In the Plateau-Mont-Royal neighbourhood, flat-roofed brick buildings often present a unique HVAC challenge: improving comfort (both summer and winter) without adding visual weight to the façade, without cluttering a narrow backyard, and while maintaining a clean, safe, and durable system despite freeze/thaw cycles. This is precisely the context of this installation by AirGreen , where we installed two Sharp (Eco Inverter) outdoor units on a rooftop to power wall-mounted heat pumps in a residential building.
Why a Sharp wall-mounted heat pump on the Plateau?
In this area of Montreal, you frequently encounter:
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stacked dwellings (plexes) with limited ground-level access;
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aesthetic constraints (facade, close proximity);
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noise reduction requirements;
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winters that demand a stable, efficient and well-installed machine.
Sharp wall-mounted heat pumps are particularly well-suited to this type of project thanks to their Inverter technology, designed to modulate power rather than operating on an "on or off" basis. The result: a more stable temperature, improved efficiency, and generally quieter operation—a crucial factor when the units are located near other residences.
Type of machine installed
Here, we have a typical residential “mini-split” setup:
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Type: Wall-mounted heat pump (mini-split / wall unit)
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Brand: Sharp (brand name provided manually, used as a reference)
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Model (consistent with the Sharp range): Sharp ZU1 (wall-mounted series)
In practice, the exact model is always confirmed via the nameplate, but the installation and format observed correspond very well to a Sharp wall-mounted configuration of this family.
In this project, we can clearly see two Sharp outdoor units installed side by side, which is very common when serving:
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two dwellings (or two zones) with separate systems;
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or a dwelling requiring two separate circuits to better distribute the load (e.g. living area + bedrooms).
Prominent installation details (as revealed in the photo)
This roof demonstrates exactly the kind of precautions that AirGreen prioritizes for a sustainable installation:
1) Installation on raised supports (and this is not a minor detail)
The units are placed on raised metal supports , which offers several advantages in the Quebec climate:
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reduction of risks related to snow and ice accumulation;
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better protection against standing water on the roof membrane;
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reduction of vibrations transmitted to the structure;
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easy access for maintenance (and for interventions in the cold season).
2) Proper management of connections and routing
A structured routing of the connections (refrigeration piping + communication cable) is observed, grouped and neatly routed. On the roof, this is essential for:
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avoid premature wear (friction, pinch points);
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limit unnecessary exposure to temperature variations;
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to maintain a professional appearance (and easier to inspect).
3) Actual site conditions: cold, humidity, safety
The presence of frost/snow on the roof serves as a stark reminder: this type of installation demands a rigorous methodology (appropriate tools, surface protection, stable supports, equipment management). Work is carried out cleanly, but above all , without compromising safety .
Our AirGreen approach for this type of project (flat roof in Montreal)
Every roof is different, but our logic remains the same: reliability + performance + easy maintenance .
Key steps that we systematically apply
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Site validation: air clearance, distance from obstacles, wind orientation, future access.
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Leveling and anchoring of supports: to prevent vibrations and seasonal movement.
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Careful connections: brazing/crimping according to rules, vacuum pulling, leak tests.
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Complete commissioning: parameters, modes, validation of heating and air conditioning behavior.
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Explanation to the customer: best practices for use, filter maintenance, preferred modes.
Expected comfort: stable heating in winter, efficient air conditioning in summer
A properly sized and installed wall-mounted heat pump truly transforms life in a Montreal home:
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Winter : more uniform warmth, fewer variations, better feeling of comfort.
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Summer : fast and stable air conditioning, with precise zone control.
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Mid-seasons : yield often excellent, especially when the device modulates correctly.
And on a building in the Plateau, this solution often makes it possible to obtain modern comfort while respecting the reality of the building (structure, access, aesthetics, neighborhood).
Common mistakes to avoid on roofs (and why it matters)
On flat roofs, problems rarely arise "right away"... but rather after one or two winters. Here's what to prevent from the start:
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Unit placed too low : increased risk of ice, water, corrosion and failures.
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Improvised supports : vibrations, noise, instability, premature wear.
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Poorly protected connection pathways : cracks, friction, damage and leaks.
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Forgotten maintenance access : more costly intervention, longer delays, higher risks.
At AirGreen, we install so that it looks good on day 1 — but above all, it's reliable on day 700.
For whom is this type of installation ideal in Plateau-Mont-Royal?
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Plex owners who want to improve comfort without altering the facade.
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Housing where floor space is limited (backyard, alley, easements).
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Customers who want a zone-based solution (personalized temperature per floor or per dwelling).
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Buildings where silence and mechanical discretion are important.