We have some old storage heaters (safety tested and working fine) on a tariff that gives them two power cycles per day. (Unlike E7 with one, as I understand it.
I just wonder if these older storage heaters are still available from anywhere? I've heard all sort of stories about E7 with the heaters being too cold before the next cycle. I know this could be as they could be the wrong heaters/settings etc - but at the moment it would be nice to know if I could replace our existing heaters had to. Thanks
I was thinking that an E7 heater would (on our older tariff) get two cycles a day when it only needs one, so cost much more to run. Actually now you say that - I suppose the thermostat will only ask for power when the setpoint is reached so maybe situation is not as I thought (not as bad anyway). (?)
The older heaters only needed an afternoon boost because they didn't store enough heat for long enough.
AIUI you are probably on a "preserved" tariff which is not offered to new customers, so if you change your heaters to modern ones you will probably be able to change to a standard E7 tariff with a more competitive supplier, and save money. Probably not enough money to be worth changing the heaters for though, unless they're useless (or big and bulky)
Dimplex have about the widest range of storage heaters although there are several manufacturers of the "standard" ones.
You're right, you can set the stat (input) and delivery (output) controls to suit your needs and I'd expect you to be able to get away with less input or smaller heaters on the tariff you describe. Is it E10 or something else?
Do watch out for tariff creep, my father was conned into using under-floor off-peak electric heating in the early sixties (2 periods per 24hrs) based on a very generous off peak discount but by the nineties the discount was negligible and their heating bill was eye-watering.
E7 storage heaters tend to be disliked for 2 reasons... o Too hot overnight
---- they leak 40-60% of their capacity during charging
---- so 24kWh leak 12kWh over 7hrs (near 2kW/hr) o Too cold in an evening
---- remaining 12kWh released over 17hrs (just 0.7kW/hr)
Recent designs do 2 things... o Improve brick thermal capacity -- eg, 670-690oC core
---- this allows a physically smaller storage heater cabinet o Improve insulation level -- eg, Microtherm
---- this reduces the leakage over very old big storage heaters
All still mix rockwood, microtherm & other insulation, indicating they engineer in some leakage to prevent core over temperature.
Alternative Designs.
Fan Storage Heater with BOTTOM vent.... o No top vents - stops heat convecting out when you don't want it o Thermostat fan on bottom vent -- pumps heat when you do want it
---- also reduces stratification problems of traditional convector heaters o Example -- Dimplex CFM, Creda TSF -- large 24-42kWh capacity o Problem -- typically manual, not automatic, charge control
---- why I've no idea, it seems illogical re under/overcharge, inefficiency
Electric Central Heating... o E7/10 Storage & Peak Convector combined
---- Dimplex Duoheat has a thin-film panel heater over whole surface (good)
---- Creda equivalent isn't quite so good a design, despite a better brand o Electronic controller talks to each heater
---- you tell each heater what temp to maintain over what period
---- you have a Setback temp (16oC) & Comfort (18oC) setting
---- wireless or pilot wire methods available o Electronic controller sets the charge rate based on temperatures
---- if the E7 charged part runs out, it uses PEAK charged convector
---- this is ok IF a) loft/wall insulated b) E7 storage heater part sized ok
---- realise a Duoheat tops out at 2.6kW and PEAK convector is 1.5kW o Example -- Dimplex Duoheat, Creda Credanet-II
---- Credanet-II uses 3 day rolling average of heat needs re charge
---- no idea what Dimplex uses, probably not too dissimilar
Essentially the electronic control system claims 10% gain over conventional storage heaters, but do not specify if "conventional" is auto or manual charge.
Automatic charge controlled heaters (Creda TSR Sensor Plus) do achieve a
15% energy saving over their manual counterparts, but still need a rough guess at the overnight charge re 1-6 (eg, 1 at 4oC overnight, 6 at 0oC overnight).
E7 vs E10 Tariffs... o E10 Tarriff was intro'd 1998 by Southern Electric as I recall
---- 3.5hrs overnight, 3.5hrs afternoon, 3hrs in late evening (or such like) o E7 Tarriff was intro'd by neolithic man (not Prescott)
---- 7hrs typically 12-7am or small variations thereof
---- 8hrs is pretty rare, despite many heater makers quoting an 8hr capacity :-)
The benefit of E10 is quite noticeable... o Far less chance of cooking-then-running-out -- if heaters sized correctly o Matches 40-60% heater loss -- charge 3hrs, release 3hrs, charge 3hrs etc
So it is not difficult to see why E10 users of storage heaters may find them actually quite reasonable. However *as I recall* E10 only permits heating to be on the cheap rate, you do not get the whole house on it as with E7. So you lose the energy saving ability of running tumble dryers overnight.
Now, is it worth changing your heaters? o You are on E10
---- so losses from older-big-designs are less important
---- also combined storage/peak heaters have little to offer you
---- electronic control may interest, but £350 Heaters + £100 Controller o If you were on E7 things would be different
---- recent designs cook you less overnight & go cold much later on
---- electronic control is useful, either per heater or centrally
So I would not look at heating, but at draught excluder maintenance, loft insulation (200mm+) & cavity wall insulation if not already done.
I would also check your E10 tariff against alternatives carefully. If you find E7 tariff is cheaper check your storage heater age. Essentially if 140-180mm thick they are likely "modern slim".
Zooming forward to 2075 we may have mostly nuclear... o In theory nuclear favours electric heating over gas re overnight load shedding o In reality I think at best you may see electricity achieve parity with gas o Either way both fuels are likely to see considerable price increases
Storage heaters on E7 work ok for halls where primary heating is high efficiency gas fires, such as 70-89% efficiency outset gas fires and the like. Otherwise storage heaters on E7 for primary heating requires good insulation.
Anyone considering Credanet-II or Duoheat ensure the number of heaters is sized correctly, otherwise the programmers will rely on the peak convector heating elements. That is 10p vs 4p, a very subtantial difference in running cost.
EA did research on storage heaters in 1996, and some more recently. The Dimplex Duoheat literature shows a chart of temperature drop off of storage heater section (from about 1pm) and growing reliance on peak convector side.
The Duoheat uses a huge flat-film panel element across the entire front, so it does heat the room. They also use a single electronic control for thermostat & charge. Others tend to stick the element in less ideal positions re achieving room heating.
Stay away from any "gimmick" peak-oil-filled-radiators Kirel or similar... o Heaters are expensive, remote LCD controllers even more so o They are not storage heater, they rely on peak energy usage o They are ideal for South of France or similar - rarely a -1oC January
The only situation where such on-peak systems work is... o Where everyone is out all day except for the evening o Thus heating is only required from say 6-12pm (peak), rest can be on E7 o Rest of the time it is frost protection, high levels of insulation in use
We use a storage heater at home for the hall (& bedrooms) only. Rest is gas fire or gas wall heater electronically controlled (drugasar proportional are ok). The hall also has a gas wall heater, although that may go someday, so I may be tempted by Duoheat re simple control & electronic remote control. However looking at prices I think electricity companies should subsidise :-)
I would not like to rely on E7 storage heating alone in a typical 3-bed semi. Using E10 would probably make a very considerable difference to usability.
By 2075 we may end up going with storage heaters re temperatures, if only because we also have heatpumps to also handle air conditioning needs :-)
The ideal storage heater is not yet in production. It would require truly better insulation for neglidible leakage and so any overcharge truly remains for the next day & avoiding cooking overnight; auto-charge control; thermostatic fan control; plus a reasonable price. So far the designs are still quite simplistic - E10 makes them workable.
Have no worries about old or new, plenty of online places still do parts.
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