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Octopus Cosy Heat Pump Owners & Discussion Thread

AndrewJ · 2025-10-23T11:37:06Z

I'd like to discuss how you find it, how you run it and so on.

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AndrewJ

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Topic starter 24/10/2025 2:45 pm

Posted by: @jamespa

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Yes if it results in the heat pump being cycled on and off, which clearly it does. In this circumstance it's the average you need to think about which is 0.8kW consumption. It's on-off control not proportional control

Thanks. Hopefully others will be along to comment on their experiences and set up.

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JamesPa

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24/10/2025 2:49 pm

The cycling suggests that there may be scope to reduce the WC a bit. This should give a performance improvement overall, although you may not immediately be able to see that.

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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Toodles

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24/10/2025 4:08 pm

@andrewj In case the comparison is worth anything, here is a chart showing the Homely controlled 8 kW Daikin EDLA08 monobloc for the day of 23rd. October. The values are for IAT (set to 22.5 degrees C 24/7) OAT and power used. More details of my home and insulation etc. in my profile if you wish to read it. The COP was reported as being 4.2 over this period. Regards, Toodles.

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

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AndrewJ

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Topic starter 24/10/2025 4:35 pm

Posted by: @toodles

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@andrewj In case the comparison is worth anything, here is a chart showing the Homely controlled 8 kW Daikin EDLA08 monobloc for the day of 23rd. October. The values are for IAT (set to 22.5 degrees C 24/7) OAT and power used. More details of my home and insulation etc. in my profile if you wish to read it. The COP was reported as being 4.2 over this period. Regards, Toodles.

Interesting, thanks. It looks like yours is operating on/off as well (currently) - I don't see the total power input or a kWh scale. The Cosy yesterday, showing input/output and OAT:

It reported a COP of 4.37 so very similar.

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Toodles

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24/10/2025 5:04 pm

@andrewj The power consumption varies between the peaks at switch-on of ~1.7 kW and ‘tickover’ at about ~300 - 400 Watts. I note that today with lower temperatures, the pump is running most of the time - ticking over between ~400 - 800 Watts. Regards, Toodles.

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

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Toodles

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24/10/2025 5:22 pm

@andrewj Here is a chart of ‘Today so far’, I have added the ‘Heating on/off’ data from which you can see that at the overnight temperatures, the pump stayed on ticking over; the system returned to cycling as the temperature rose this morning of course. Regards, Toodles.