Different Heating Concepts Compared

I am now in the situation that, due to working from home in the attic, I have installed a multi-split air conditioner with 4 indoor units. The energy label values promise a SCOP of 4.6 and a SEER of around 8-9, I don't remember exactly. In any case, I also heated with it this winter, usually when it was above zero outside. The unit then constantly freezes up and has to defrost, the efficiency was really bad then.

I recalculated it and compared it with last year's consumption. I come up with a lousy 2.4 with the heat pump. That's really bad, how can that be? I have a few pipes going up the facade from the outdoor unit for a few meters, in a cable duct. The pipes each have insulation on the outside but overall are not very well insulated. The company says that's normal and you don't do more there, it doesn't help to insulate the stuff because it is converted to gas or liquefied at the unit, so you really don't need to insulate it more. Is that true? 2.4 is really nothing...

This way I can just keep heating with gas...

Just reveal some numbers. How did you calculate?

House was handed over turnkey in summer 2014 with 1692 kWh gas consumption due to screed drying.

Installed is a gas heating system, as well as hot water preparation with solar storage 300 liters + 2x collectors for hot water.

Gas meter readings converted to kWh (1 m³ = 11.28 kWh)
Summer 2014 1692 kWh
Summer 2015 11426 kWh = Consumption 9734
Summer 2016 19356 kWh = Consumption 7930
Summer 2017 27636 kWh = Consumption 8280
Summer 2018 34979 kWh = Consumption 7343
Summer 2019 41758 kWh = Consumption 6779
Summer 2020 48300 kWh = Consumption 6542
Summer 2021 56490 kWh = Consumption 8190
Summer 2022 63089 kWh = Consumption 6599
Summer 2023 65875 kWh = Consumption 2786

In summer 2022, an air/air heat pump was added.
Panasonic outdoor unit in combination with 4 Panasonic Etherea indoor units.
The outdoor unit has a design cooling load of 6.8 kW.
Power consumption in heating mode min. 580 watts up to max. 2,680 watts.

Electricity meter
Summer 2017 7123 kWh
Summer 2018 9023 kWh = Consumption 1900
Summer 2019 11010 kWh = Consumption 1987
Summer 2020 13266 kWh = Consumption 2256
Summer 2021 15721 kWh = Consumption 2455
Summer 2022 18265 kWh = Consumption 2544
Summer 2023 22512 kWh = Consumption 4247

The control of the Viessmann heating system indicates the following regarding solar system – hot water preparation:
39247 kWh over solar collector, period 2014-2023.

The following consumption data I have according to the heat pump app:
Jul 22 Consumption 21 kWh
Aug 22 Consumption 62 kWh
Sep 22 Consumption 33 kWh
Oct 22 Consumption 90 kWh
Nov 22 Consumption 243 kWh
Dec 22 Consumption 385 kWh
Jan 23 Consumption 197 kWh
Feb 23 Consumption 332 kWh
Mar 23 Consumption 87 kWh
Apr 23 Consumption 189 kWh
May 23 Consumption 45 kWh
Jun 23 Consumption 46 kWh
12 months total: 1,730

I had tried mainly to heat with the heat pump, however I switched it off during very cold temperatures and activated the gas underfloor heating.
In the months November and April there was little to gain from the solar system, but no gas heating was on either. Here the consumption was 115 kWh and 120 kWh respectively for hot water preparation with gas. In the months December, January, February, March the gas heating was on, but I tried to estimate the hot water gas consumption. In May there was more sun, here it was only 70 kWh. In June 18 kWh gas for hot water, now again completely via collectors. In summer, gas basically never runs through.
I estimate that I had a total of 1170 kWh gas consumption for hot water from summer 2022 to summer 2023.
That in turn means 1617 kWh gas consumption for heating.

Normally we had a total gas consumption per year of around 6,500 - 8,300 kWh. The winter 2022-2023 was quite cool comparatively, so let's assume 7,700 kWh estimated.
7,700 - 1,617 = 6,083 kWh which the heat pump had to provide as heating output.

According to the app, the heat pump consumed: 1,730.
The "COP" value is thus 6,083 / 1,730 = 3.52

So I had initially miscalculated, but although I switched off the heat pump at very cold temperatures, only 3.52.

Thanks for the information!

I have a few more questions:
Was the solar collector also used for heating before and no longer now?
How is it ensured that it is not warmer now than before?
Where in your calculations is it taken into account that cooling was also done?
Because the gas heating did not take over that before. ;-)

Was the solar collector previously also used for heating and now no longer? No, it only heats water. How is it ensured that it is not warmer now than before? We even had it colder this winter! We had gas running 24/7 in all rooms. The heat pump was rather activated on demand per room. Where in your calculations is it accounted for that cooling was also done? True, that was stupid of me. 162 of the 1,730 were for cooling, so 1568. That results in a COP of 3.88.