cooking on gas” (I hate to think how old that advert is now).

I did look at @QrizB link in his footer to see what difference E7 might make but couldn’t make head or tail of it. ChatGPT couldn’t give me a good percentage of saving for E7 compared to non-E7. Best it could do after a long chat was suggest savings between 7 and 30%. Let’s be optimistic and use the 30% figure.

We are currently with Utility Warehouse Double Gold tariff and manage to run our home on about 10,000 kWh a year (rolling 12 month average) and £200 per month (again rolling 12 month average) which covers (obviously) all heating and cooking, computers, lighting etc. January is usually the worst month and last month’s bill for December was 1206 kWh at £282 or £299 including standing charge. (UW put our 12 month usage as 9183 kWh),

Assuming £1000 per room to convert (ignoring all the sockets which have been switched in the home and cost of converting the wiring), we have, downstairs, bathroom, two bedrooms, one home office, and a hall heater, upstairs a hall heater and a large odd split-level room with three heaters in it. I’ll call that seven rooms for ease. Call it £7k to convert.

Electricity bills at £200x12 = £2,400.

Assuming that we could save as much as 30% on our usage pattern and bringing £2,400x0.7=£1,680 saving £2,400-£1680=£720 per year.

£7,000/£720=9.722 years to recoup the outlay. Certainly power prices will only go up so it may be less, and if heating is our main component of our bill then savings could be higher and payback time sooner.

That’s a heck of a long payback time.

Which is why I have to look at it in terms of comfort and convenience first and foremost. At our age a long payback time isn’t something to ponder too hard. Real cost savings are all very well… once any changes have paid for themselves.

We took the same approach for getting the place double glazed and used some of a pension lump sum to have more comfort - not to save money. Well worth it!

Updating a few key rooms for comfort (our bedroom, my office, and our lounge) and then, if we can afford it later, changing the hall, spare room, and bathroom, is more likely.

I heat my 2 bed home with just 3 nsh - in both halls and living room.

But to be honest it's likely you will need more than 1 nsh in your bigger rooms if like it warm.

Your £25 is around 100kWh - that's a lot but 4 large nsh could store that daily on e7. 5 at a push if that suits your living arrangements.

My neighbours replaced one 3.6kW input on e10 with 2x2.7 kW input quantum 125s and replaced their old  1.7kW input ones in halls with same.

They wanted to guarantee 21C in living room - about 4x4.5 cavity wall filled end of terrace intheir case so 2 external walls - but with lossy double glazed but large metal frame sliding patio door. 

Alnat1

Another suggestion to ponder, would you be happy to run your washer and dishwasher overnight on an E7 tariff? That could save some money but some are wary of doing this or it would be too noisy in their house.

wrf12345

There are all in one air to air heat-pumps that look like extra large radiators and go for £700-800 on eBay, they do need two large holes drilled in an external wall, not sure if your listed status would allow that. COP is around three and allied with half price electric on Octopus Cosy they would be cheap enough to run, and being air to air provide heat only when you want it (they have in-built timers).  They are internal, all that is seen from the outside is two six inch diameter grills.

Scot_39

Typhoon2000 said:

Economy 7 historically had two circuit. Everything plugged in to the 1st circuit will be normal rate during the day and cheaper during the E7 hours. The second circuit only switches on during the E7 hours allowing you to use storage heaters without having to use a programmer to switch them on at the appropriate time. You have never needed to use the second timed circuit to benefit from E7, you could plug your heater into the main circuit and use a timer.

Not quite true for all old E7 billed or many other RTS legacy tariff installs - that were dual metered.

As often the off peak rate only applied to the second meter - and so only typically the HW immersion and storage heaters (or equivalent boiler store).

That was true of some both RTS and electromechanical time switches too - depending on how the metering was arranged.

Normally if you had 1 dual rate meter - with RTS or timeswitch selecting the rate on it - it also operated as you say

But with two meters (or in my old Heatwise days - 1 normal meter and 1 combined RTS meter / switch ) - the normal circuits never saw the off peak rate.

Modern flats I have seen dont actually rely on split circuits - they rely on device timers - say on the immersion heater - and often only the immersion heater per se - to block peak hour use - and use normal daytime panels for heating - at peak rate. 

But water is a surprisingly large share of many low heat users total energy demand - it's probably more than the 35%-45% needed of total - of many couples in a small efficient flat if covers shower / bath etc - enough on its own to make e7 pay.