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Discussion Starter · #1 ·
Hi all! Need some advice - having a hard time finding clear answers to some of my questions. We will be trying to take on a kitchen remodel and I need/want to FINALLY replace the range hood with something that actually works properly. We have a Wolf 4-burner + Charbroiler grill and can’t use the grill, and even sometimes can’t cook bacon without the smoke alarms going off throughout the house. We know that the unit is not strong enough (the builder clearly did not install the proper hood vent for the stove range!!!). we plan to upgrade to a 900 or higher CFM (based on BTU, I think the min reco shows 800 as each device has 16k BTU output)

my questions are:
1/ we need to verify whether our duct is large enough (need 10’) - how can I figure out the duct size that we currently have? Attached is a pic of our covered chimney hood
2/ in terms of size, our range is 36”. The existing hood is 36”. I have read that the hood should extend about 3” to each side of the stovetop - is this absolutely necessary? In looking at kitchen pics, the majority of the hoods look like they are the same size as the stovetop range. Obviously, if we have to go up to a 42” hood, it means we have to make adjustments to the cabinets 😒
3/ with some basic research, seeing this will be a pretty penny expense line on our budget sheet (like everything! Ha!) any advice on solid quality and price/value brands that will “align” with the top-of-the-line Wolf stovetop that we have? I want a chimney style stainless steel hood.

thanks everyone!
651866
651867
 

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As for current duct size, what do you see on the outside?

May be an issue of insufficient incoming air. Newer homes can be too tight.

In an air tight home make-up air needs to be considered especially if you have and combustion appliances like water heater, furnace, or fireplace that are not sealed combustion. Even if that side of the problem is ok a large exhaust fan may still be limited.

Exhaust fans above 400 cfm usually come with a requirement for a designed incoming air source, not a reliance on "just opening a window".

Bud
 

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Discussion Starter · #3 ·
As for current duct size, what do you see on the outside?

May be an issue of insufficient incoming air. Newer homes can be too tight.

In an air tight home make-up air needs to be considered especially if you have and combustion appliances like water heater, furnace, or fireplace that are not sealed combustion. Even if that side of the problem is ok a large exhaust fan may still be limited.

Exhaust fans above 400 cfm usually come with a requirement for a designed incoming air source, not a reliance on "just opening a window".

Bud
Thx Bud for your thoughts - super helpful and I continue to learn so much for you all!!!

i didn’t think about the incoming air source...

yes, luckily my HVAC guy is coming today so asked him if he could double Check the duct size from the outside.
 

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How old is the house and has it ever been pressure tested to give it a leakage number. Some states require testing (called a blower door test) and that report should be available to new owners.

The pictures don't show the hood height above the burners but that is part of the consideration.

My guess would be your current hood has a 6" exhaust duct, builders rarely install more than minimum. Do you know the capacity of what you have?

Bud
 

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You may not need a new hood, just proper ductwork for it.
Another issue may be that the hood is too far above the stove.

If your smoke alarm on the same floor as the kitchen is ionization, switching to photo-electric should help.
 

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Discussion Starter · #6 ·
How old is the house and has it ever been pressure tested to give it a leakage number. Some states require testing (called a blower door test) and that report should be available to new owners.

The pictures don't show the hood height above the burners but that is part of the consideration.

My guess would be your current hood has a 6" exhaust duct, builders rarely install more than minimum. Do you know the capacity of what you have?

Bud
So the house was newly built approx 15yrs ago. No pressure test obviously that was done through us, as it was new and nothing was called out during the inspection. I had to reach out to the mfr of the blower to get a model # & specs. She advised it’s 600CFM but that out axial fan is probably not the right one (& it’s old at this point anyhow) for that CFM. The height is just a tad under 32”, and best measurements show from the vent base to the ceiling is approx 40”.
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I just did a quick romp through the website of our local appliance store. A wall mount in stainless steel with the air you want to move was the most expensive they had, and the smallest was 42" (none of the 42" ones were 'chimney type'). You might have trouble finding one with that capacity in the width and style you want.

I agree that make-up air will be a problem. As for height from the stove, you local building code might have hard rules (particularly depending on fuel type) or accept the manufacturer's specs.
 

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Hi all! Need some advice - having a hard time finding clear answers to some of my questions. We will be trying to take on a kitchen remodel and I need/want to FINALLY replace the range hood with something that actually works properly. We have a Wolf 4-burner + Charbroiler grill and can’t use the grill, and even sometimes can’t cook bacon without the smoke alarms going off throughout the house. We know that the unit is not strong enough (the builder clearly did not install the proper hood vent for the stove range!!!). we plan to upgrade to a 900 or higher CFM (based on BTU, I think the min reco shows 800 as each device has 16k BTU output)

my questions are:
1/ we need to verify whether our duct is large enough (need 10’) - how can I figure out the duct size that we currently have? Attached is a pic of our covered chimney hood
2/ in terms of size, our range is 36”. The existing hood is 36”. I have read that the hood should extend about 3” to each side of the stovetop - is this absolutely necessary? In looking at kitchen pics, the majority of the hoods look like they are the same size as the stovetop range. Obviously, if we have to go up to a 42” hood, it means we have to make adjustments to the cabinets 😒
3/ with some basic research, seeing this will be a pretty penny expense line on our budget sheet (like everything! Ha!) any advice on solid quality and price/value brands that will “align” with the top-of-the-line Wolf stovetop that we have? I want a chimney style stainless steel hood.

thanks everyone! View attachment 651866 View attachment 651867
I recently did a kitchen reno and went through the same frustrating research. I have a 30" Wolf and Wolf stainless steel hood (just an FYI)

Here's what I learned about hoods and exhaust:
  • Specs and claims about sound levels is absolutely meaningless. I went to a showroom in Connecticut which carried most brands and tested each with a sound-level meter. None are 'whisper' quiet as advertised. The only way to ensure silent operation is to use an in-line blower.
  • You have to think carefully about make-up air. A high CFM blower has to suck the air in from somewhere. If the CFM is too high, you'll end up sucking air in from your fireplace, furnace, bathrooms, and any other opening in your house. Worst-case scenario is a build up of carbon monoxide inside your house. So I ended up with a 900 CFM blower, (CORRECTION: 600 CFM) which is as strong as you can get (i.e. in my house) without having to add a make-up air vent.
  • Smoke and steam rise, obviously, but when combined with the heat from the burner, the smoke and steam rises rapidly. Based on what I see in your photo, the smoke/steam from your front burners will hit the front of your exhaust. The hood should be high and deep enough to cover the front burners.
  • Your duct is 10' long? In that case, you should consider an in-line blower. You can mount it away from the hood. That way you'll truly get a quiet exhaust.
  • Yeah - it should be wider than your range because it can get pretty darn hot with all four burners on. Otherwise, make sure your fan comes on automatically if it senses heat.
 

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@Ronnie833 "So I ended up with a 900 CFM blower, which is as strong as you can get without having to add a make-up air vent."

I've always read that anything above 400 cfm potentially needed make-up air. Is the 900 referring to just the range or whole house concerns?

Just asking, trying to keep up.

Bud
 

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Discussion Starter · #10 ·
Wow Ronnie. Super helpful and especially from someone with very similar first hand experience.

  • You have to think carefully about make-up air. A high CFM blower has to suck the air in from somewhere. If the CFM is too high, you'll end up sucking air in from your fireplace, furnace, bathrooms, and any other opening in your house. Worst-case scenario is a build up of carbon monoxide inside your house. So I ended up with a 900 CFM blower, which is as strong as you can get without having to add a make-up air vent.
Great call-out reminder, that our HVAC guy also mentioned. He did say that maybe our house is big/open enough to not not need a make-up air unit...but he did say, he doesn't know & we would need a professional to advise. But helps to know 900 is the strongest without one. I was envisioning going up to 1000 or 1200 CFM...not b/c of any expert calculation, but based on user experience with what we have :) (probably not the best way to go about! haha!)

  • Smoke and steam rise, obviously, but when combined with the heat from the burner, the smoke and steam rises rapidly. Based on what I see in your photo, the smoke/steam from your front burners will hit the front of your exhaust. The hood should be high and deep enough to cover the front burners
interesting observation on the hood perhaps not being far out enough to cover the front burners. I need to go take another profile look to see... It's just interesting b/c in almost all the kitchen reno photos that I have been digging through for design inspiration, it looks to me like most vent hoods match the size of the range top. But perhaps it's the optics of the photos (?)

  • Your duct is 10' long? In that case, you should consider an in-line blower. You can mount it away from the hood. That way you'll truly get a quiet exhaust.
Sorry - I meant 10" in diameter, not length. Most standard I have learned is 6" but with 900-1200 CFM, I think the recommended is about 10" with the minimum being 8". I didn't think about length...how would that play into this installation of a new one?

And on this side note, does anyone have any idea of how much the job would cost for the re-ducting and/or installation of a new range vent?
 

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I Googled this: "when is makeup air needed for a range hood"
Got this:
"New building codes require what is called “make-up air” to be installed when a kitchen ventilation hood exceeds 400 CFM (cubic feet of air per minute). Many gas range and cooktop manufacturers recommend well over 400 CFMs for a ventilation hood especially when you exceed 4 burners on your appliance."

Don't be too quick to assume the 900 is acceptable.
Is your furnace a sealed air unit? They would usually have pvc intake and exhaust pipes.
Same question for your source of hot water?
Do you have a wood burning fireplace or wood stove?

If any of the above apply then you need to get the house tested. If too tight even 400 might be an issue. Energy auditors can do a blower door test to advise what you need.

Bud
 
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Discussion Starter · #12 ·
I Googled this: "when is makeup air needed for a range hood"
Got this:
"New building codes require what is called “make-up air” to be installed when a kitchen ventilation hood exceeds 400 CFM (cubic feet of air per minute). Many gas range and cooktop manufacturers recommend well over 400 CFMs for a ventilation hood especially when you exceed 4 burners on your appliance."

Don't be too quick to assume the 900 is acceptable.
Is your furnace a sealed air unit? They would usually have pvc intake and exhaust pipes.
Same question for your source of hot water?
Do you have a wood burning fireplace or wood stove?

If any of the above apply then you need to get the house tested. If too tight even 400 might be an issue. Energy auditors can do a blower door test to advise what you need.

Bud
Thanks Bud. All clear and certainly will be sure to ensure we have the appropriate makeup air ventilation. Sorry if a stupid question - but if we have to install a new makeup air vent, where do these usually get installed and what do they look like? And my HVAC guy said it’s not his speciality - which trade are experts in this?

to answer some of the question you posed. We have water-baseboard heaters, not forced air. Yes a-fireplace but not wood burning - it’s electric (and come to think of it, I think is broken! & we’ve only used it once in over 10 yrs). Hot water source - gas water tank in the basement.
Does the size/layout of the AC system in the house play a part in whether or not we need makeup vents for a new/stronger one?
 

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Your problem is indeed make up air related.
Getting a more powerful range hood won't help the problem, may make it worse.
Before you replace anything, try cracking a window first next time you use the grill.
About your water heater...how is that vented? That needs makeup air but usually basements leak enough air....unless they are finished.
ERV's and HRV's often take care of the make up air needed.
They are a good investment in keeping your house climate fresh. Perhaps look into that.
Whole house ventilation systems exhaust stale air and "condition" outside air to avoid bringing in air that would hamper the effectiveness of your HVAC system.
And make up air vents can sometimes be tied into your HVAC ductwork.
 

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Discussion Starter · #15 ·
Your problem is indeed make up air related.
Getting a more powerful range hood won't help the problem, may make it worse.
Before you replace anything, try cracking a window first next time you use the grill.
About your water heater...how is that vented? That needs makeup air but usually basements leak enough air....unless they are finished.
ERV's and HRV's often take care of the make up air needed.
They are a good investment in keeping your house climate fresh. Perhaps look into that.
Whole house ventilation systems exhaust stale air and "condition" outside air to avoid bringing in air that would hamper the effectiveness of your HVAC system.
And make up air vents can sometimes be tied into your HVAC ductwork.
Goodness Bud. I’m learning so much from your questions! I have no idea how the water heater is vented. It’s in the basement which is a finished basement. If I go down and look around the boiler room who I be able to see how it’s vented?

this whole ERV/HRV mention has me intrigued. Never heard of it but tried to google some. Are these considered “upgrades” for home/lifestyle improvements? I assume they’re rarer?
 

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Post a picture of your boiler and water heater.

The HRV's and ERV's are similar, one exhausts any moisture (humidity) in the air while the other attempts to recover some of it.

New tighter homes can experience a poor air quality and need outside air introduced and inside polluted air exhausted. But that also is exhausting some of your expensive conditioned air (heated or cooled). To reduce the penalty they pass incoming over a heat exchanger simultaneously with the outgoing air. Not 100% efficient but you get the fresh air and save some of the energy.

Bud
 

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@Ronnie833 "So I ended up with a 900 CFM blower, which is as strong as you can get without having to add a make-up air vent."

I've always read that anything above 400 cfm potentially needed make-up air. Is the 900 referring to just the range or whole house concerns?

Just asking, trying to keep up.

Bud
Thanks for your question. I misspoke earlier - my fan is actually 600 CFM, not 900. I was referring to the range. Each house is different. Factors include how airtight the doors/windows are, types of furnace and water heaters, and the overall size of house. 400 seems low. I mean I already have 300 CFM by just adding up my bathroom fans.
But don’t quote me, I’m not an HVAC professional. :)
 

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Post a picture if you can that will help all of us.

Bud
 

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this whole ERV/HRV mention has me intrigued. Never heard of it but tried to google some. Are these considered “upgrades” for home/lifestyle improvements? I assume they’re rarer?
They are fairly common up here in newer builds. Our house was built in '95 and has one and they have been mandatory (Ontario) since 2017. I don't know how feasible they would be as an upgrade since they use separate ducting.
 

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An energy recovery ventilator is not designed to handle the volume of exhaust you are talking about. They are designed to match inflow with outflow. They also utilize ducting to draw from all over the house and distribute incoming air to desired locations.

Bud
 
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