I recently moved in to a new apartment that has a gas range and oven. I have never had a gas stove before, and so I am not sure how it should work.

While cooking the other night, our Carbon Monoxide detector went off. I was using the fan on the hood, and could "see" the gas/exhaust being sucked up into the hood. I opened the windows, and turned off the oven, and we were fine.

After inspecting the hood, I am curious to know if this is how it should be set up.

Hood above the stove
Here is the hood above the stove.

Opening above the hood
Here is the opening that empties into the cabinet above the hood.

Hole cut in cabinet above the vent
The hood doesn't vent outside of the kitchen, just flows up into the cabinet and out the hole cut into the top into the room.

  • Do I need to be concerned about this setup? Is this dangerous? We use the stove an awful lot, the oven less frequently. Are we at risk for CO poisoning?
  • Should my landlord have mentioned this to me, and maybe said "hey, open the windows when you use the stove"?


Can anyone direct me to where I can get a definitive answer on whether this is a real issue? My landlord disagrees and says "modern gas ranges do not emit carbon monoxide"

However, the CDC Carbon Monoxide FAQ website says:

All gas appliances must be vented so that CO will not build up in your home, cabin, or camper.
Never burn anything in a stove or fireplace that isn't vented.

I would like to know if I need to get out of this apartment, since the landlord refuses to acknowledge this as an issue, or whether he actually is right, and there is nothing to worry about.

EDIT: This is in Chicago, IL if that helps anyone.

  • 5
    Somebody stole your pipe! There should be a vent pipe attached to the hood, that leads to the outside. Call the landlord and ask them to install a proper vent pipe. As it is now, you're just blowing warm moist greasy air into the cabinet.
    – Tester101
    Commented Sep 6, 2011 at 17:36
  • @Tester101, haha, I would assume that someone stole it, but that would make more sense if there was another hole to connect the pipe to, but there isn't. This is an interior wall, and there are no other holes in the ceiling or wall that I can find to vent out the air. The cabinet above the stove is also covered with grease.
    – jjeaton
    Commented Sep 6, 2011 at 19:10
  • 8
    Looks like the landlord updated the kitchen then realized how much work it would be to properly vent the stove, so they decided just to make it look nice (when the cabinet is closed). Ask the landlord to finish the job.
    – Tester101
    Commented Sep 6, 2011 at 20:25
  • Mega. Usually people do not even bother to cut out the palce for a pipe and they think that it works just like that. But this.. is just a joke. Ideally there should be a vent over gas stove because it can a health hazard. demand it be installed or sue!
    – Piotr Kula
    Commented Oct 21, 2011 at 16:29
  • 1
    You will probably have to check laws(tenant, rental, building code) in Chicago to see if this is illegal. It definitely violates modern building codes, and most cities use a building code from a specific year as a base for their laws. Perhaps there was no vent before this (seemingly) recent renovation, so the landlord incorrectly assumes he doesn't have to install one, but a recent renovation is not likely grandfathered in.
    – Hemm
    Commented Oct 25, 2011 at 19:51

6 Answers 6


I would say that this is highly dangerous. It is against US and Canadian code to not have outside ventilation for any fuel-burning appliance in your home; that's your furnace, HWH and stove/oven, assuming all are NG or propane. It is only acceptable to have a "filter-only" vent hood for your stove if it's all-electric (which BTW is the case for every single apartment I've ever rented; gas appliances may be cheaper on utility bills in the US, but a gas stove is a huge fire hazard and general liability for any landlord).

The code is in place for a very good reason; not only can inefficient burning of fossil fuels produce carbon monoxide and smoke (both of which continue to cause damage long after you've reached fresh air), but even when these fuels burn ideally, they remove oxygen from the air and replace it with CO2. CO2 in itself is not toxic in the same way CO and soot smoke are; as soon as you reach fresh air the symptoms of CO2 asphyxia begin to dissipate, while soot and CO poisoning ("smoke inhalation") can kill you hours after you reach fresh air. However, the consumption of oxygen and production of CO2 in a space with inadequate ventilation is a double-whammy for anyone in the same space; the oxygen is being consumed so there's less of it even in upper strata of the room's air, and as the CO2 builds it settles downward in a "blanket", pushing oxygen up towards the ceiling and away from you.

As the CO2 level builds, your body's natural "inhale/exhale" reflexes go haywire in a Catch-22 condition called hypercapnia; your natural breathing while in a high-CO2 atmosphere actually increases the CO2 levels in your blood, but the only thing your body can do to reduce CO2 levels is breathe. So, you start hyperventilating, which only exacerbates the problem. Should you pass out from lack of oxygen, you will not wake up if someone else doesn't get you out of the room or get some ventilation of fresh air through it.

Your landlord is running illegal housing. However, he may not know it, so be nice at first. Follow standard procedure for maintenance requests, and ask the landlord to install a proper outside vent line for this fume hood. If he refuses or drags his feet, you can call in the city's Code Compliance officials, or federal HUD (Housing and Urban Development) representative, and they will MAKE the landlord comply. Depending on the terms of your contract, the landlord may be giving you a free out by not living up to his end, meaning you may be able to break the lease at no cost if this has gone on for some time with the landlord's knowledge and inaction.

Understand that the cheapest way for your landlord to fix the problem with tenants still occupying the units may well be to cap off the gas feed and replace all the gas cooktops with the cheapest electric setups he can find. If this was the reason you moved in, and you don't get a "free out" from this debacle, you may find yourself stuck with a spiral-coil POS.

  • CO is not CO2. Carbon monoxide (CO) and carbon dioxide (CO2) are completely different. CO kills. CO2 in the atmosphere is necessary for life, but too much warms the planet. CO2 is the main focus of the Paris Accords.
    – Bryce
    Commented Dec 6, 2019 at 5:32

There's two issues here. The first is the CO alarm. SOMETHING is wrong. It may be the stove, or some other combustion device in your house, but it's definitely something to pay attention to. I'd suggest getting a second CO detector and place it around the house and monitor the levels carefully. If it's the stove, it's less of a ventilation issue and more of a combustion issue with the stove...maybe it just needs a cleaning. Maybe you need a new stove.

The second issue is that hood vent. This is one of the more hilarious installs I've ever seen. Your landlord has an exhaust hood without it exhausting. It's just going into a closed cabinet. If you leave it as-is, that's OK, but it means you will have to take off the cabinet doors and remove everything from that cabinet so at least you get a circulating effect.

What is bizarre is that that appears to be a relatively high-end vent hood for an apartment. Why they invested money in that, but not properly installing it is a bit confusing.

  • 5
    Carbon "MONoxide" is CO; it is roughly the same molecular weight as diatomic O2/N2 and thus mixes readily into normal air; it has no odor, and it will actively poison you by attaching to your blood hemoglobin and refusing to be released, reducing blood oxygenation long after its inhaled. Carbon "DIoxide" is CO2; In atmospheric content it too has no odor, but it is heavier than air, and is only toxic in the sense that it is not oxygen and will displace oxygen in the air without proper ventilation.
    – KeithS
    Commented Sep 6, 2011 at 20:45
  • @KeithS Actually I think CO2 is also toxic, separately from low O2 (Asphyxia). I understand that high CO2 concentrations can lead to a potentially lethal condition called Hypercapnia. Commented Oct 20, 2011 at 22:31
  • The body does react to CO2 as a toxin, but it's a toxin we create with each exhalation so the body knows (or thinks it does) how to get rid of it. However, you're right, in a high-CO2 atmosphere, the body's natural respiration reflexes go haywire, causing hypercapnia.
    – KeithS
    Commented Oct 21, 2011 at 14:11
  • But, in comparison to other combustion byproducts, CO2 is one of the lesser worries from a toxicity standpoint. CO and soot will both cause lots of damage and can kill you hours after you reach fresh air. Hypercapnia symptoms go away relatively quickly once the person is getting enough oxygen.
    – KeithS
    Commented Oct 21, 2011 at 14:14

Have a look at the 2006 International Residential Code. Here are a few sections that may apply.

Chapter 15 - Exhaust Systems


M1501.1 Outdoor discharge.

The air removed by every mechanical exhaust system shall be discharged to the outdoors. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.

Exception: Whole-house ventilation-type attic fans that discharge into the attic space of dwelling units having private attics shall be permitted.


M1503.1 General.

Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

Exception: Where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.


M1505.1 General.

Domestic open-top broiler units shall be provided with a metal exhaust hood, not less than 28 gage, with ¼ inch (6 mm) between the hood and the underside of combustible material or cabinets. A clearance of at least 24 inches (610 mm) shall be maintained between the cooking surface and the combustible material or cabinet. The hood shall be at least as wide as the broiler unit and shall extend over the entire unit. Such exhaust hood shall discharge to the outdoors and shall be equipped with a backdraft damper or other means to control infiltration/exfiltration when not in operation. Broiler units incorporating an integral exhaust system, and listed and labeled for use without an exhaust hood, need not be provided with an exhaust hood.

Make sure to check with your local government to determine what codes apply in your area.


To answer your question directly (without looking at the obvious issues), no it is not very dangerous. MANY people have stoves / cooktops without any hood, or if they do, they simply filter the air and blow it back out into the kitchen. Many of the over range micorwaves do this as well. These filters would do nothing to filter the CO.

You would need to be cooking at a high temp for a VERY long time to reach a level that the CO detector would go off. I have never heard of a coooktop doing it, although I have heard of a gas oven doing it when left on for hours at a time.

So to be short, NO, it is not dangerious. But obviously it is not being effective and it relatively useless as it.

  • Our gas oven had been on for over an hour, and I had just turned on the gas stove to heat something up when the CO detector went off.
    – jjeaton
    Commented Sep 6, 2011 at 20:15
  • 4
    It could potentially be dangerous if the stove is not working properly, and is not burning the gas efficiently enough.
    – Tester101
    Commented Sep 6, 2011 at 20:23
  • Also, do I need to request that the landlord put in a pipe to vent this outside, or is it not that big of a deal?
    – jjeaton
    Commented Sep 6, 2011 at 20:23
  • Personally, for a gas cooktop I would insist that this be properly vented to the outside. It's not just CO, but CO2; burning any fossil fuel in an unventilated space can suffocate you or anyone in the room even if the fuel burns ideally (no CO) by using up the oxygen in the air.
    – KeithS
    Commented Sep 6, 2011 at 20:40
  • 2
    CO poisoning is cumulative, so a long-term low-level exposure is as bad as a short-term high-level exposure. If the CO detector is alarming, it means that there's a dangerous level of CO.
    – Niall C.
    Commented Sep 6, 2011 at 20:48

That is the most absurd set up I've ever seen and Yes it is dangerous. The toxins are built up accumulatively however the end result could also be overnight depending on the way stove is running. Chances are with a landlord allowing a set up like that I wouldn't trust it. Your family is to important. Write her/him an immediate letter and include the housing code she/he is in violation of. Giving her/him knowledge of the problem(as if they didn't know) will put the ball in their court. Make a copy and cc at bottom. Cc: Dept of HUD Housing Sign it and personally hand her/him letter. This is an urgent matter.


There are multiple purposes to an external vent for a cooking appliance. I would focus with the housing provider/landlord on the issue of odors and grease permeating the unit, and moisture from boiling and burning activities and the affect on the unit (doubly so the particle board cabinet).

No, not all gas appliances are vented. It's a good idea to, but they're not.

See https://www.nytimes.com/2010/04/01/garden/01fix.html

The CO alarm it its own thing. That's not normal. Has nothing to do with the lack of hood, it's not normal at all. Immediately get a recording model that can give you a CO level, and install it. You can very reasonably as the housing provider to pay for that (asking first is generally better, you can insist in most States).

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