Preserving the past while heating the future: our intervention on a heritage building in Montreal
In the world of commercial heating, it's rare to come across a project as delicate as working on a heritage building. These buildings, emblematic of Montreal’s history, present unique challenges that few companies can take on without compromising their architectural integrity. At AirGreen, we were recently commissioned to efficiently heat a heritage property located in Old Montreal, while strictly respecting its character and structural limitations. Here’s a behind-the-scenes look at this complex HVAC installation, carried out with precision, innovation, and respect for history.
A project rich in both historical and technical value
The building in question, a grey stone construction dating back to the 19th century, now houses several professional offices. The owners wanted to modernize the heating system while reducing energy consumption and accessing available subsidies in Montreal. The main requirement: no visible damage to the façade or interior walls, which are classified as heritage assets.
We therefore developed a custom strategy that combined modern comfort with historical preservation.
Building analysis: constraints and possibilities
The thickness of the stone walls
With walls up to 60 cm thick, drilling for traditional ductwork would have required invasive work, which was incompatible with heritage regulations. We therefore opted for a mostly ductless solution: using wall-mounted heat pumps and compact floor units, with a minimal and discreet duct network hidden within baseboards.
Deficient thermal insulation
Like many old buildings, this one had outdated original insulation, making energy efficiency a top priority. We chose a Fujitsu KRL 18,000 BTU wall-mounted heat pump, a high-performance unit capable of heating large spaces even during extreme cold, all while maintaining excellent energy ratings (SEER 20 / HSPF 10.5).
Aesthetics: a critical criterion
All visible equipment had to be discreet, compact, and aesthetically compatible with the heritage setting. Indoor units were installed in existing alcoves or behind removable decorative panels. As for the outdoor unit, it was concealed in an interior courtyard, not visible from the street.
The AirGreen solution: an ingenious hybrid system
To meet all the constraints, we designed a hybrid system combining:
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One 18,000 BTU Fujitsu KRL wall-mounted heat pump using R-32 refrigerant for efficient and quiet heating in the main areas.
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Two compact Fujitsu RLS3 floor units for smaller zones.
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A mini central air handling unit with a heat recovery ventilator, to improve indoor air quality.
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A smart centralized control system, allowing for zone-by-zone scheduling, tailored to commercial use.
Installation stages: precision and discretion
Preliminary study and heritage consultation
Before beginning any work, our team collaborated with a heritage architect to ensure that the proposed solutions respected the guidelines of the City of Montreal’s Urban Planning Department.
Technical installation without damage
We used non-invasive anchoring techniques, including freestanding supports and chemical anchors in the mortar joints, so as to avoid damaging the original masonry.
Noise and vibration control
The outdoor unit was installed on a reinforced anti-vibration base, to limit noise disturbances for neighboring offices. This detail proved essential, especially in a professional workspace.
System startup and client training
Once the system was installed, we conducted a full commissioning, including performance tests, fine-tuning of the zone temperatures, and in-depth training for the building managers on the use of the centralized interface.
Results: performance, efficiency, satisfaction
Thanks to this intervention:
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Energy consumption was reduced by over 30% compared to the previous natural gas system.
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Temperatures are now consistent and comfortable throughout all areas, even during extreme cold spells.
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The building’s interior and exterior appearance has remained completely intact.
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The project was fully eligible for Hydro-Québec's LogisVert subsidies, totaling $1,704 per unit installed.
Client testimonial: a successful partnership
“We were impressed by AirGreen’s ability to work on such a sensitive building. The team demonstrated outstanding professionalism and a deep respect for our heritage. The system is efficient, discreet, and easy to manage. Thanks to the entire team!”
— Building Manager, Old Montreal
Why trust AirGreen with your heritage buildings
At AirGreen, we understand the intricacies of HVAC system installations in complex environments. Whether for a century-old building, a mixed-use property, or a commercial space housed in a historical structure, we implement custom solutions that respect the legacy of the site while delivering modern performance.
Our expertise spans Montreal, Laval, Longueuil, the North Shore and the South Shore, where we carry out large-scale projects like this one every week. Each installation is an opportunity to showcase our technical know-how, but also our ability to listen, advise, and guide our clients toward the complete optimization of their comfort.