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Cosy Octopus and heat pump settings

Josephiah · 2023-12-12T22:35:13Z

Hi folks, A quick question I thought I'd canvas opinion on: We're on our very first day of the Cosy Octopus Tariff, and certainly at this outdoor temperature (1-5°C today) it looks like it's worked well for us. I scheduled our Vaillant AroTherm Plus to do all its DHW runs during the cheap periods (remains to be seen whether this is quite sufficient - will have to poll the shower users!) and also boosted the indoor target temperature to 20°C in the afternoon cheap period before dropping to the 18°C setback to coast across the peak period. Worked pretty well. On this particular day/temps, no HP usage at all in the peak period, and a reasonable amount shifting into the cheap periods. I calculate a 21.6% cost saving on heating/hot water today compared to the base rate, solely using the house as a heat store. (No battery yet; hopefully coming in January). I did notice, though, that the house temp did not reach the 20°C target in the three hour cheap window before switching off for the peak time (it would get there if I let it run longer). So, while I know that generally lowering the heat curve is a good plan for efficiency (and is what I have targeted up until now), it seems to me that on a cost basis, there is a fairly solid argument for bumping the heat curve back up again somewhat in order to make best use of the TOU tariff. (On a similar basis, there is also a disincentive to run the DHW on eco mode to maximise efficiency.) Do you agree? Have you tried similar strategy? Or something else? (Ideally, one might want to have different heat curves set for the cheap periods than for the rest of the day, but life's too short to manually adjust several times every day!) Cheers, Jo

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Air Source Heat Pumps (ASHPs)

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Josephiah

(@josephiah)

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Topic starter 14/12/2023 6:39 pm

Posted by: @toodles

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600 litres! Ouch!!!

Usually closer to 300 at present, but we are gradually moving from the childhood to the shower-hogging teenager phase of life, so only anticipate it getting worse over the next few years! Part of the motivation for all our upgrades 🙂

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Toodles

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14/12/2023 6:47 pm

@derek-m Information for this at:

GOV.UK "https://www.gov.uk/tax-on-shopping/energy-saving-products"

Tax on shopping and services: VAT on energy-saving products - GOV.UK

VAT and other taxes on shopping and services, including tax-free shopping, energy-saving equipment and mobility aids.

It does require an installer to carry out the workas in my own circumstances. Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

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Toodles

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14/12/2023 6:49 pm

@josephiah Roll-on the days of ‘Fledging’ eh?! Though as I understand it they may grow their wings but still stay ‘at home;! Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

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Derek M

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14/12/2023 6:52 pm

Posted by: @toodles

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@josephiah Roll-on the days of ‘Fledging’ eh?! Though as I understand it they may grow their wings but still stay ‘at home;! Regards, Toodles.

That is easily remedied, you just change all the locks whilst they are out. 😋

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Toodles

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14/12/2023 6:56 pm

@derek-m Do they ever all go out at the same time though? Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

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Toodles

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14/12/2023 6:56 pm

@derek-m Do they ever all go out at the same time though? Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

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Josephiah

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Topic starter 23/12/2023 12:21 am

Quite a nice illustration of the effect of switching to Cosy - guess which day we started!

On the data I've had so far (my smart meter's horribly laggy, though seems to catch up after a few days), we're hitting a 14-15% saving on our total electricity bill.

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Toodles

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23/12/2023 12:14 pm

Because I have battery capacity for the day, (so far at least) I have only needed to use the lowest rate 6 hours each day to keep the Powerwalls topped up to cover the other 75% of the day. (Capacity that is also useful when we have saving sessions!) Whilst we have 10 degrees C. plus temperatures, the Daikin 8 kW heat pump is ticking over at 0.5 kW/h or less. 🙂 I still receive the daily summaries for Agile and although the lowest rates have dipped to negative here and there, I’ll be sticking with Cosy for simplicity and to save my better half having to worry should I be unable to pick out the cheapest half-hours with Agile. Regards, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

👍

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