Indoor air quality: an overlooked trigger of seasonal allergies
In Montréal, every spring and fall brings a wave of allergy symptoms: sneezing, nasal congestion, itchy eyes, fatigue. While these reactions are often blamed on pollen or outdoor pollution, the real cause may actually be inside your home. At AirGreen, we’ve seen, through our service calls across Montréal, Laval, Longueuil, the North Shore and the South Shore, that poor ventilation is a key contributor to worsening seasonal allergies.
How inadequate ventilation makes your allergies worse
Indoor air: more polluted than outdoor air
Modern homes and condos are built to be airtight to reduce energy loss. But there’s a downside: allergens get trapped indoors. These include:
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Pollen brought in on clothes or through slightly opened windows.
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Dust mites, which thrive in warm, humid air.
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Pet hair and dander, which accumulate in fabric surfaces.
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Mold spores, especially common in basements or poorly ventilated bathrooms.
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Volatile chemicals from cleaning products, air fresheners, paint, and more.
Without proper air renewal, these particles build up in bedrooms, living rooms, offices — exactly where you spend the most time.
Humidity: a dangerous ally for allergens
Humidity levels above 60% promote the growth of mold and dust mites — two major allergy triggers. But many HVAC systems in Montréal are not equipped to manage indoor humidity effectively, especially in condos without air exchangers.
Case study: high-performance ERV installation in Outremont
We were recently contacted by a family living in a renovated duplex in Outremont. Both of their children were experiencing chronic seasonal allergy symptoms, especially during spring. Despite having no pets and keeping a clean home, the symptoms persisted.
Technical diagnosis
Our technicians performed a complete air quality assessment using a fine particle monitor, a hygrometer, and an air circulation test. The results:
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Average humidity of 68% in the bedrooms.
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No mechanical ventilation in closed rooms.
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High concentration of suspended dust.
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Built-up VOCs in enclosed areas.
AirGreen solution: installation of a VENMAR AVS® N SERIES ERV 160
To restore healthy indoor conditions, we installed a high-efficiency ERV system with an energy recovery core and MERV 13 filters, designed to trap pollen, mold, fine dust, and other allergens.
Main features of the installation:
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160 CFM airflow, sufficient for the entire home.
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Wall-mounted electronic controls for smart operation.
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Discreet duct network, with no impact on home aesthetics.
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Continuous ventilation mode, with automatic humidity detection.
Results after 2 weeks
Post-installation:
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The children experienced a noticeable drop in allergy symptoms.
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The home felt fresher and less humid.
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There was an immediate sense of purified air in the home.
Why air exchangers are essential in Montréal
Adapting ventilation to Québec’s climate
Montréal’s damp spring and fall conditions contribute to moisture and mold buildup, especially in older or overly airtight homes. A well-performing air exchanger helps control these factors without sacrificing heat efficiency.
Allergen filtration
The models we install come equipped with high-efficiency filters (MERV 11 to 16, depending on the need), which:
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Capture pollen before it enters the home.
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Reduce dust mites by lowering humidity.
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Eliminate mold spores by renewing stale air.
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Provide continuous air exchange, even when windows stay closed.
AirGreen’s tips to reduce seasonal allergies
Do
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Vacuum the ducts and change ventilation filters every 6 months.
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Use a dehumidifier in high-risk areas.
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Choose a central ventilation system with a built-in air exchanger.
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Air out bedding and textiles regularly.
Don’t
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Use chemical air fresheners.
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Keep windows closed without active ventilation.
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Neglect the maintenance of return air grilles.
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Let condensation form on windows, a sure sign of excess humidity.
AirGreen: your ventilation ally for respiratory health
At AirGreen, we understand the specific challenges of indoor air quality across Greater Montréal. Our installations are designed to integrate seamlessly into your home while delivering long-lasting, quiet performance. Thanks to our expertise in residential HVAC, our clients consistently report noticeable improvements in breathing comfort, year after year.