Renovations in Longueuil: What You Absolutely Must Not Forget Before Insulating Your Home (Hint: Ventilation)

Good insulation is often seen as the miracle solution to improve energy efficiency in a home in Longueuil. But what happens when you forget one crucial element in the equation? The answer is simple: without proper ventilation, you risk turning your home into a trap for humidity, pollutants, and problems. At AirGreen, we've seen far too many renovation projects where people invest in energy-efficient windows, sealed walls, and insulated roofs, without planning for an appropriate mechanical ventilation system. In this article, we explain why HVAC ventilation should be your top priority before any insulation work, and how our interventions in Longueuil and across the South Shore help you avoid costly mistakes.

Why is ventilation critical before insulating a house?

When you improve your building's thermal envelope, you significantly reduce air leaks. That’s great for your energy bill, but it also means that indoor air no longer renews naturally. The result: excess humidity, condensation on windows, mold inside walls, and degraded air quality.

This is where mechanical ventilation systems (HRV or ERV) come into play. They ensure a continuous and controlled renewal of indoor air by expelling stale air and bringing in filtered fresh air from outside — all while conserving as much heat as possible thanks to a heat recovery ventilator (HRV or ERV).

What we’ve observed in the field in Longueuil

In our many service calls throughout Longueuil — especially in older residential areas like Vieux-Longueuil, Saint-Hubert, and LeMoyne — we've noticed a recurring issue: homes that underwent insulation upgrades without upgrading the HVAC ventilation system quickly develop problems like condensation, mold, and poor indoor air quality.

We were recently called to a renovated home on Montarville Street, where major insulation work had been done without any consideration for ventilation. Three months after the renovations, the homeowners noticed persistent damp odors and mold forming in the bathroom and basement. Our team installed a Venmar AVS N Series heat recovery ventilator, paired with a high-performance centralized ventilation system, to restore a healthy balance throughout the home.

Common mistakes during residential renovations

1. Thinking that openable windows are enough: opening a window is not the same as continuous mechanical ventilation, especially in winter.

2. Ignoring the humidity produced indoors: every occupant generates water vapor by breathing, cooking, and showering.

3. Installing an HRV unit without calibration: poor balancing can create harmful positive or negative pressure.

4. Neglecting HVAC maintenance: a poorly maintained ventilator becomes ineffective, even counterproductive.

What we recommend BEFORE insulating

1. Full HVAC audit

Before starting any insulation work, we perform a comprehensive assessment of your current ventilation system. This includes:

• Airflow analysis by room

• Evaluation of pollutants (CO₂, humidity, particulates)

• Function and performance check of the existing equipment

2. Recommendation of an appropriate system

We recommend systems EnerGuide-certified and eligible for government grants, such as:

• Venmar AVS or Lifebreath for HRV/ERV units

• Centralized ventilation systems integrated with central heat pumps (Trane, Bosch, Goodman)

3. Seamless integration into your renovation project

We work directly with your general contractors or architects to integrate ventilation into your renovation project before walls are closed up. This allows for optimized duct routing, discreet vent placement, and future access for maintenance.

Examples of successful projects by AirGreen in Longueuil

Residence on Normandie Street (Saint-Hubert)

In this fully renovated 1970s bungalow, we installed a complete system including:

• A Venmar HRV 2600 heat recovery ventilator

• Insulated rigid ducts to minimize heat loss

• Integration with a central heat pump system by Fujitsu for total comfort control

Result: a more comfortable, healthier home with energy consumption reduced by 28%, based on the client’s own readings.

Duplex on Joliette Street (Vieux-Longueuil)

Here, we upgraded an outdated system with:

• A separate ventilation system for each floor

• Smart wall-mounted controls for precise airflow management

• HEPA filters for advanced air filtration

What you gain with proper ventilation before insulation

• Improved indoor air quality

• Reduced risk of mold growth

• Extended lifespan of your renovation

• Compliance with current codes (Quebec Building Code)

• Eligibility for certain provincial grants (LogisVert, Rénoclimat)

Maintenance: an often overlooked pillar

A good ventilation system only performs long-term if it is regularly maintained. At AirGreen, we offer annual HVAC maintenance contracts that include:

• Complete filter and duct cleaning

• Airflow calibration

• Inspection of motors and sensors

Conclusion: don’t leave ventilation for later

At AirGreen, our experience in Longueuil and across the South Shore has taught us one thing: ventilation is not optional — it’s essential. Before investing in insulating your home, contact our team for a full HVAC ventilation audit. A healthy home starts with healthy air — and that’s exactly what we guarantee.