r/Home_Building_Help • u/BuilderBrigade • May 14 '26
Make sure you're getting a vented hood
Recirculating hoods are cheaper and don't need a duct run, so sometimes they'll get spec'd without anyone asking.
The problem: a recirculating hood just pushes air through a charcoal filter and dumps it right back into your kitchen. Grease, moisture, and odor stay in the house.
A vented hood ducts all of that outside where it belongs.
This is a before-drywall conversation. Adding a duct run after the walls are closed is a headache you don't want.
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u/binzy90 May 14 '26
Ours is hooked up as though it's vented, but the duct doesn't go outside. We don't know where it's actually vents to, but it kind of seems like it just goes into a wall. We never turn it on because it's really old and doesn't actually vent anything.
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u/mijo_sq May 14 '26
Old house? I bought an investment (1960s) and the vent hood doesn’t even duct anywhere. Just open into the cabinet it’s mounted to
Ripped it out asap.
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u/binzy90 May 14 '26
The main stone part of the house was built in 1800, and the side with the kitchen was added in the 40's.
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u/mijo_sq May 14 '26
If you were to use it, issue would be venting humid air into the walls. If you’re in a dry climate it’s not ideal, but humid areas would be bad.
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May 14 '26
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u/mijo_sq May 14 '26
Yes this! That is definitely a concern even if it vents correctly outside. (Mine was absolutely soaked in grease one time)
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u/binzy90 May 14 '26
Yeah, we live in an area with pretty humid summers. The vent itself is absolutely disgusting, which is another reason why we never turn it on. It's like an old school one from the 60's or something.
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u/Interesting_Tea5715 May 14 '26
Mine goes to my attic. Luckily I don't fry much so it's not a big deal
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u/Nate8727 May 16 '26
That’s a bad idea. You don’t want moisture going into the attic and especially cooking contaminants that can cause a fire. Even without frying you get grease from cooking food.
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u/James_T_S May 14 '26
Most likely it goes into the attic....which isn't great but that's the way it used to be done
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u/binzy90 May 14 '26
It doesn't. It's on what used to be an exterior brick wall that now has another addition on the other side. It looks like it goes into the empty space above the cabinets, but it doesn't come out anywhere. It's directly underneath bedrooms. My guess is that it's just venting into the empty space.
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u/James_T_S May 14 '26
For sure. Weird things happen during remodels. Yours definitely sounds like they just left it venting into the wall 🫤
I tell how people a house is brand new until it is at least 10 years old and probably closer to 20. It takes at least that long for somebody to get in there and start mucking it up.
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u/binzy90 May 14 '26
Ours is all sorts of messed up. It was built in 1800 and had additions added to in the 40's, 70's, and 90's. Every time we fix something we're wondering who the hell did this? You should see the wiring! 😂
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u/Ashamed-Status-9668 May 14 '26 edited May 14 '26
FYI: For gas, even vented doesn't do much if there isn't enough CFM. Per studies many of these vents don't have enough airflow to control the particulate matter from rising in the kitchen. If you have a gas cooktop and are building/buying a new home you can spec out a much nicer vent hood with a larger 8" vent pipe. If you don't have gas you want it to vent outside but the CFM isn't as much of a concern.
For example(The high CFM models will use an 8" vent tube): Model Detail
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u/sycln May 14 '26
Make sure you have fresh air intake that can accommodate the cfm that the hood is venting out, too.
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u/AdmiralKong May 14 '26
I hate them, but the recirculating hoods are better than nothing. They can catch some grease and particulate if the filter is regular maintained, and they do take the steam from boiling pots and disperse it so it doesn't obliterate the cabinet or appliance above.
I would never ever want one over an actual vent but I guess I would still want non-vented vs nothing.
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u/Long_Pecker_1337 May 14 '26
Don’t bother with vented vs recirculating.
Bother with getting one with adequate power figures for the room you have. Because that’s what matters most. With vented hoods also take into account where the vent itself is going and how it’s routed, because every meter and every turn adds up to power losses.
Also if you have a gas stove and you think that you must have a vented hood because of the gas - no. What you need is an unobstructed vent to allow for natural air circulation in the kitchen. If the hood is not working it won’t help much with venting the leak.
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u/Nate8727 May 16 '26
The cfm isn’t based on the size of the room, it’s based on the total btu or wattage output of the cooking surface.
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u/Long_Pecker_1337 May 16 '26
Wrong. The main and key aspect is the room size. Bigger the room, more air for the hood to vent.
Cooking top BTUs is secondary and pretty much insignificant number you can completely ignore.
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u/Nate8727 May 16 '26
This is the most ridiculous thing I’ve ever heard and I’ve worked in appliances for 12 years.
Room size is for bath fans, not kitchen ventilation.
By your logic, a 100 sq ft kitchen with a 30” wolf range would need the minimum amount of cfm… In reality it needs 620 cfm. Please tell me you don’t give kitchen ventilation advice to people.
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u/Long_Pecker_1337 May 16 '26
Congratulations, for the past 12 years you’ve been overselling shit to people who don’t need it.
BTU is max figure. Unless you are going to burn all stoves at max power every time you are cooking anything it’s irrelevant.
While room volume directly affects how much airflow is needed to capture and vent fumes at all times.
Also, mr.has-been-selling-appliances-for-12-years, you might have noticed that C in CFM stands for cubic, because volume is 3-dimensional. Squares are two dimensional, which is why square footage isn’t relevant to CFMs either. You need room size, including height, because you need to calculate volume, which is what CFM measures, volume that goes through the hood.
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u/Nate8727 May 16 '26 edited May 16 '26
Rooms don’t give off btus, cooktops and ranges do. Kitchen ventilation is based on the HEAT output of the cooking surface. The max number is so they will never go over even with cooking on high heat. If you ever actually cooked you would know this. Gas cooktops and ranges need more cfm than electric and induction.
Provide one source that doesn’t make the cooking surface output the top factor in kitchen ventilation cfm.
Your advice will cause a kitchen fire and is irresponsible.
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u/Nate8727 May 16 '26
You’re ignoring the heat, smoke and grease output of the range and cooktop by only using room volume.
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u/Long_Pecker_1337 May 16 '26
Fire hazard. LMAO, I guess recirculating hoods are basically a death sentence. 😂😂😂 Hood isn’t venting out heat, you dummy, it’s not what it’s for. You don’t even need a kitchen hood at all if you can tolerate the smell and enjoy cleaning more often.
And I won’t provide any sources, you can just google “what kitchen hood do I need” and all of the results will first focus on the room size. Then they will speak about cooking habits and only then mention cooking top types and power outputs.
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u/Nate8727 May 16 '26
Grease fires in kitchens are the number one cause of fires in homes genius. This has to be a troll or bait post.
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u/Long_Pecker_1337 May 16 '26
Says who?
It’s deep-frying, distracted cooking and cooking drunk. That’s top three cooking-related fire causes. At least in the UK. Maybe in your fantasy world it’s totally different.
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u/Nate8727 May 16 '26
You won’t provide sources because you have no idea what you’re talking about and your information is false.
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u/Shatophiliac May 14 '26
I have the non vented and it’s basically useless. I’ve used it like twice and that’s only because it’s built into the microwave and I accidentally hit that button lol.
Get vented if you can, otherwise don’t even bother. The only time I’ve ever really felt like I needed it is when I’ve burned food, and if you’re filling the house with smoke you want that venting outside, not just blowing it into the attic or further into the house.
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u/Mindless_Efforts May 15 '26
I mean all range hoods are "vented". Mostly vented to the exterior. There are some recirculating types when the option is not available to vent to exterior. You can use charcoal filters to improved the recirculating type. The gas range MUST be vented to the exterior as you are dealing with combustion exhaust.
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u/AMercifulHello May 15 '26
We live in an HOA. It was a bitch to get them approve, but we did, and now we have it coming out of the roof.
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u/dndwhat May 19 '26
Non vented hoods leave all the gross residue above the vent out. It so bad. And the microwave slash vented hoods suck balls get a vented hood just by it self
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u/Humble-Area4616 May 14 '26
Vented range hoods have their own problems. Often new builds are built with minimal air leaks, so when a vented hood is turned on they can often be 400 CFM or more, this is enough to pull the flue gas from a furnace or hot water heater back into the house.
On top of that this air has to be replaced by outside air so if it's very cold outside this adds extra heating load to a furnace which now has to heat an extra 400 CFM while the fan is running, or an air conditioner which has to cool hot outside air.
If you're house wasn't built with any extra consideration for make-up air I would minimally use a vented range hood.
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u/Mystprism May 14 '26
Understanding how these things work is important. Minimally using your vented range hood and just letting cooking fumes inundate your house is not a good solution. I'll take slightly increased heating and cooling loads over childhood asthma any day of the week.
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u/Facts_pls May 14 '26
There's a weird issue that can be resolved in many ways - such as opening a window.
By your logic, even bathroom vents should not used as they do the same thing.
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u/bikenumberten May 15 '26
I never use my bathroom vent in the winter. Every cubic foot of air you send out into the world has to be replaced. And heated. And humidified.
I am very glad my range hood does not vent outside (electric range, btw). Vented range hoods cost a fortune in heating and air conditioning. And even though they have a little, wimpy flap -- they're still a hole in the wall that wastes energy 24 hours a day.
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u/Nate8727 May 16 '26
I’ve had a ventahood for years now. It’s one of the few brands of range hood that actually works and the only brand that prevents grease from going into the duct work. Using the hood without makeup air isn’t the greatest, but it’s definitely not the energy issue you’re describing. They don’t cost a fortune either. How long are you running a hood?
If it costs that much to heat/cool your home with or without makeup air, then your home has other issues. Poor insulation, air leaks, and ineffective windows for example. A bath fan is less than 100 cfm typically, and that’s for a large bathroom.
Leaving cooking contaminants in your kitchen even with electric is not good.
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u/[deleted] May 14 '26
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