A HVAC modernization project in the heart of Longueuil
AirGreen recently completed a full retrofit of a ventilation and heating system in a mixed-use building in Longueuil, housing office space and basement service areas. The existing system, installed over 20 years ago, was showing signs of wear and tear and experiencing recurring thermal comfort issues . Our mandate: to modernize the air handling unit while ensuring the continuity of the occupants' operations.
Context and initial diagnosis
The building had a York brand horizontal ventilation unit , installed in a small technical space in the basement. Several observations motivated the project:
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Unbalanced airflow and excessive noise in the ducts.
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Leaks at the duct sections and significant pressure losses.
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High energy consumption due to a fixed-speed motor.
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Limited control, without a building automation regulation system.
After a detailed inspection and thermodynamic analysis of the airflows , our HVAC engineering team recommended the complete replacement of the unit with a variable flow system with heat recovery .
Proposed technical solution
AirGreen has designed a customized solution including:
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New Daikin air handling unit , compact horizontal model with integrated energy recovery (high-efficiency rotary heat exchanger).
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Variable speed EC motor , allowing precise adjustment of flow rates according to actual occupancy.
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Building automation (BMS) control via BACnet interface, integrated into the existing building system.
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Enhanced internal acoustic insulation to limit blowing noise in the ducts.
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MERV 13 filters for improved indoor air quality (IAQ), in compliance with ASHRAE 62.1 recommendations.
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Connection of existing conduits with adjustments in galvanized sheet metal, final balancing carried out by our TABB certified technicians.
Construction progress and constraints
The work was planned over a period of 5 days , including:
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Dismantling of the old enclosure and securing of the electrical network.
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Reinforcement of the support structure to accommodate the new, more compact but denser unit.
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Coordinated crane operation via lateral access to the building, with municipal permit obtained by our team.
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Installation and calibration of CO₂ and temperature sensors .
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Performance testing and complete balancing at the end of the project.
All work was carried out outside of office hours to avoid any disruption to tenants' activities.
Results and Key Performance Indicators (KPIs)
The gains measured after commissioning were significant:
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32% reduction in the annual electricity consumption of the ventilation system.
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24% improvement in measured air quality (average CO₂ level brought below 800 ppm).
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Noise level reduction in work areas of 5 dB.
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Uniform temperatures in peripheral areas, ensuring constant comfort.
The building managers particularly appreciated the speed of execution , the cleanliness of the site and the transparency of the technical monitoring provided by AirGreen.
Maintenance, monitoring and compliance
To ensure the system's longevity, an annual preventative maintenance contract has been signed. It includes:
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Quarterly inspection of EC motors and belts.
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Semi-annual checks of filters and cleaning of energy recovery sections.
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Remote monitoring via BMS: real-time alerts on flow rates, pressures and anomalies.
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Annual update of the compliance register (CSA B52 / RBQ).
Each maintenance report is digitally archived and accessible to the manager via a secure client portal.
Compliance, security and financing
The project complied with all applicable standards: CSA B52 , ASHRAE 62.1 and 90.1 , as well as the City of Longueuil's mechanical ventilation requirements.
AirGreen also assisted the client in preparing the application for a Hydro-Québec subsidy , due to verifiable energy savings exceeding 25%.
Return on investment
Thanks to energy savings combined with reduced service calls, the project's ROI is estimated at 3.8 years . Furthermore, the increased system reliability reduces the risk of critical outages during peak periods, ensuring business continuity and occupant satisfaction.
AirGreen , your commercial HVAC partner in Montreal, Laval, Longueuil, North Shore and South Shore, puts its expertise in retrofit, maintenance and design-build at the service of companies that seek sustainable, high-performance solutions that meet the highest industry standards.