Buying new storage heaters

macman

In response to a couple of issues raised, while I accept that Quantum's (which are not the only choice of Lot 20 compliant NSH's available) can be run on a single supply, it does require the E7 metering to be installed on a 'whole house' basis, whereas a lot of the older NSH's had a dedicated night rate circuit that only became active during the cheap rate hours. To run Quantum's on these, you would need a change of metering, and some rewiring of the E7 radial circuits. Whether this applies to the OP, I don't know.
I do not accept that older NSH's 'degrade'. What exactly is there to degrade? It's a tin box, filled with bricks and some heating elements, a thermostat and some baffles. The only thing that could degrade is the insulation, and if that breaks down, it is not reducing the efficiency, just reducing temperature control and allowing faster release of heat. It still remains 100% efficient.
Quantum's are good heaters, as they offer more control and flexibility using dual rate, but they are not more efficient.

Gerry1

macman said:

it does require the E7 metering to be installed on a 'whole house' basis

If you have only an existing E7 meter on an E7 tariff then by definition all consumption will be on a 'whole house' basis regardless of the wiring.

To use Lot 20 fan assisted NSHs cost effectively the OP can rewire the existing switched E7 circuits(s) at the meter so that they are 24h and programme the NSHs to 'shadow' the E7 off peak hours, OR install a separate 24h circuit to each new Lot 20 NSH.

The former is cheaper and avoids redecorating problems, the latter avoids any risk of incorrect timing causing some unintentional peak time usage.  Either way, very important to make sure that the top-up NSH heater isn't used except on rare occasions.

EssexHebridean

Curious to know how you go about programming the charging time for the Quantum NSH's Gerry? Ours has no means of programming the charge times at all - it charges to the required level when the current is flowing (during the off-peak period) and stops charging either when it reaches its desired capacity or when the current switches off - usually the former in my experience. There is no obvious route in the control menus to programme the charging period, and nothing in the user guide we have with it, either! 

The boost setting is actually nowhere near as power-hungry as I suspected it would be either, out of interest - it's not cheap, and we certainly wouldn't want to run it all day using that, but for the odd hour here and there when you need to take the chill off urgently, it runs at a bit under 20p an hour on our current rates. 

Gerry1

EssexHebridean said:

Curious to know how you go about programming the charging time for the Quantum NSH's Gerry?

According to the Dimplex instructions:-

Note that the four values will accommodate the split charging times in South East England (Region 19), 2230 - 0030 and 0230 - 0730 GMT.

EssexHebridean

Good info - thank you. There's far more there than there is in the manual supplied with the heaters. 

Gerry1

EssexHebridean said:

Good info - thank you. There's far more there than there is in the manual supplied with the heaters. 

Important that the OP (and anyone else) checks that this feature is still available before proceeding, models and specifications tend to change from time to time.