Do you smell damp every time your heating system starts up? Has your family been coughing more often in recent weeks? These signals may seem harmless, but they may be hiding a serious problem in your ventilation ducts.
Mold in air ducts is more common than you might think in Montreal. According to the Institut national de santé publique du Québec (INSPQ), about a third of Montreal households are affected by mold problems at one time or another. And with our climate - humid summers, harsh winters, heavy rainfall - our ventilation systems become perfect environments for fungal proliferation.
The real question isn't whether you'll ever get mold. It's when you should take action.
At Vortex Air, we've been helping Montreal families breathe easy for over 10 years. We know the signs, we understand the risks, and most importantly, we know exactly when intervention becomes necessary. In this guide, we'll show you how to recognize the warning signs and make the right decisions to protect your indoor air.
Request your free inspection today - we come to your home, assess your pipes at no cost or obligation, and tell you exactly where you stand.
Why mold in air ducts is a real risk to your health
Mold isn't just an aesthetic problem. It's a public health issue that directly affects the quality of the air you breathe 24 hours a day.
When contaminated, your ventilation ducts become highways for spores. Every time your furnace starts up or your air conditioner runs, these microscopic particles are dispersed throughout your home.
The problem in Montreal is that we combine several aggravating factors. Our climate, with its extreme variations, creates condensation in the systems. Our long winters force us to keep houses closed for months on end. And our intense rainfall episodes - like those of July 2025 - cause water infiltration and backflow.
Local causes: humidity, flooding and poorly maintained systems
In Montreal, certain neighborhoods are particularly vulnerable. Ahuntsic, Rivière-des-Prairies and many parts of Laval have clay soils that retain moisture. If you live in these areas, your basement ducts are exposed to more ambient humidity.
Recent floods have made the situation even worse. After the events of July 2025, La Presse reported a 30% increase in mold cases in affected homes. Water seeped into basements, climbed walls and contaminated ventilation systems.
But even without major flooding, moisture builds up naturally. A poorly maintained air exchanger, a blocked condensation drain, or simply a damp basement - all create the perfect conditions for mold.
Poorly maintained systems are another major cause. If your ducts have never been cleaned since your home was installed, dust, debris and moisture form a layer where mold and mildew grow easily.
Effects on health and family comfort
Mould spores irritate the respiratory tract - this has been documented by the INSPQ for years. For asthma sufferers, it's even worse. Continued exposure can trigger attacks, worsen symptoms and require more medication.
Children are particularly sensitive. Their developing respiratory systems react more strongly to airborne contaminants. If your child coughs at night, wakes up congested, or misses school because of recurring respiratory problems, your ducts deserve an inspection.
But even healthy adults feel the effects. Chronic fatigue, frequent headaches, eye irritation - these vague symptoms we attribute to stress or lack of sleep sometimes come from the air we breathe.
And the smells? That damp basement smell rising in the house is not normal. It's a direct sign that something is developing in your ventilation system.
Have your air quality assessed by a certified expert. At Vortex Air, our INVC technicians use endoscopic cameras to see exactly what's going on in your ducts. You deserve to know what your family is breathing.
Signs that it's time to remove mold from your ducts
Recognizing the warning signs is the first step in protecting your family. Here are three categories of signs to watch out for.
Musty odor and visible stains
Smell is often the first indicator. If you smell musty when your ventilation system is running, there's something growing in there. That characteristic damp basement or old wet laundry smell comes directly from the volatile organic compounds (VOCs) that mold releases.
Visible stains around the ventilation grilles are another clear signal. Black, green or brownish marks on the edges of the grilles are not normal dust. It's mold overflowing the system.
If you've had a disaster recently - sewer backup, water infiltration, basement flooding - consider that your ducts are probably contaminated. Water always finds its way in, and your ventilation ducts are easy entry points.
A chronically damp basement is also a major risk factor. If you have traces of condensation on your ducts, beading water droplets, or high ambient humidity, your ducts are creating an environment conducive to mold.
Recurring symptoms in occupants
Your body is talking to you. If several people in the house develop similar symptoms that improve when you leave the house, it's a strong signal.
A persistent cough that doesn't respond to the usual treatments is suspect. Especially if it gets worse at night or early in the morning when the heating system starts up again.
Unexplained fatigue is part of the picture. Mycotoxins produced by certain molds affect your energy and concentration. Do you wake up tired even after a good night's sleep? Check your air.
Seasonal allergies that become chronic or persist into winter should raise a red flag. If antihistamines help temporarily but symptoms keep coming back, the problem may be inside your home.
Recommended technical checks (RBQ 15.7 / CMMTQ)
Quebec has professional standards for ventilation system maintenance. The Régie du bâtiment (RBQ) regulates these interventions under articles 15.7 and 15.8. The Corporation des maîtres mécaniciens en tuyauterie du Québec (CMMTQ) recommends regular inspections.
Endoscopic camera inspection is the most reliable way to see what's really going on in your pipes. This technology allows you to see inside without having to dismantle the entire system. You see exactly where the problems are.
HEPA (High Efficiency Particulate Air) cleaning is the industry standard. These filters capture 99.97% of 0.3 micron particles - including mold spores. It's this level of filtration that ensures contaminants are captured, not just displaced.
INVC and NADCA certifications are your guarantee of professionalism. A company that is a member of the National Institute of Ventilation and Air Conditioning (INVC) follows strict protocols. NADCA (National Air Duct Cleaners Association) certification adds an extra layer of training and standards.
48 h post-flooding checklist (according to GouvernementQC)
The Quebec government is clear in its Flood 2025 leaflet: act fast.
Within the first 48 hours:
- Dry all affected areas completely
- Remove contaminated porous materials
- Start ventilation and dehumidification
- Have your ventilation ducts inspected
This is the critical period. After 48 hours, mold begins to colonize. Once they've taken hold, removal becomes much more complex and costly.
Need help after a flood? See our complete guide to air duct decontamination after flooding in Montreal for full details of the process.
How often should you have your air ducts cleaned or decontaminated in Montreal?
There's a difference between regular preventive maintenance and emergency intervention. Understanding this distinction helps you plan properly.
General recommendations (3-5 years) and special cases
For a typical home in Montreal, preventive duct cleaning should be done every 3 to 5 years, according to the CMMTQ. That's enough to maintain good air quality under normal conditions.
But here's the reality: according to our data at Vortex Air, 25% of the homeowners we meet have never had their ducts cleaned in over 5 years. Some have never had it done since they bought their home.
If you have pets, shorten this interval. Hair, scales and dander quickly accumulate in the ducts. 2-3 years is more appropriate.
People with allergies or asthma also benefit from more frequent cleaning. At least every 2 years - your respiratory system will thank you.
Smokers (even those who smoke outside) should consider a cleaning every 2-3 years. Smoke still seeps in, leaves residues in the ducts, and these residues retain moisture more easily, promoting mold growth.
If you've just bought a house, have the ducts inspected and cleaned in the first few months. You don't know when it was last done, and it's an investment in your health right from the start.
After water damage: intervention within 48 hours
We're not talking about preventive maintenance here - we're talking about emergency maintenance. After any significant exposure to water, your pipes need to be inspected and decontaminated quickly.
The Quebec government's Flood 2025 leaflet is categorical: 48 hours maximum. That's how long you can still prevent major mold growth.
Insurance companies like Desjardins, Intact and La Capitale now require proof of professional decontamination to cover future claims. If you neglect this step, you risk having your next claim denied.
We're not just talking about major flooding. Even a minor sewer backup contaminates your pipes. A water heater leak in the basement, no matter how quickly you dry it out, leaves residual moisture that causes problems.
Fall and spring are the best seasons for preventive cleaning in Montreal. In autumn, before the heating goes on full blast for the winter. In spring, after thaws that can cause infiltration.
Plan your Fall 2025 preventive cleaning with Vortex Air. We offer flexible hours 7 days a week, and our prices are transparent all year round. No «high season» surcharges - just honest service.
Facts and myths about mold in air ducts (don't ignore)
There's a lot of conflicting information out there about mold and duct maintenance. Let's separate the true from the false.
MYTH: «My filters are clean, so my ducts are clean».»
False. Filters catch dust that enters the system. They do nothing for what's already growing INSIDE the ducts. A house with filters religiously changed every month can still have ducts full of mold.
TRUTH: Odor + symptoms = time for action
If you smell musty and your family develops respiratory symptoms, it's no coincidence. These two signals together almost always indicate contamination that requires professional intervention.
MYTH: «I can clean my own ducts».»
Not only is it inadvisable, it's also dangerous. Without HEPA equipment, you disperse spores throughout the house. Without training, you'll miss contaminated areas. And in Quebec, for post-disaster decontamination, your insurance requires an RBQ-certified professional.
TRUTH: 48 hours post-flood maximum
This is the scientifically established time limit. After 48 hours of exposure to water or high humidity, spores begin to colonize rapidly. Every hour counts.
MYTH: «All mold is toxic».»
It's more nuanced. All molds produce allergens and irritants. Some also produce dangerous mycotoxins. But even «non-toxic» molds cause respiratory problems and allergies. No mold in your ducts is acceptable.
TRUTH: HEPA cleaning is recommended by the industry
The NADCA and INVC standards specify the use of HEPA filtration for decontamination. It's not a luxury - it's the minimum standard to ensure that contaminants are actually captured.
GREY ZONE: The ideal frequency varies according to your situation
Between 2 and 5 years, it really depends on your risk factors. Pets, allergies, smoke, humidity in the basement, age of the system - these all influence the optimum frequency. An inspection allows you to customize your schedule.
GREY ZONE: Visible mold is not the only indicator
You can have significant contamination without ever seeing mold. It grows in dark, inaccessible areas of your ductwork. Smell and symptoms are often more reliable indicators than visual inspection.
Download our free checklist «Signs of mold in your ducts».» - a handy PDF guide that lists all the warning signs to look out for. It's free, in French, and easy to print for your fridge.
How the pros at Vortex Air remove mold - step by step
Transparency is important to us. Here's exactly how we proceed when we decontaminate mold-contaminated ducts.
Free inspection and photo report (endoscopic camera)
We always start by looking. Our endoscopic cameras enable us to inspect the inside of your pipes without having to dismantle everything.
You're right there with us during the inspection. We show you the images in real time on our screen. If we see mold, debris or condensation, you see it too. No mystery, no fear mongering.
We take photos before the procedure. These images serve as proof for your insurance in the event of a claim. And they allow us to show you the results after cleaning - you can see the tangible difference.
The inspection report we give you includes our honest recommendations. If your ducts need a complete cleaning, we tell you. If only certain sections are problematic, we'll tell you that too. We never recommend unnecessary services.
This inspection is completely free and without obligation. You then decide whether or not to proceed. No pressure, no aggressive follow-up calls.
Suction-pulse cleaning and HEPA filtration
If you decide to go ahead, we use the SFP (suction-pulse) method with HEPA filtration. It's the industry standard for a reason - it works.
We create negative pressure in your ducts. This means the air is drawn into our equipment, not pushed into your home. Any contaminants we dislodge are immediately captured by our HEPA filters.
Each section of duct is mechanically brushed. Rotary brushes are used to dislodge build-up stuck to the walls. It's not just vacuuming - it's a thorough cleaning of every inch.
For mold, we then apply a Health Canada-approved disinfectant with DIN number. A fogging technique is used to ensure complete coverage of all interior surfaces. This product eliminates remaining spores and prevents recolonization.
Complete drying is the final step, often overlooked by other companies. We make sure your ducts are completely dry before closing the system. Residual moisture opens the door to new contamination.
The entire process complies with safety protocols. We protect your floors, seal off work areas, and clean up after ourselves. You'll find your home in the same condition - just with much cleaner air.
Final verification + INVC/NADCA report
After cleaning, we do a full inspection again with the camera. You see the results: clean ducts, no debris, no visible mold.
The final report you receive documents the entire process. It includes..:
- Before and after photos
- Treated areas
- Products used (with DIN numbers)
- Date and duration of intervention
- The signature of our INVC-certified technician
This report is your proof for insurance, for your property file, and for your peace of mind.
We guarantee our work. If you have any concerns within a few weeks of the job, we'll come back and check it out at no charge. Our reputation is built on your satisfaction - we take that seriously.
At Vortex Air, we are INVC certified and in the process of obtaining our NADCA certification. These certifications guarantee that we follow industry best practices. We continually invest in training our 5+ technicians because your safety deserves it.
We've served over 500 customers in the Greater Montreal area - from Brossard to Laval, from Ahuntsic to Saint-Laurent. Families like yours who just wanted to breathe easier in their own homes.
Why choose Vortex Air for duct decontamination in Montreal?
There are many duct cleaning companies in Montreal. Here's what sets us apart.
Local expertise, 10 years' experience
We know Montreal. We know that houses in Rosemont face different challenges than condos in Brossard. We understand the impact of spring flooding in Rivière-des-Prairies and the persistent humidity in Ahuntsic basements.
Mohamed and Omar, our owners, are involved in every project. This isn't an impersonal franchise - it's a family business where the leaders work in the field. You talk directly to the decision-makers.
Our team of technicians lives here. We know Quebec building codes, RBQ requirements, and the specifics of our local ventilation systems. This expertise makes all the difference in the quality of the result.
We have over 10 years of combined experience in the air quality industry. We've seen it all - from minor contamination to major post-disaster decontamination. This experience allows us to advise you with confidence.
24/7 transparent, human service
At Vortex Air, you're never just a file number. We take the time to listen to you, understand your concerns, and answer all your questions.
Our approach is pressure-free. We present you with the facts, show you the condition of your pipes, and let you decide. You never feel we're trying to sell you something you don't need.
Prices are transparent from the start. No hidden charges that magically appear at the end. The quote we give you is the final price. Period.
We're available 7 days a week, from 7 a.m. to 9 p.m., with a 24/7 emergency hotline. Air quality problems don't wait for Monday morning. When you need help, we answer.
Personalized follow-up continues after the procedure. We call you to make sure everything is going well. We're available to answer your questions. And we help you plan future preventive maintenance.
Health commitment: improving family IAQ
For us, it's not just a job. It's a mission.
We believe that every family deserves to breathe healthy air in their own home. That's why we put so much effort into every project, no matter how big or small.
Protecting your family is important to us. When we work for you, we think of our own children, our own parents. This human perspective guides all our decisions.
Prevention is at the heart of our approach. We educate you about preventive maintenance, give you practical tips for maintaining good air quality, and help you avoid future problems.
And beyond respiratory health, we also contribute to fire safety with our dryer vent cleaning service. It's just one more way we protect Montreal families.
Call now for a free inspection: 514-214-7492 - Available 24/7. Or visit vortexair.ca to book online. We promise: honesty, transparency and impeccable service.
FAQ - Everything you need to know about mold and air ducts in Montreal
How do I know if I have mold in my ducts?
The main indicators are: a musty smell when the system is running, visible stains around the grilles, worsening respiratory symptoms in the home, or a history of water exposure. The only way to be sure is an endoscopic camera inspection. At Vortex Air, this inspection is free of charge.
How much does professional cleaning cost?
For complete decontamination with mold removal, expect to pay between 800 $ and 3,500 $ depending on the size of your system and the level of contamination. It's an investment in your health, and it's often covered by home insurance if you've had a claim. We always offer a free, detailed estimate before we begin.
Do I have to clean up after every flood?
Yes, absolutely. Even a minor flood or sewer backup can contaminate your pipes. The Quebec government recommends action within 48 hours. It's also a requirement of most insurance companies to maintain your coverage.
What's the difference between cleaning and decontamination?
Regular cleaning removes normal dust and debris. Decontamination goes further - removing mold, bacteria and biological contaminants with specialized disinfectants approved by Health Canada. After a flood or in the presence of mold, you need complete decontamination.
Can I do the cleaning myself?
This is strongly discouraged, especially in the presence of mold. Without professional HEPA equipment, you risk dispersing spores throughout the house. In Quebec, for post-disaster decontamination, your insurance requires a report from an RBQ-certified company. DIY may invalidate your coverage.
Is it covered by insurance?
In most cases, yes, if the contamination is the result of a covered loss (flood, backflow, water damage). But you must use a certified company and keep all reports and invoices. Check your policy - some insurances require preventive decontamination after certain events to maintain your coverage.
Which certifications to check?
In Quebec, an RBQ license is required for this type of work. INVC (Institut National de Ventilation et de Climatisation) and NADCA (National Air Duct Cleaners Association) certifications are indicators of professionalism and ongoing training. Always ask to see these certifications before hiring a company.
Which neighborhoods are most at risk?
In Montreal, Ahuntsic, Rivière-des-Prairies, certain sectors of Rosemont and several areas of Laval are particularly vulnerable due to soil composition and flood zones. Homes with finished basements near watercourses are also at high risk. But honestly, with our humid climate, any neighborhood can be affected.
What's the best time to do it?
Autumn is perfect - you clean up before the heating goes on full blast all winter long. Spring is also good, after the thaws that can cause infiltration. But if you detect signs of mold, don't wait for the «right season» - act immediately, whatever the time of year.
What are the health benefits?
Reduced allergies and asthma symptoms, fewer respiratory infections, better sleep, more energy, and less eye and throat irritation. Children and the elderly often see the greatest improvements. It's an investment that pays off in quality of life and healthcare savings.
Protect your family, protect your air
Mould in your air ducts is not a problem that can be solved by itself. The longer you wait, the more the contamination spreads, and the greater the risk to your health.
The signs are there. The smell, the symptoms, the history of water exposure - your home speaks to you. The question is: are you ready to listen and act?
At Vortex Air, we've been helping Montreal families breathe easy for over 10 years. We understand your concerns because we live here too. We know the stress of a flooded basement, the worry of your kids coughing constantly, and the desire to simply breathe freely at home.
Our promise is simple: honest service
