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Things You Must Know About CO Alarms

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Most CO poisoning related hospitalizations or deaths are preventable, and CO alarms can prove to be that life saving device for you and your family!!


Photo: CO Alarm installed in the ceiling of a home

How many alarms does my home need?

That is a good question to ask! The U.S. Consumer Product Safety Commission (CPSC) recommends that every level of a home should have a CO alarm, and preferably one outside each bedroom or sleeping area.

CO alarms are available for boats and recreational vehicles too and must be installed. The Recreation Vehicle Industry Association requires CO alarms to be installed in all motor homes and trailers.

What kind of alarms are the best?

CPSC (n.d.) recommends an alarm  which meets  the UL (Underwriters Laboratories)  2034 safety standard. UL recommend that since various different types of alarms are available in the market, an easy way to decide is to look for the UL Mark on the alarm. All UL alarms sound an alarm to alert members of a home about the elevated CO levels. An audible alarm is very important because if the levels increase during the night time, when a family is asleep, the alarm will help to wake them up and take precautionary measures.

CO alarms are available in different types: outlet plug-in, ceiling, wall and table top. These can be hard wired into building wiring or could be battery operated. It is recommended though that even if an alarm is wired it should have a battery back-up for power-outage kind of situations, when people tend to use unconventional means (such as generators, gas powered range or oven) for heating their homes, which are also the high risk situations when CO poisonings have most likely chance to occur.

What is UL 2034?

UL 2034 is an the independent standard developed by Underwriter Laboratories (UL) in 2007 and requires the CO alarms to have an end-of-life warning (continuous beep beep noise). The warning noise alerts the homeowner that the battery pack in the alarm needs to be changed so that the alarm can continue to function as per its design. The alarms which do not have this feature, at the end of battery life, fail to intimate the homeowner about their incapability of detecting hazardous concentrations of CO in the home. UL 2034 is the only standard that most U.S. manufacturers tend to comply with in the absence of other standards for residential homes. CPSC has worked in close collaboration with the UL to develop this standard.

Several states in the U.S. now require UL 2034 compliant CO alarms to be installed in all residential dwellings (single-family homes, apartments, town-homes etc).

National Conference of State Legislatures has put all State statutes regarding CO detectors here. Another good place for a homeowner to find out about the local and state statutes applicable in his/her state are the state/local housing department.

What to do if an alarm sounds at your home?

NEVER IGNORE the alarm!!!

That is the first rule- a CO alarm should never be ignored.

If your CO alarm starts sounding, immediately stop doing whatever you may be and move outdoors for fresh air. And, now call 911 right away!!

Next ensure all persons in your home are also outdoors and accounted for. If someone is missing, do NOT try to enter the home to find them until the emergency responders have arrived and allow you to do so. Re-entering the home and getting exposed to high CO levels even for a small duration of time can lead to loss of consciousness or fatal consequences.

Helpful tips regarding CO alarms (Universal Security Instruments, Inc., n.d.)

1. Check and replace the alarm battery annually:  The battery in the carbon monoxide alarms drains down over time and on an average needs replacement annually. Often a homeowner will forget when the battery was replaced last. If this is what you are facing too, the best way is to go ahead and replace the battery now without taking any chances.

2. Battery back-up is a must: All alarms even if wired-into the building wiring of your home should have a with battery backup.

3. Interconnect alarms in the different parts of  home: Interconnected alarms installed in different parts of a home are an excellent added safety cushion and can provide those extra few minutes of safety if a distant part ( or the part not occupied in that particular moment) of the home has the situation of carbon-monoxide poisoning. Interconnectivity allows all alarms to start beeping at the same time alerting the resident of the CO poisoning risk. Such interconnected alarms are called multiple station alarms and can connect upto 24 alarms.

5. Batteries should NEVER be removed or used for any other purpose even temporarily: The batteries in the CO alarm should not be removed even temporarily for use in other equipment such as stereo or games.

6. Do not disable the alarm at any time: If your CO alarm turns out to be nuisance at cooking times, do not do not disable it even temporarily. Open a door or a window,  turn on the exhaust, wave a towel near the alarm or press its silence button (if available) to stop the alarm from sounding.


CPSC. (n.d.). Carbon Monoxide Questions and Answers. Retrieved February 03, 2015.

Universal Safety Instruments Inc. (n.d.) Carbon Monoxide Alarms. Retrieved February 09, 2015.

National Fire Protection Agency (NFPA) website:

U.S. Consumer Product Safety Commission website:

Page Last Updated: 4 weeks ago
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