2023,  June 479, Nov 1,120, Dec 1,359, Jan 2024 1,491

These are total kWh per month from which you can subtract 8-10kWh per day for non-ASHP use - say 300kWh per month.

100% electric home. 10KW Grant Aerona, 3 bed detached (150 sqm), mixture of cavity wall insulated new build and internally insulated original stone, double glazed, UFH no radiators. 20c heating. ASHP left on same settings 24/7. UFH off during summer months, 2 occupiers.

How old's your home?

2023 Nov 608, Dec 690; 2024 Jan 886, Feb 564

100% electric 1990ish home, 8.5kW Mitsubishi Ecodan, 4 bed semi (128 m² IIRC), injected cavity wall insulation, double glazed, all radiators, 20c heating (give or take a degree), ASHP set back to 18c overnight, heating does its own thing so rarely on in summer, 2 occupiers.

https://youtu.be/Z_5F5V4nxY4

We used the immersion for DHW and the bills (including standing charges) are £114 £157 £154 £131 respectively.  We still have a gas meter but it's turned off, so the bill includes a standing charge for that. With Octopus Cosy and batteries we pay about 20p/kWh. We also have MVHR and generated 517kWh of solar in those four months.

To answer your specific question, yes 442kWh is the Ecodan's estimate and 399 is what the third-party consumption meter measured for that month. 

The controller generally over-estimates the power consumption. My previous table with Ecodan power replacing 

-October 2023 157 kWh (Ecodan 188- woops, mixed that one up last time!) (2022- not recorded)

-Nov 399 kWh (442) (2022- not recorded)

-Dec 436 kWh (478). 2022- 809 kWh (851)

-Jan 2024 633 kWh (686). 2023- 726 kWh (769)

-Feb '24 (so far, updated) 215 kWh (241). 2023- 484 kWh (521), full month

2023 full year 3144 kWh (Ecodan 3590). 2022- from installation to end of year 1713 (1897).

Annoyingly the disparity in figures is not consistent which undermines my confidence in its estimates of the power delivered so I have done my best to train myself to ignore the calculated CoP and focus on power consumed. (I'd like to believe that its error is consistent in its estimates for power consumed and delivered so the ratio might be roughly OK.

Hi @glpinxit your reply to @skd is very enlightening. Am I right in interpreting your numbers in brackets? 

For example  “Nov 399 KWh (442)”

Is the 442 the data estimated and produced from the main controller on the Ecodan? While the 399 is your actual energy consumed as derived from your HP energy meter?

I’m thinking the ecodan estimates are likely to deviate in variability from one month to another because they are after all, estimates. So consistency isn’t something I would be looking for but rather, a general trend of inaccuracy. In all monthly sets the main trend appears to be an over estimation of around 10.7 to 8.4 percent. This to me is a good starting point in accounting for ecodan over estimated consumption. 
But obviously this is only relevant if you don’t have an actual consumption meter. 
I don’t have a consumption meter, whereas you do. So perhaps it means more to me than it does to you. So thanks for posting it….

House is a converted bungalow, downstairs being around 100sqm; upstairs 40sqm. Radiators only. Downstairs also has a flat roof extension. Cavity walls insulated in 2005. Cumbrian village.

Making changes throughout winter to improve efficiency, and hoping for better by next winter.