Complex meters need to be changed - advice needed

  • Kodak's Avatar
    Level 5
    Was an nPower customer on Super Tariff complex meter (E7 rate day/night, plus standard rate Night storage & afternoon boost).

    Meter failed & was put onto two times switched meters (one E7 rate for day/night supply, one standard rate for night storage heaters & afternoon boost).


    Discovered by chance in Jan 2025 that eON.Next intend to switch my meters by March & turn off the RTS signal so that neither of my supply meters will work correctly.


    The replacement options are a standard smart meter or an E7 smart meter.


    If I go standard, my night storage heaters become useless. Replacing them & redecorating after the changes could cost £4k.


    If I go E7, I lose the afternoon boost and so the house will be too cold from 7pm onwards, necessitating more stand alone heating & more cost.


    I can't switch suppliers due to complex metering, either...& no one offers E10 anymore.


    Someone at eON.Next call centre suggested going E7, but adding a timer of my own on my side of the supply so I could add my own manual boost to my night storage heaters, but I don't see how that works as the heater circuit will be unpowered outside of the overnight E7 period.


    To complicate things, my water heating is connected to the standard supply, not E7, and has it's own timer to control it.


    If I switch to an E7 meter, the water heater will be on the wrong circuit.


    To say the configuration is complex is an understatement, but it works.


    Sadly, it won't work after the changes eON.Next are about to make and it won't be simple to correct.


    Getting any advice is proving impossible.


    So if anyone on here can help, I'd be very grateful.
  • 24 Replies

  • retrotecchie's Avatar
    Level 92
    @Kodak

    Switch to E7. You'll need an electrician to rewire your storage heaters, but that's your responsibility rather than the supplier. A timer similar to what you have on the water heater is not a big problem and will still allow you to boost the heaters during the day, but you'll be paying peak rate for the privilege..

    Complex systems went out in the mid 90s along with the Magnox power stations. They were only really implemented by regional boards that had access to cheap baseline energy generated by Magnox, so really only Scottish Electricity Board and Southern Electricity Board areas. No thought was given to modernising such legacy systems when the energy industry was denationalised.. This is why we have the energy supplier SSE...a merger between Scottish and Southern makes no sense if it wasn't for those two regions using complex systems.

    Anyway, the current setup doesn't support these 30 year out of date systems, so it's E7 or nothing really. Simple enough to remedy by any competent electrician, but it's down to you, not the supplier.

    A five terminal meter will give you just the separate timed feed for the water otter and the heating, but if you want boost, you are better off with a regular 4 terminal non-switching meter and a more up to date timing system.

    I've done enough of these conversions myself, so they ain't rocket science, but anything forward of the meter is the responsibility of the consumer, not the supplier so they aren't likely to offer any assistance with the conversion.
    Last edited by retrotecchie; 2 Weeks Ago at 16:35.
    Don't shoot me, I'm only the piano player. I DON'T work for or on behalf of EON.Next, but am willing to try and help if I can. Not on mains gas, mobile network or mains drainage. House heated almost entirely by baby dragons.
  • Kodak's Avatar
    Level 5
    @retrotecchie So if I switch to plain E7 and add my own time switch, rather than have the heaters wired to their own timed on/off circuit on the meter, I can retain the boost?

    The switch I have at the minute is a Horstmann, but they don't seem to do an equivalent switch that would handle a bunch of night storage heaters all coming on at the same time.

    Is there a device you could recommend? I'm at a complete loss at the moment and, so far, electricians I've asked don't seem keen to take to work. I got the impression it's the E7 and timer bits they don't like.
  • retrotecchie's Avatar
    Level 92
    @Kodak

    Here's how I would do it:

    Get an electrician to wire the existing storage heater feeds into the existing normal consumer unit. Obviously using a suitably rated circuit breaker. That is to say, the storage heater feeds are permanently live.

    Replace each of the faceplates for the storage heaters with a switched 13A socket.

    Rewire the storage heaters with a standard 13A plug on the cables.

    Use a suitably rated plug in timer on each heater. Set the timers to operate when the off-peak rate is in effect. Use a decent timer rated for the full 13A, not a 'Mickey Mouse' one only rated for switching the Christmas tree lights or a table lamp!

    If you need a boost, use the override switch on any individual heater timer to give you the extra heat you need. Just remember to set it back to Auto when you're done. Of course, with a modern timer, you can set individual boost periods as required. You will, of course, be paying daytime rates for that boost outside of the usual E7 times.

    If you already have a separate breaker/fuse box for the storage heaters, that just needs to be fed in parallel with the existing consumer unit from the single meter - that is something a meter engineer can do.
    Last edited by retrotecchie; 2 Weeks Ago at 17:43.
  • Kodak's Avatar
    Level 5
    @retrotecchie
    Thanks for that.

    Heaters are currently hardwired, each through its own fused switch. Is it safe to switch them to a regular 13 amp fuse as they're never sold that way.

    I vaguely recall being told to hardwire them as they draw a higher, forgive my ignorance on this, current (?) than regular heaters.
  • retrotecchie's Avatar
    Level 92
    @Kodak

    I don't think I've ever met a storage heater bigger than 3kW which is safely inside the limit of a 13A plug. The usual reason for hardwiring is so they only use dedicated heating citcuits driven by RTS or E7. It also prevents people plugging in other appliances to benefit from the cheap off-peak electricity on the complex heating schemes.

    If the heater draws more than 3.25 kW, dedicated hard-wired timers can be used. Even B&Q sell higher power hard-wired timers that can be used for immersion heaters or storage heaters.
  • Kodak's Avatar
    Level 5
    @retrotecchie
    Thank you. I'd hoped to put a single timer in the meter cupboard so I could send a boost to all heaters at the same time.

    All I can find are units to control immersion heaters on E7.

    Do you know of anything that would control 4 night storage heaters with a boost option?
  • meldrewreborn's Avatar
    Level 92
    @Kodak
    @retrotecchie is the expert on this. But on E7 you will not have the cheaper additional hours so using the storage heaters for a boost seems to be an expensive and inflexible option to me. A couple of inexpensive thermostatic fan heaters in selected rooms to use only when the temperature drops would be my preference.
    Current Eon Next customer, ex EDF, Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but I’ll continue to express my opinions nonetheless.
  • Kodak's Avatar
    Level 5
    @meldrewreborn
    Due to space constraints, additional heaters are not an option.

    Currently, on the complex meters I have, I pay an E7 rate for general energy, but standard rate for 7 hours overnight and 2 hours afternoon boost on my storage heaters.

    This arrangement began when nPower botched a meter change and forced us off the old NEEB Super tariff.

    The new arrangement is incredibly expensive but the cost of changing the heaters (& decorating afterwards) or the loss of the afternoon boost meant it was as cheap to leave the setup as it was.

    Now that the time signal is being switched off, I have to choose between a range of unsuitable options.

    Even so, it looks as if E7 with an expensive afternoon boost is still going to be hundreds of pounds cheaper than my current tariff.

    All it needs it a timer with a boost for 4 storage heaters that I can control.

    I hoped it'd be easy, especially as my water heater is already on a Horstmann unit that has a boost that I control.
  • retrotecchie's Avatar
    Level 92
    @Kodak

    Ah...the old story of a 'dual meter' setup with one meter charged at E7 rate and the time switched one charged at standard rate when in fact, the tariffs should actually be applied to the meters the other way round.

    And this is EXACTLY the reason why complex systems MUST be replaced by a single meter system. Because everyone on a 'complex' legacy system has been paying way over the odds for years!

    Yes, a Sangamo or other mechanical timeswitch rated at 60A will do the job of controlling all heaters together. When you want the boost, is that a manual boost or you want them all to come on for that hour or two every day? Because that is not how RTS complex systems work. RTS alters the switching times and boost durations remotely according to local prevailing weather conditions. You get more boost when it's cold out and less when it's not so cold. That was the whole point of RTS....you are not actually in control, but rather your supplier is. Otherwise, why bother with a radio control system when a simple clock would do.
    Last edited by retrotecchie; 2 Weeks Ago at 11:33.