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Kitchen Exhaust - 8 or 10 inch in lieu of 6 inch

  • Last Updated:
  • Sep 10th, 2020 11:25 pm
[OP]
Jr. Member
May 29, 2007
111 posts
23 upvotes
Toronto

Kitchen Exhaust - 8 or 10 inch in lieu of 6 inch

Hi All!
We booked a new construction being built in Vaughan. I was wondering if it makes sense to increase the kitchen exhaust opening to 8 or 10 inch in lieu of the standard 6 inch hole from builder.

We do a lot of oily, spice cooking And 6 inch will definitely won’t do. Are there any 10 inch hole sizes range hoods for residential use or it’s only commercial applications only?
I will do 8 inch in any case.
13 replies
Member
Jan 19, 2013
496 posts
289 upvotes
Ottawa
Depends on CFM
Mostly seen 6" sometimes 7" on residential range hood.
Builder should be putting in some kind of makeup air system if your putting in a high cfm exhaust hood btw
Deal Expert
Aug 2, 2004
32934 posts
6537 upvotes
East Gwillimbury
If you plan to upgrade the range hood, definitely get an 8"

I regret not doing it. I am using an 8" to 6" duct and I doubt it is effective
Deal Addict
User avatar
May 18, 2004
2742 posts
365 upvotes
Ontario GTA
satin1410 wrote: Hi All!
We booked a new construction being built in Vaughan. I was wondering if it makes sense to increase the kitchen exhaust opening to 8 or 10 inch in lieu of the standard 6 inch hole from builder.

We do a lot of oily, spice cooking And 6 inch will definitely won’t do. Are there any 10 inch hole sizes range hoods for residential use or it’s only commercial applications only?
I will do 8 inch in any case.
depends on size of stove and fan you are getting.. 6 inch is standard.. 8 inch would be for very high cfm hoodfans and 10inch for the really big ones e.g. if you have a 36-48" stove
if you connect a fan to the lower size pipe it will get considerably more noisy.

one other thing to note, if you have a 30 inch stove, there are not a lot of fans that have high cfm for that size.
another thing to note is that if you truly get a high cfm fan, you will need a make up air otherwise you will run into issues.


lastly, when it comes to hoodfans, most people use them wrong. it's not about turning them on max after you already started cooking, you need to turn them on before you start to start the circulation.
secondly, depending on the type of burner depends a bit on what style fan, induction heat is different than gas.

lastly, there is no industry standard for how you should report the CFM, some may try to get a high as possible number by just showing what the motor can do, another may take into consideration the actual output after it's installed, e.g. with filters and a bend in the pipe and with equal motors those numbers will be very different.
Deal Addict
User avatar
May 28, 2009
1389 posts
354 upvotes
Ottawa
Gee wrote: If you plan to upgrade the range hood, definitely get an 8"

I regret not doing it. I am using an 8" to 6" duct and I doubt it is effective
many years ago we had a 4 " duct and bought a high CFM exhaust which needed 6". since it was winter we used a 6 to 4 converter or diffuser or reducer for a few months. this is an issue because it creates a blow back (more vol is trying to get out of a 4 " duct) and you could feel the air coming back into the house. you can go higher but shouldnt go lower.
Deal Addict
Nov 17, 2012
2958 posts
1945 upvotes
Toronto
I have an 8" duct servicing my Vent-a-Hood. It's a dual blower unit which pumps out 900 cfm if you believe them and it's 30 inches wide.

I got it used on eBay from the US back almost 10 years ago when I gutted our kitchen. $500 US shipped to Buffalo and CAD/USD were about on par at the time (0.98 or so). Has the dual blowers, lighting and heat lamps (the halogen bulbs in the photos have since been replaced with clear warming lamps).

IMHO the best option for serious venting and 8" duct is the minimum required. Mine is on an outside wall so there's a very short duct run.

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Member
Apr 19, 2018
208 posts
51 upvotes
Scarborough
Always get an 8" vent duct for sure!
Don't worry be happy - Bob
Member
Apr 19, 2018
208 posts
51 upvotes
Scarborough
torontotim wrote: I have an 8" duct servicing my Vent-a-Hood. It's a dual blower unit which pumps out 900 cfm if you believe them and it's 30 inches wide.

I got it used on eBay from the US back almost 10 years ago when I gutted our kitchen. $500 US shipped to Buffalo and CAD/USD were about on par at the time (0.98 or so). Has the dual blowers, lighting and heat lamps (the halogen bulbs in the photos have since been replaced with clear warming lamps).

IMHO the best option for serious venting and 8" duct is the minimum required. Mine is on an outside wall so there's a very short duct run.


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Not to hijack but how do you like you're vent-a-hood? Would you recommend it?
Don't worry be happy - Bob
Deal Addict
Sep 6, 2017
3208 posts
1910 upvotes
8" minimum but since you plan to do a lot of oily food I would go 10". You definitely don't want back pressure with the fan on max.
Deal Addict
Nov 17, 2012
2958 posts
1945 upvotes
Toronto
Prestonxavier wrote: Not to hijack but how do you like you're vent-a-hood? Would you recommend it?
I'd highly recommend them, but would have a hard time paying full retail for it.
Deal Expert
Aug 2, 2004
32934 posts
6537 upvotes
East Gwillimbury
torontotim wrote: I have an 8" duct servicing my Vent-a-Hood. It's a dual blower unit which pumps out 900 cfm if you believe them and it's 30 inches wide.
I have a Vent-A-Hood

Great unit. I just need an 8" exhaust
Last edited by Gee on Sep 10th, 2020 11:08 pm, edited 1 time in total.
Member
Apr 19, 2018
208 posts
51 upvotes
Scarborough
torontotim wrote: I'd highly recommend them, but would have a hard time paying full retail for it.
Is there significant mark-up on them? Wondering if i can negotiate the price with the retailer.
Don't worry be happy - Bob
Member
User avatar
Sep 25, 2003
271 posts
73 upvotes
Scarborough
Vent size selection will be dependent on the size of hood you plan to use and the volume of air you plan to move.

The roof cap on my 10” Vent is massive, about 27 x 20 inch in size and tbh looked a little silly on my house given its low roof line. But we have a 48” hood range and the manufacturer spec’d the vent size at 10”.
Deal Fanatic
Jul 7, 2017
5017 posts
2195 upvotes
SW corner of the cou…
I'm on my 2nd 2 motor Vent-a-Hood. First one came with the house when I bought it. Was impressed enough that I bought one for the house I am in now (came with a short-rise Faber downdraft which is powerful but so powerful it also sucks the gas flame away from the burner at lowest speed). 1st Vent-a-Hood only has a short run up and then 90 degrees and out. Current install has a 2' rise then a less than 90 degree turn running another 4-5' before another 90 degree turn and out through the roof.

Both work well so well I can make blackened foods indoors. Also have halogen lights while the old one only has a fluorescent tube and have warming lamps and a fold-away warming shelf. The only quibble I have is where the grease collects. On the VaH it collects on the grease collector just before the fan. Sort of a PITA to get up there to remove the grease trap and the wheel housing and wheels also get covered in grease. I have to take out the housing 2x a year to clean and the wheels once every 2 years.

I think the better design is where you have the grease traps somewhere before that. Makes cleaning easier and less grease might get up to the fan.

As for pricing you can always look in the used ads and also keep in touch with the distributor or dealer. I bought the current one I have at a distributor old demo close out (the model was obsolete, new model has non-replaceable LEDs in place of the GU-10 halogens I simply replaced with GU-10 LEDs) for quite a bit less than list (still expensive).

If anyone wants a 8" VaH roof exhaust jack for steeper roofs, I have a BNIB one for sale.
Cream rises to the top. So does scum.

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