I'm planning to run our kitchen exhaust duct straight up through the roof, and it will be about 17 feet long with a 6" diameter. We're using a 300 CFM (equivalent to 450 CFM) Vent-A-Hood. I wanted to know if there are any potential issues we should consider with this setup, especially since recirculating hoods seem to be a bad option for us. Any advice would be appreciated!
3 Answers
Going straight up is usually the best option for exhaust ducts, but keep in mind that 300 CFM isn’t super powerful. If you can, consider a fan with more settings. Also, check the spec sheet for your hood; it’ll give you info on efficiency with different setups.
I'm a bit skeptical about whether your fan will be strong enough to effectively move the air. It might be a good idea to have an engineer look at it. A booster fan could help if you're not feeling much airflow on the roof. Keep an eye on that!
I'd definitely steer clear of recirculating hoods; they don’t perform well and need constant filter changes. Regarding the CFM ratings, Vent-a-Hood's are based on a standard length of duct. Since your setup is straight up, you should be just fine. If you're still worried about airflow, you might think about upsizing the duct once it's in the attic, but honestly, it shouldn't be necessary!
Thanks for the heads up! I didn't think about getting an engineer to check that, but it sounds like a solid plan. I'll definitely look into the airflow thing before finalizing.