Thread: Carbon monoxide detector required or not?

In a home yesterday with no gas fired appliances. Everything is electric. Would a CO detector still be called for?

Similar Threads:

• Smoke detector --AFCI?
• listed carbon monoxide alarms versus monitors
• Floor Covering Required?
• Sweeping Required?
• Vapor barrier not required w/ Hardi Plank?

It is not required.

Originally Posted by Joe Van Orsdol

In a home yesterday with no gas fired appliances. Everything is electric. Would a CO detector still be called for?

If it is not required would you not comment when they're absent? You don't need a gas appliance to have CO.

BTW - the question is too open ended. The answer can depend upon location and when particular requirements may have gone into effect. If you want a definite answer go to the AHJ. If you want to make it easier then say that CO detectors should be installed and base that on your opinion and conviction.

Originally Posted by Joe Van Orsdol

In a home yesterday with no gas fired appliances. Everything is electric. Would a CO detector still be called for?

Originally Posted by Steven Turetsky

It is not required.

Yes they would be required ... if ...

If there is an attached garage.

...Or any fuel burning devices/mechanicals/appliances...such as a pellet stove, coal fired equipment, oil-burning equipment, wood burning fireplace, etc. Any combustion equipment can produce CO.

Originally Posted by Jerry Peck

Yes they would be required ... if ...

If there is an attached garage.

I agree.

In Colorado, the answer is yes if there is a fuel burning appliance (fireplace, for instance) or an attached garage. But, do all other states actually require CO detectors like Colorado or merely recommend them?
Just wonderin'......

Originally Posted by Lon Henderson

In Colorado, the answer is yes if there is a fuel burning appliance (fireplace, for instance) or an attached garage. But, do all other states actually require CO detectors like Colorado or merely recommend them?
Just wonderin'......

Tennessee does not.

Check 2009 IRC 315.1 which requires CO detectors for new construction with an attached garage.

Wisconsin has the same requirements as Colorado, but here it written in state law that there must be one present on each level of the house.

Originally Posted by Lon Henderson

In Colorado, the answer is yes if there is a fuel burning appliance (fireplace, for instance) or an attached garage. But, do all other states actually require CO detectors like Colorado or merely recommend them?
Just wonderin'......

Not that this matters to you non Coloradan guys, but two years ago, Colorado passed a law requiring all homes for sale to have CO detectors installed before the home can even be listed in the MLS. For a few months, nearly every home I inspected had the required detectors, but then, HUD, the banks, and then real estate agents, realized that it was a law without enforcement. There is no CO policeman going around checking for compliance. Now, I rarely find CO detectors placed as required by the law. It is the single most written up item that I find.
Municipalities around here adopted the CO requirement for their building codes, and so all new construction has CO detectors.

Yes, required by Minnesota Law for single family homes, not building code. Doesn't matter if there are gas burning appliances or not. There may be exceptions for multifamily homes.

299F.51 REQUIREMENTS FOR CARBON MONOXIDE ALARMS.

Subdivision 1.Generally.

Every single family dwelling and every dwelling unit in a multifamily dwelling must have an approved and operational carbon monoxide alarm installed within ten feet of each room lawfully used for sleeping purposes.

Subd. 2.Owner's duties.

The owner of a multifamily dwelling unit which is required to be equipped with one or more approved carbon monoxide alarms must:
(1) provide and install one approved and operational carbon monoxide alarm within ten feet of each room lawfully used for sleeping; and
(2) replace any required carbon monoxide alarm that has been stolen, removed, found missing, or rendered inoperable during a prior occupancy of the dwelling unit and which has not been replaced by the prior occupant prior to the commencement of a new occupancy of a dwelling unit.

Subd. 3.Occupant's duties.

The occupant of each dwelling unit in a multifamily dwelling in which an approved and operational carbon monoxide alarm has been provided and installed by the owner must:
(1) keep and maintain the device in good repair; and
(2) replace any device that is stolen, removed, missing, or rendered inoperable during the occupancy of the dwelling unit.

Subd. 4.Battery removal prohibited.

No person shall remove batteries from, or in any way render inoperable, a required carbon monoxide alarm.

Subd. 5.Exceptions; certain multifamily dwellings and state-operated facilities.

(a) In lieu of requirements of subdivision 1, multifamily dwellings may have approved and operational carbon monoxide alarms installed between 15 and 25 feet of carbon monoxide-producing central fixtures and equipment, provided there is a centralized alarm system or other mechanism for responsible parties to hear the alarm at all times.
(b) An owner of a multifamily dwelling that contains minimal or no sources of carbon monoxide may be exempted from the requirements of subdivision 1, provided that such owner certifies to the commissioner of public safety that such multifamily dwelling poses no foreseeable carbon monoxide risk to the health and safety of the dwelling units.
(c) The requirements of this section do not apply to facilities owned or operated by the state of Minnesota.

Originally Posted by Lon Henderson

In Colorado, the answer is yes if there is a fuel burning appliance (fireplace, for instance) or an attached garage. But, do all other states actually require CO detectors like Colorado or merely recommend them?
Just wonderin'......

Florida requires CO detectors when there is an attached garage as cars are fuel burning.

As does every state which uses the 2009 IRC as its base code ... and has not mutilated the code by taking safety features out of it ... there are some here (Garry ) who seem to think that we might as well go back to allowing wood chimneys in the code because the code does not need to address stupid things that stupid people do, such as building a fire in a fireplace with a wood chimney ...

I wish you guys could once in a while break away from what some code may or may not require. Smoke and CO detectors save lives, you don't need any other backup info than that. Instead of dwelling on some requirement I suggest you instead learn about the difference between ionization and photo-electric smoke detectors and the life cycles of the sensors in smoke and CO detectors.That effort would be much more beneficial to your clients.

Originally Posted by Eric Barker

I wish you guys could once in a while break away from what some code may or may not require. Smoke and CO detectors save lives, you don't need any other backup info than that. Instead of dwelling on some requirement I suggest you instead learn about the difference between ionization and photo-electric smoke detectors and the life cycles of the sensors in smoke and CO detectors.That effort would be much more beneficial to your clients.

I agree with Eric...

This is pretty much the verbiage I use when I talk about smoke detectors. I then add a line that says smoke detectors should be replaced around 7 years of age and CO detectors around 5 years if age. I also add as needed that CO detectors need to be added............

This is what the NFPA states about smoke detectors:
The two most commonly recognized smoke detection technologies are ionization smoke detection and photoelectric smoke detection.

•Ionization smoke detection is generally more responsive to flaming fires.
How they work: Ionization-type smoke alarms have a small amount of radioactive material between two electrically charged plates, which ionizes the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm.

•Photoelectric smoke detection is generally more responsive to fires that begin with a long period of smoldering (called “smoldering fires”). If you have to choose one detector this is the type I would select for my own home.
How they work: Photoelectric-type alarms aim a light source into a sensing chamber at an angle away from the sensor. Smoke enters the chamber, reflecting light onto the light sensor; triggering the alarm.

For each type of smoke alarm, the advantage it provides may be critical to life safety in some fire situations. Home fatal fires, day or night, include a large number of smoldering fires and a large number of flaming fires. You can not predict the type of fire you may have in your home or when it will occur. Any smoke alarm technology, to be acceptable, must perform acceptably for both types of fires in order to provide early warning of fire at all times of the day or night and whether you are asleep or awake.

The best evidence has always indicated that either type of smoke alarm will provide sufficient time for escape for most people for most fires of either smoldering or flaming type. However, research is ongoing, and standards are living documents. If at any time, research points to a different conclusion, then that will lead to proposals for changes in the NFPA standard or the closely related Underwriters Laboratories standard for testing and approving smoke alarms. Both organizations currently have task groups looking at smoke alarm performance in the current home environment.

For best protection, use both types of smoke alarm technologies
For best protection, it is recommended both (ionization and photoelectric) technologies be in homes. In addition to individual ionization and photoelectric alarms, combination alarms that include both technologies in a single device are available.

Originally Posted by Eric Barker

I wish you guys could once in a while break away from what some code may or may not require. Smoke and CO detectors save lives, you don't need any other backup info than that. Instead of dwelling on some requirement I suggest you instead learn about the difference between ionization and photo-electric smoke detectors and the life cycles of the sensors in smoke and CO detectors.That effort would be much more beneficial to your clients.

I whole heartily agree, but you can not force a builder to do something not required by code, you can recommend it, but they only have to comply with the requirements. At one time, smoke detectors were not required by code and we knew they saved lives, but builders and homeowners fought the requirement because they were ugly on the ceilings, caused false alarms, added expense to the home, etc. When the CO requirement came out in WI, you thought the world was coming to an end.

Just recently, this will sound scary, there was a "proposal to revise the WI State code" floating around to remove the AFCI, GFCI, and Tamper Resistant outlet requirements for WI and make them optional, which baffles the mind, builders complained of reliability issues and added costs... thankfully it was killed. It never went very far, but the real scary part, reading between the lines, was the talk about "devices to detect fire-causing conditions" which might have opened the window to optional smoke detectors, if it passed, talk about lack of common sense...

Originally Posted by Eric Barker

I wish you guys could once in a while break away from what some code may or may not require. Smoke and CO detectors save lives, you don't need any other backup info than that.

Sure, he could argue that CO detectors "save lives" but it's more emphatic and professional to state, "It's required by State Law. Here's the statute".

Originally Posted by Eric Barker

Instead of dwelling on some requirement I suggest you instead learn about the difference between ionization and photo-electric smoke detectors and the life cycles of the sensors in smoke and CO detectors.That effort would be much more beneficial to your clients.

Really? So if your client asks you if CO detectors are required it's better to say, "I don't know." Then explain the difference between different types of smoke detectors?

Originally Posted by Mike Kleisch

I whole heartily agree, but you can not force a builder to do something not required by code, you can recommend it, but they only have to comply with the requirements. At one time, smoke detectors were not required by code and we knew they saved lives, but builders and homeowners fought the requirement because they were ugly on the ceilings, caused false alarms, added expense to the home, etc. When the CO requirement came out in WI, you thought the world was coming to an end.

Just recently, this will sound scary, there was a "proposal to revise the WI State code" floating around to remove the AFCI, GFCI, and Tamper Resistant outlet requirements for WI and make them optional, which baffles the mind, builders complained of reliability issues and added costs... thankfully it was killed. It never went very far, but the real scary part, reading between the lines, was the talk about "devices to detect fire-causing conditions" which might have opened the window to optional smoke detectors, if it passed, talk about lack of common sense...

Home inspectors can't make a builder do anything! But, we can simply say For increased safety and good building practices dictate that ______________. I use statements like this all the time with new construction and builders who try to go cheap and minimal. I also use statements like this when a code does not address something. I would say it works more often than not.

CO statute by state was updated Nov 2012, ymmv
Carbon Monoxide Detectors - State Statutes

Originally Posted by Ken Rowe

Sure, he could argue that CO detectors "save lives" but it's more emphatic and professional to state, "It's required by State Law. Here's the statute".

If they want that kind of info they can follow me on the job. That's when I can explain some of the implications of conditions found. For the most part the report is more to the point - it's wrong, have it fixed. In my experience clients don't make much of an effort to read reports so why give them a bunch of explanatory text and reasons for my pointing things out?

In Ontario,all houses are required to have on carbon monoxide detector,no matter what the house has in it,plain and simple.

Originally Posted by Eric Barker

If they want that kind of info they can follow me on the job. That's when I can explain some of the implications of conditions found. For the most part the report is more to the point - it's wrong, have it fixed.

Let me get this straight. You're saying that you would not write that "carbon monoxide detectors are required by state law" or anything to that effect, in your report...even though you know they are? Remember, state laws are not the same as building codes.

Originally Posted by Eric Barker

In my experience clients don't make much of an effort to read reports so why give them a bunch of explanatory text and reasons for my pointing things out?

Ummm,.. because Sect 2.2 c, 3 of the ASHI Standards says Inspectors shall report "reasoning or explanation as to the nature of the deficiencies reported in 2.2.C.1, that are not self-evident" . I see ACI in your signature and according to your Linkedin profile you're also a board member of ASHI national. You should know this.

Originally Posted by Ken Rowe

Let me get this straight. You're saying that you would not write that "carbon monoxide detectors are required by state law" or anything to that effect, in your report...even though you know they are? Remember, state laws are not the same as building codes.



Ummm,.. because Sect 2.2 c, 3 of the ASHI Standards says Inspectors shall report "reasoning or explanation as to the nature of the deficiencies reported in 2.2.C.1, that are not self-evident" . I see ACI in your signature and according to your Linkedin profile you're also a board member of ASHI national. You should know this.

Actually he has to report under the IL Standards, ASHI takes a back seat with their SOP when it comes to a licensed state.

Originally Posted by Scott Patterson

Actually he has to report under the IL Standards, ASHI takes a back seat with their SOP when it comes to a licensed state.

Agreed. Then he's also violating his state's standards of practice.

Section 1410.200 Standards of Practice

E, 2) Report on those systems and components inspected that, in the opinion of the inspector, are significantly deficient including:

A) A reason why, if not self evident, the system or component is significantly deficient.

My point is there are reasons why we actually put explanations of our recommendations in our reports and don't just put "it's wrong, have it fixed".

Washington State started requiring CO's in all house at the point of sale in 2012. HI's found themselves in the position of interpreting and forcing installation. This was regardless of new home or pre-owned home. Doesn't matter if there are garages or fossil fueled appliances. Washington State learned the hard way that during a power outage people will do all sorts of stuff to stay warm and cook inside their homes. For that reason the lawmakers in a moment of clarity said all homes regardless of type of heat or configuration.

Here is an explanation of Washington's requirements:
Carbon Monoxide LawsÂ* By Pacific Crest Inspections located in Anacortes offeringÂ* Inspections in Skagit, Snomish, Whatcom and Island Counties

California has required CO detectors when remodeling for several years and made it a requirement in all residences as of 7/2011. Though not in a residence with no attached garage or fuel burning appliances. The requirement to install CO detectors in residences with out CO producing appliances, is the kind of no logic law that causes these uproars from the builders.

Besides the fact that approximately 250 people, in the United States, die from CO poisoning each year from a multitude of sources, what does not get reported are the numerous other adverse health effects of exposure to the deadly gas.


Symptoms of carbon monoxide poisoning can be so varied and imitate so many common health issues the link to carbon monoxide exposure is very frequently missed in emergency rooms - and even more commonly missed in clinics and doctors’ offices.


The world is packed with an almost endless number of sources of carbon monoxide.This means there are potentially a significant number of people being poisoned without knowing the cause of their health issues. These poisonings are never tracked or even estimated in carbon monoxide statistics

Those that do survive such exposure may never learn that they have been the victims of carbon monoxide poisoning even though they may continue to seek treatment for directly related health issues and experience short or long term effects, neurological problems, endocrine problems, and other health issues, all without ever knowing the real cause.

And that only addresses the people that actually do seek medical attention.

Many sources of CO have been previously identified by others in this post.

I could delineate numerous others as well.

Carbon Monoxide, CO, not CO2 as it is often misidentified, is a colorless, odorless gas that is the result of improper or incomplete combustion.


It is “neutrally buoyant� with the air that we breathe every day. That means that it has virtually the same atomic weight as air and therefore neither rises nor falls on its own. It must be acted upon by some other source. That’s why CO detectors are manufactured to plug into a wall receptacle or be installed on a ceiling.


Regardless of what the laws of your particular state may be, a brief recommendation to consider installation of CO detectors where such are absent is the decent thing to do.


Unless someone can offer an opinion related to incurring liability by merely recommending the installation of such, I personally will continue to advocate their installation wherever such devices are absent.

I agree that we all should be recommending CO detectors in homes that have fuel(gas, oil, wood) based heating, water heaters, or cooking appliances.

Where I have a problem recommending CO detectors would be in ALL Electric Homes that do not have a fireplace. Yes, the home might have an attached garage but IMVHO I find it a stretch that CO is going to enter the home via a garage, unless you keep the door closed and the car running in it.

You can not protect stupid! Although our government is attempting to do it and has done it in some locations with knee jerk regulations. At what point do we say enough is enough? But then, I'm also for less regulation by our government and I feel that I might be among a minority in many areas of the country.

Originally Posted by Richard D. Fornataro

It is “neutrally buoyant� with the air that we breathe every day. That means that it has virtually the same atomic weight as air and therefore neither rises nor falls on its own. It must be acted upon by some other source. That’s why CO detectors are manufactured to plug into a wall receptacle or be installed on a ceiling.

Carbon monoxide has a molar mass of 28.0, which makes it slightly lighter than air, whose average molar mass is 28.8. According to the ideal gas law, CO is therefore less dense than air. Neither gas is "ideal", however, so neither exactly has the densities predicted by the ideal gas law.

Pure CO is about 3% lighter than air. Years ago, I read some information that CO is slightly heavier than air and this myth continues. However, it is so close to the common density of air, that in a normal house, its distribution is nearly even through out the volume of the house.
At some other source, I read that placing CO detectors on the ceiling will trigger the earliest alarm in a home with forced air heating because warm air carrying CO from a defective furnace will rise to the ceiling first. Years ago, a fire department website, said to place the plug-in detectors close to a forced air register for earliest alarm. But in truth, the even distribution of CO happens quickly and it doesn't really matter a lot where a CO detector is located, although if the manufacturer has a location recommendation, it should be followed.

As far as sensitivity of smoke detectors, I used to actually smoke test smoke detectors and found that even very old ones, were still functioning. So, while they loose some sensitivity, based on my experience, it isn't much. Of course, while that's interesting for my own information, I advise clients of the industry and fire department recommendation to replace them every ten years.

Local codes often mandate requirements beyond the national code. Many towns in MA have differing requirements, some of which are not intuitive. The only way to be sure about the requirements is to contact the local fire department.

2012 NFPA 720

9.4 Required Protection.
9.4.1* Carbon Monoxide Alarms and Detectors.

The warning functions intended in this standard shall be performed by single or multiple-station alarms or by detectors connected to a control unit and associated equipment, in accordance with 9.3.3.

9.4.1.1*

Carbon monoxide alarms or detectors shall be installed
as follows:
(1) Outside of each separate dwelling unit sleeping area in the immediate vicinity of the bedrooms
(2) On every occupiable level of a dwelling unit, including basements, excluding attics and crawl spaces
(3) Other locations where required by applicable laws, codes, or standards

9.4.1.2*

Each alarm or detector shall be located on the wall, ceiling, or other location as specified in the manufacturer’s published instructions that accompany the unit.

9.7 Installation.
9.7.1 General Provisions.
9.7.1.1

All carbon monoxide alarms or detectors shall be installed in accordance with the manufacturer’s published instructions.

9.7.1.2

All carbon monoxide alarms or detectors shall be located and mounted so that accidental operation will not be caused by jarring or vibration.

9.7.1.3

All carbon monoxide alarms or detectors shall be supported independently of their attachment to wires.

9.7.1.4

All carbon monoxide alarms or detectors shall be tested in accordance with the instructions provided by the supplier or installing contractor (see 9.9.2 and 9.9.3) to ensure
operation after installation.

9.7.1.5

All carbon monoxide alarms or detectors shall be restored to their normal mode of operation after each
alarm or test.

9.7.1.6

The supplier or installing contractor shall provide the owner with the instructions required in 9.9.3.

Originally Posted by Scott Patterson

I agree that we all should be recommending CO detectors in homes that have fuel(gas, oil, wood) based heating, water heaters, or cooking appliances.

Where I have a problem recommending CO detectors would be in ALL Electric Homes that do not have a fireplace. Yes, the home might have an attached garage but IMVHO I find it a stretch that CO is going to enter the home via a garage, unless you keep the door closed and the car running in it.

You can not protect stupid! Although our government is attempting to do it and has done it in some locations with knee jerk regulations. At what point do we say enough is enough? But then, I'm also for less regulation by our government and I feel that I might be among a minority in many areas of the country.

I agree. Has anyone put their CO detector in their tailpipe? You would be surprised, like I was.