Granny flat / Semi-detached house advantages

Hello dear community,

we are planning to build our own home in Münster next year. Since the plot size and the cost plan would allow it, we are considering building a duplex and renting out one part.
Our architect has now advised us to plan the whole thing as a single-family house with a granny flat, as this could offer some advantages regarding the Heizkostenverordnung and des Sonderkündigungsrechts.
Maybe someone has some experience and can share what to watch out for?

Best regards from Münster

Maybe someone has experience and can report what to watch out for?

Advantages related to the Heating Cost Ordinance

Which ones? Every house has its own heating system and payment is made exclusively according to consumption.

Advantages related to ... Special Right of Termination

Then it can't be a semi-detached house. Because to simplify termination, you have to live in the same building as the tenants (two-family house). The Federal Court of Justice (BGH) has already ruled accordingly. So a common entrance to the house and then each branching off left and right into their respective "apartments" would be a first step. But the architect has to plan that according to your wishes. The problem, of course, is the marketability of the rented unit. If you want to sell the "apartment" later, it will be worth less than if it is a detached single-family house. I would, just to be able to terminate more easily—and that is the only advantage—not bother like that. Take the plot, divide it or create residential property and enjoy the house. You can look up deadlines and reasons for termination in the Building Code, by the way.

Which ones? Each house has its own heating system and payment is then made exclusively based on consumption.

Then it must not be a duplex. Because for simplifying termination, you need to live in the same building as the tenants (two-family house). The Federal Court of Justice (BGH) has already ruled accordingly. So a shared entrance to the house and then each going left and right into their respective "apartment" would be a first step. But the architect must plan that according to your wishes. The problem, of course, is the marketability of the rented unit. If you want to sell the "apartment" later, it will be worth less than if it is a separated single-family house.

I would, just to be able to terminate more easily – and that is the only advantage – not fuss around like that. Take the plot, divide it or create residential property and enjoy the house. By the way, you can read the deadlines and reasons for termination in the Building Code.

Thank you very much for your explanations. If the house must have a shared entrance to be considered a two-family house, we will probably rather refrain from that after all. The joy of owning a home would be significantly less….

If the house must have a shared entrance to be considered a two-family house, we will probably rather refrain from it. The joy of owning a home would be significantly diminished....

Whether it has to, I can't tell you. It just has to be considered "one building." But no matter what, it will not be a semi-detached house. In any case, your joy in owning a home will definitely be dampened.

The joy of owning a home would be significantly less….

Keep in mind that this can also apply if the tenant has their terrace 3m next to yours or if the garden shrinks to the size of a towel. With current construction costs and interest rates, a new building for rental purposes is unlikely to generate the necessary return to cover interest and maintenance, let alone make money for you. I would calculate that critically.

With current construction costs and interest rates, a new build for rental purposes is unlikely to yield the necessary return to cover interest and maintenance, let alone make money for you. I would calculate that critically

Don't talk it down. After all, the second semi-detached house no longer requires a separate plot. That should (as long as you can get along with a tenant as a neighbor – but I'd rather have the tenant than the owner as a neighbor) enable a reasonable return. 140 sqm house at €2,750/sqm (it doesn't have to be built as for own use) is €385k. Plus some additional costs and garden/parking space, so maybe €450k for the house. Rent then €1,500 + X monthly – that should be the minimum in any reasonably normal area = €18k p.a. This leaves a gross yield of 4%. That is totally fine. There are no management costs.