Distance of niche cabinet to side walls

Hello,

we have a niche in our bedroom for a wardrobe and want to have it custom-made to exact measurements. At Höffner there is a program where you can specify width, height, and depth down to the millimeter. So we are very flexible.

Now the questions: how large should the distance to the sides (and to the back and top) be so that ventilation is sufficient and there is no mold formation? I think we were told 5 cm at the furniture store. That would be quite good, as we could achieve a depth of 65 cm and still have space up to the window. Attached is the construction drawing, the wardrobe should be in the niche next to the fireplace.

Thank you very much in advance for your answers.

Had a suitable wardrobe with a 2cm gap in a niche for 17 years. No mold. However, installed only one year after the completion of the house.

Alternatively, a real built-in wardrobe, which would then be flush on the side and possibly open at the back, so that no mold forms here either.

Is the house already built? Based on the plan, I would not commission a custom-made item. Firstly, not all walls are exactly where planned, and secondly, the interior plaster thickness can vary from ... to .... That applies to both sides of the cupboard niche, and suddenly you are missing 5 cm. It was no different with the kitchen, so spacer strips were planned on the right and left, which are only cut to size on site. Not an optimal solution, really, but otherwise the delay in kitchen planning would have been too long.

Alternatively, a real built-in closet, which would then be flush on the side and possibly open at the back, so that no mold can develop here either.

I have thought about that too. But it’s quite difficult to get something exactly flush on the sides like that. And the provider does (not yet) offer trim strips that would compensate a few centimeters.

Is the house already built? Based on the plan, I wouldn't order custom-made items. Firstly, not all walls are exactly where planned, and secondly, the interior plaster thickness can vary from ... to. That on both sides of the closet niche, and suddenly you're missing 5 cm. It was no different with the kitchen, so fitting strips were planned on the right and left, which are only cut on site. Actually not the optimal solution, but otherwise the delay in kitchen planning would have been too long.

Yes, the house is already built and the plaster is already done, or rather, the drywall is plastered.
The exact measurements exist, but walls are not always 100% straight, etc., so I wouldn't dare to order down to the millimeter. It would be possible, but if it doesn't fit then...

Therefore, I thought about leaving a few centimeters free on all sides; it doesn't look bad either.

With the kitchen, we also have fitting strips that can compensate a few centimeters.