Kitchen Exhaust Make Up Air 'Hood within a Hood' System: Devil in the Details with Ross Trethewey

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  • Опубліковано 26 гру 2024

КОМЕНТАРІ • 66

  • @adammattivi3151
    @adammattivi3151 Місяць тому +3

    I actually did a version of this in my home and so far it’s been great! I had a custom duct boot made so it only sticks out 2 additional inches from the front edge of my Vent a Hood. I haven’t ever tested with smoke, but as far as I can tell i get really good capture and exhaust with no visible disturbance to my gas burners.

  • @timdestasiohvac
    @timdestasiohvac Місяць тому +5

    This was so insightful. I've designed make up air systems using this hood strategy, but it requires the home owner to be on board with the size hood required. I found I had to draw CAD details showing the minimum distances to keep the active MUA velocity low. However, I can't say I agree with bringing in MUA across the kitchen. This spikes the load in the kitchen. I had a customer in TX who didn't go with my hood within a hood system and instead put the MUA across the kitchen. He regretted it with comfort problems and even condensation as high dewpoint comes dumping out of the register hitting cooler ceiling and wall surfaces. If you introduce 1000 CFM of 91/74 air across the kitchen, you are adding, 40,000 BTUh into the kitchen! That's 3.5 tons cooling that your HVAC system has to deal with at least a portion of. Commercial kitchens dump MUA right infront of the exhaust hood for that reason.

    • @HomePerformance
      @HomePerformance  Місяць тому

      Excellent my man

    • @maurozammarano6651
      @maurozammarano6651 Місяць тому +2

      An hybrid design sounds like the best compromise

    • @rosstret
      @rosstret Місяць тому +2

      Hi Tim, thanks for the comment. There is a balancing act between IAQ (risk of spillage, etc), comfort, aesthetics and equipment/cost.
      Our work is mostly in cold climates, so we generally need to provide filtration and heating of the outdoor air. We have been very successful introducing this at a low velocity on the opposite side of the kitchen or through the AHU serving the kitchen.
      For CZ 1, 2, 3 especially marine climates with humidity, we would need the air to be treated (filtered, cooled, dehumidified) before introducing to the room or connected to the AHU serving the kitchen space, or some combination. As you mentioned introducing that amount of outdoor air in a TX climate, without at least dehumidification will be problematic and uncomfortable.

  • @olivierlacan
    @olivierlacan Місяць тому +2

    The stack effect and wind effect explanation in this video is really helpful. Thanks!

  • @JohnLee-db9zt
    @JohnLee-db9zt Місяць тому +2

    I was going to do the hood within hood after watching NS Builder video, but now I’v decided against it. I was waiting for this exact video to see how effective it is. Great video. Thanks.

    • @ryan52403
      @ryan52403 24 дні тому +1

      I wonder how well it would have worked if actually implemented as designed. I bet it would solve the depressurization issues, but no way to know for sure since they didn't actually build what was designed.

  • @larryseibold4287
    @larryseibold4287 Місяць тому +3

    Lot of good points discussed in this video. Clearly it is a difficult balance of many important variables: the worse the air is at the stove, the more air flow is needed (reduce first); then the closer the return air is to the exhaust, the less the humidity and delta T will affect the rest of the house for the same air flow; but, you are generating gas at the stove top etc., which needs to be encapsulated and then exhausted, so some air needs to come from behind and away from the hood (pushing excess from the hood return will not work on its own); heating and dehumidifying even a few hundred cfm of air from outside of the hood space takes an enormous amount of energy (ex: i think that heating 1000cfm 40F is around 60,000BTU or 18kW). You are spot on with regards to noise and usage.
    Thoughts: 1) Have the CFM scale with BTU automatically; 2) Design the house to deal with up to -15Pa (normally much less), so that the 20% fraction of make up air can come from where you want it to passively; 3) Cook high heat and smoky stuff outside on your Blackstone or BBQ.

    • @keletienne7947
      @keletienne7947 Місяць тому

      I laughed at 3) because that is exactly what i do with stinky stuff like shrimp or high heat potentially smoky things like fajitas. Less mess to clean up too.

  • @NicZweifel
    @NicZweifel Місяць тому +5

    I really appreciate this conversation. We were right in the middle of our home design phase when that NS Builders video was published and I was so intrigued. I advocated for doing something similar for our project but my design team was rightfully skeptical that it would be a good option for our project. I now have better understanding as to why. MAU was by far one of the most complex components of our certified PHIUS build. Keep educating us Corbette!

    • @Th3120ck
      @Th3120ck Місяць тому

      How is MAU more complex than your ERV??

  • @GlenS123
    @GlenS123 19 днів тому

    Another great video! On the comercial kitchen side we have been putting this kind of system in for decades.

  • @TransNeingerian
    @TransNeingerian Місяць тому +2

    NS Builders is TOP NOTCH.

  • @LewHarriman
    @LewHarriman Місяць тому +2

    Impressive engineering, Ross! (And thanks for the video, Corbett)

    • @LewHarriman
      @LewHarriman Місяць тому +1

      I'm especially glad that both you mentioned the subject of range hood noise. In my view, the current ASHRAE Std for max range hood noise (3.0 sone) is ineffective. 3.0 sone is, as Ross mentioned, too dang loud for people to actually use. In my experience, a better number (for a hood that people would actually use when they need it) would be 0.3 sone. In other words, 90% less noise than the current ASHRAE standard. Why that number? Because in our house we have both a 3-sone hood and a 0.3 sone lavatory fan (Panasonic whispergreen select) near each other. With eight years of experience to compare, it's clear that 0.3 sone is just fine for conversation... and 3.0 sone is simply-not.

    • @HomePerformance
      @HomePerformance  Місяць тому

      Thanks for watching Lew! And I think HVI actually lets the manufs report the low speed noise for that!

  • @mil-specgarage55
    @mil-specgarage55 Місяць тому +2

    Love these videos as I noodle all of these variables on my home.

  • @davidkahler9390
    @davidkahler9390 Місяць тому +8

    I don't understand most of this discussion, but I'm glad smart people are working on it :P

  • @sam_fujiyama
    @sam_fujiyama Місяць тому +2

    I wondered how this system performed... thanks for the follow up !

  • @BrianBaldridgeC
    @BrianBaldridgeC Місяць тому +3

    Another great and insightful video. Thank you!
    Makeup air in a laundry room for the dryer was not something I previously considered. That gave me something to think about. 😅
    14:55 - 16:00 sounds like downdraft is the more efficient solution there.

    • @chuckmcvicker2353
      @chuckmcvicker2353 Місяць тому +1

      A downdraft vent does a wonderful job of distorting the heat transfer signature; layman's terms it is a horrible solution.

  • @mjbates
    @mjbates Місяць тому +2

    Noise cancelling headphones became one of my favorite cooking tools when I started using my hood on blast.

  • @bradleysargent9803
    @bradleysargent9803 Місяць тому +3

    What a great video. I got to design a large residential home in (NW Texas) and the kitchen hood was the hardest part to design. There just isn't any "packaged" stuff to do it right. It was a challenge.

    • @HomePerformance
      @HomePerformance  Місяць тому

      Glad it was helpful man! Keep up the great work.

  • @chaseweeks2708
    @chaseweeks2708 Місяць тому +3

    Why didn't they just add an inline fan to the intake to increase the airflow and balance the pressure? Maybe put a slightly undersized fan on the intake to keep it slightly negative pressure if that's what you want.
    Also, here's an idea that I'm considering. Wire the stove up with a smart breaker or a sensor to read the current going to the stove, and hook the intake and exhaust fans to a smart switch to control the speed. Maybe another smart switch for the dampers too. A little futzing with some IFTT configuration and you've got an range hood that comes on automatically and ramps up automatically if you're cooking more and/or hotter. Thoughts?

  • @UnderBakedOverEngineered
    @UnderBakedOverEngineered Місяць тому

    I've been kicking around a similar idea for a bit and couldn't find a way to make it work without using a series of air curtains. Essentially the same idea they are to keep the majority of fumes within the exhaust hoods' effective range with additional makeup coming down from ceiling at ~4' and ~12' in front of the stove.
    Defense in depth that gives you a large surface area to insert makeup air. The problem is of course complexity and the energy lost treating any air passing through on the final curtains.
    Another alternative would be doing an up draft on the the back and two sides of the stove. If you set them back a few inches from the edges and shape the flow you could mostly not disturb the flames and most of the useful temperature gradiant. You'd have to oversize the vent hood so the air flow has a smooth surface to redirect it towards grease trap. You'd still have to provide additional make up air to the rest of the kitchen but you only have to treat a much smaller portion of air. The problem is nothing fits relatove to standard cabinets/counter tops, having several fans to maintain, and either compressing the intake air to fit the ducts underneath or sacrificing a cabinet on either side of the stove.

  • @ZergZfTw
    @ZergZfTw Місяць тому

    I would definitely pick out my own fans, just to make sure that they have the static capacity I want; plus, I definitely want to have the option of speed control. Also, you might think about adding a vertical divider in between the exhaust and make up airflow paths; it might help control air distribution. You might also want to think about adding run-around coils if you do a lot of cooking and live in an extreme environment, they will save energy and take some of the load off of the duct heater.

  • @adamliberman6767
    @adamliberman6767 Місяць тому +1

    You mentioned short-circuiting on the exterior, but not about short-circuiting at the hood. It looked to me like the blue smoke from the makeup was not going down near the cooktop but was going straight back out the exhaust. Isn't that going to severely affect the capture efficiency?

  • @davidhoover2446
    @davidhoover2446 Місяць тому

    He brought up a great point with ERV’s and fresh air. Everyone’s house I’ve worked at is different. At personal house I usually run like 100 cfm of fresh air to maintain low VOC’s, but I have a multi speed fan where I can adjust it. At another home, I did 110 cfm because of the exhaust cfm needed. It’s just enough. Then, surprisingly at my mom’s mobile home, about 30cfm fresh air is plenty. But, she hardly cooks inside also and the place is old and leaky and I figure it has off gassed a lot already. I haven’t found any “standard” that works for CFM of fresh air. It needs to be tested and have built in adjustment which is easy and inexpensive to have. Then, the demand can be dialed up and down. I guess the important thing is to calculate the maximum fresh air that you will need and make sure that the dehumidification can handle it.

  • @danslickers8166
    @danslickers8166 Місяць тому +1

    Another killer video.
    Grace and Peace
    Slick

  • @RSWarriorLuv2LafMcc
    @RSWarriorLuv2LafMcc Місяць тому

    Great Video. Please check the listed link for TE2 as I believe there may be a typo.

    • @HomePerformance
      @HomePerformance  Місяць тому

      Thanks- link works fine for me, just tried it…

  • @thenexthobby
    @thenexthobby Місяць тому

    When I do my kitchen remodel I’d like a retrofit solution. I need either a floor solution (an old coal room is below the kitchen) or the ability to go thru the kitchen ceiling and out the roof above.
    It has to be “OK” to accept sacrifices for retrofits, with noise and/or CFM. The house never had any type of kitchen exhaust, with predictable results.

  • @ncbarndobuild
    @ncbarndobuild Місяць тому

    Interesting topic. In our design we will actually have a wall on 3 sides of the cooktop.
    If you put the makeup air ports down lower on the side walls would that help with particulate capture as opposed to having the inlet and outlet on the ceiling?

  • @ducagace1390
    @ducagace1390 Місяць тому +1

    Corbett, you make some of the most best video on building science. Great quality and content.
    I was thinking about why not put slot for the MUAS on the two side and the back near the stove (maybe with the slot on the top like this one). Sure, for gas stove meehhh, but with electric it could be optimal. What do you think?
    I wish you the best for you and your family. Thank you and take care!

  • @trickstothetrades1801
    @trickstothetrades1801 Місяць тому

    As always thanks for the info. I guess we are the only people that are not bothered by fan noise (unless it sounds like the bearings are going out of it)

  • @Geoff9001
    @Geoff9001 17 днів тому

    Question for your engineer: why not have the makeup come up from the left and right of the range so it affects the home air the least amount snd doesn't mix much? Don't commercial kitchens do this already (supply make up air close as possible to the appliances that need the hood) ?

  • @ScottAllenFinance
    @ScottAllenFinance Місяць тому +3

    The homeowner should be aware that an in-line kitchen exhaust fan is going to contribute to a major grease build-up in the ductwork and at the fan assembly if it is not cleaned regularly. Personally if it were my system (I wouldn't use an in-line fan, but if I did, I would be SURE it was a grease-rated centrifugal fan, not a cheap axial fan from the Home Dep'Lowes) with an in-line fan, I would clean it, or at least check it, quarterly.
    When I oversaw maintenance for the restaurant group/catering company, the kitchen hood cleaning was (subbed out, of course) - along with the ANSUL system inspections and ice machine cleanings - among the most critical maintenance items for safety. I would really hate to have to worry about this in my home. Having come from a commercial kitchen environment, my inclination would be to go more commercial with the design, either a packaged unit with built-in make-up, or a couple CaptiveAire/Greenheck external units and call it day. I certainly wouldn't put the fan assembly in an enclosed area. I'd also put a temperature sensor up in there and tie it in to the main fire/alarm system.
    Just my two cents. Grease is insidious. If they're cooking Asian or fried foods or with high heat.... add grease filters at the hood itself. Have fun and be safe with your kitchen exhaust adventures!

    • @adamliberman6767
      @adamliberman6767 Місяць тому

      Assuming that the duct length is the same, why would having the fan at the hood vs at the discharge end of the duct affect the grease accumulation in the duct?

  • @joeshearer1247
    @joeshearer1247 Місяць тому +2

    They sealed that fan off in the garage bulkhead huh 🤔 great for access

  • @RaoulHira
    @RaoulHira Місяць тому +1

    Are there any hoods that can detect heat and switch on automatically? Ideally both the hood and make up air system

    • @HomePerformance
      @HomePerformance  Місяць тому +1

      Yes, Broan’s SmartSense feature is a tiny infrared thermal camera.

  • @SchondorfEnt
    @SchondorfEnt Місяць тому +1

    Love it!!!!

  • @mickbutler6671
    @mickbutler6671 Місяць тому +1

    What do you think about the 80-20 rule? Putting 80% of the make up air at the exhust hood like discussed then putting the other 20% somewhere else in the room?

    • @HomePerformance
      @HomePerformance  Місяць тому +1

      Did you hear that somewhere, Mick? Haven’t heard that application of the ‘80/20’ rule…

    • @mickbutler6671
      @mickbutler6671 Місяць тому

      ​@@HomePerformance Well I thought I saw someone make a video about it but I cannot find it anywhere.

  • @annakissed3226
    @annakissed3226 Місяць тому

    Haven't watched yet but I had been thinking of replacing the cooker extractor in my 2nd floor kitchen with a mini-split but this looks like a MUCH better solution. Sadly whilist I would love to come home to my commonwealth I now reside near Bernies left wing brother who besides once being my representative is also a really great guy. I met him quite a few times before I discovered his brother was Bernie! I hope you get to meet him someday!

  • @vics128
    @vics128 24 дні тому

    I had a question and probably haven’t seen enough videos to know if this is even a good idea, but would it be ok to vent the make up air near my return vent so it gets circulated into the hvac system right away? Instead of putting the make up air near the range hood.

    • @HomePerformance
      @HomePerformance  24 дні тому

      You want it to go right back outside again, NOT to circulate through the home. It was outside 2 seconds ago, with all yhe heat and cold and bugs and pollen and humidity.

  • @davidgagnon2849
    @davidgagnon2849 Місяць тому

    For those of us that have an over-the-range microwave (with a vented exhaust that performs poorly) that we want to keep, could a vent be installed into the ceiling near the stove to capture the steam, smoke and smells? I'm referring to someone who either has or will be installing a fresh air recirculating system to their home.

  • @coolbydesign
    @coolbydesign Місяць тому

    Maybe I missed in the video, any reason they opted not to use a powered make up air fan to compensate for the undersized passive duct?

    • @HomePerformance
      @HomePerformance  Місяць тому

      Probably saving $2200 on equipment was a factor, but they were trying new things

  • @JayKast
    @JayKast Місяць тому

    Can you apply this same concept to a fireplace in a passive house or PGH?
    Having a normally closed vent to the roof through the chimney that can be manually opened when fireplace Is in use. With a normally closed make up air vent that uses the same chimney yet maybe the intake port is at a lower height on the chimney and on the side of it to prevent bringing in the same smokey air that is being exhausted.
    Also, the exhaust vent would have an inline fan that can withstand those type of temperatures.
    If this concept can work for the hood above the stove/cooktop, why cant this work for a fireplace?
    Thank you, I enjoy alot of your material. Keep up the informative content!

    • @ZergZfTw
      @ZergZfTw Місяць тому +1

      There are plenty of wood-burning stoves and even masonry heaters that have dedicated outdoor air. They can work perfectly fine in a passive house if you design and install them correctly. And in regards to fans, a wood-burning stove will have exhaust gases hot enough to draft naturally, no fans required.

  • @ronm6585
    @ronm6585 Місяць тому

    Thanks gents.

  • @squeekhobby4571
    @squeekhobby4571 Місяць тому

    Would having the makeup air come from behind the cooktop be more effective??

    • @HomePerformance
      @HomePerformance  Місяць тому +1

      Worse- it would shove the fumes into the room

  • @ClipSwitchFlashlights
    @ClipSwitchFlashlights Місяць тому +1

    This old new house, eh? :)

  • @annakissed3226
    @annakissed3226 Місяць тому

    I love my condenser (pre heat pump) dryer from Bosch despite the expense. I just wish I knew how to get it to dry super king sized Duvet covers (and Duvets). I have heard that the US still uses sheets?? Please tell me its fiction, like the you not using fast boil, specify temperature, electric kettles. In the Uk, we simply don't have the space for classic air pipes. Yes, it has to be active, but local generation or off peak store is constantly getting cheaper.
    Btw, if you don't know about Octopus Energy and Kracken their genetic AI solution for Energy companies and (l)users alike, you really should look into them

    • @johnhaller5851
      @johnhaller5851 Місяць тому

      In the summer, I leave the AC at 77F/25C, and run a ceiling fan for air flow. There's no way anything more than a sheet is acceptable during the summer.
      The utility companies are regulated by each state, so there is a big disparity of rate plan designs, ranging from fixed rates all day long, to extremely variable rates, and other things in between, and which of these is offered in a state vary. I live in Texas, where there is a lot of both solar and wind power, with an increasing amount of storage. I had one provider who had rates which change every 15 minutes. This one was banned when the rates spiked to $9 per kWh for three days during a severe winter storm. Now, I have a fixed rate plan, which is still cheaper for my existing use pattern than any of the variable rate plans. I likely could adjust some of my usage to change this, but I currently have some fixed usage which I haven't all found.

    • @MorryB
      @MorryB Місяць тому +2

      I'm in Canada. I use a duvet AND sheets! :D

    • @franceshawe9572
      @franceshawe9572 Місяць тому +1

      I'm in Ireland and I use a sheet and duvet. Much easier to launder a sheet frequently and at times it's all that is needed.

    • @annakissed3226
      @annakissed3226 Місяць тому

      ​@@franceshawe9572 I use what everybody, as far as I can tell, use's in Europe: a fitted elasticated bottom sheet to lie on and a easy to change duvet cover on top a Duvet. The problem is that I screwed up by trying using a SuperKing sized duvet. Which has been a bitch to get washed & dried.
      Thanks for the replies to my questions & notes!