Anyone using a 6" vortex inline with a 4" reducer?

I was all set to start ducting. My plan was to use a 6" inline vortex fan with a 6" to 4" reducer right at output side of the fan that will be attached to 4" PVC pipe.

I was planning to use 6" ducting elbow from the fan to the hood.

Then the HD guy told me that I was loose too many CFM reducing to 4"

Anyone else doing this? Will I loose too much CFM reducing to 4" form 6"?

6" PVC is not at the big box stores and its kind of... big....

here is a link to a picture in my build thread. http://www.homebrewtalk.com/f170/ju...y-build-thread-317746/index2.html#post3978218

 

I recommend checking out this site:

http://www.freecalc.com/ductloss.htm

This will let you enter your duct length / size and the number of reducers and elbows and it will tell you how much loss you'll have.

 

Stick with 6 if you can. 4" will halve your flow rate. Have you looked into metal ducting?

 

I have but then I gotta buy crimping tool and cutter which looked like $75 bucks! Looks like I'll just have to suck it up.

 

Self-tapping screws, tin snips and some aluminum tape should be all you need. I've only worked with it replacing my cooktop so may be wrong.

I think you can get pre-crimped on one side if you don't have to run it too far.

 

thanks. looks like another trip to HD is in order! 6" galvanized ducting instead of PVC it is!