Mold Infestation: How AirGreen Saved a Family in Longueuil from a Sanitary Nightmare

An Invisible Infiltration with Very Real Consequences

When we were contacted for a routine inspection at a family home in Longueuil, nothing initially indicated the emergency that was about to unfold. A faint, lingering musty smell, recurring headaches among the residents, growing discomfort in certain rooms: all seemingly minor symptoms that had gone unnoticed for months. Yet, behind freshly painted walls and spotless floors, toxic mold was spreading dangerously.

What seemed like a simple humidity issue turned out to be an advanced mold contamination, putting the health of an entire family at serious risk. At AirGreen, we know that residential ventilation is not a luxury — it's an absolute necessity. Here’s how our team quickly identified the problem, proposed a long-term solution, and restored safety and comfort to this Longueuil home.

Identifying the Problem: Invisible Symptoms, Real Threat

When the client first called us, they mentioned only minor issues: a musty smell, thermal discomfort, mild coughing among the children. Our technicians, trained in indoor air quality assessment, immediately performed a full inspection using humidity detection equipment and thermal imaging cameras.

The results were undeniable: stagnant humidity in the attic and air ducts, excessive condensation in the bathrooms, and no proper air exchange in the bedrooms. A perfect storm for mold development.

An on-site microbiological test confirmed the presence of active spores of Stachybotrys chartarum, commonly known as toxic black mold, which is well-known for its harmful effects on the respiratory system.

Technical Diagnosis

Our technicians compiled a detailed report identifying three major issues:

• There was no mechanical ventilation system (HRV/ERV) operating in the home.

• The bathroom fan vented directly into the attic instead of outside.

• The air ducts had not been insulated or cleaned in over 10 years.

These three factors combined created a situation of critical indoor air pollution.

A Custom Solution: AirGreen’s Signature HVAC Expertise

Decontamination and Sanitation

As soon as the quote was approved, we launched a multi-step operation:

1. Full decontamination of all affected zones using certified fungicidal products and localized thermal treatments.

2. Complete ductwork cleaning using motorized rotary brushes and HEPA-grade disinfectants.

3. Replacement of mold-contaminated drywall and accelerated drying using industrial-grade dehumidifiers.

Installation of a High-Performance Ventilation System

To prevent any recurrence, we installed a Venmar EVO5 700 HRV air exchanger, a high-efficiency model that ensures constant renewal of indoor air. This system features:

• An ECM energy-efficient motor,

• A MERV 8 filter effective against fine airborne particles,

• A programmable digital controller tailored to the home’s specific needs.

We also reconfigured the entire ductwork system, adding thermal-reflective insulation to prevent heat loss and reduce condensation risks.

Lower Energy Bills and Enhanced Comfort

Once the system was in place, the results were immediate:

• Indoor relative humidity stabilized at 45%,

• Complete elimination of musty odors,

• Improved air quality based on post-intervention measurements,

• Reduction of respiratory symptoms among household members.

Thanks to the integrated heat recovery core of the Venmar EVO5 700 HRV, the family also saw an 18% reduction in energy costs related to heating.

AirGreen Expertise: When Prevention Meets Rapid Response

This case in Longueuil is far from unique. Every week, our team intervenes in homes across Montreal, Laval, Longueuil, the North Shore and the South Shore, where poor ventilation causes invisible — yet major — issues: allergies, discomfort, and building material deterioration.

Our strength lies in our comprehensive and personalized approach:

• A thorough technical evaluation of each property,

• Deep product knowledge of HVAC systems best suited for Quebec’s climate,

• Flawless execution, clean and on schedule,

• Full support with grant applications, including Hydro-Québec’s LogisVert program.

The Importance of Preventive HVAC Maintenance

This project is a strong reminder of the importance of regular HVAC maintenance. Our experts recommend:

• Duct cleaning every 3 to 5 years,

• Annual inspection of your air exchanger,

• Regular filter replacements,

• Humidity level monitoring with smart sensors.

Preventive maintenance is a minimal investment compared to the high cost of mold decontamination, which can reach several thousand dollars when the spread is advanced.

A Healthy Home Thanks to Proper Ventilation

At AirGreen, we believe every family deserves clean and safe indoor air, year-round. Through our residential ventilation services, we protect homes in Longueuil and across Greater Montreal from invisible threats like mold.

Think your home might have ventilation or humidity issues? Don’t wait. Contact our team today. Our specialists are ready to conduct a free evaluation and guide you toward a long-lasting solution tailored to your needs.

AirGreen is more than an installer — it’s your trusted partner for thermal comfort, energy efficiency, and indoor air quality.