recommendations for heating small house

danrv

Gerry1 said:

Surprisingly, although the Quantum has lots of clever programming, it doesn't seem to have this key feature, at least in the info I've seen.  Some German storage heaters can be operated from a 24/7 circuit, but the programming seems to be very limited, just a countdown duration starting from 0000 hours.  That would catch out many people in Britain who have cheap rate E7 from 2230 - 0030 and 0230 to 0730.

Yes. Option of using them on a 27/4 circuit would be useful. They have four charge period options so can be set to charge during off peak hours from a single 
supply.
Just need to get an E7 meter installed.

danrv

matelodave said:

As Gerry says, makes sure that the storage capacity is correctly dimensioned to suit the heating requirements of the room.house. I've noticed that there seems to be a tendency to under dimension them because they have the back-up capability of the auxiliary heater which uses peak rate leccy. There's no point in installing a storage heater that's undersized and then having to top up your heating at peak rates.
Also bear in mid that you may need to have additional wiring or the existing wiring reconfigured. These heaters either need dual power feeds  - a dedicated off-peak supply for the storage element and an always on for the thermostat/backup heater and fan or a single always on feed withe the off peak demand being controlled by the inbuilt timer. It will depend how your supplies are metered and controlled.
You'll also need to take into account how your hot water is supplied - has it got a dedicated off-peak supply or has it's own time switch.I'm guessing that you've got a dedicated off-peak supply for your heater and hot water (with a big time switch or contactor next to the main meter to control it)

The QM125RF or 150RF should do for my 14 sq. mtr lounge.
Hot water is via immersion which is on the whole home E10 circuit. Manual switch only so I make sure I only heat it during off peak hours.

Pennylane

Oh wow! thanks everyone for the replies. I am going to be busy tonight checking it out.  Will report back.

macman

NSH's 'expensive to run' is meaningless. Compared to what? Gas CH? Without mains gas, NSH's and an immersion heater on E7 are the cheapest option by far. 
The old ones have crude controls, if necessary replace with more modern versions.
Many LL's don't care about their tenant's bills and would simply fit cheap convectors on single rate. Which will probably triple the heating bill.

danrv

Agree about storage heaters being best if electric is the only option.
The Quantums seem to lead the way in modern NSH tech. They get mentioned a lot but not Elnur High Heat Retention ones.
These look pretty clever, a bit cheaper and use a ‘balancing element’ on the 24/7 supply instead of a boost fan on the Dimplex Quantum.
Explained here but not sure if it’s a more efficient design.
https://www.elnur.co.uk/news/hhr-high-heat-retention-balancing-element-function/

Gerry1

The Elnur HHR ones seem unconvincing.  They don't seem to be particularly well insulated, as evidenced by not having a fan.  The article has loads of weird and wonderful calculations saying how the use of the peak rate element is cheaper than using extra overnight energy, but that's probably only because so much is wasted by overnight usage.  There's also no evidence given that using the using less overnight and more in the day delivers the same result more cheaply, it's just an presented as an unverified fact.

They seem to be just conventional NSHs with a timer and real time heating element bolted on, so that would make them cheaper than Dimplex Quantum which, if dimensioned and programmed correctly, should seldom require any use of expensive peak rate electricity.

danrv

Gerry1 said:

The Elnur HHR ones seem unconvincing.  They don't seem to be particularly well insulated, as evidenced by not having a fan.  The article has loads of weird and wonderful calculations saying how the use of the peak rate element is cheaper than using extra overnight energy, but that's probably only because so much is wasted by overnight usage.  There's also no evidence given that using the using less overnight and more in the day delivers the same result more cheaply, it's just an presented as an unverified fact.

They seem to be just conventional NSHs with a timer and real time heating element bolted on, so that would make them cheaper than Dimplex Quantum which, if dimensioned and programmed correctly, should seldom require any use of expensive peak rate electricity.

Thanks. Useful info. 

danrv

Hope this is still relevant to the OP.
Regarding wiring for storage heaters, there was a mention a while ago about running heaters on a ring main.
Could work ok if total power consumption of the heaters was under 7kw. Spurs with timers could be used for the off peak switching. 
This would save a big rewiring job as the warm air heater is central so no individual room sockets on that circuit.
Correctly sizing the power to the rooms and keeping under 7kw could be a bit tricky.

Specs for Quantum heaters:
QM100RF Input 2200w  Output 1000w
QM125RF Input 2760w  Output 1250w
QM150RF Input 3300w  Output 1500w

I assume the output rating is equivalent to an electric rad of the same power.
The Electricaire that these would be replacing is 10kw/73kwh so an input wattage total of around 5kw may be sufficient for downstairs level. 

matelodave

You really need to do some heat loss calculations for the rooms that you are going to install the heaters otherwise they will be undersized. Try to decide if a 1-1.5kw heater would be adequate for somewhere like your lounge because if it isn't then you'll end up using the boost fan and dissipating all the heat over a shorter time and then the peak-rate boost heater to keep warm.

You need to do your sums to avoid installing undersized heaters.

Make sure that they are dimensioned correctly rather than guessing by using an on-line heat loss/radiator sizing calculator. like this - https://www.cityplumbing.co.uk/heatlossCalculator 

danrv

matelodave said:

You really need to do some heat loss calculations for the rooms that you are going to install the heaters otherwise they will be undersized. Try to decide if a 1-1.5kw heater would be adequate for somewhere like your lounge because if it isn't then you'll end up using the boost fan and dissipating all the heat over a shorter time and then the peak-rate boost heater to keep warm.

You need to do your sums to avoid installing undersized heaters.

Make sure that they are dimensioned correctly rather than guessing by using an on-line heat loss/radiator sizing calculator. like this - https://www.cityplumbing.co.uk/heatlossCalculator 

Thanks. Calculator link is useful.
Lounge heat loss in watts is 1177.
4015 BTU’s shows in the summary.

Not sure how to use these calculations though. Would 1177w mean that a heater of that output would do?
Don’t see any mention of BTU’s in the heater specs.