I would like to revisit the topic.
So far, we decided on a venting hood for the new kitchen because of the advantages over a recirculating hood (moisture is expelled, quieter operating noise of the hood). However, regarding the issues of "süff" (grease) on the exterior wall below the wall box and thermal bridging, we have started to have doubts. We would like to avoid that.
What should be considered with the exhaust duct construction and the choice of the right wall box to prevent these problems for years to come?
For your information: We have chosen the head-free hood Refsta Vento III, the finished room height will be approximately 2.50 m, and a duct just over 2 m in length must be used horizontally below the ceiling to the exterior wall with a wall box. The kitchen planner said we need a duct with a diameter of 15 cm. We would like to use a circular duct toward the ceiling and then an oval duct running horizontally (with a very slight slope) to the outside.