Single storage heater, would it be worthwhile?

[ericmark]

What does oil cost me, I really don't know, but to make it last a little longer, so only one fill up per year, would improve things, and we have off-peak for 5 hours per day, so is oil less than 8.5p/kWh? And would the heater say a 2 kW version, last 19 hours? I have a large hysteresis in the living room, so a heater giving a little out all the time, may reduce the hysteresis, but is it worth it? Would not want to change from Octopus "Go" to "Economy 7" so if it would not last 19 hours likely non-starter, but it is a thought, not looked at how much a storage radiator stores?

Tried websites answer I got was

Thanks, Eric. That's a great question! Our Fischer Heat-Only Electric Boiler is a zero-emission, 100% efficient heating system that is manufactured in Spain and comes with a 5-year warranty. It is available in 7.5 to 21-kilowatt options and is nearly silent, making it ideal for home use.

Which was simply not answering the question.

I was actually involved in making the bricks, but I never worked out how much they stored. That website was clearly not going to help, god knows what size a 7.5 kW storage heater is, must be massive, unless they don't know the difference between kW an kWh. I did find this

So it would not fully charge in 5 hours, but looking at the smallest as an example, one would hope it would not simply give out 500 watts for 14 hours, the instructions I found says "Minimum heat output (indicative)" 0.0 kW" can't believe that's true with a fully charged unit, and settings seems to be room temperature, which is not really what I want, the oil will top up the temperature as required, but I suppose 99 watts is still within 0.0 kW? But same for all models. At 268 watts ((1020x5)/19) it should help a little with the hysteresis.

However that's the same as swapping to tungsten lights, so not sure if really worth the effort?

 

[Johntheo5]

I know someone who installed them a few years ago and were very pleased with them but installed them instead of oil fired heating, not to supplement it.

Dimplex Quantum speak in italics.
"The storage heater comes in four sizes: QM070,QM100,QM125&QM1.50.which are respectively 0.7KW,1.0KW,1.25KW&1.5KW (Outputs)
Designed to retain over 50% of heat 24 hours after the initial charge"

My speak
These are fan assistid
Using the QM1.5, 1.5 KW heater, as an example, this has a fully charged capacity of 23.1 Kwh
So constant "parasitic" heat loss ~ 50% X 23.1/24X1000 watts/hr. 480 watts (per hour)

 

[Rodders53]

Oil - what is it currently delivered to you at 500 litre and 1000 litre rates?https://homefuelsdirect.co.uk/home/heating-oil-prices/powys suggests it's around the 6p per kWh inc vat mark? (Roughly 10kWh per litre of kerosene.) Then multiply by your boiler efficiency estimate...

Payback time on the capital is likely to be 'never' unless you 'reclaim' a storage heater from the dump.

Capital may be better spent on split pack air to air heat pump (aka aircon)? COP of 3-4 on electric makes peak rate electric use 'acceptable' in my opinion.

I appreciate that oil deliveries to remote locations can be troublesome... or impossible if the roads get blocked; and getting the oil low enough to take a refill at the right time of year to get best prices is not easy either.

 

[Harry Bloomfield]

What does oil cost me, I really don't know, but to make it last a little longer, so only one fill up per year, would improve things, and we have off-peak for 5 hours per day, so is oil less than 8.5p/kWh? And would the heater say a 2 kW version, last 19 hours? I have a large hysteresis in the living room, so a heater giving a little out all the time, may reduce the hysteresis, but is it worth it? Would not want to change from Octopus "Go" to "Economy 7" so if it would not last 19 hours likely non-starter, but it is a thought, not looked at how much a storage radiator stores?

The major issue with any form of heat storage, for later use, is predicting how much you might actually need. That will depend on what the weather will be, in up to 24 hours time. Underestimate, and you will be cold, overestimate and you waste money.

Gas, or oil, you can get it just right, because it's on demand.

 

[ericmark]

@Rodders53 has really answered the question, no monetary saving, and the hysteresis problem not really bad enough to be worth the expense. Emergency I have an oil filled radiator should oil fail, and have back up batteries if electric fails, I did look at storage heaters and see now far more electronics, and wonder with a power cut can the heat be released?

Heat pumps at best 500% so would need heat in the day, so can't compete with oil, even with a perfect installation. Main reason why people think heat pumps work, is the original installation was so bad, I look at how we select which rooms are heated, and wonder how one would do that with a heat pump, plus all piped in micro bore, so it would be ceilings out to run pipes job, so non-starter.