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CVC Commercial à Laval : Rétrofit d’un Système Rooftop Allied pour un Immeuble de Bureaux
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Commercial HVAC in Laval: Retrofit of an Allied Rooftop System for an Office Building

Energy modernization and increased reliability on a roof in an urban area

AirGreen recently completed a full retrofit project for an Allied rooftop system used for commercial heating and cooling in an office building in Laval. The goal was to replace aging, energy-inefficient, and noisy equipment with a more efficient unit that meets current HVAC energy efficiency and safety standards .

Project context

The building in question houses several commercial tenants. The property manager was facing recurring complaints related to:

  • unstable temperatures in office areas,

  • high operating costs due to excessive energy consumption,

  • and overly frequent corrective maintenance .

After a complete diagnosis of thermal loads and airflows, our engineers recommended a complete retrofit of the existing rooftop with a high-efficiency Allied unit, adapted to the existing roof and duct system.

Technical and logistical constraints

This project presented several challenges:

  • Roof access is restricted , requiring the use of a mobile crane with a lifting plan approved by the City of Laval.

  • Limited intervention windows (work carried out at night to minimize the impact on tenants).

  • Limited mechanical space with the need to preserve clearances for future maintenance .

  • Winter conditions at the time of installation required close coordination between our teams and the electrical trades.

Our technicians also had to verify the structural load of the roof , in accordance with the requirements of the Quebec Building Code and ASHRAE 62.1 and CSA B52 standards.

Technical solution chosen

The AirGreen team opted for a single-unit Allied rooftop with integrated digital control (BMS-ready) , capable of:

  • Providing heating and air conditioning via a variable-speed compressor

  • Provide variable air volume (VAV) ventilation with heat recovery,

  • Improve indoor air quality (IAQ) through MERV 13 filtration and precise humidity control,

  • Reduce energy consumption thanks to a high SEER efficiency compressor and an ECM fan.

The system was connected to the existing building management system (BMS) via a Modbus gateway, enabling real-time monitoring of temperatures, pressures and alarms .

Construction progress

  1. Preparatory phase:

    • Structural and electrical studies.

    • Lockout/tagout plan and securing of the lifting perimeter.

    • Coordination with the municipal department for crane authorization.

  2. Removal of old equipment:

    • Dismantling of the existing unit.

    • Environmental management of refrigerants according to federal standards (Halocarbon Regulations).

  3. Installation of the new Allied rooftop:

    • Installation by crane.

    • Mechanical and electrical connection.

    • Calibration of the control system and balancing of airflows.

  4. Testing and commissioning:

    • Checking static pressure and supply/return temperatures.

    • Alarm validation and integration with the BMS.

    • Performance tests in heating and cooling mode.

Results and Key Performance Indicators (KPIs)

Since it was put into service:

  • A 27% reduction in annual energy consumption was measured over the first 3 months.

  • Indoor temperature stabilized between 21°C and 23°C , even in periods of extreme cold.

  • Noise level reduced by 6 dB(A) on the roof, improving the acoustic comfort of the upper floors.

  • Zero corrective service calls since installation, proof of system reliability.

These results allowed the owner to extend the useful life of the HVAC system by approximately 15 years and improve the rental value of his building.

Preventive maintenance and monitoring

AirGreen now provides quarterly preventative maintenance for the Allied rooftop:

  • Checking the cleanliness of the filters, batteries and coils.

  • Monitoring of refrigerant pressures, motor currents and electrical connections.

  • Performance log update via the remote monitoring platform.

A 24/7 SLA service contract guarantees intervention within 4 hours in the event of a critical alarm.

Compliance, safety and subsidies

This project complies with:

  • ASHRAE 90.1 (energy efficiency) and CSA C282 (electrical safety) standards.

  • CNESST safety procedures applicable to working at heights.

In addition, the client was able to benefit from a subsidy from Hydro-Québec under the "Energy Efficiency in Commercial Buildings" program, covering up to 20% of the installation cost .

Return on Investment (ROI)

Thanks to the combination of targeted retrofit , integration with existing BMS and a structured maintenance plan , the estimated ROI is 3.8 years .
Energy savings, reduced service calls, and subsidies received all contribute to lowering the total cost of ownership (TCO) of the HVAC system.

Why trust AirGreen

At AirGreen , we design, install and maintain complete commercial HVAC solutions in Montreal, Laval, Longueuil, on the North Shore and the South Shore.
Our technical teams are available 24/7 to:

  • preventive maintenance,

  • emergency repairs,

  • custom design and construction,

  • and the modernization of rooftop units, VRFs, boilers, chillers and building management systems.

Each project is planned with technical rigor , safety and transparency , in order to ensure continuity of operation and long-term energy performance.