Carbon Monoxide: A Silent Killer in Your Home

When the alarm goes off, you get up nauseous, groggy and with a mean headache – “Oh no,” you think. “Another round of the flu? That’s winter in Edmonton for you.” With no fever, you drag yourself to work to finish off a few things, suspecting you’ll probably be out sick for the next few days.

Unknowingly and somewhat ironically, your work ethic probably just saved your life.

After midday, you’re feeling better though the headache remains.  Dr. Google informs you that its likely not the flu, but Carbon Monoxide poisoning.  Could be fatal it says.  Don’t go home – hit the hospital and call the fire department from there.  This is serious business.

At the hospital, you’re given tight-seal 100% oxygen, kept overnight and released the next morning.  At your meeting with local fire officials, you learn that a cracked heat exchanger in your natural gas furnace was the culprit.  It had been leaking CO at low levels – less than 35 PPM – for the past year from the looks of it.  As the damage worsened, so did the CO levels in your home.  You’d meant to have it looked at in the fall, but figured that you’d save the extra $200 toward Christmas presents instead of the furnace guy.

Carbon monoxide, also known as CO, is called the silent killer.  As we know, laws in Ontario changed in 2014 to make it mandatory for CO detectors to be present in homes with certain kinds of appliances.  Let’s take a closer look at the hows and whys of this legal situation, what it means for Alberta, and what you can do to protect yourself.

What is Carbon Monoxide?

Let’s define the basics first.

Carbon monoxide or CO is a colourless, odourless, poisonous gas by-product that is produced by incomplete combustion (burning) of fossil fuels. Carbon monoxide is the same weight as air and disperses evenly throughout a closed room.

Carbon dioxide or CO2 is a colorless, odorless gas that is critical for the functioning of plants on earth.  Carbon dioxide occurs naturally through breathing.  While it is a key factor in climate change, low concentrations are not harmful and a high concentration can displace oxygen in the air.  It is non-carcinogenic, not poisonous, and poses very little threat to a person’s health.  Carbon dioxide is heavier than air and therefore sinks to the lowest level in a closed room.

Back to Carbon MONoxide

It is odourless and tasteless.  Contrary to popular opinion, carbon monoxide has a mass almost equivalent to air and therefore disperses evenly throughout a room.  In the past, pets and small children have been shown to be more susceptible to CO poisoning but – myth busted! – it’s because of their smaller size and physiology NOT because CO is heavier than air and sinks to the floor.

How Does Carbon Monoxide Occur

The easiest way to explain carbon monoxide is that when you burn a fossil fuel, the by-product of that burning should be carbon dioxide.  However, in an environment with limited oxygen, the burning process forms molecules that have one carbon and one oxygen (CO – deadly) instead of one carbon and two oxygen (CO2 – no problem).

For this reason, CO as a byproduct of burning fossil fuels is known as ‘incomplete combustion’. With any of the following list of devices, there is a risk that without enough oxygen to make CO2, carbon monoxide could be accumulating in a confined area near the appliance.  When these devices are properly installed, maintained and vented, the CO produced can be prevented from reaching unsafe levels in the home.

  •         Natural gas furnace
  •         Natural gas space heater
  •         Natural gas boiler
  •         Natural gas water heater
  •         Natural gas cooktop
  •         Natural gas oven
  •         Natural gas fireplace
  •         Natural gas dryer
  •         Propane, natural gas, or charcoal BBQ
  •         Woodstove
  •         Wood burning fireplace (closed flue/dirty chimney)
  •         Gasoline car
  •         Gasoline lawn tractor or lawn mower
  •         Gasoline generator

Note that there are no ‘electric’ devices on the list.  Without the action of burning, carbon monoxide is not a risk factor in ordinary circumstances.

Also note that smoking cigarettes contributes to higher blood levels of carbon monoxide.  More about this later.

What is Carbon Monoxide Poisoning

Carbon monoxide poisoning is two-fold.  This lethal gas is poisonous in itself, but also fools the body into trying to use it as the air we breathe.  Carbon monoxide quite literally displaces oxygen in our lungs, blood, brain, and organs, damaging them almost immediately.


Symptoms of carbon monoxide poisoning fall into two categories, acute (immediate and obvious signs of poisoning) and chronic or subacute poisoning (low levels of poisoning) that over time may lead to additional health risks.

Acute symptoms

  • Chest tightness
  • Headache
  • Fatigue
  • Dizziness
  • Drowsiness
  • Nausea
  • Nausea
  • Vomiting
  • Collapse
  • Sudden chest pain in people with angina

** CO poisoning poses additional health risks to fetuses.

CO poisoning and related symptoms may occur sooner in people who are more susceptible – as you can imagine, those are infants, children, elderly people, people with lung or heart conditions, people living at high altitudes, and smokers (who already have elevated blood levels of carbon monoxide)

If caught in time, CO poisoning can be reversed but you may experience permanent damage to the parts of your body that require lots of oxygen – namely your heart and your brain.  CO poisoning also affects reproductive health.

How Can I Protect my Family From Carbon Monoxide?

Protecting your family from CO poisoning comes down to a solid maintenance plan, and routine care of both your detectors and your appliances.

  • Ensure you have working CO detectors throughout your home; replace them as per the manufacturer’s directions (approximately every 5-8 years).
  • Make sure to service all combustion appliances and vehicles regularly.
  • If the CO alarm sounds, gather everyone in your home and leave immediately.  Call emergency services from a safe location outside the home.  Do not allow anyone back into the home until it has been given the all-clear by emergency personnel.
  • Administer cardiopulmonary resuscitation if the victim has stopped breathing.

Best CO Alarms for Homeowners

Carbon monoxide alarms monitor the airborne concentration levels of CO in parts per million (PPM).  Most detectors are designed to sound an alarm when harmful levels are present both at low concentrations over time as well as at high concentrations over a short period of time.

CO detectors range in price from approximately $30 to over $100 depending on the features that the unit is equipped with (battery backup, hardwiring, digital display, wireless or Bluetooth messaging).  The units are priced to be within the range of affordability for homeowners.  The average plug-in unit with battery backup is approximately $40 and is widely available at chain retail and hardware stores.


Rescuers who attend a CO alarm call should be aware that they may be exposed to fatal levels of CO poisoning in the course of a rescue attempt.  Rescuers need to be skilled at performing recovery operations using necessary equipment.  Employers should make sure that rescuers are not exposed to dangerous CO levels while performing rescue operations.

Ontario’s CO Detector Law

I know – we’re from Edmonton…why be concerned about Ontario’s home and builder rules and regulations?  Simple.  If one province raises the bar, it’s only a matter of time before the other provinces follow suit and match the regulation with one of their own.  As well, laws are actually the ‘best practice’ of what to do in a particular situation – so knowing the best practice, why wouldn’t you do it?

The newest version of the CO Detector Law in Ontario now makes it mandatory to have one – or maybe a few – CO Detectors installed in your home.

Ontario’s law classifies ‘high-risk’ homes as homes that have at least one combustion appliance as we talked about before – the law is clear that high-risk also means having an attached garage.  The law, passed in October of 2014, gave a grace period of 6 months for every homeowner to install the necessary number of CO detectors in proper locations throughout their home.  Beginning in May of 2015, some municipalities in Ontario will send crews door-to-door to check on the installation and to advise or fine where appropriate.  Fines range from $360 to $50,000.

Condominiums, townhomes, and apartments have until October 2015 to install CO detectors in every unit.  In most instances, the property owner bears the responsibility of installation and upkeep of the detector, however, when condos are independently owned, this responsibility might be negotiated between the owners and the condominium board.

All newly construction residential buildings that contain a fuel-burning appliance or a storage garage require CO alarms(s) installed at any height, as carbon monoxide disperses evenly through a room.  However, if a combination smoke-carbon monoxide alarm is installed, it needs to be near the ceiling as per manufacturer’s instructions so that it can detect smoke as well.

Until recently, there have been no provincial regulations for CO alarms in homes constructed prior to 2001, however municiapalities have been tightening regulations through by-laws.

Ontario law is now very clear about all the types of residential buildings that CO alarms must be installed in.  The following is a list of examples, however there may be more types of buildings that fall within the regulations:

  • Single family dwellings, semi-detached, townhomes, row housing
  • Multi-level apartments and multi-level condominiums with communal entry
  • Multi-level apartments and multi-level condominiums with private entries
  • Hostels
  • Social housing
  • Student residences
  • Dormitories
  • Retirement homes
  • Camps
  • Convents and Monasteries
  • Residential clubs
  • Hotels and Motels
  • Residential schools
  • Shelters for vulnerable persons
  • Detention facilities
  • Some trailers and RVs

If there are no combustible heat sources as outlined in the first portion of the article, and no attached garage, CO alarm installation regulations do not apply.  For this purpose, carports are not considered to be garages.

Finally, the minimum requirement for CO alarms in a residential dwelling is that they must be positioned adjacent to each sleeping area.  This phrase has caused some confusion because it means a different placement in almost every residence.  For clarity, the law outlines that a CO alarm must be located within 5 meters of every place that someone sleeps.  This requirement may or may not be met with one CO alarm, or by placement between rooms.  More alarms may be required.  It is up to each individual homeowner in consultation with their local fire officials if required, to determine the ideal placement.

Best Practices for Albertans

I know this has been a fairly lengthy article – I did go looking for clear resources that we here in Alberta can use, and didn’t find what I was looking for, so I decided to create it here for our customers and readers.

Looking at Ontario’s laws make it clear that Albertans only stand to gain by following the standard that has been set forth there.  The best way to take advantage of that information is for every Edmonton homeowner to do the following:

  • Buy a CO alarm – in fact buy two.
  • Place one adjacent to the sleeping areas in the house
  • Place the other one on the main level of the house
  • Take careful inventory of how your combustible appliances are functioning – should they be serviced?  Make a plan now.
  • Contact your landlord to see about CO alarm installation.
  • Test the alarm annually – replace batteries twice a year.
  • Replace the unit itself according to the manufacturer’s guidelines

As we move away from one of the harshest winters that we’ve had in years, many of us are all too eager to turn on the AC and forget the furnace, generator, and hot water heat – but now is the best time to plan and maintain these devices so that next autumn brings no surprises.

For more information about hardwiring options for CO detectors or for our thoughts on the latest technology in CO detectors like this one from Nest, contact Select Security at (780)451-8067 or email us at

Stay safe and healthy!

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