Thanks for that really rather good user experience post of the Quantum system. We have some E7 here with ancient (20 odd years) old storage heaters. No mains gas, solid floor and the only half sensible space for an oil boiler would be the loft that is pitched and only 5' high.
to be good, some others were £70-110 cheaper (John Cribb & Sons).
I haven't googled yet, I'll take the hint and be sitting down. Fortunately we probably don't need that many.
Current ones are 9" deep. The slight snags I see for an upgrade) is that they also need a 24 hr supply, that would have to be installed, plaster chases etc. And what form does that 24hr supply take? A ring or individual spurs like the switched supply?
A 32 A "heaters ring" ought to have the capcity for the boost on say
4 medium units but presumably these things don't work at all without the 24 hr supply so if one devlops a fault and trips the ring *all* the heating goes off...
Our 24 hr CU doesn't have the space for four more MCBs but the switched one does. Would putting a 24 hr feed from a suitably sized MCB in the 24 hr CU to four more MCBs in switched one fall foul of the regs?
The largest Quantum (QM150) peak/boost heater element demand is 1380W at 240V, and storage element is 3300W at 240V.
In most cases you'd probably be able to put the peak supply on the ring, depending on the other ring loading. Or you /could/ put 3 of them on one 20 amp radial. I'd probably put 2 on a 20A radial.
There's a coin battery which backs up the clock (and hopefully the programming).
In an "all electric" place that might be an issue... Sudden cold snap (like what happened here last week, 20 C one day 5 C and windy the next) so the storage heaters go into "boost" and a portable fan/convection heater brought into service. One also might want power on the normal ring when maintaining the heaters.
Think seperate radials would be better provided that mixed 24 hr / switched in the same CU is allowable.
I would assume so but it ain't going to run the fan. B-)
3 of them would still leave another 10 amp on the ring for a fan heater.
If your house is big enough to need 5 large Quantums (Quanta?) which would fully load one ring, then it's big enough for 2 general rings and probably a third for the kitchen stuff.
An alternative is a conventional fan assisted storage heater
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no boost heating, but only needs a 24-hour supply to run the fan (50 watt, so an inverter could be used)
Years ago (late '70's) I had a council flat heated by a large night storage lump on Economy 7. If you kept an eye on the weather and continuously adjusted its input thermostat it wasn't too bad. Turn it up to full and the bill (as elderly neighbours found) was horrendous. Over £200 a quarter in 1978 (£1002.86 at today's prices ref This Is Money website) I, like everybody else, eventually gave up with it and used bottled gas heaters.
Think, if I was you, I might look at ground source or air source pumps. There are grants available. Google it. Dave
Trouble is heat pumps only produce "low grade" heat, fine for under floor heating but not much good for a conventional wet system and useless for DHW. There are two stage heatpumps about these days but they cost more.
I don't think there are any grants available, the RHI is though. Similar to FITs but only 7 years and lower per unit rates.
Now that RHI is in they have fiddled with the conditions somewhere between the consultation document and implimentation. Solar thermal now only qualifies if it's a stand alone HW only system. Hybrid systems, ie solar thermal feeding a thermal store also connected to an oil/gas boiler are excluded. Swap the oils/gas for biomass or heatpump and the solar thermal RHI is included, in addition to the RHI for the biomass/heatpump. Guess what sort of hybrid we have... grrr.
I can't see the logic, heat is heat, OK the solar thermal can't provide anything like the amount of heat required for space heating but it still heats the store and reduces the amount of gas/oil burnt. I have the figures...
I'm letting them waste my time next week just out of morbid curiosity as they do heat pumps. I cannot see a heat pump being viable here - but I'm curious as to the cost...
Could a heat pump be used to feed a small buffer (mini thermal store) which would preheat either/both the incoming mains water and the CH return before sending both into a combi boiler to do the last bit?
The former - clearly so - the latter - how hot does the output of a single stage heat pump get?
Having been "fortuitously" spammed - I can now add some facts (maybe).
The company that spammed me got this company to call me:
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On there is an interesting calculator and some background info on air source heat pumps (ASHPs) (air to water). The bloke who called me, to his credit, seemed to know his stuff.
However, I have concluded, if you have mains gas, it's a complete waste of time. Here's why:
My heating load (peak) is around 10kW (about right in the coldest depths of winter - I have electric heaters so I know this). Average load is of course a *lot* less.
They make a single stage ASHP in 14kW that is rated to do that at about
-1.5C but will function down to -15C with corresponding tail off.
The efficiency is claimed to be 1kW in, 2.5kW out - so 250%.
However, that needs:
1) Peak rate electricity which is typically a bit over double the price of gas per kWh
2) Produces a water temperature of about 45C needing radiators sized on a 45/37C differential (ie quite large phsically).
3) You need a HW tank (unlike a combi).
4) But it would combined with solar HW panels quite well.
Even their own calculator shows that for my house, an ASHP would have £1026pa running costs vs mains gas boiler at £1149 which seems about right.
Then there's the installation cost. Combi boiler - what, 2k all inc?
This would be about 9k just for the ASHP assuming your rads were already sized appropriately for 45/37C flow. If now, add lots more plumbing work plus a tank if you don't have one.
Now there's a gov scheme that if your house meets the requirements and you stump up the installation costs, would pay you back £8.6k over 7 years.
The ASHP has a warranty of 10 years, with an expectation of the full life being perhaps double that and it needing a compressor replacement perhaps once (1k IIRC)
I'm not seeing the benefit here?
GSHPs (ground source) are even worse in terms of installation cost unless you just happen to have a field next to your house for a wide field pipe array (about 600m2 in my case) - you can run the calculation yourself.
Borehole versions are *very* expensive and also require an EA abstraction license at around £200pa because of the amount of water being sucked out (although I don't get that as the same water is put back down a 2nd borehole presumably into the same layer the water came from?)
Starting to sound like tree shagging fairy time again like so much green stuff - although in the grand scheme of things, a heatpump is actually saving energy for the country as a whole - but for me it's not economic on running costs plus capital despite the mega payback deal.
Certainly not as lucrative as FIT PV though that was just robbing people outright.
If you have mains gas you don't qualify for the RHI. Also to qualify you have to have had a Green Deal survey done and have and Energy Performance Certificate (EPC) and of course the system needs to be covered by the Microgeneration Certification Scheme (MCS).
Assuming that getting a GD and EPC costs about £250 my Solar Thermal could have gained me just under £1000 over the seven years. I might jump up and down on Ofgem and my MP to ask why Solar thermal has to be stand alone or only when a hybrid with a non fossil main heat source and where this was mentioned in the consultation documentation (I can't find it). But for £150/year it hardly seems worth it, the synic in me says that is the intention.
Aye, though the current rates are not as profitable.
Do you have a citation for that? Because I think you are not correct.
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"The domestic RHI is targeted at, but not limited to, homes off the gas grid. Those without mains gas have the most potential to save on fuel bills and decrease carbon emissions."
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