Range Hoods & Vents

[cupcake]

We currently have a Dacor 30" all gas/convection oven slide-in range that's about 13 years old. We have a microwave/hood that basically does nothing as far as ventilation goes. We live in an 1885 home with no chance of venting outside. We need to replace our range. Dacor does not make the quasi-professional type we have that can safely go under a microwave hood. I really love my range, and to get the features I would like, it appears I need to get a professional range (DCS, Dacor, Viking, etc.).

This means we cannot have a microwave hood, which is not a problem as far as losing the microwave. We were told that the Viking wall hood with the recirculating conversion kit would work. Does anyone have any experience with a recirculating hood and the BTUs of a professional range in our small kitchen? Our current set up makes the kitchen very warm in the spring/summer.

Also, I have read that the professional ranges are not that insulated-- if we are looking at Viking or Dacor, will it be even hotter than it is now?

What we are contemplating now is removing the cabinet over our microwave hood and swapping it out for a shorter cabinet (to gain enough clearance btwn the hood and the range), and then swapping the microwave for a recirculating hood and getting a professional range. Any advice or thoughts would be very welcome.

Cynthia & Jim

[LindaK]

cupcake, if I understand your question, you want to know whether the BTU output from one of today's professional style ranges (as opposed to a 13 yr old range) can be accomodated by a recirculating hood.

I don't know the BTU output of your current Darcor, but you should know the specs of any new range before you go hood shopping. For the ranges you mention, I would imagine that the BTU output is significantly higher than what you have now. You really have two issues: grease capture and heat generation. Will a good recirculating fan capture the grease and smoke produced by a high BTU range? Probably. Will it dissipate the heat generated by a high BTU range? I can't imagine how it could do so, if all it does is pump the filtered hot air back into your kitchen. And these ranges generate serious heat.

re: insulation. I believe that all professional style ranges (emphasis on "style") are insulated for safe residential use. Real commercial ranges are a different matter.

[cupcake]

cupcake, if I understand your question, you want to know whether the BTU output from one of today's  professional style ranges (as opposed to a 13 yr old range) can be accomodated by a recirculating hood. 

I don't know the BTU output of your current Darcor, but you should know the specs of any new range before you go hood shopping.  For the ranges you mention, I would imagine that the BTU output is significantly higher than what you have now.  You really have two issues:  grease capture and heat generation.  Will a good recirculating fan capture the grease and smoke produced by a high BTU range?  Probably.  Will it dissipate the heat generated by a high BTU range?  I can't imagine how it could do so, if all it does is pump the filtered hot air back into your kitchen.  And these ranges generate serious heat.

←

Thank you! I have the long-ago discontinued Dacor Preference 30" all gas slide-in -- 15,000 + 12,500 + 9,500 + 9,500. Due to where my gas is and the fact that it's in a brick wall, I am contemplating the Dacor Epicure, which is 18,000 + 15,000 + 9,5000 + 9,5000.

So this is actually quite encouraging as my current set-up (microhood) does virtually nothing as far as grease and smoke. I am looking for tolerable, not great, given my limitations.

Other info: I have 11 foot ceilings, so I am hopeful that something moving heat up (heat rises and all that) has to be an improvement. While a new range would have a higher output, so far, what makes the kitchen unbearable in the summer is the oven, and I don't think anything I can do can change that. I have two huge windows on one side of my kitchen, live in Chicago, and love it when it's cold since I can open the windows.

If I continue my practice of really only using two burners (which admittedly will have a greater BTU output), am I living in a dream world when I think that during most of the year, I will view this as an improvement? The new range will give me a total of 5,500 more for the burners I actually tend to use, and theoretically, I will not have both cranked all the way up at the same time.

I'm massively second guessing myself here since I have not been able to find anyone who's even remotely positive about the recirculating hood concept. I know it's not ideal, but the thought of something with less BTUs than what I have (which is what I will end up with if I don't get a professional range) makes me really unhappy. BUT then I read how much people dislike the recirculating hood and envision myself in a kitchen that everyday is the temp I currently get in the summer when I make pizza. So I'm not being very articulate here, but I guess what my question comes down to is if you compare my current Dacor Preference with the Dacor Epicure plus a good recirculating hood, will I be miserable except in the dead of winter with all the windows open?

I have never used anything with higher BTUs than what I have, so can't tell if the increase is no big deal or a lot.

I'd love any thoughts, esp since the only feedback I have gotten from friends is advice to under no circumstances get rid of my microwave...

Cynthia

[DerekW]

Cynthia, our Bluestar has over 60k BTU on the top [ignoring the oven / grill]. We almost never have it running at that level of output of course, but I still can't abide the thought of going back to the day when we had a recirculating hood.

In your situation I would do what ever it took to duct and vent to the outside. Oversized ducting, changing the window configuration to obtain some outside surface area for the vent. What ever it took.

cheers

Derek

[LindaK]

...I have never used anything with higher BTUs than what I have, so can't tell if the increase is no big deal or a lot.

I'd love any thoughts, esp since the only feedback I have gotten from friends is advice to under no circumstances get rid of my microwave...

It sounds as if you need to compare the performance of your current microhood to other recirculating hoods. If there are recirculating hoods that do a better job capturing grease and smoke, then you should go for it. More BTUs from the new range will generate both. You can always get a countertop microwave--they weren't born to live above a range. But recirculating hoods will not help you with the heat or odors.

I feel your pain. For almost 20 yrs, I lived in apartments with either recirculating hoods or no hood at all. Since finishing my kitchen reno 9 months ago, I've had an external vented hood and the difference is remarkable. I know I'm lucky.

[VivreManger]

Has anyone any experience with the quality of post-sale service offered by different hood/vent manufacturers? I have seen very little discussion of this issue.

Before I buy a big-ticket item I like to establish what the local service is. Normally I contact the manufacturer and get the name and number of the authorized service representative. Over several weeks I have tried to get this information about Independent

Independent Inc. 3663 Barron Way Reno, NV 89511 775-358-0263

Toll-Free: 800-7-NEVADA 1-800-763-8232, Fax Number: 775-358-0288

independent@kitchenhood.com

Sales manager:

Gary L. Schnepel

Sales Manager

cell 775.343.8123

fax 831.303.4349

gschnepel@kitchenhood.com

www.kitchenhood.com

Despite multiple phone conversations and email exchanges and despite their claims that they would provide the information, they have failed. Finally I made one last effort and they said they would no longer discuss the matter with me directly and instead I must deal with their so-called "local" sales representative who is located about 200 miles away. The sales representative then sent me this statement: "Independent will pay reasonable service claims to any qualified servicer for warranty work. However, in the off chance you will need work done; a quick call to the factory to let them know of the problem would be wise. You might have a minor problem that you could fix yourself, or they will be able to tell the technician what is needed."

This policy seems reasonable, but it would have saved a lot of bother, if they had shared it initially. There still remain the problems of who defines "qualified" and how to contact a factory when they failed to respond to my simple inquiry.

Bottom lines: How finicky are hoods? How likely are there to be service problems? What is Independent's track record?

[mindphlux]

I'm a soon-to-be first time homeowner, and am looking at adding a vent hood to our new place before we move in. My wife and I are currently in a condo with a pitiful recirculating hood/microwave combo, and are sick to *death* of it. I've worked in a few professional kitchens in my time, and my cooking tends to reflect that - lots of high heat, smoke, vaporized oil, wok use, etc.

 

I've promised I'd sort out our vent hood situation, and after pouring over this forum (and others) know I need A. a fuck off vent hood, preferably several inches larger than our cooking surface, with baffle filters. B. an external blower, because I'd like this to be as quiet as possible C. a CFM rating of 1200+ (rather go overkill than be disappointed), and D. to put my DIY tendancies in the closet for a weekend - I want this to get done properly.

 

My problem is, I can't seem to find any site (After hours and hours of googling) that has any sort of comprehensive or reliable comparison of range hoods, or their accompanying blowers. I don't really want to just walk into a home depot or something, because I don't trust a random home depot guy would understand the kind of shit I want to throw at this vent hood, or have any sort of off-the-cuff expertise in venthoods with external blowers - something I gather is sort of rare in home kitchens. I also don't know how to find someone who would have hands on experience with a variety of blowers / external venting setups, and know how to minimize noise and maximize airflow/effectiveness of the hood.

 

Anyone have any resources or experience to share on the topic? Or am I basically just buying a giant metal box and a fan, and design / brand doesn't matter all that much?

 

Thanks!

[lesliec]

Restaurant supply/design places?

[daves]

I think you're on the right track with a few things: external blower and the larger-than-cooking-surface size of the hood.  Some notes to think about:

 

In general, a remote/external blower will be quieter than an in-hood blower, but don't underestimate the noise created by 1000+ cfm moving through those baffles.

 

If you really want to minimize noise, consider the construction of the ductwork including caulking the junctions/joins/whatever they're called.

 

I can't tell if you need 1200+ cfm without knowing the total BTUs of the cooking surface.

 

Most homes installing high BTU cooking surfaces are all show and no go: these are 'trophy' kitchens and rarely really used.  The huge wolf range is paired with really inadequate ventilation.  The real problem here is finding someone in the home space that can design the right hvac system including the make-up air system that will be required to replace that 1200+ cfm of air as your hood pulls it outside.  Depending on where you are located, that make up air system might even need to be tempered to not shock the furnace.  But most contractors have *NO IDEA* about how to design this.

 

We have a 1400 cfm external blower on a 66" hood, and even after specifying to the general contractor that we would need a make-up air system, the subcontractor (who claimed experience) was not able to design it properly.  I ended up learning way too much about ventilation and make-up air system, we had to threaten to take them to court for non-performance, and finally it ended once a professional hvac mech engineer was brought in to re-design the system (which ended up validating my design).  We absolutely love the final result in terms of functionality, but I don't think there was any way to arrive there with a home hvac subcontractor. 

 

And if you specify a design, make sure that you specify multiple use cases: full on to remove smoke from blackening a steak to low extraction to remove seafood stock odor during a 5 hour reduction.  Subs who are familiar with restaurant use cases are usually thinking full-on all-the-time.

[mindphlux]

I think you're on the right track with a few things: external blower and the larger-than-cooking-surface size of the hood.  Some notes to think about:

 

In general, a remote/external blower will be quieter than an in-hood blower, but don't underestimate the noise created by 1000+ cfm moving through those baffles.

 

If you really want to minimize noise, consider the construction of the ductwork including caulking the junctions/joins/whatever they're called.

 

I can't tell if you need 1200+ cfm without knowing the total BTUs of the cooking surface.

 

Most homes installing high BTU cooking surfaces are all show and no go: these are 'trophy' kitchens and rarely really used.  The huge wolf range is paired with really inadequate ventilation.  The real problem here is finding someone in the home space that can design the right hvac system including the make-up air system that will be required to replace that 1200+ cfm of air as your hood pulls it outside.  Depending on where you are located, that make up air system might even need to be tempered to not shock the furnace.  But most contractors have *NO IDEA* about how to design this.

 

We have a 1400 cfm external blower on a 66" hood, and even after specifying to the general contractor that we would need a make-up air system, the subcontractor (who claimed experience) was not able to design it properly.  I ended up learning way too much about ventilation and make-up air system, we had to threaten to take them to court for non-performance, and finally it ended once a professional hvac mech engineer was brought in to re-design the system (which ended up validating my design).  We absolutely love the final result in terms of functionality, but I don't think there was any way to arrive there with a home hvac subcontractor. 

 

And if you specify a design, make sure that you specify multiple use cases: full on to remove smoke from blackening a steak to low extraction to remove seafood stock odor during a 5 hour reduction.  Subs who are familiar with restaurant use cases are usually thinking full-on all-the-time.

 

Thanks, this is really helpful. I had run across the 'make up' air problem on a few sites, but wasn't sure how much that was an actual issue vs a made up one / people being paranoid about pulling co2 from their furnace.

 

In the end, how did you figure out that your HVAC mechanical engineer knew his stuff well enough to complete the project / do you have any suggestions for finding one if you were starting from square one?

 

I'd go the restaurant design route, but I'm afraid I'd be just taken for my money - I'm actually afraid of this in all cases, because like you said most high end home ranges tend to be mainly showpeices / not used like I plan to use mine. Can I ask how much you paid in the end to have yours done properly? I'm not looking at a 66" - most likely a 36/42 - but still curious. I've budgeted 2-3k, hoping that is not unrealistic. Also so long as I'm asking about your system - with regards to noise, how does your system compare to an in-vent blower hood? And I haven't run across anyone talking about caulking joints/90 degree sections - could you elaborate on that at all?

 

again, thanks for your reply - really great to hear from someone who has been through it themselves!

[dcarch]

You should check your local building Code first.

 

There are rules for high CFM exhaust fans. You may need to provide separate  makeup air intake also. It can be dangerous if you have a fireplace. The exhaust fan can pull CO down the chimney into your living space.

 

dcarch

[daves]

dcarch is right: check with local code first, because it will be inspected.  Unfortunately, that doesn't mean it'll work -- it'll just pass inspection!

 

Make up air is a real thing.  If an exhaust fan wants to pull 1200 cfm out of the house, there better be 1200 cfm coming back in.  In older construction, that'll be satisfied by leaks throughout the house.  In better construction, especially in the snow zone, houses are more airtight and the exhaust fan will lower air pressure and won't move nearly that much air.  Instead of lowering air pressure in the house, it might pull air into the house from fireplaces and heater exhausts (pulling in CO/CO2).  If you need to actively add air to the house, then you'll need a make up air system.

 

Part of the frustration is that the sub designed the system, initially without a mech engineer. The sub got the broad strokes right on the design: a damper opens when the exhaust fan is on, allowing outside air into furnace return air, and if outside temps are low enough, there is an inline electric air heater to temper the air before it hits the heat exchanger.  I live in the PNW where outside temps average mid thirties in the winter, and the furnace spec said that the min return air temp was 55F.  When outside temps were high enough, their design worked great, but once temps lowered and I needed the air tempered, the faults were easy to see (the air was either not or over heated).  As I investigated, I discovered that almost every detail in their heater design was wrong: heater was 2 stage, they placed the thermostat probe to measure incoming air (the combo resulted in no variability on the incoming air temp or actual volume of air), and the ducting was too large (resulting in dangerously low air velocity for their spec'ed heater).  The sub tried to make a bad design work with increasingly stupid hacks, and I kicked them out of the house when they were going to install an intake fan to push even more air into the MUA intake.

 

That's when I threatened to sue the general contractor, and he offered to bring in a prof engineer to evaluated or redesign.  At this point, I had learned enough about these systems that I insisted in sitting down at the table with the general and sub, and got the ok.  The sub started by stating that the only use case was "exhaust fan full on for <10 minutes per session" as in a quick high temp cook.  The prof engineer said their design would work (which was mostly true with a certain range of outside temps).  Then I spoke up and said another use case was "exhaust fan on low for many hours" eg. reducing stock for 5 hours.  Contractor agreed this was a valid scenario, and the engineer rejected their design.  I then offered up changes to their specifics that would satisfy both use cases (and also all the ones in between and all outside temps): smaller ductwork and a small but continuously variable duct heater driven by final temperature.  Engineer said this was a much better design for homes (much to the chagrin of the sub), stamped the design, and contractor had the sub revise everything.

 

My wife jokes that I know enough about MUA systems that I should open a consulting service.  The joke is unfortunately on others since our contractor is now advertising expertise in MUAs based on eventual success with ours, and I don't think they understand why the system now works instead of the unworkable and dangerous system originally installed.

 

Leaving out the hood itself, the cost is in your ballpark.  I think the 1400cfm external blower was $1000 or so, the custom made duct heater was probably another $1000, and then the control electronics were probably less than $100.  The duct work, electrical (duct heater is 220V ~50amps), and labor probably cost another $1000.  I haven't compared the external blower vs, in-hood since the hood we ended up choosing required an external blower.  As for the caulking/taping the seams of the ductwork: that's to reduce any rattling of the metal-to-metal contact.  I think taping is actually code around here now.

Edited May 10, 2014 by daves (log)

[daves]

On more thing: IMO make sure that you have a full variable control on the exhaust fan speed (and not 2 or 3 speed buttons), and then get as much exhaust/MUA cfm as you can budget.  With the variable control and a big fan, you can always turn down the fan to what you need, but you can't go higher than your installed fan.  When I looked into sizing the cfm, most guides were based on total BTUs of the cooktop.  That might be useful to exhaust the heat/CO2, but those measurements don't cut it if you're blackening something.

[glepore]

Echo the above. I have a remote fan of approx 1000cfm (Fantech) with their continuously variable control. I didn't install their muffler but wish I did, its noisy even though you can't hear the fan itself. Makeup air is an issue, but I'm in an old farmhouse, if I wasn't I'd want a system. Also keep in mind that these systems can put quite a load on HVAC when in operation.

[malok]

Thanks in advance for anyone who is willing to throw their two cents in:  We are in the process of renovating a town house which has an adjoining house on either side, and a facade which is considered " historic" and cannot be altered.  The current kitchen has  electric range with a recirculating microwave hood.  As a result anything that is cooked there lingers for days.  We are planning on remodeling the kitchen entirely and are installing a induction range and wanted to install a hood.  Our issues are the following:

1) the hood can only be vented to the roof( two floors up) or the back patio.  Our contractor was suggesting, as an alternative, tapping into the ductwork for the bathroom( no shower, just toilet) on the same floor that has a fan and using its ductwork to vent to the back patio.  They want to install a flap system to keep odors from being vented into the bathroom.  I am concerned about that in a general sense and wonder if anyone has specific concerns that I should discuss with my contractor about that plan.

2) Make up air--does anyone have experience putting a make-up air system into their house without redoing HVAC?  That would increase cost significantly and would like to avoid it.

Thanks

[Smithy]

I'd be concerned about the shared ductwork on a couple of fronts.

1. How will the two fans be balanced so that, if they're both running, they both exhaust to the outside instead of one overpowering the other?

2. Not only will the bathroom need to be protected from kitchen odors when the kitchen fan is running, but the reverse is also true: you don't want bathroom odors blown into the kitchen. Some kind of double-flap system would be needed, and then see item 1 again.

3. Does the building code allow it?

With regard to makeup air, I doubt you'd need it unless you live in a very tight house. The cheapest option would be to open a window, although that isn't practical in all seasons. :-)

[gfweb]

That would be an unusual BR vent system with ductwork big enough to support a hood.  Also don't forget that resistance to flow is a function of both the duct size and length. A long duct could easily cut hood efficiency.

 

You might want an HVAC pro to do the math first.

[AlaMoi]

there's a multitude of issues you'll want to consider.

 

the "flapper" is as form of "check valve" preventing exhaust from the kitchen being pushed into a bathroom.

it's not 100% effective; you will get fish and liver in the bathroom....and you will get bathroom into the kitchen; and when both are fans are running who the heck knows....

 

and, depending on where you live, it may not be a legal code option - and past that on resale any house inspector is not going to be impressed.  call a local home inspection service - as in a place that does inspections for potential buyers - and ask about the legalities and downsides.

 

you really should consider a totally separate venting outlet.

 

venting to the roof - kool if you're already ripping out walls, etc., such that the entire path is open.

consider however that stove top vents convey a lot of moisture and entrained oil in the air - and when the hot air hits the cold environment, you get condensation.  the longer the "run" the more likely the problem.  some provision must be made to 'trap' the condensation - and drain and clean out and . . . - otherwise you'll have junk dripping on your stove.

 

if you can reach the outside patio in a short path, much better long term solution.  the shortest path is the best.

 

as to make up air, with a historical facade.... sufficient amounts of leaks that no specific make up air provisions are needed - unless you're installing a 5-6-8 foot size 50 burner stove with a 25,000 cfm exhaust.  and if you're into doing a huge stove / burner top with that kind of hood you really should be getting some qualified professional help/engineering.

[Smithy]

In addition to the comments you've already gotten, there's some very good information earlier in this topic that you may find helpful. Go up just a few posts to see about makeup air. I'm relearning some things that surprised me this time last year.

[malok]

Thanks for all the helpful comment.  Re: condensation and trapping of grease if vented to the roof---would this be affected by whether the blower for the vent was mounted on the roof vs at hood level?

Smithy:  the preceeding comments were really helpful--half the contractors we interviewed didn't even know what MUA was, the only reason I did was based on these comments and some garden web forum posts

Thanks again for everyone's input

[AlaMoi]

...whether the blower for the vent was mounted on the roof vs at hood level?

 

no.  whether it's being sucked or blown, as it travels it cools, and moisture / oils condense out.

[radtek]

This is fantastic!

 

Had me looking at my greasy 40yo Kitch-n-vent and 7" ducting at 0430...

 

I really want to gut my kitchen and redo the entire area. 

 

The ROT for my range is just over 300cfm and I doubt the existing fan meets 100cfm. Good luck finding that in the economy brands of vents. What I may end up doing is placing an external fan/blower myself until the kitchen remodel can come together.