Range vent u-turn

hoodrange

I am remodeling and adding a dedicated range vent hood. When removing the above-range microwave I found a vent opening that runs down inside the wall to the basement, and then out through the banding board (rim joist) of the house. Since the range hood I was planning to use vents towards the ceiling, I would need to make an immediate 180 degree U-turn to have air vent downwards. Does this present a problem, or should I find a vent with rear discharge and modify the opening on the wall as necessary?

Best Answer

As long as you can maintain adequate cross-sectional area through the entire path it's probably not an issue (assuming few bends downstream). There may be slightly more noise due to turbulence, but it probably won't be noticeable over the sound of the fan itself.