Switching away from Economy 7 - Multiple Questions

Discussion in 'Electricians' Talk' started by Chiu, Jun 27, 2021.

  1. Chiu

    Chiu New Member


    Looking for some advice on switching away from Economy 7.

    Currently have a 2 bedroom flat, all electric, no gas, There's 1 storage heater in each room, 2 in the living room and 1 in the hallway. The water heating system is an Immersion Heater.

    I understand the concept of E7, off-peak rates at night so the flat can heat up all storage heaters and immersion water heater and then the heat is released by the storage heaters throughout the day and the water is hot ready in the morning.

    I have control over when the Immersion Heater as it starts and stops via a timer, but I can't seem to locate one for the storage heaters so I don't have much knowledge over when the heat comes on.

    I would like to rip out all my storage heaters as they are bulky and replace them with slimmer electric heaters so I have the ability to turn them on and off for instant heat.
    - Would this work on E7 tariff?
    - Would the electric bill be very high?

    If I were to rip out all the storage heaters, do I need to stay on an E7 tariff due to the Immersion Water Heater?

    Is there a way I can completely change the way heating is wired in my apartment?
    Is there a way to switch out the water heater system to a more instant hot water tank?

    Would the full switch over away from E7 cost a lot?

    Thank you in advance for any advice
  2. Bob Rathbone

    Bob Rathbone Screwfix Select

    Taking the questions in turn,
    The proposed heaters would not work in the daytime on E7, yeas it will cost you a fortune to run it on 'On Peak'. Keeping the water only on E7 will be OK, their should be a timer by the tank to give you a 1 hour boost during the day if you use it.
    You will need an electrician to move the E7 wiring from the E7 restricted CCU to the unrestricted CCU.
  3. Bazza

    Bazza Screwfix Select

  4. Tony Goddard

    Tony Goddard Screwfix Select

    There are modern electric radiators like those made by Rointe, Gabarron and Fisher that are very efficient compared to older electric heaters - they achieve this by having on board thermostatic and timer control and lower wattage ratings, its not a miracle, just the benefit of more sensitive control.

    Correctly selected and installed they can be more economical that gas or e7, our local GPs had the gas heating taken out and Rointe rads put in, and have saved a lot. I have fitted them commercially in porta-cabin classrooms to replace old Drugassar gas heaters. I have a little one in my hallway.

    If you ventured down that road you would get rid of the night stores, have the E7 fuse box moved across to regular power and connect, via FCUs the new rads to the old heater radials. each heater then has a 7 day programmer and stat on board.

  5. MGW

    MGW Screwfix Select

    An electric heater comes in three groups, resistive, inferred, or heat pump.

    First the resistive, watts in = watts out, simple, it does not matter what you do, it can't be any more or less efficient, but getting the heat to the area when required can be seen as being more or less efficient, so if using room for 1 hour, and it takes 1 hour to heat, it could be seen as 50% efficient, not really true as heat used during hour of use will be reduced, so it really depends on heat loss as well, but a fan heater can be said to be more efficient to a oil filled radiator as it can be switched on latter to get room to temperature, but an oil filled radiator because it stores the heat, can use mark space control to regulate output better than the fan heater.

    Inferred does not heat the air, it heats anything in line of sight, so nearly instant, but it has a problem with control, as also instant cooler when switched off, so control is a problem, you can have a 4 bar inferred heater which gives 4 outputs, but also it will not work a thermostat as they measure air temperature, so in real terms only really used with resistive heaters, one way is to use tungsten lights so switching on lights means the room feels two degrees warmer, and set other heaters two degrees lower.

    The heat pump transfers heat from outside, how efficient depends on temperature outside, but better than resistive and more controllable than inferred.

    So in real terms not really looking at heating, but looking at cooling, how fast will the premises cool? With no heating on, this room is 8 degrees warmer than outside, both heat retained from when warmer outside and some solar energy through windows. Heat is retained by the fabric of the building. And it is down to how much is retained as to if storage radiators save money or not, using a low loss heat store like a tank of hot water, over night energy can be stored until 5 pm and only then released into the building, but with a high loss system even when output is turned off, the heat escapes, so even with no one in the building it is still heating it.

    So the brick filled storage radiator is over heating the home from 9 - 5 when empty, so using more energy, but the energy is cheaper, high rise buildings are often not permitted gas since Ronan Point failure, not sure about oil, I have used heat pumps (AC units running in reverse) but had problems freezing up, and heating air from cold, loads of fresh air, but the stand alone units not cheap to run.

    If forced to use electric heating I would want to measure the heat used, simple fan heater through an energy meter, since retired storage heaters would work for me, but if out at work all day, then really down to how long you heat the home for, there is no magic figure, but best option is work 3 pm to 11 pm so flat heating turns on as you get home and the stored energy does not run out until your ready to go to work.
  6. The Happy Builder

    The Happy Builder Screwfix Select

    If you replace the storage heaters with any other kind of direct electric heating the Energy Performance Certificate rating may fall to below the required minimum standard for a rental property.

    So if this is a flat that is rented out or you intend to rent out, it may become illegal to let it out to tenants if you replace the storage heaters with any other kind of electric heating, unless you spend money improving floor, wall and roof insulation or replace doors and windows, etc to get the EPC rating back up.

    Don’t believe the Snake Oil salesmen who will try and sell you “Energy efficient panel heaters” particularly those which are labelled as storage heaters with “ceramic cores” and the like, their claims are untrue and the flat may be unfit to rent out if you fit those heaters.

    There are only two kinds of direct electric heaters, storage heaters and everything else, the only difference in running costs is the tariffs they run on.

    So check out all the available tariffs, do the sums and see what answers you get, which is probably keep the existing storage heaters or replace them with new storage heaters.

    There is the other option of a air source, but that almost certainly isn’t a real option.
  7. Tony Goddard

    Tony Goddard Screwfix Select

    Is it a rental?
  8. The Happy Builder

    The Happy Builder Screwfix Select

    Would you want to live in a flat that is technically unfit to rent out?

    In the 1960’s the Government set up the Parker Morris committee which set the minimum standards for social housing, the private housing developers were then in the situation where they had to work to the same standards, because who wanted to buy a new house or flat that wasn’t up to the standard of a Council house?
  9. Tony Goddard

    Tony Goddard Screwfix Select

    To be honest yes!, my house probably couldn't be rented out without some works, I don't think the Ascot 503 flueless water heater in my utility would satisfy rental requirements!
  10. Bob Rathbone

    Bob Rathbone Screwfix Select

    You hit the nail straight on the head with that. All electric heaters are 100% efficient, they have no flue losses and all other losses are dissipated as heat, they are heaters so that 'loss' is utilized. The only difference in running cost for an electric heater is the price of the electricity used, Of peak suffer from not having the heat available when you really need it, at about 19:00 hrs., on peak have the heat when you need it but run on expensive electricity. All of the garbage spoken about fancy control systems will not affect the efficiency of the heater, all it will do, if set correctly, is only allow the heater to switch on when the room is in use and to limit the maximum temperature attained.
  11. Tony Goddard

    Tony Goddard Screwfix Select

    All electric heaters are 100% efficient in terms of energy in/energy out, but the modern electric radiator has clear design advantages over the designs of yesteryear. These are not magic or snake oil, just a combination of pre-existing elements that make for an efficient radiator.

    For example the Gabarron and Rointe oil filled models are based are based on an italian water radiator design from the 60's, made from aluminium, with a large surface area to optimise convection and air movement, therefore alowing a faster, more uniform heating of the space.

    The simple control method of measuring the temperature of the air drawn into the bottom of the convection path permits the radiator to be switched off promptly when the correct temperature is reached.

    Compare that with the original Dimplex panel oil filled radiators where there was virtually no method of channeling convected air and the bimetal thermostat relied on air eventually getting in to it via the holes in the control box, or open coil convectors that would stink of burning dust when fired up - I think its safe to say design has improved making for a superior product to that of yesteryear.

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