Calculation of ongoing ancillary costs

Yes. Do you find that too much or too little? My exact calculation came to about 600 EUR. In my opinion, you can very conservatively estimate using the rule of thumb and should be on the safe side.

I come to 4000 per year for the items you mentioned, if I calculate with a solid 200€ for electricity per month.
That still puts me under 400€ per month.

Edit: Underlying:
Municipal fees (waste, sewage, property tax) approx. 500 / year.
Building insurance approx. 500 / year.
Water approx. 600 / year
Electricity approx. 2400 / year.

For 2022

Property tax	€ 343.29
Insurances	€ 838.57
Gas	€ 1,921.00
Electricity	€ 2,320.10
Garbage collection	€ 123.00
Water	€ 510.39
Sewer	€ 458.25
Chimney sweep	€ 189.79
Telekom (phone and internet)	€ 695.88
Total:	€ 7,400.27

6 adults / 2 households. 260 m2 living area

that is 2.37 euros /m2 and month.

2 households. 260 m2 living space

Well, for this question it needs to be converted to one household/single-family house. Some costs are divided into fixed and consumption-based costs. So if you base it on an average of 160 sqm on your property (property tax), the cost curve shifts. It doesn’t have to be decisive now, but you shouldn’t compare one household with two. Then you might as well add the 4-family house ;)

For 2022

Property tax	€ 343.29
Insurances	€ 838.57
Gas	€ 1,921.00
Electricity	€ 2,320.10
Waste collection	€ 123.00
Water	€ 510.39
Sewage	€ 458.25
Chimney sweep	€ 189.79
Telekom (telephone and internet)	€ 695.88
Total:	€ 7,400.27

6 adults / 2 households. 260 m2 living space

that is 2.37 euro /m2 and month.

In my view, GEZ is missing twice (220 euros per household) and the costs for heating maintenance (140 euros per boiler).

We have just under 170m² of living space, KFW55 with air-water heat pump. Electricity consumption is about ~5000 kWh general electricity and ~3000 kWh for the heat pump.

Our numbers:

Water and sewage €1232.00
Property tax €232.36
GEZ €220.32
Garbage €205.08
Residential building insurance €674.16
Electricity (photovoltaic available) €2000.00
Telecom €611.52
Household insurance €220.94

I always do the annual inspection and cleaning of the heat pump and ventilation system myself.

Water and wastewater are so expensive for you?