Additional Costs Statement - How should the list be created?

Hello

We have a single-family house with a granny flat. There is a central heating system (Viessmann air-to-water heat pump) as well as a hot water buffer.

A heat meter is installed on each floor heating distributor.

In the granny flat, there is also a hot water meter.

I have tried to research on the internet how to create a utility bill, unfortunately without success.

I would be very grateful for any tips or explanations.

Add up. Electricity of the heating. Maintenance costs. Determine the heat meter readings. Both apartments together are one hundred percent. Now distribute the determined costs according to the reading values.

I do hope that the distribution of costs is regulated in the lease agreement - even if your question doesn't sound like it.

Allocate the electricity consumption based on the heat meter readings?

How do I do this for hot water?

Why? The heating costs are included in the heating expenses, meaning electricity. For water in general, there are water meters.

Hello,
I would recommend having the billing done for the first few years. Once you understand it, you can do it yourself in the following years. If a completely unrelated tenant lives in the apartment and the billing is incorrect, it could potentially be expensive if the tenant challenges it.
I also hope that not only the tenant but also you have a water meter for the hot water. Because then it works like with the heating. The electricity consumption is either divided proportionally or, if applicable, using data from the heat pump between heating and hot water. Then, from all costs—fixed costs and variable costs—the price per unit is determined, and both you and the tenant pay according to your consumption.