hm...... the most important thing is wall surfaces to accommodate various things like distribution, meters, inverter, heating, buffer storage, washing machine, etc. if necessary, a partition wall should be placed somewhere where you can at least store something else..... possibly also consider above the ceiling where you might be able to place something (no joke) in total we have 27sqm [Technikraum] and there is not a single unused area and we also have an additional wall built in otherwise it would not have worked at all.