Air-to-water heat pump consumption at 30 kWh per day

How do you determine the electricity consumption only for heating?

well, it’s like with cars, right? These test cycles from manufacturers never correspond to real-world conditions. So I would always deduct 20% there. By the way, this also applies to consumption of electronic devices, etc.

Hm, I don’t find the comparison fitting. With a car, I can determine many more parameters. How hard do I accelerate, how hard do I brake, how fast do I drive, how do I shift, etc. All these influence the consumption. With an air-water heat pump, there are two factors: outside temperature and water temperature. 35°C for the flow temperature is even quite high here. Only for the TWE could it make sense to set the temperature higher, which would negatively affect the COP. It’s the same with electronic devices like a refrigerator. The temperatures at which the measurement is taken are realistic and then I don’t see any way to optimize much for the measuring procedure.

Are you a salesperson for "Kermi" (whatever that is)? Do you want to "push" your heat pump on me :cool:?
I have 160m2 and yesterday a consumption (heating only) of about 25kWh! Temperatures 20-22°C...

No, definitely not, but so far I am very satisfied. Our architect initially planned with a monoblock and we wanted a split unit for cost reasons. Our plumber usually installs Weishaupt but said he could also offer Kermi. We then looked at Kermi and finally decided for the monoblock. But I wouldn’t recommend it generally to anyone. If someone only looks at money, a split unit can be cheaper. We never did the calculation. I informed myself here and in the purple forum, and the statements indicated an efficient device.

How do you determine the electricity consumption just for heating?

You can do that with a second meter. You need this anyway with an air-water heat pump electricity tariff, or you install one yourself. I haven’t put in the effort/cost yet. But since I measure electricity consumption in the house, I know e.g. my continuous load. So if we are not at home, any additional energy is from the heating. That’s not exact to the watt, but very close (20-50 watts). The consumption values of the air-water heat pump then match my other data.

Hello everyone, we have an air-water heat pump from Kermi with 8kW output and a KfW55 house with about 200m². Currently, it is also relatively warm with 24.5°C in the house. Yes, yes, I know that's quite a lot. The consumption figures are only for the underfloor heating and separate from the domestic hot water. I am aware that due to the high temperature we also have a higher consumption, but could it possibly be too high? We live a little north of Hanau and in December the temperature was about ~23°C and sometimes consumption was 6-8kWh per day. When it got colder around Christmas, it was about 20kWh. It has now gotten a bit colder again (-6 to 2) and at the same time we set the temperature to about ~24°C and now have a consumption of 30kWh. I had read that the average consumptions are based on 19°C and that for each degree about 10% more energy is needed. That would mean about 60% more, but then are the 30kWh appropriate? According to the KfW application we need about 30W/m2, so we come to 6kW, but to what are the 6kW related? 24h? Which outside temperature? 19°C indoor temperature? We had a consumption of 6kWh per day in December, which I find quite good, but a few degrees colder and the heating curve raised by 1°C and then such an increase? By the way, we only heat via the heating curve, without any other regulators. Thanks in advance :)

Hi funny there are 2 units with a total of 240 sqm. For 5 years I have been recording the consumption and calculating average values per day. Currently, the beginning of the year is really tight in consumption, matching your consumption. We are also in Hesse and have similar minus values

I have to correct the consumption that the system shows here!

I made a mistake and because the official consumption values were questioned here, I checked it again. I don't want to manipulate any values here.

Kermi indicates the "Current compressor power consumption." However, apparently, an additional 200Wh occurs during the operation of the system. In other words, if the system shows a consumption of 1.9kWh, I see a consumption of 2.1kWh in the system. An email to Kermi is sent. I suspect this is correct and that the COP is only determined based on the compressor power consumption. Now I would be interested to know how this is with other manufacturers.

If I now assume a flat additional consumption of 10%, the COP decreases by about 10% and we get closer to the official figures.

Hi

funny

there are 2 units with a total of 240 sqm. For 5 years I have been recording the consumption and calculating average values per day. Currently, the beginning of the year is really tight in consumption, matching your consumption. We are also in Hesse and have similar negative values

What data exactly do you record? Where do you read these from?

I have to correct the consumption that the system shows here!

I made a mistake and since the official consumption values were questioned here, I checked it again. I definitely don’t want to manipulate any values here.

Kermi specifies the "Current compressor power consumption." However, apparently, an additional 200Wh arise during the operation of the system. In other words, if the system indicates a consumption of 1.9kWh, I see a consumption of 2.1kWh in the system. An email to Kermi is going out. I suspect this is correct and that the COP is only determined based on the compressor power. Now I’m curious how it is with other manufacturers.

If I now assume a flat extra consumption of 10%, the COP decreases by about 10% and we get closer to the official figures.

What data exactly do you write down? Where do you read it from?

I keep an Excel list and write down the meter readings and calculate a daily average per year. This way I also notice if something isn’t right.

My brother-in-law had a water damage and never noticed it. I would notice “outliers” then in the consumption.

How could he not notice a water damage?

We have now lowered the heating curve by 1 and the consumption has dropped from 30kWh per day to 20kWh per day. Back then, the consumption increased from 20kWh to 30kWh and I could not quite believe that it was only due to that one degree, but apparently that is the case.