ᐅ Extremely High Heating Costs with Underfloor Heating: Incorrect Settings?

Good day.
We have noticed that our neighbor in the multi-family house (6 units, KfW 70 standard, built in 2016) has extremely high heating costs.
We have underfloor heating throughout (standard windows with mechanical ventilation), pellet heating.
We suspect that his heating habits may not be quite correct.

Can anyone say what might possibly be done wrong?
90 m² (970 ft²), upper floor, single household (retiree). Consumption in October was about 400 kWh for 90 m² (2 weeks quite warm, 15–10°C (59–50°F) in October, 2 weeks around 10–0°C (50–32°F) in Bavaria).
Rooms such as the living room, bathroom, hallway, and bedroom are heated to about 21°C (70°F) using room thermostats.
The office is not heated at all.
In general, he likes it warmer.
However, he does not heat the office at all.
Ventilation is done normally through the window (occasionally tilted).

Who can advise on how to properly heat with underfloor heating for a single person (retiree)?

Thank you very much.

Is hot water consumption included in this usage? How was the consumption measured?

What is the comparison value, for example from your experience, or where does the assumption that it is high come from?
400 kWh of gas costs about 24€, and I believe pellet fuel costs are still slightly lower. Where is the issue?

guckuck2 schrieb:

Is hot water consumption included in that figure? How was the consumption determined?

What is the comparison value, for example from your side, or where does the assumption come from that it is high?
400 kWh of gas costs about 24€; I think pellet fuel costs are still slightly lower. So what is the problem?

Good day.
No, hot water is not included. This is pure kWh for the underfloor heating.
The comparable apartment (but facing east/south) has about 60 kWh (compared to 400 kWh).
Same household (one person). Here, however, all rooms are heated between 18 and 20 degrees Celsius (64°F and 68°F).
Ventilation is done by brief airing (instead of leaving windows partly open).

fraubauer schrieb:

Here, however, all rooms are heated to between 18 and 20 degrees.

In that case, the neighbors are also heating the apartment. At 18 degrees, I can almost keep the heating off all year round in the apartment building if the neighbors are heating.

fraubauer schrieb:

Leaving windows partly open).

That’s not something people do anyway.

The orientation, especially during the transitional season, also plays a role, along with a three-degree lower desired temperature, different ventilation behavior, and so on.

Keep observing this, particularly during the heating period. At the moment, there is no reason to be alarmed.

At 18°C (64°F), I wouldn’t even need to turn on my heating; 4° more makes a huge difference in energy consumption... not to mention leaving the windows open.