Home » Home Safety » Where to Put Carbon Monoxide Detectors in Your Home

Where to Put Carbon Monoxide Detectors in Your Home

A lack of information about carbon monoxide poisoning means many of us will have questions: do I need a carbon monoxide detector? How many carbon monoxide detectors do I need?

Fret not—find out all you need to know, including where to put carbon monoxide detectors, below.

Where to Place Carbon Monoxide Detectors

Understanding a little about the gas helps one to find the best places for alarms. For instance, does carbon monoxide rise or stay low to the ground as it is produced?

Carbon monoxide is a gas that’s formed when fuels fail to combust properly. As such, you can’t smell it (chemicals are added to natural gas before it is distributed to give it an odor), nor can you see it.

CO gas is lighter than air, meaning it can rise. It also tends to be found in warm spaces, which further encourages it to rise, so carbon monoxide detectors should always be placed up to five feet off the ground. If you’re unsure, simply attach it to the ceiling as you would a smoke detector.

Credit: The Air of Authority

CO alarms installation best practices

Place CO alarms in homeAt least 5 foot off the ground. Attached to the ceiling or a wall. Prioritize the kitchen and sleeping areas.
Place CO alarms in basement3-5 meters from flammable/gas producing appliances and objects, like BBQs, heaters, and cars in storage.
Place CO alarms in bedroomClose enough to sleeping areas for the alarm to wake up occupants in the night. If placed in the hallway or corridor, test loudness of alarm from each bedroom.
Place CO alarms in kitchen3-5 meters from flammable/gas producing appliances and objects, like gas ovens and boilers (the most likely place for CO leaks to occur).
Place CO alarms in officePrioritize office kitchenettes. Always use professional installation and annual servicing. Ensure employees have undergone relevant health and safety training regarding CO poisoning and what to do in the event of an alarm.

How to Install a Carbon Monoxide Detector

While specific installation may vary product by product, the good news is that installing a carbon monoxide detector is generally an easy task. 

Always consult the product manual before attempting installation if you have it. If not, here’s how to install a wall-mounted detector.

  1. Use a tape measure to measure 3-5 feet away from gas-producing appliances (namely, gas ovens and boilers). If this isn’t possible in your property, simply find the place in the room furthest from these appliances.
  2. Measure vertically at least 5 feet off the ground (eye level). CO rises, so it is essential that the monitor doesn’t sit far below this threshold.
  3. Measure horizontally to find the most appropriate place on the wall.
  4. Many detectors include a mounting guide (a piece of paper you can use to mark the screw holes). Tape this to the wall, using a leveler to make sure it is straight, and use it to drill accurate holes. If there isn’t one included, simply measure the distance between the screws on the back of the device and mark this on the wall with a pencil.
  5. Insert wall anchors into the holes. If you are drilling into wood, you can screw directly into the holes. Wall anchors can help maintain the integrity of the wall.
  6. Tighten the screws into either the anchors or the wall, leaving a gap of about one millimeter for the device to hang off.
  7. Slide the device over the screws, using a leveler to ensure it is straight.
  8. Test the detector by touching the large button on the front. It should beep. If not, try changing the battery.

If you’re looking for a visual guide, here is one:

Credit: Ace hardware

Best Carbon Monoxide Detector | Our Top 3

Google Nest Protect

Best overall

Available on the Google Store. Starting at $114.

A ceiling-fixed, battery-powered alarm that combines smoke and carbon monoxide detection, this smart-home device is, as one might expect from Google, a little savvier than your average alarm. 

It communicates with you primarily through your phone, allowing you to hush it and check its batteries without annoying chirping. Custom algorithms detect steam, and it tests itself 400 times a day, so you don’t have to. Did we mention it’s an automatic night light as well?

Best for smart home

Available on Amazon. Starting at $228.

Similar to Google’s namesake product (but significantly more expensive), Onelink’s Safe & Sound instead incorporates Amazon Alexa and Apple’s Airplay 2. Weirdly, this makes it not just a rather effective smoke and carbon monoxide alarm (at a whopping 85dB, you’re unlikely to miss its siren), but a comprehensive smart speaker. 

Yes, you can now play music and get the news through your smoke alarm. Unlike Nest, it is hardwired with a backup battery, so expect a tougher set-up.

Kidde Carbon Monoxide Detector (Plug-In)

Best on a budget

Available on Amazon. From $20.

A wall plug-in option for those with an aversion to charging, Kidde offer a well-trusted and budget-friendly detector. Battery back-up makes it reliable in the event of a power outage, a ten-year limited warranty comes with every product, and its simple design keeps it discreet. 

Just make sure your AC socket isn’t level with the floor—it needs to be at least 5 feet off the ground. Otherwise, you can’t go wrong.

Carbon Monoxide Alarm Installation Do’s and Don’ts

Place it next to a fireplace or gas/flame producing applianceWhile fireplaces and gas/wood-burning appliances can produce CO when fuel burns inadequately, it’s not a good idea to have a detector placed right next to it. Detectors should be away from appliances and several feet above them because carbon monoxide rises.
Place it inside a bathroomAs with anything that functions via a battery, it’s best to keep carbon monoxide detectors away from wet environments. Steam can rise into the detector and damage it as it condenses.
Just use oneEven in smaller homes, installing only a single carbon monoxide detector fails to completely mitigate the risk of having carbon monoxide go undetected. Kitchens and sleeping areas must have separate detectors—ideally, however, all rooms should have their own detector.
Position it five feet off the groundCarbon monoxide rises, so instead of having alarms be at ground level or next to gas-producing appliances, install detectors about five feet off the ground. To avoid confusion over heights, simply attach to the ceiling.
Prioritize sleeping areasInstalling a detector in every single room of the house is, obviously, a rather tall order for most of us and an unlikely expectation. With the detectors you do have, prioritize sleeping areas. Alarms must wake you up; it’s when we are asleep that we are most vulnerable.
Test regularlyMuch like smoke detectors and other security devices, it’s important to regularly test your carbon dioxide monitors throughout the house. Get into the habit of testing all your alarms on the same day each month.

CO Detectors vs Smoke Alarms: What’s the Difference?

Both carbon monoxide detectors and smoke alarms are essential devices that every home should have. As inexpensive as they are, they can mean the difference between life and death in the event of a CO leak or a fire.

In recent years, more and more alarm products are available that combine both, making it easier than ever for homeowners to simply and affordably protect themselves against fires and CO leaks.

How Do Smoke Alarms Work?

Smoke alarms detect smoke in one of two ways. Photoelectric detectors shine a light onto the alarm which sounds when smoke enters the chamber and obstructs the beam. Ionization detectors have an electrical current sent through the chamber, which also sounds an alarm when it is obstructed by smoke. 

Credit: AMRE Supply

How Do Carbon Monoxide Detectors Work?

Carbon monoxide detectors work via either a biomimetic sensor, an electrochemical sensor, or metal oxide semiconductor. Despite the names, each of these are fairly similar to one another.

The first is a sensor that monitors the color of a gel stored in the chamber. When CO is absorbed into the chamber, the gel changes color. The sensor detects this change and sounds the alarm.

An electrochemical sensor is similar in that it also sounds the alarm when something is altered by the presence of CO; a chemical solution, into which tiny electrodes are inserted. They sound the alarm when the solution changes due to carbon monoxide exposure.

Metal oxide semiconductors function like a circuit, which contains silica. Again, this chemical changes when exposed to carbon monoxide, causing the semiconductors to reduce or break the current and thereby sound the alarm.

Do I Need a CO Detector?

With such seemingly poor functionality, we wouldn’t be surprised if you were to ask, ‘do I actually need a carbon monoxide detector?’

While the study suggests that there’s some work to do in improving both education around carbon monoxide and the effectiveness of detector products, it is still essential that you have them in your home.

But stay on your P’s and Q’s; if you hear your carbon monoxide detector beeping, for example, it means it needs its battery replacing. If replacing the battery fails to stop the beeping, the product itself may be faulty.

As the old adage goes, half a loaf is better than none at all, and when the prize is the health and wellbeing of you and your family, it really isn’t worth the risk of going without. 

5 CO Detector Maintenance Tips

You’ll notice that many CO alarms available come with a 10 year guarantee. Follow these essential maintenance tips and you won’t be falling short of the decade promise.

1. Replace batteries

Dying batteries can significantly impact the effectiveness of any alarm system, not least of all a CO alarm. Replace batteries annually even if you don’t hear warning signs from the device itself, so that you can be sure it functions optimally.

2. Chamber hygiene

Since each of the three main types of CO alarm all function by having something in the chamber altered chemically by the presence of carbon monoxide, the chamber needs to be free of debris, dust, and dead bugs at all times to avoid false alarms. Wipe the inside gently when you replace batteries, while regular use of a damp cloth should suffice for the outside.

Credit: The Alberta New Home Warranty Program

3. Location, location, location

The evidence about ineffective carbon monoxide alarms, though not exactly the most reliable, is troubling. However, it does bring attention to the fact that they must be installed in appropriate places for them to work properly. Remember to place detectors at least 5 meters up the wall and as far from gas producing appliances as possible. Kitchen and sleeping areas are priorities. 

4. Test

Once you build the habit of testing all your alarm/detector devices on a regular basis, it no longer feels like a chore. Mounting them on a wall as opposed to the ceiling may help increase the likelihood of testing. By testing them weekly, you’ll greatly reduce the risk of false alarms and faulty products failing to sound in the event of a leak.

5. Replace detectors

Ultimately, if you suspect your detector is a faulty product, then do not let the need to replace it fall by the wayside. Do it immediately by consulting our top 3 carbon monoxide detectors list rather than delaying. Sure, it’s a nuisance, but thankfully carbon monoxide detectors can be quite inexpensive. Not to mention, you’ll be endlessly glad of it should an actual emergency occur.


What is carbon monoxide?

Carbon monoxide is produced when fuel doesn’t burn fully. This could be gas, oil, coal, or wood, among other things. Small amounts will be produced whenever something burns. It is poisonous, so an excessive amount can potentially kill you.

How far should the carbon monoxide detector be from the furnace/boiler?

Carbon monoxide detectors should be at least a meter from the boiler. CO rises, so it needs to be five feet off the ground.

Does carbon monoxide rise or stay low?

Carbon monoxide rises, so alarms must not be plugged into ground-level sockets.

How many carbon monoxide detectors do I need?

Ideally, a detector per room. In reality, of course, this is not only financially infeasible for most of us, but somewhat laborious. One alone will not cover the entire home, so having a few is wise. Prioritize sleeping areas and the kitchen, avoid bathrooms.

Are there different types of carbon monoxide detectors?

Yes. They all sound an alarm based on a change caused by carbon monoxide exposure, but work in one of three ways: through a biomimetic sensor, an electrochemical sensor, or a metal oxide semiconductor. 

A biometric sensor detects a color change on a piece of gel as it is exposed to carbon monoxide. 

An electrochemical sensor detects changes in the current of a chemical solution. 

Metal oxide semiconductors create a circuit, which contains silica. The silica changes when exposed to carbon monoxide, causing the semiconductors to reduce or break the current.

What to do if my CO alarm goes off?

If you hear your carbon monoxide detector go off, immediately turn off whatever gas appliances you might be using, snuff any candles, and quickly open all windows and doors. Then exit the property, evacuating children, animals, and the eldery first. 

What is the average level of carbon monoxide in homes?

According to the US Environmental Protection Agency, the average home without a gas cooker contains 0.5 to 5 parts per million (ppm). Those with gas stoves are 5 to 15 ppm, while those with poorly adjusted gas stoves could be higher than 30 ppm. 

Are CO alarms mandatory?


The only way to detect dangerous levels of carbon monoxide in the home is using a detector, and ensuring it is placed properly will enable it to work most effectively. Knowing where to put carbon monoxide detectors in the home can potentially mean the difference between life and death.