Anyone else had a bill for the recent cold snap?

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SafetyThird
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Location: North Devon

Re: Anyone else had a bill for the recent cold snap?

#61

Post by SafetyThird »

Hi all, not been about much over the past few weeks but catching up again now.

December has been a really interesting month for us after the switch to Octopus and running on the batteries and heat pump. What I've found is that on cold overcast days when we get bugger all from the solar, we can't get through the day on battery power alone, sometime around late afternoon/early evening, the batteries are done, despite adding two extras to the four we originally installed. I don't have room to add more at the moment but when the extension goes on this spring, there'll be a storage room that all the batteries will move to and I'll add a couple then. Current capacity is 21kwh and another couple should take care of the additional needed capacity.

Financially, they've been an absolute win, moving a significant chunk of our electricity use to night rate. The back of the proverbial envelope suggest a 3-4 year payback on the battery install, though that'll probably push to 4 years with the extra couple of batteries. Showed the recent bill to my wife and she just smiled and gave me a big hug, I think that makes up for all the 'how much!' exclamations as I paid for everything.

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6kw PV (24 x REC Solar AS REC 250PE)
Clausius 5-25kw GSHP
Luxpower Squirrel Pod
Pylontech 21kwh
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250l hot water tank with 2 immersions
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NikoV6
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Re: Anyone else had a bill for the recent cold snap?

#62

Post by NikoV6 »

14Kw Ecodan ASHP heating very poorly insulated Welsh cottage
Not too unhappy with that
Image
14Kw Mitsubishi Ecodan ASHP
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marshman
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Re: Anyone else had a bill for the recent cold snap?

#63

Post by marshman »

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Last edited by marshman on Sun Jun 11, 2023 1:49 pm, edited 1 time in total.
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Fintray
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Re: Anyone else had a bill for the recent cold snap?

#64

Post by Fintray »

NikoV6 wrote: Tue Jan 03, 2023 4:22 pm 14Kw Ecodan ASHP heating very poorly insulated Welsh cottage
Not too unhappy with that
Image
Is that with underfloor heating, radiators or a mix of both?
3.87kWp PV
10.24kWp PV SolarEdge system
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100 x 47mm Navitron tubes (still being installed!) Now likely to be removed for more PV.
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Fintray
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Re: Anyone else had a bill for the recent cold snap?

#65

Post by Fintray »

marshman wrote: Wed Jan 04, 2023 7:16 pm I waited until now before posting as I wanted to gather all the info for this December and then compare to last December.

Firstly it's worth mentioning that living in the South East we get it fairly easy when it comes to really cold weather, our location is very exposed so we do get subjected to biting cold winds from the North/East. House is large old detached farmhouse approx. 240m2 floor area -nice thick stone/brick walls and underfloor heating, all electric, no gas or oil.

Over all this years little cold snap was a bit of " blink and you will have missed it" as far as energy consumption for heating was concerned. The GSHP barely broke a sweat peaking at 14.5kWh in one 24 hour period (including aproviding a 300 litre tank full of hot water). Incoming "brine" temperature still solid at 11 deg C.

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Although the house is pretty good insulation and airtightness wise I have done a few small bits over the last year - insulating the large window reveals on the four most exposed windows (they are nearly two feet deep!) , added some more draught sealing around some the window lintels and other places where I have detected unwanted air movement. "triple" insulated the two velux roof windows by adding a layer of 3mm perspex over the inner pane - has made a massive difference to the comfort levels in the rear "sunlounge". The biggest improvement cost wise has to be the battery storage - shifting all but 31kWh onto off peak. I plan to increase the capacity further as 21kWh is not quite enough to get through the peak period with the heatpump running and SWMBO deciding to do the washing etc when it is dark and overcast outside. Plans for this year are better insulation and draught proofing on the main entrance door, more battery storage to eliminate any peak time grid use and possibly shifting some of the PV -particularly the EW system to make it more productive in the winter months.


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You must be well pleased with that 45% cost reduction thanks to your battery and insulation efforts.
3.87kWp PV
10.24kWp PV SolarEdge system
Tesla Powerwall 2
100 x 47mm Navitron tubes (still being installed!) Now likely to be removed for more PV.
MK2 PV router DHW diverter
Morso 5kW WBS
Vaillant AroTherm 10kW ASHP
Nissan Leaf
NikoV6
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Re: Anyone else had a bill for the recent cold snap?

#66

Post by NikoV6 »

Fintray wrote: Thu Jan 05, 2023 11:33 am
NikoV6 wrote: Tue Jan 03, 2023 4:22 pm 14Kw Ecodan ASHP heating very poorly insulated Welsh cottage
Not too unhappy with that
Image
Is that with underfloor heating, radiators or a mix of both?
Just rads sadly, but ones specifically for ASHPs.

Underfloor will be an addition as we extend. Much research going on at the moment into super insulated slabs!
14Kw Mitsubishi Ecodan ASHP
22 x JA Solar 455W Mono Perc Half Cell Silvers
Solis 8.0Kw 5G Dual MPPT Inverter
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marshman
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Re: Anyone else had a bill for the recent cold snap?

#67

Post by marshman »

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Last edited by marshman on Sun Jun 11, 2023 1:48 pm, edited 1 time in total.
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Fintray
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Re: Anyone else had a bill for the recent cold snap?

#68

Post by Fintray »

NikoV6 wrote: Thu Jan 05, 2023 11:50 am
Fintray wrote: Thu Jan 05, 2023 11:33 am
NikoV6 wrote: Tue Jan 03, 2023 4:22 pm 14Kw Ecodan ASHP heating very poorly insulated Welsh cottage
Not too unhappy with that
Image
Is that with underfloor heating, radiators or a mix of both?
Just rads sadly, but ones specifically for ASHPs.

Underfloor will be an addition as we extend. Much research going on at the moment into super insulated slabs!
Which ones did you put in and are you happy with the output, also what temp do you normally run the heat pump flow at?
3.87kWp PV
10.24kWp PV SolarEdge system
Tesla Powerwall 2
100 x 47mm Navitron tubes (still being installed!) Now likely to be removed for more PV.
MK2 PV router DHW diverter
Morso 5kW WBS
Vaillant AroTherm 10kW ASHP
Nissan Leaf
NikoV6
Posts: 217
Joined: Thu Aug 11, 2022 6:42 am

Re: Anyone else had a bill for the recent cold snap?

#69

Post by NikoV6 »

Fintray wrote: Thu Jan 05, 2023 2:26 pm
NikoV6 wrote: Thu Jan 05, 2023 11:50 am
Fintray wrote: Thu Jan 05, 2023 11:33 am

Is that with underfloor heating, radiators or a mix of both?
Just rads sadly, but ones specifically for ASHPs.

Underfloor will be an addition as we extend. Much research going on at the moment into super insulated slabs!
Which ones did you put in and are you happy with the output, also what temp do you normally run the heat pump flow at?
Ultraheat rads, they were selected by the ASHP installers. Several are significantly thicker than traditional rads we have had before.

Heat pump flow temp is an interesting one. I have the temp set using the timer function, 16degs when I want the heating off (overnight and during main part of the day) and 18degs when I want the heating on. This is in conjunction with Honeywell Wifi TRVs on each rad. They are also set to 16 degs when I want them off and 18 when we want heat. Its a work in progress but seems to be a fairly good compromise. Although, if a room is calling for heat, i.e. its dropped below 16 degs but the ASHP controller is registering its thermostat at 17degs for example it will not kick in. I do not know how the ASHP gets its room temp as it does not have a separate thermostat that I can see??
14Kw Mitsubishi Ecodan ASHP
22 x JA Solar 455W Mono Perc Half Cell Silvers
Solis 8.0Kw 5G Dual MPPT Inverter
13.5Kw Tesla Powerwall
Zappi 2 Charger
iBoost
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Fintray
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Location: Aberdeenshire

Re: Anyone else had a bill for the recent cold snap?

#70

Post by Fintray »

Thanks for the info NikoV6.
3.87kWp PV
10.24kWp PV SolarEdge system
Tesla Powerwall 2
100 x 47mm Navitron tubes (still being installed!) Now likely to be removed for more PV.
MK2 PV router DHW diverter
Morso 5kW WBS
Vaillant AroTherm 10kW ASHP
Nissan Leaf
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