Possible storage heater replacements

HuggyHermit

Hi all,
I live in a first-floor flat in a building with no gas, so unfortunately I'm stuck with electric heating. Right now, I have four Dimplex DuoHeat storage heaters (around 12 years old), but two of them have just broken down in quick succession and they've never been very controllable. (You have to set input and output levels, then tinker with them until you get the temperature you want. I'd *love* to just be able to set a thermostat.) As such, I'm considering whether to repair the broken ones (at around £100 each, with the possibility that the remaining two will also break down soon) or replace them with more modern high-heat-retention units. Another issue is that I'm currently on Economy 10 (because I need 10 hours of charge in the winter to keep the place warm through into the evening) but it's getting harder and harder to find competitive deals and it seems to be a dying tariff. Given that, I'm also considering getting more heaters so I can switch to Economy 7.

Now, HHR storage heaters aren't cheap (to put it mildly) so the decision will hinge on just now much more efficient they're likely to be (in terms of less heat wasted at night and when I'm not there) and how long they'll take to pay off. (I work from home, so I'm in pretty much all day. Current usage is around 10000 kWh a year, 80% of which is off-peak.) Marketing fluff aside, does anybody have a ballpark figure for how much they would *actually* save me, or any idea of how to calculate one? Or have any other realistic ideas for how to proceed?

Thanks in advance,

Peter

Gerry1

Welcome to the forum.

I'd keep the existing ones if they'd be happy on E7.  Try switching them off for three hours during the E10 charge periods and see how they cope.  If the existing NSHs are different sizes you could consider increasing the capacity by buying a bigger NSH and cascading them down.

Dimplex Quantums can be more efficient because they don't waste heat when you're not there, but your savings will be modest if you're not out all day.  Just remember to turn down the existing output controls before going to bed and turn them up in the evening if it gets cool.

matelodave

Be aware that Quantums tend to be spec'd undersized working on the assumption that they are supposed to retain the heat a bit longer and that they've got a supplementary heater if it isn't sufficient. So make sure that you size whatever you get correctly to heat your place.

Interestingly, Although one or two on here suggest installing Quantum's I dont think I've yet seen a forumite who's got them and given their opinions (either good or bad). So I'd like to hear what people who've got them really think. Are they any good or are they really not a lot better than basic heaters or even HHR's. ie are they worth the money

TBH there's not a lot to go wrong in an older storage heater - the element and the thermostat although duo-heat are a bit more complex so £100 spent could keep them going for another 12 years whereas £400-£500 (or more ) on an HHR heater is likely to take some considerable time (if ever) to save their capital cost in reduced leccy bills

Regarding E& v E10, do as Gerry suggests and try yours out just running them for seven hours. E7 charges  all in one go (ie 3kw x 7 = 21kwh)  whereas E10 usually gives you 5+2+3 spread over the day so not only do you store more (ie 3kw x 10 =30kwh)  but its better distributed so you might find that you actually need bigger heaters for E7 than the ones you've got to be able to store it all in just 7 hours.

So it would be a good idea to try Gerry's suggestion to turn yours off for the three hour session during the day to give you some idea of how they'd perform

coffeehound

Are the DuoHeat heaters not the same as Quantum in heat retention?  Perhaps the spec will have evolved over the years, but when they were introduced, I was under the impression that it was the advanced predictive controls that differentiated Quantum from Duoheat.

If that is true, then -- aside from the stores capacity issue -- the only saving to be made from installing Quantum NSHs is any further efficiencies from the clever controls.  Dimplex claim savings over old technology NSHs of 'up to' 10% for DuoHeat and 27% for Quantum.  So very roughly potential net saving of 17% by swapping all Duoheats for Quantum.  If it cost say £3000 to convert to new Quantums, then that would be a payback time of roughly . . . . . forever!   If you state your current off-peak annual usage, it might be possible to give some better numbers.

Perhaps most realistic way forward would be to add one or more NSHs as required and repair the existing ones.  Quantums range from £500 to £700 plus installation, so the £100 repairs sound like good value.  In terms of capacity it's going to be better to over specify since you can always charge a large heater less, but you can't give a higher charge to an undersized NSH.

Gerry1

matelodave said:

E7 charges all in one go (ie 3kw x 7 = 21kwh)

Not strictly true, my E7 hours are 2230 - 0030 and 0230 - 0730 GMT, which can be handy because you can 'double dip' last thing at night and first thing in the morning with other appliances.

But for NSHs it's effectively a single charge because unlike E10 there's no boost in the afternoon or mid evening.  There's probably a slight advantage with the split E7 tariff because it will warm up coming up to midnight, whereas the traditional charge of 0030 - 0730 or whatever might leave things a bit chilly towards bedtime.

matelodave

That's OK if you've got the option, but generally you get what you are given and it depends where you live whether you get a split charge or all in one lump

Gerry1

matelodave said:

That's OK if you've got the option, but generally you get what you are given and it depends where you live whether you get a split charge or all in one lump

Yes, that seems to be the case now but many moons ago mine was 7 uninterrupted hours, but I discovered that split hours were possible and I opted to change.  However, it now seems that split hours are the standard in my area.