Electricity costs for an air heat exchanger?

We took possession of our prefabricated house from the company Streif Haus 14 months ago after a 9-month construction period (including planning, it was even 17 months), but after one year we noticed that the house consumes an excessive amount of electricity (about 10,500 kWh in one year). Our photovoltaic system including battery storage produced about 2,600 kWh, so nearly 8,000 kWh still had to be purchased. Previously, my wife, our 21-year-old daughter, and I lived in an almost equally large rental apartment and consumed about 2,500 kWh of electricity annually. Our new house is equipped with the most modern and energy-efficient appliances (at least A+) and all lamps are LED-based. In winter, our wood stove keeps us warm, and in summer, food is prepared almost daily on the gas grill. Since we also do not heat excessively (always only on the lowest or second lowest setting of the underfloor heating) and the ventilation system does not run continuously, and if it does, only on the lowest setting, we cannot imagine the excessively high consumption. In addition, we had the company Streif Haus build us a KFW-40-Plus house, which is supposed to be particularly energy-saving. The company Streif Haus is not cooperative at all and does not take responsibility, but rather shifts the blame onto our consumption, which, as mentioned, should actually be lower than in our previous rental apartment. My question now is: What is the normal electricity consumption in a KfW-40-Plus house with a photovoltaic system and battery storage for the ventilation system and the air heat exchanger?

Thanks in advance for the answers. Achim D., 85395 Attenkirchen.

What kind of heating do you have? How big is your house? Normally it should be more like 3-5000 kWh. The [rosa Forum] is very helpful with that.

Is that the complete household electricity? So including heating?

If yes, the heating is "wrongly" set, just a shot in the dark.

That means you don’t have underfloor heating but a real air-to-air heat pump? Since when are air-to-air heat pumps economical, I heard you should only install such a thing in passive houses.

Which heating system do you have specifically? You write "Luftwärmetauscher," which sounds like an air-to-air heat pump, but on the other hand, you have underfloor heating, so an air-to-water heat pump?

No matter what: a reasonably modern heating system records its annual demand and displays it on the screen.

House electricity should be max. 5000 kWh per year, heating/hot water electricity 2000 kWh per year. Otherwise, something is wrong.

The fact that you heat the rooms little usually makes things worse with underfloor heating; the consumption is much higher than maintaining a pleasant temperature constantly. Here, Streif Haus does not seem to be entirely wrong.

When he writes underfloor heating, it cannot be an air-to-air system.