Case Study: Upgrading the Heating System of a Historic Building in Montréal – Challenges and Results

A custom HVAC renovation for a heritage building in Plateau-Mont-Royal

In the vibrant heart of Plateau-Mont-Royal in Montréal, AirGreen was recently entrusted with a complete upgrade of the heating system in a historic residential building dating back to the early 20th century. This project perfectly illustrates our expertise in adapting modern commercial heating solutions to the unique constraints of heritage architecture.

The challenge was significant: preserve the building’s integrity, optimize energy performance, and ensure optimal comfort for occupants—all while minimizing visible alterations. Here's the detailed story of this complex intervention, our technical choices, and the results achieved.

Understanding the building’s specific features

The building in question, located on Laval Avenue, is a former rooming house converted into rental apartments. Built in 1911, it features solid brick walls, ceilings over 3 meters high, and many original moldings and decorative elements that had to be preserved. The existing heating system relied on an outdated oil boiler with cast iron radiators.

The client’s objectives were clear:

• Replace the obsolete heating system with an energy-efficient solution.

• Reduce operating costs.

• Preserve the building’s heritage appearance.

• Qualify for government grants related to energy efficiency.

HVAC diagnosis and customized recommendations

Our experts conducted a comprehensive energy audit of the building, analyzing insulation, heat loss, required output, and room configuration.

We recommended installing a central forced-air heating system powered by a high-efficiency central heat pump, specifically the Bosch BOVA 36 IDS Premium model, using R-454B refrigerant—known for its outstanding performance and low environmental impact.

This system offered several benefits:

• A 36,000 BTU output ideally suited to the building’s size (about 3,200 sq. ft.).

• Seasonal efficiency rating of SEER 20 and a heating performance factor of HSPF 10.5.

• Eligible for a $3,800 LogisVert grant.

• Quiet operation and discreet integration through upgraded interior ductwork.

Technical challenges encountered

1. Narrow duct pathways and load-bearing brick walls

Installing a new duct system without damaging load-bearing brick walls posed a major challenge. We opted for a hybrid solution using low-profile oval ducts and distribution boxes concealed within existing closets.

2. Preserving architectural heritage features

To comply with heritage preservation standards, no visible outlets were allowed on the façade. We therefore placed the outdoor units at the rear of the building in a courtyard, mounted on elevated anti-vibration supports, reducing noise and minimizing snow accumulation risks.

3. Limited space for the indoor unit

The mechanical room was cramped. We selected a compact vertical Bosch indoor unit, built into a custom-fitted utility closet. The electrical panel was upgraded to accommodate the new system, including the installation of a dedicated 240V breaker.

Installation steps

1. Safe removal of the oil boiler, along with decontamination of the tank.

2. Partial demolition of the old ducts and radiators.

3. Installation of the Bosch BOVA 36 IDS Premium central heat pump.

4. Integration of a smart connected thermostat, enabling building managers to remotely control temperatures by zone.

5. Performance testing, fine-tuning, and full system commissioning.

Results achieved

After three weeks of meticulous work, the results speak for themselves:

• Estimated 40% reduction in energy costs compared to oil heating.

• Noticeable improvement in thermal comfort, with even temperatures across all units.

• No visible impact on architectural or decorative elements.

• Successful application for a $3,800 LogisVert grant, thanks to the system’s energy certification.

Client testimonial

“We were very concerned about modernizing the heating without altering our classified building. AirGreen proposed a perfectly adapted solution, with impressive attention to detail. We are extremely satisfied with the result.”

Why AirGreen stands out in heritage HVAC projects

At AirGreen, we understand that every building has a story. Our HVAC solutions are always custom-designed, taking into account the technical, aesthetic, and regulatory constraints of each project. Our certified technicians collaborate with architects, engineers, and heritage bodies to deliver turnkey service, without compromising on quality or respect for the structure.

Recommendations for heritage building managers

• Avoid off-the-shelf solutions: heritage buildings require a tailored approach.

• Plan a detailed energy study before any HVAC renovation.

• Take advantage of financial incentives: many programs exist to support energy-efficient upgrades, even for historic buildings.

• Work with an experienced company like AirGreen, which fully understands the challenges of traditional architecture and modern standards.

We serve the entire Greater Montréal area

This project is just one example of our expertise. Whether you own a residential, commercial, or institutional building in Montréal, Laval, Longueuil, on the North Shore or South Shore, we’re ready to design and install the central heating or heat pump system best suited to your needs.

Trust AirGreen to modernize your HVAC systems with peace of mind—while preserving the charm and legacy of your buildings.