ᐅ Drilling for a Vent - What Size?

Created on: 15 May 2025 11:50
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LarsBr80
LarsBr8015 May 2025 11:50
Hello everyone,

I want to install decentralized ventilation units from Südwind in our house (model Ambientika smart). According to the technical datasheet, they have an internal duct with a diameter of 162mm (6.4 inches).

Now I’m wondering: What diameter should the core drill hole be? Does the hole need to be larger so that the duct and the wall mounting sleeve fit well and can still be sealed properly? What exact diameter should I use? Thanks, Lars
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nordanney
15 May 2025 12:35
LarsBr80 schrieb:

Now I'm wondering: What diameter should the core hole drilling be?
It's specified in the instructions. I assume at least 180mm (7 inches). You also need a slight outward slope.

Instruction page for installing decentralized fans with wall opening and mounting block
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Tom1992
15 May 2025 17:33
Check the manufacturer's installation manual! For Südwind (and other brands as well), it will definitely specify the exact diameter required for the core drill hole. This can vary depending on the model and the included wall sleeve. Make sure to check the manual before drilling!
Lüftermax15 May 2025 17:41
For installing a pipe with an outer diameter of 162mm (6.4 inches), a core drill hole slightly larger than this diameter is necessary. However, the hole should not be oversized to the point that subsequent mounting and sealing become problematic. Having a small clearance between the pipe and the hole is useful to facilitate inserting the pipe and, if needed, accommodating a suitable wall sleeve.

Moreover, this additional space is essential for effective sound decoupling of the ventilation system from the building structure. Based on practical experience, a hole diameter of 180mm (7.1 inches) is recommended for the specified pipe diameter and corresponding model. This recommendation has been confirmed by several professionals.

The installation manual from Südwind might still specify a drill diameter of 162mm (6.4 inches) for this device. In practice, however, this exact diameter is less advisable because it offers little room for necessary adjustments, such as implementing a slight slope, and it significantly complicates the soundproofing-related decoupling.
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nordanney
15 May 2025 20:54
@Lüftermax @Tom1992
Why are you still writing such confusing messages when the exact answer has already been provided, and the screenshot from the manual with the necessary measurements is attached?
Tolentino15 May 2025 20:58
I suspect AI bots from the forum operator.