A neat HVAC upgrade in the underground garage of a residential building
In Saint-Laurent , we modernized the comfort of a residential building by replacing an old air conditioning system with a TOSOT central heat pump , from the FLEXX side-discharge range. The client's objective: to obtain stable, quiet and energy-efficient heating and cooling , while respecting the constraints of an underground garage (cement block walls, technical passages, vehicle circulation, safety clearances). Our team delivered a clean, durable and compliant HVAC installation , ready to face the winters of Greater Montreal .
Why the TOSOT FLEXX range for this project?
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Continuously modulating inverter compressor : excellent temperature stability, energy savings and reduction of ON/OFF cycles.
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Side discharge format : compact size ideal for constrained areas (technical walls, service corridors), while providing sufficient air flow if the manufacturing clearances are respected.
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Central air compatibility : easy coupling with an existing air manager /plenum, MERV filters, and modern thermostat .
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Well-designed acoustics : contained sound levels, appreciable in a basement used daily.
Context and constraints of the site
The outdoor unit (condenser) is installed against a block wall of the garage, on a raised galvanized support . This positioning was chosen for:
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Protect the device from puddles, de-icing salt and underbody impacts.
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Facilitate maintenance (access to panels, cleaning of the exchanger, checking of connections).
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Optimize ventilation : the side discharge requires a free section in front of the grille; we have guaranteed continuous frontal clearance and adequate setback at the rear and sides, in accordance with TOSOT requirements.
The utility corridor also houses gas lines and other services. We therefore coordinated the layout with the building manager to avoid any risky co-operation, maintain clear leak paths , and protect existing networks.
Refrigerated and electrical path: clean, protected, durable
The image illustrates three key points of our AirGreen method:
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Rigid ceiling capping : the insulated refrigeration lines (Armaflex) and the communication cable are guided in an anti-corrosion metal capping, fixed on mechanical dowels. This approach protects the insulation from friction and vandalism, and provides a clean finish .
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Convenient disconnect box : The electrical disconnect is installed in a sealed metal box, with conduit and wiring sized according to the compressor's rated amperage and actual draw length. The assembly complies with the Quebec Electrical Code and the manufacturer's recommended gauge charts .
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Sturdy raised support : The galvanized steel structure rests on mechanical anchors suitable for concrete. Anti-vibration pads limit transmission to the walls, reducing the resonances typical of closed garages.
Result: a straight, readable and accessible path, which facilitates any future maintenance work (inspection of shaping, leak tests, replacement of insulation).
Central air integration and four-season comfort
On the interior side, the TOSOT FLEXX supplies an air manager connected to a plenum and a duct network. We have:
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Checked static pressures and adjusted dampers to balance flows to occupied areas.
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Recommended a MERV 11–13 filter to balance air quality and acceptable load on the ECM fan.
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Set up a smart thermostat with eco modes and recovery curves adapted to winter/summer occupancy habits.
This configuration makes it possible to take advantage of the seasonal efficiency of the system: efficient air conditioning in summer and efficient heating in mid-season and in moderate cold, with possible switching to a backup source if necessary depending on the building's energy strategy.
Safety, compliance and good practices in the garage
Installing a condenser in an underground garage requires special attention:
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Air Clearances : We have a permanent air vent in front of the grille. No obstructions (bins, furniture, dumpsters) are permitted; discreet signage has been added for maintenance personnel.
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Water management : the elevation protects the unit from runoff and salt; we plan to rinse the exchanger in the spring to remove deposits.
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Mechanical protection : depending on traffic, we offer a protective profile (barrier/bollard) if necessary to prevent bumper impacts.
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HVAC maintenance : an annual maintenance plan is provided: electrical inspection, tightening, overheating/subcooling checks, exchanger cleanliness, insulation and leak testing, defrost test.
Salient details visible on the installation
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Brand : TOSOT (logo on the front).
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Type : central heat pump with side discharge .
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Fixing : raised metal support with concrete anchors.
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Power supply : dedicated wall disconnect box , protected wiring.
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Connections : insulated refrigeration lines under rectilinear metal capping on the ceiling, sealed holes.
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Environment : clean underground garage , neon lighting, orderly technical traffic.
Expected performance and sizing
Without disclosing any private building data, we sized the capacity based on:
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the cooling load of the dwellings served (surface area, orientation, glazing, infiltration);
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winter heat losses (insulation, air renewal, infiltration garages→landings);
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line length and minor losses due to bends.
The TOSOT FLEXX range offers competitive seasonal coefficients in air conditioning and low temperature heating, with intelligent defrosting . In practice, occupants benefit from gentle blowing , controlled noise levels and optimized electricity consumption thanks to inverter modulation.
Grants and Eligibility
Depending on the address and configuration (replacement of a more energy-intensive appliance, presence of an electrical system, certified performance), this type of central heat pump may be eligible for current financial assistance programs . We support our clients in Montreal, Laval, Longueuil, North Shore and South Shore in verifying criteria , preparing documents (detailed invoices, certification numbers) and submitting the file when applicable.
AirGreen Tips for Sustaining Investment
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Annual maintenance : cleaning of exchangers, checking of refrigeration parameters, inspection of electrical connections and capping .
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Garage maintenance : keep the area clear in front of the blower grille; avoid storing containers or tools under the hood.
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Winter protection : rinse the exchanger in spring to remove dust and salt; check the anti-vibration pads .
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Air Quality : Replace the air handler filter as needed and monitor the differential pressure if a high MERV is used.
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Control : program time slots consistent with occupancy; activate eco modes during prolonged absence.
What AirGreen delivers
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Site study and serious sizing .
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HVAC installation to the letter: supports, seals, covers, clearances respected.
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Complete commissioning : load tests, readings, operating instructions.
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After-sales service : maintenance visits, parts and labor according to the manufacturer's warranty and our standards.
For projects in buildings (condos/plexes, co-ownerships, rental housing) or houses requiring careful technical installation, our team operates throughout Greater Montreal with the same requirement for cleanliness , safety and performance .