Storage Heaters

[Joeboy]

I wanted one for “The Shed” (garden office). I had a small space to squeeze it into and and something old and yellow would have looked odd against the white-painted walls. I just couldn’t find anything on eBay within an hours drive. Additionally, being on the 2030-0030 cheap period at the time I wanted a HHR (high heat retention) model.

I went for a Quantum. If you remember the complex technology that decided how much to charge the SH fought against me to the point where I circumvented it. The discharge control really is very good, it doesn’t leak much heat until needed, and then carefully controls the output. I’m now on the 0230-0630 cheap period so I expect it to work even better this year.

If you’re heating living space in your home and you want to charge for 4hrs and release the heat over the other 20hrs then you need a much simpler device.

I’ve just looked on eBay and the closest SH currently for sale is a 4hr round trip…

It has taken us around 3 years to get these together (seven) at a cost of £260 and a couple of hundred miles driving. Then add £15 per Hive plug and its £365 for the system plus a few quid to rewire where needed from stock gear. I though it worth mentioning that there is time involved in the hunt.

I'd be on this if i wasnt set up already...
https://www.gumtree.com/p/heating-firep ... 1441992403

[Caesium]

Yep 200 mile roundtrip along the south coast today to Bournemouth for me to pick these 2 SH up. Might stop off at Bognor Regis for an ice cream on the way back

The units I've bought are exceedingly simple, I don't think they even have a fan (which I might look into retrofitting). The small one I can trivially control with a smart plug, I'll just stick a 3-pin on the wire leading to the elements.

The bigger one I'm not sure yet, I can't whack 3.4kw through a smart plug for 5 hours, so I might see if I can split up the elements and control them separately.

Retrofitting a fan would mean I could get even greater control over when the warm air is distributed, so actively pull out hot air when a remote room thermostat asks for it.. another project to add to the growing queue

[Caesium]

I'm not actually sure I'll save a whole heap of money doing this, given that my gas is looking like it'll be 10.3p after 1st October (as will most peoples I expect?) and I can get elec for 8.25p for 5 hours on Go Faster, there's not a lot in it. SH wins, marginally.

But nonetheless its an interesting experiment and if/when the energy price guarantee collapses and we're at the mercy of Putin for gas prices once again, hopefully offpeak electricity can remain reasonably priced..?

[Joeboy]

The gain is also in the efficiency of the storage heater compared to a gas boiler. I think you might be surprised at the heating profile (best way I can think to say it) compared to GCH? No peaks & troughs in temps in house.

Last night we ran 5 units with a total of 5.95kw power, they ran for four hours so that's 23.8kWh or £1.30 at my Go faster price. WT1 made us 95p yesterday.

Going on the previous year(s) of gas consumption even at this mild time of year I am very happy with my fuel inversion and method of payment, In fact i'd go so far as to say that we are now living the Green Dream?

Certainly up here we are entering the interesting period of the year, my whole game is to play about in the shoulder months as that's where I can make a little bit of a difference and see it happening.

Looking forward to seeing your SH's Caesium, best of fortune to you in your adventure.

P.S we are continuing to see 15 to 25kWh from the PV each day, the machines in the house are all running from solar as is the house in general. Can usually chuck an hour or two of solar power at the HWT as well but that's about it. EV is from the grid now as is a stack top up each evening(usually about 60% to full).

[Oldgreybeard]

The gain is also in the efficiency of the storage heater compared to a gas boiler.

This seems to be something that is easily overlooked, especially as true boiler efficiency seems to be a lot lower than the quoted figures in their specification for a lot of people. I did some quick and dirty estimates of efficiency at our old house, that had a condensing Valiant combi boiler that was around 5 years old (installed in 2004) when I checked on its performance. I knew that the shower ran at about 10 litres per minute, measured the shower temperature and the cold water temperature, and guestimated how much hot water we used during the day. This was during the summer, with the heating off.

By reading the gas meter and then using the numbers on the gas bill to get back to the calorific value of the gas used I was able to roughly estimate the boiler efficiency. It was supposed to be better than 85%, yet the best number I could come up with was about 70%. Pretty shocking, really. No idea if it was better when in heating mode. I had the flow temperature set as low as possible, to try and make it a bit more efficient, but TBH didn't see any real change by doing this.

[Joeboy]

The gain is also in the efficiency of the storage heater compared to a gas boiler.

This seems to be something that is easily overlooked, especially as true boiler efficiency seems to be a lot lower than the quoted figures in their specification for a lot of people. I did some quick and dirty estimates of efficiency at our old house, that had a condensing Valiant combi boiler that was around 5 years old (installed in 2004) when I checked on its performance. I knew that the shower ran at about 10 litres per minute, measured the shower temperature and the cold water temperature, and guestimated how much hot water we used during the day. This was during the summer, with the heating off.

By reading the gas meter and then using the numbers on the gas bill to get back to the calorific value of the gas used I was able to roughly estimate the boiler efficiency. It was supposed to be better than 85%, yet the best number I could come up with was about 70%. Pretty shocking, really. No idea if it was better when in heating mode. I had the flow temperature set as low as possible, to try and make it a bit more efficient, but TBH didn't see any real change by doing this.

70%, terrifying to think of that sort of loss plus pollution and maintenance. Caesium would spend £82.50 for 1MWH of power at as near as damn it 100% efficiency. That same in gas at 70% efficiency would be £103 on his 1st Oct price. To match the electricity heat output he would have to spend nearer to £150 on gas.

[Oldgreybeard]

70%, terrifying to think of that sort of loss plus pollution and maintenance. Caesium would spend £82.50 for 1MWH of power at as near as damn it 100% efficiency. That same in gas at 70% efficiency would be £103 on his 1st Oct price. To match the electricity heat output he would have to spend nearer to £150 on gas.

It really shocked me how far out the efficiency was from the spec. Nothing wrong with the boiler according to the chap that serviced it. I asked him to double check after I'd done the testing just to be sure. I have wondered if it is the start - stop nature of a combi that creates the problem. Ours always used to give a smell of unburned gas from the flue for a second or two when it fired up, so perhaps they don't burn cleanly until they've been on for a time. Could well be that when heating hot water they rarely get to run long enough to burn cleanly, perhaps.

[Countrypaul]

70%, terrifying to think of that sort of loss plus pollution and maintenance. Caesium would spend £82.50 for 1MWH of power at as near as damn it 100% efficiency. That same in gas at 70% efficiency would be £103 on his 1st Oct price. To match the electricity heat output he would have to spend nearer to £150 on gas.

It really shocked me how far out the efficiency was from the spec. Nothing wrong with the boiler according to the chap that serviced it. I asked him to double check after I'd done the testing just to be sure. I have wondered if it is the start - stop nature of a combi that creates the problem. Ours always used to give a smell of unburned gas from the flue for a second or two when it fired up, so perhaps they don't burn cleanly until they've been on for a time. Could well be that when heating hot water they rarely get to run long enough to burn cleanly, perhaps.

There is also likely to be a cost (in energy terms) of just heating up the pipework, the boiler itself and associated parts. When measuring the efficiency for a shower these aspects will have a possibly significnt impact that might not be present if heating the house where all the energy in these parts would most likely end up contibuting to the house heat. The boiler might well be achieving 85%, at the shower much less.

[Andy]

I'd be on this if i wasnt set up already...
https://www.gumtree.com/p/heating-firep ... 1441992403

They haven't replied to me for a few days so I suspect they are all taken :<

[Andy]

I think you might be surprised at the heating profile (best way I can think to say it) compared to GCH? No peaks & troughs in temps in house.

That's one of the things that struck us about using a heat pump as well. A few things got us there on the journey. Replacing the open chimney with a stove, removing all the down lights in the bedrooms which connected directly to the cold attic. And then the heat pump.