Heat pump calculation formula based on heating load

You only get certainty if you have the missed heat meter retrofitted. Everything else is just guessing.

So the heat pump was actually set incorrectly. I hope that was the reason and that the frost protection mode caused the high consumption. If I understand correctly, Rotex has a heat meter built in directly. But if there are Excel sheets, formulas or similar, I would like to calculate the theoretical consumption. I also tried the 3.3 kWh * 1800h, or heating load + Qww * f (3.3+1)*1.14 or using U values and COP I come to 9.3 kWh or V * Vn + A * An calculate * HT / 2.8 / 365. But none of the values yield a result that makes sense. If there are so many values etc., there must also be formula collections to calculate with the values. Ps. Neighbors also have heat pumps and no KFW, but a bungalow instead of 1.5 stories and said that at over -10° it can sometimes reach 15 kW per day.

Theoretically, one can do more than just guess, but it requires quite a bit of work. The heating load calculation that is usually provided for the overall calculation is mostly somewhat rudimentary and was created before the construction itself. For my house, after the construction, I calculated the room-by-room heating load myself. In principle, you just need to make an Excel spreadsheet, in which for each room and all walls the heat conduction is calculated (in principle, the formula is the same for each room, differing only in wall areas (with window/frame), temperature difference (outside variable stored in some cell), and thermal conductivity, which you can calculate, for example, using the U-value calculator available online based on the materials used). Then, in the end, you know quite accurately at which temperature which heating power is needed (controlled residential ventilation can also be included, if desired). This corresponded quite well with reality for me, but I also adjusted the heating circuits and the heating settings (heating curve) very meticulously myself. The advantage is: in the house, the temperature has been constant at about 0.3°C for 4 years (without the ERR having to intervene). I would recommend to the OP to first turn all ERRs, if available, fully up and adjust the temperature in the house over several weeks using the heating curve, so that the heating does not produce too much heat that might be throttled. Raising the hysteresis (heating flow temperature) was also useful for me so that the system starts less often and has longer continuous running times. Right now is the optimal time to make adjustments because heating is being used. When it gets warmer outside soon, make fine adjustments and with the two different points of the heating curve (which you then know) you have established the entire course.

Edit:
Heat loss of a wall for the table:
U-value (in W/m²K) * area * (inside temp - outside temp)

For the total heating load, you can of course also simply take all exterior surfaces + roof + floor.

The calculations are all static, though. So it won't be any more accurate than an estimate. You simply cannot calculate it; all verifications are only designed for an approximate annual result.

If you have a lot of free time and access to a computing center, you can recreate your house as a fem model with detailed accuracy. Theoretically, it is then possible to simulate changing external temperatures and simulate solar gains. Wind would, of course, also have to be taken into account. Inside, you actually have a relatively static temperature and can simulate internal gains.

That would be an interesting research project, but not feasible for practical use. Therefore, there are formulas so that you can roughly estimate what kind of energy goes in and out.

But the calculations are all static. So it won’t be more precise than a rough estimate. You simply can’t calculate it exactly, all proofs are only designed for an approximate annual result.

If you have a lot of free time and access to a computing center, you can faithfully recreate your house as a FEM model. Theoretically, it is then possible to simulate changing outside temperatures and solar gains. Wind would naturally also have to be taken into account. Inside, you actually have a relatively static temperature and can simulate internal gains for that.

The calculations are only quasi-static because you can use references in spreadsheets, so it is indeed possible for yourself to get an outside temperature dependency into the calculation. Especially for winter/autumn in dull weather (and preferably with a white exterior wall) such a thing is already a very good estimation. The U-value (etc.) basically applies to a static/stationary condition. A dynamic calculation of heat conduction is actually "overkill" for a house and slow processes.

Otherwise, you are right to some extent that you can hardly use the information from the heating load/annual heating energy calculation—except for individual bits, for example, wall/window areas, etc. are mostly calculated quite precisely, so you can adopt these values into your own calculation. But I wouldn’t use FEM for a house either; that’s basically like shooting mosquitoes with a mini-gun...

The calculation of the U-value (thermal conduction) must be supplemented by ventilation losses (convection).

Static/dynamic: The U-value is not constant, but essentially depends on the weather, especially the wind.