Under the Ontario Fire Code and the Hawkins-Gignac Act (O. Reg. 194/14), carbon monoxide alarms are mandatory on every floor and outside all bedroom areas in any home with gas heating, a fireplace, or an attached garage. Winter is peak risk season because furnaces run non-stop, windows stay sealed, and exterior exhaust pipes can get blocked by drifting snow. Testing the horn only confirms the battery works—it does not test the chemical sensor. By law and safety standards, all smoke and CO alarms must be replaced every 7 to 10 years based on the date stamped on the back.
Why Carbon Monoxide Emergencies Spike in Ontario Winters
Every year between November and March, fire departments across Ontario respond to hundreds of emergency calls for carbon monoxide poisoning. Emergency responders call carbon monoxide (CO) "the silent killer" for a good reason: you cannot see it, smell it, or taste it. It gives no warning before it starts making people sick.
When you breathe in carbon monoxide, it enters your bloodstream and binds to your red blood cells hundreds of times faster than oxygen does. It essentially starves your brain, heart, and body of oxygen. The early symptoms feel just like a winter flu—headaches, fatigue, nausea, and dizziness. Because people assume they are just catching a cold, they go to lie down in bed, which is when tragedy happens.
Winter brings three dangerous conditions together:
- Homes Are Sealed Tight: Windows and doors are shut all winter to keep the cold out. In a modern insulated home, there is very little fresh air leaking in to dilute gas. If a slow exhaust leak starts in your basement, the fumes have nowhere to go and quickly build up to dangerous levels.
- Heating Equipment Runs 24/7: Your gas furnace, tankless water heater, and gas fireplace are burning fuel all day and night during freezing weather. High workloads mean higher chances of mechanical wear and tear.
- Snow and Ice Block Outdoor Exhaust Vents: High-efficiency furnaces vent their exhaust through white PVC pipes that stick out of your home's exterior side wall. In heavy snowstorms or when wind drifts snow against the side of your house, those vent pipes can get buried. When exhaust cannot get out, toxic combustion fumes back up into your basement.
- Cracked Furnace Heat Exchangers: An aging furnace heat exchanger expands and contracts thousands of times every winter. Over 10 to 15 years, metal fatigue can cause hairline cracks. When the furnace fan blows, it can push carbon monoxide straight through your heating vents and into your bedrooms.
The Law in Ontario: What Does the Hawkins-Gignac Act Require?
Ontario has the strictest carbon monoxide laws in North America. It is called the Hawkins-Gignac Act (Ontario Regulation 194/14), and it became part of the Ontario Fire Code following a heartbreaking tragedy.
In December 2008, OPP Constable Laurie Hawkins, her husband Richard, and their two teenage children, Cassandra and Jordan, died in their home in Woodstock, Ontario. The exhaust chimney from their gas fireplace had become completely blocked. Toxic fumes accumulated in their house while they were asleep. At the time, carbon monoxide alarms were not mandatory under Ontario law. Laurie’s uncle, John Gignac, spent years advocating for change until the provincial government made CO detectors legally mandatory in every home.
Under the Ontario Fire Code, if your home has any fuel-burning appliance (gas furnace, water heater, gas stove, fireplace) or an attached garage, you legally must have an approved carbon monoxide alarm:
• On every level of your home, including basements.
• Directly outside all sleeping areas, close enough to wake people through closed bedroom doors.
Failing to comply can result in fines up to $50,000 for homeowners and up to $100,000 for landlords.
The 10-Year Expiry Reality: Why Pushing the Test Button Can Trick You
Here is the most dangerous misunderstanding in home safety: "I pressed the button on my alarm, it beeped loudly, so I know my family is protected."
The test button only checks whether the battery is connected, the electronic chip works, and the horn makes sound. It does not test whether the chemical sensor inside can still detect carbon monoxide gas.
Inside every CO detector is an electrochemical sensor containing a special chemical solution and metal catalysts (like platinum). When carbon monoxide hits the sensor, a chemical reaction creates a tiny electrical current that triggers the alarm.
Over 7 to 10 years, that chemical solution naturally dries out, and airborne cooking oils, household cleaners, and dust oxidize the sensor. The sensor goes chemically deaf. The alarm will still beep loudly when you press the test button, but it will sit completely silent if real carbon monoxide fills your house.
What you should do today: Unclip every alarm in your house from the ceiling. Look at the sticker on the back. Find the manufacture date. If that date is more than 10 years old (or 7 years on older models), that alarm has expired. Replace it immediately.
Photoelectric vs. Ionization: What Type of Smoke Sensor Should You Buy?
When you replace your old alarms, make sure you choose the right sensor technology. Not all smoke detectors work the same way:
| Feature | Photoelectric Smoke Sensor (Recommended) | Ionization Smoke Sensor (Older Style) |
|---|---|---|
| How it Detects Smoke | Uses an optical light beam. When smoke particles scatter the light, it triggers the alarm. | Uses a tiny amount of radioactive material to electrically charge air inside a chamber. |
| Best Fire Protection | Smoldering, slow fires: Electrical shorts in walls, overheated furnace wiring, space heaters burning drapes. Responds up to 30 minutes faster to smoldering smoke. | Fast, open flaming fires: Quick paper or grease fires. Slower to detect heavy smoldering smoke. |
| False Nuisance Alarms | Very rare: Ignores cooking steam, boiling water, and bathroom humidity. | Frequent: Constant false alarms from toasting bread or opening the oven door, leading people to yank the battery out. |
| Recommended Use | The modern standard for hallway and bedroom safety in Canadian homes. | Legacy technology; generally being phased out by fire services. |
Why Hardwired Interconnected Alarms Save Lives in Two-Storey Homes
Under the Ontario Building Code, modern homes must have hardwired, interconnected alarms.
Here is why interconnectivity matters: imagine a typical two-storey house in Vaughan, Oakville, or Ottawa. Your gas furnace and water heater are in the basement. Your family is asleep on the second floor with the bedroom doors closed.
If a heating fire or CO leak starts in the basement utility room at 2:00 AM, a standalone battery alarm in the basement will go off at 85 decibels. But by the time that sound travels up two flights of stairs, through insulated subfloors, and through a closed wooden bedroom door, the sound level drops down to around 30 decibels. That is no louder than a quiet whisper. A sleeping child or deep sleeper will sleep right through it.
With interconnected alarms, when the basement unit detects trouble, it instantly sends an electrical signal through the red interconnect wire to every other alarm in the house. The alarm right outside your bedroom door screams at full volume at the exact same second. Your family gets minutes of warning instead of seconds.
Kidde Alarm Comparison: Which One Fits Your House?
Kidde 120V LED Strobe & Talking Combo
Kidde DETECT 10-Year Battery Smoke & CO
Your Ontario Winter Furnace Safety Checklist
Keep this routine every winter to keep your heating equipment safe and reliable:
- Check Outdoor Vent Pipes After Every Snowstorm: Walk outside to the side of your house where the white PVC pipes exit. Shovel snow back at least 3 feet so the pipes have clear access to fresh air. Knock down any large icicles hanging directly above the vents.
- Test Alarms on the 1st of Every Month: Press and hold the test button on each floor until you hear the spoken voice and beep. Make sure all interconnected alarms sound together.
- Vacuum Dust Once Every 6 Months: Run a soft vacuum brush attachment over the outside vents of your ceiling alarms to clear away household dust and cobwebs that can cause false optical sensor triggers.
- Book an Annual Furnace Maintenance Check: Have a licensed TSSA gas technician inspect your furnace heat exchanger for hairline cracks, check the flue draft, and clean the burner assemblies before deep winter arrives.
Frequently Asked Questions
Where should carbon monoxide alarms be mounted—high or low?
There is an old myth that carbon monoxide hugs the floor because it is heavy. In physics and chemistry, carbon monoxide has almost the exact same density as air (molecular weight of 28 compared to air's 29). It mixes evenly throughout room air. If you are installing a combination smoke/CO alarm, it must be mounted on the ceiling or high on a wall because smoke rises rapidly with heat. If you use a standalone plug-in CO alarm, it works fine plugged into an outlet at knee or waist height, as long as it is not hidden behind a sofa or heavy curtain.
What should I do immediately if my CO alarm goes off?
Do not open windows to air the house out, and do not waste time searching for where the leak is coming from. Taking deep breaths inside the house increases how much poison enters your bloodstream. Immediately get all family members and pets outside into fresh air. Once outside, call 911 immediately. Stay outside until the fire department arrives with calibrated air-testing equipment and tells you it is safe to go back in.
Why does my alarm chirp once every 30 to 60 seconds?
A single chirp every minute usually means one of two things: a low backup battery, or the unit has reached its 10-year expiration date. On modern 10-year alarms, the internal chip counts the days; once it reaches its operational lifespan, it chirps continuously to force you to replace it. Replacing the battery will not silence an expired alarm; the entire unit must be replaced.
Can I replace an old hardwired smoke alarm with a combination smoke and CO unit?
Yes. Modern Kidde combination alarms (like the Model 30CUA10) are specifically designed to plug directly into existing 120V ceiling electrical boxes and communicate through the existing interconnect wire. You can swap out an old builder smoke detector for a dual smoke/CO detector in about 5 minutes with a screwdriver.