Heat pump calculation formula based on heating load

Hello, maybe someone has an Excel sheet or formulas for me to calculate the theoretical consumption of my heat pump on a specific day?

The average consumption of 23 kWh/day seems a bit high for a new KFW55 house. I know there is still residual moisture inside, but does that make such a big difference?

What would really help me are formulas with which I can calculate the consumption, or the heating load calculation seems a bit low to me.

Regarding the data:
KFW55 house 132 m2 living area. Dec. Lunos heat recovery, aerated concrete 42.5 cm
Floor area 9m x 10m, 1.5 stories, floor height 2.59m
3 people, including 1 toddler
Water-saving shower heads + Amphiro Smartmeter Temp. max. 38°

Heat pump consumption in 18 days 413kWh
Average temp day/night 5° / -1°
Utility shutdown 2 times 1.5 hours

Heat pump
Rotex HPSU 308 6kW 300L tank
Domestic hot water temp. set to 48°
COP A-7/W35 2.53 Heating capacity 4.2 kW
COP A2/W35 3.47 Heating capacity 5.5 kW
COP A10/W35 4.94 Heating capacity 8.6 kW
Standby heat loss at 60° kWh/24h 1.3
Surface area domestic hot water heat exchanger 5.8 m2
Average specific heat output 2790 W/K
Domestic water volume 27.8 L
Storage charge/discharge heat exchanger
Volume 12.4 L
Surface area charge heat exchanger 2.5 m2
Average specific heat output 1200 W/K

Room temp. average 21°

Heating load calculation
HT 83.11 W/K, HV 28.94 W/K, H building 112.05 W/K
T building 2681W, Vmin 186W V building 638W
N building 3320W, HL building 3320W
Area building 145.8m2, Volume net building 384.0 m3, A 388.9 m2
HL building / Area building 22.8 W/m2
HL building / Volume net building 8.6 W/m3
HT 0.21 W/(m2*K)

I would like to calculate the following:
How many hours does the heat pump run, e.g., per day?
Power consumption in kWh per day?
What does a ±1° temperature difference make?

Thank you very much

The power consumption is initially meaningless. You need the heat. Assuming the pump has a COP of 3, you are at about 81kWh of heat, including hot water, which is not unusual at these temperatures.

Isn't there a formula? For example, if it is -10 degrees outside, then the heating energy demand is such and such. The house loses so and so many degrees per hour. If the house is 2 degrees below the setpoint, the heat pump turns on until 1° above the setpoint and takes such and such time to do so.

A rough estimate is possible. You take the heating load and multiply it by the 'heating hours'.. These are usually around 2000 for old buildings. For new buildings, rather 1800. If you take 2000 and the heating load of 3.3KW, you get about 6600 kWh energy consumption per year. That divided by the annual performance factor. Let's take a poor 3, you have to pay 2200 kWh. I currently pay 21.5 cents per kWh of electricity. So you end up with 473€ per year in heating costs. At least estimated.

What the OP envisions here cannot be calculated, hardware is needed for that. Here is a heat meter. With it, you can then evaluate your outdoor temperature-dependent heat demand and check if the values a) match the heating load calculation and b) correspond to the electricity consumption.

At 5° outside temperature and your given (very good) heating load specifications, the heat demand (if I compare it now with my consumption and my heating load calculation) should not exceed 30...40 kWh. At these temperatures, your heat pump should achieve a COP of 3.5 (which is not exactly great) and thus have an electricity consumption of max. 12 kWh + about 2 kWh for hot water = 14 kWh.

Your 23 kWh therefore points to:
- a poorly adjusted heat pump and thus a COP of about 2
- or a house that is worse than stated in your calculation
- or very high hot water consumption
- or a malfunctioning controlled residential ventilation system
- or uncalculated window ventilation
- and possibly residual moisture (can make a big difference)
- etc. there are many more things that could be listed here.

Hi,
no matter how I try to calculate the average daily consumption, I always end up with 9-14 kWh.
Water consumption is not high, we control the showering with the Amphiro Meter. Washing up is done with the dishwasher.
The controlled residential ventilation is from Lunos, standard system, could it be that the wind load is too high and cold air is being forced in?
Window ventilation is not done because of the controlled residential ventilation.
Residual moisture is definitely present, it is a new building.
Does that really make a difference of 12 kWh?

Yesterday I noticed that the consumption was 26 kWh. The EVU lock was blinking on the system, outdoor unit not reachable and frost protection was active. Now the electrician, when changing the meter, made it so that the outdoor unit is without power. Could it be that the heat pump is now trying to defrost with the heating rod for 1.5 hours or is in error mode?

Thank you very much for the good hints