Kitchen range hood spliced to bathroom vent legal?

Don't know the legalities. but the people who live in apartments above you will probably complain, very loudly, right after you do this, because your smoke and smells will be wafting into THEIR bathrooms.

Definite code violation

odd are that the microwave circ hood does a better job.

Oh, I forgot to add that our bathroom vents are a passive suction system - meaning there aren't any exhaust fans in the bathroom. It's constantly on, quiet, sucking air out (I think around 50-75 cubic fps?). So, I don't think my upstairs neighbors would be bothered by it. I do know that in some of the other line units and floorplans, there is a passive suction vent (like the bathroom vent) in the kitchen wall.

I want to get replace the microwave/recirculating air filter with a dedicated wall range vent.

hypothetical question -- would you like an entire line of your neighbors' bathroom fragrances backed up into your kitchen through a shared duct when a hypothetical "pressure anomaly" occurs?

Think the comments basically show that ProperSevice is ProperlySelfish

I dont know the layout of your unit other than the kitchen and bath share a wall. The best thing to do would be to run the duct up and out right above a window or try to tap into an existing ventilation riser that may have been covered up. if you run it out obove a window you box the duct work in and finish it off against the ceiling and wall. Looks nice and clean.

jasieg - it is best to run a duct OUTSIDE the wall, but the minute someone on building staff looks up and wonders "WTF is going on" it will probably be gone.

ProperService -- I think your question and search for an affordable legal solution is perfectly reasonable. I've also struggled, unsuccessfully so far, to find a solution in Manhattan kitchens for active exhaust. Can't tell you how many smoke alarms I've hit with baseball bats to shut them up. Let us know if you come up with any more news!

No. Grease build up from kitchen vents requires different type of venting than passive bathroom vents which carry no risk of fires. You need an engineer or architect to give you the exact answer.

In NYC, in 99% of cases, there is no way to vent a stove if such a vent was not part of the original apartment structure. Over-the-range venting convection microwaves that are a necessary alternative include the Viking and Dacor models that function well enough over a semi-pro 4-burner range. Place the venting microwave as high above the stove as possible while still allowing you to access it and see inside it. Heat build up from high-BTU burners is enormous if you have more than one or two burners going at a time.

Exhausts in interior bathrooms have to draw 50 cfm per minute, or something like that. Same for interior kitchens. The fan on the roof is therefore sized to handle all the baths and kitchens in the line. Stove vents move much more than 50 cfm (see story in today's paper.)

If you start pushing all that volume into the vent, while the fan on the roof continues to pull whatever it was designed for, then, as others above have said, the excess air has nowhere to go but out into other people's baths.

Besides that, you don't want to be coating the ducts with grease.

You could exhaust out the upper part of a window, as most people do, but I think there's some code prohibiting that if the window is within x feet of some other window.

kylewest -- let me join the chorus who appreciate the depth of your practical wisdom and gracious willingness to share your hard won experience with others

Well, I figured as much that it is a no-no, but I wanted to verify the popular opinion before I made any formal steps. Our condo is new and doesn't have the proper SOPs and processes in place. When I do burn something like steak and fish, the first thing I do sometimes is take my frying pan with the lid on and take it to the bathroom and take the cover off and have the vent suck it out. I wanted to avoid having to do this and stinking my entire apartment up.

I guess I'll look into a dedicated wall mount range hood that is a high volume recirculating air filter as opposed to a vented model.

@ kylewest - well said

@ProperService - As you figured out, it's a no-go. However, I just wanted to mention that it's also a good idea to ask your building's super. I was thinking about putting an electric fan in my bathroom vent and asked my super about it. He explained that it would mess up the building's vents so it was a no-go also.

Thanks for all the info....

2 other items:

1) In older buildings, many of the kitchen vent lines were lined with asbestos for fire prevention, whereas the bathroom vents were not.

2) While also not really up to code, many buildings have people venting their dryers into bathroom exhausts. Kitchen vent into lint filled vent stack = potential for disaster.

sounds v. dodgy.

Guys, need your help! I live in a Manhattan apartment, my bathroom has a square 6" exhaust vent, but no fan, and the other end of the venting duct at the roof has no fan either. So I need to install my own venting fan. I couldn't find a quiet straight up fan for the purpose. (The famous panasonic models are all side-vented, but not straight up).

Can any one tell me where can I find a good straight up fan? Thanks a lot!

Did you check out the Broan catalog?

http://www.broan.com/display/router.asp?docid=45&CategoryID=500

Thanks Reo, but I have already checked boran/nutone, their quiet bathroom fans are all side-vented. And their straight up fans are all too big and too noisy.

Does any one know a small straight up fan that can be used in bathroom?

Looks like you might have to use a "L" shaped duct-work to make it work.

Thank! By L shape, do you mean attach the quiet bathroom fan unit on the ceiling, then use the L duct to connect its side vent to the existing straight up duct?

but then the whole fan unit looks too big an object attached on the ceiling....any better idea?

"their straight up fans are all too big and too noisy."

I don't think you realize the physics involved here: you need a certain CFM level to accomplish what you want, and I don't think you are going to get it with the products you are looking at.

Reo, actually CFM level is not important at all in my case. I just need the air to vent out, any volume any speed is good in my case.

Can any one just help me accomplish even 1 cubic fps?

Why? Are you on the top floor? The reason you need a certain minimum CFM is that you are pushing a column of air from your vent all the way to the roof. That column of air has weight to it (remember the High School Physics calls demo where they weighed 2 balloons, one empty and one full of plain air?) if you don't have enough pressure, the air you are exhausting (or attempting to exhaust) won't make it to the roof and out. Basically, you have to create a negative pressure environment between the room and the outside (i.e. roof line). Or you could just be venting you bathroom into your upstairs neighbor's (which could happen even with a lot of CFM depending on how the duct work is laid out).

BTW, are you sure it is "straight up"? have you removed the grill and looked? Because I'm trying to figure out how that is physically possible. the main duct has to run in a "chase" straight up and down. So if your vent is in your ceiling, odds are that unless you are on the bottom floor, there is a horizontal duct which feeds into the main duct at somewhere around a 90 degree angle. If, OTOH, the vent is on the wall, then you actually do want a fan which vents to the side (that "side" being up).

So, 30yrs, say you had bought an apartment on that is on the top floor of a new building, and have been promised a kitchen vent, and it turns out to be recirculating crap. How hard is it to make a real kitchen vent?

(assuming you wanted to go up thru the roof, not thru the facade because then top floor wouldn't matter) Not easy at all. Firstly, you've have to make sure there was open roof above as opposed to a mechanical room, etc. Then you would need to get permission to pierce the roof membrane, which might void the warranty. Then, you'd have to remove everything including the cabinetry above the range hood. Then, you would have to see if the existing range hood was dual use (i.e. either recirculating of venting - which a lot are but not all.) If not, you have to buy a new range hood.

Next, you would have to see what the roof is made of: is there a poured concrete floor like the other floors (I'm assuming it's poured concrete floors because you said new construction, but you never know about the roof if it's in an area they never expect to be load bearing). Then you'd have to drill or otherwise make a hole in that concrete or whatever material and the roofing material to vent thru. You have to be very precise as to where the hole is so that is matched up directly over where the exhaust in the venting hood is.

Next, you have to fabricate a duct to go from the vent hood up thru that hole (note, it has to be fairly long because it not only goes up to your celing, but thru the roof and has to be at least some distance above the roof - it can terminate right at the level of the roof). Next, you'd have to put some sort of "cap" on the duct work which stuck out above the roof (don't want rain/snow/etc. coming down thru the vent hole). Then, you'd have to properly seal the roofing material so it didn't leak into your unit (and make sure it satisfied the roofing company).

Then you'd have to cut the cabinet above the hood to allow for the duct work to pass thru it. Then you'd either have fairly ugly sheet metal exposed whenever you opened that cabinet, or you would have to "box it in" and finish it similarly to the already existing finish of that cabinet's interior. Then you have to put everything back together and properly seal all the pieces together because it is much easier to get air leaking if there are any gaps when the air is being "pushed" from the range hood than "pulled" from a roof fan. Which does bring up another issue: a better way of doing it would be to install a fan on the roof at the top of the duct work, but then you have to get permission for that 9hader because it is more likely to disturb people using roof space like on a common roof deck, etc. AND you have to run electric up to the roof for the fan. It does tend to work much better though - drawing instead of pushing - and if sometime in the future your duct work develops gaps, holes, or whatever, it will have little of no effect because everything is getting sucked into the duct work and up to the rood rather than getting pushed from the bottom and going out any place it "finds" an opening.

I haven't reviewed what I just wrote to double check, but you get the general idea. (and also note you will lose a little cabinet space if you actually intend to use the cabinet above the hood, because now the duct will run thru it.)

eek.