reduce range hood vent size or elbow it all over the place?

Question

I have a high performance range hood that I need to vent up and then sideways about 10 feet to the outside. The manufacturer requires a 7" round duct. In order to use a 7" duct I'll have to vent it up, put in a

90, run it across the top of my cabinets, put in a 45 to get in front of a joist, then another 45 to get back straight, then a 90 up, and then a 90 to go to the outside. If I reduce it to a 4" duct, I can go up, put in a 90 and go straight to the outside.

So, which is the lesser of the 2 evils? Any help would be very much appreciated.

Bubba · Accepted Answer

If the manufacturer requires a 7" vent but a 4" will work much easier then by all means, reduce the vent size by almost 50%. It wont hurt a thing. The manufacturers usually take things to the extreme and allow for a lot of fudge factor. I would reduce it to 3" but NO smaller. 3" pipe is cheaper and will do the same job as the 4". You should be all set to go. Bubba

fourempties · Answer

OK- thanks for your help. I may have to cut some of the duct pipe shortand blow it through the baby's nusery for about 2 or 3 feet, but I canset up a fan to direct the air back into the ductwork before it reachesthe corner where the crib is. I should be able to go back up to a 5"pipe at that point and just hang a furnace filter from the ceiling tocatch any food debris and grease. You are a real asset to this board.Thanks for all of your insight.Bubba wrote:

Steve Scott · Answer

Let's see.  Reduce the pipe size to less than 1/3 the manufacturerrequirements?  Why not?

Steve Scott · Answer

Didn't he just help you figure out what to do?

Murdentech · Answer

ROFLMAO... good reply.

fourempties · Answer

Lesson #1- don't ever expect a real answer to a real question on this thin rag of a bulletin board. Thought I would give it a try but all you self-professed experts who masquerade as real do-it yourselfers are more than a little pathetic. If anyone wants to seriously answer my question, I would be more than happy to enter a real dialogue. I wish I had a filter to screen out the mental midgets who feel the need to give their 2 cents to a question that someone is actually trying to get an answer to. Yes - I am talking to you Steve Scott, Bubba. Leave the basement once and awhile.

NO TIME FOR D> Let's see. Reduce the pipe size to less than 1/3 the manufacturer

Bubba · Answer

Your welcome. Looks like maybe you are catching on. Would you like itdrawn out in crayon form so its something clearer you can recognize?Bubba

Oscar_Lives · Answer

Can't you just go up and vent it in the attic?  That is what we do around here.  An added bonus is that the air blown up in the attic helps heat it in the winter and cool it in the summer.

Stormin Mormon · Answer

Area is based on the square of the diameter. So,  4 instead of 8 wouldbe 1/4 the area.

Stormin Mormon · Answer

First, refer to the book.Second, since area relates to the square of the diameter, your 4 inchpipe is (about) a quarter of the area of the 7 inch.My best SWAG is that the longer 7 inch pipe will flow a lot more air.

no one that you know · Answer

You lieing sak of shit.So if you order a 15 inch pizza and get a 12 inch that is the same thing?Bubba wrote:

reduce range hood vent size or elbow it all over the place?

Join the Discussion

Didn't find your answer?