Has anyone used a ducting transition so their 6" duct will work with the 8" inch exhaust on their kitchen hood?

Curious how well this works with the hood and higher cfms.

For lower CFM settings that should work, but not ideal since you aren't maximizing your range hood's potential. I wouldn't recommend that -- it can strain the fan motor & add extra noise. I also read that it could be a fire hazard if hot grease builds up inside. Our new 850 CFM kitchen hood exhaust was 7", but I changed out our 6" ducts to 7" (including widening the wall hole). Huge difference.

Thank you. About what did it cost you to change out the ducting from 6 to 7?

I probably spent about $200 in parts from Home Depot. No labor cost, since DIY.

Agree with Slacker. If you do your middle school calculation of a circle's area, pi*r squared, a 6" duct has an area of 28 square inches. An 8" duct has an area of 50 square inches, almost double the capacity.