Carbon Monoxide: The Invisible Danger of Old Commercial Heating Systems (and How to Protect Yourself)

Outdated systems, an invisible threat: why old commercial heating units must be inspected without delay

In the world of commercial heating, a silent and deadly enemy too often lurks unnoticed by building owners or property managers: carbon monoxide (CO). This odorless, colorless, and tasteless gas can quickly accumulate in enclosed spaces when heating equipment is no longer operating efficiently. At AirGreen, we frequently respond to calls in Montréal, Laval, Longueuil, as well as on the North Shore and South Shore, to resolve issues related to outdated heating systems in commercial buildings. These service calls often uncover risks our clients had no idea existed.

Understanding the danger of carbon monoxide in heating systems

Carbon monoxide is produced by the incomplete combustion of fossil fuels such as natural gas, oil, or propane. In older, poorly maintained, or improperly installed commercial heating systems, this combustion often becomes inefficient. A cracked heat exchanger or a blocked exhaust duct is all it takes to let CO seep back into the building, endangering the health and lives of its occupants.

Health effects of carbon monoxide

The effects of CO exposure vary depending on concentration and length of exposure:

• Low levels: headaches, nausea, fatigue

• Moderate exposure: dizziness, confusion, blurred vision

• High exposure: loss of consciousness, brain damage, and even death

In a commercial setting, this can lead to serious consequences: sick employees, forced closures, mandatory inspections, and even legal action if safety was not ensured.

Real case: a service call in Laval avoids disaster

During a recent maintenance visit to a restaurant in Laval, our team detected elevated carbon monoxide levels in the oven room, caused by a gas heating system over 25 years old. The exhaust duct showed advanced corrosion and was allowing CO to backflow into occupied spaces. Thanks to our rapid intervention, which included:

• a full system inspection,

• the immediate shutdown of the defective unit,

• temporary installation of electric heating systems,

• and the complete replacement of the old system with a high-efficiency gas unit with sealed combustion and proper ventilation,

we were able to prevent a disaster and bring the space back up to safety standards.

How to know if your system is at risk?

Here are some warning signs we often find during our inspections:

• Presence of black soot around vents or on the unit itself

• Heating unit that shuts off frequently without clear reason

• Strange odors or poor air circulation

• Equipment that is over 15–20 years old

• No working CO detectors installed in the building

In all these cases, we strongly recommend a comprehensive HVAC inspection, including combustion gas analysis, duct integrity check, and a full energy efficiency assessment.

AirGreen solutions: prevention and modernization

At AirGreen, we go far beyond basic repairs. We offer complete and preventive solutions to make sure carbon monoxide never becomes a threat in your facility.

Steps in our professional approach:

1. Specialized HVAC inspection: includes carbon monoxide tests, thermal inspection of heat exchangers, airflow analysis

2. Tailored advice: equipment upgrades or replacements based on your needs, budget, and commercial reality

3. Installation of modern systems: sealed combustion units, controlled mechanical ventilation, integration of smart CO detectors

4. Ongoing maintenance: preventive care plans to ensure your building remains safe year-round

Why are old units so dangerous?

Older heating systems, especially those with atmospheric combustion, don’t meet today’s safety standards. Their design can sometimes allow combustion gases to remain partially in the heated space, especially in buildings with negative pressure or poorly designed ductwork.

Add to this:

• Lack of proper ventilation in older buildings

• Build-up of combustion residues

• Natural wear and tear of internal components

A precise diagnosis from our technicians can prevent carbon monoxide poisoning and improve your building’s energy efficiency.

Securing your building: what AirGreen recommends

We strongly encourage all our commercial clients to:

• install carbon monoxide detectors on every floor

• have all heating systems inspected annually, especially in the fall

• plan for replacement of equipment older than 15 years

• consider rebalancing or recalibrating your ventilation system if renovations were done recently

System upgrades: an opportunity to seize

Did you know there are several grants available to help upgrade commercial heating systems in Greater Montréal? With our expertise, we help clients benefit from:

• Hydro-Québec’s LogisVert Program

• Grants from Transition énergétique Québec

• And municipal assistance available in specific boroughs of Montréal, Laval, Longueuil, the North Shore and South Shore

Our experts support you from grant application through to safe, compliant installation.

AirGreen expertise: a safety standard you can count on

By choosing AirGreen, you’re working with a certified HVAC team of professionals, specialized in commercial building safety. Every service call is documented, tracked, and certified according to the highest standards. Our top priority is to ensure your comfort, code compliance, and building safety, while also boosting your energy efficiency.