In several recent buildings in Griffintown , wall-mounted heat pumps are working hard: urban dust, pollen, fine particles from busy streets and winds on the roofs… As a result, the outdoor coil gradually gets dirty, heat exchange is less efficient, and the unit has to run longer to provide the same comfort.
At AirGreen , we regularly work in this area of the Southwest to perform complete cleanings (exterior + interior) which extend the life of the equipment and stabilize performance, both in air conditioning in the summer and in heating during the Quebec winter.
Context: an outdoor rooftop unit, exposed to deposits
The photo clearly shows an outdoor unit installed high up (technical area/roof), protected by a metal grille . A film of deposits (dust and particles) is also visible on the coil fins, more pronounced in the center and towards the bottom. This type of fouling is typical of rooftop installations: the air circulates well, but it carries a large number of microparticles that eventually stick to the fins.
When the coil is partially obstructed:
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the airflow through the exchanger decreases;
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the heat pump loses efficiency ;
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the cycles are getting longer (and the bill follows);
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In heating, a decrease in performance and more defrosting phases can be observed.
Machine type: wall-mounted heat pump (mini-split)
The equipment consists of a wall-mounted heat pump : a compact outdoor unit that supplies one or more indoor wall units. This is the most common format in condos in Montreal, particularly in buildings where room-by-room control, discreet installation, and good energy efficiency are desired.
Brand and model: Sharp (consistent model: Sharp ZU1 – R-32 )
The brand supplied manually is Sharp — and we retain it as the primary reference.
The exact model is not legible in the photo, but, in this type of residential configuration, a consistent choice is a Sharp ZU1 (R-32) wall-mounted heat pump , known for its performance and stability in real-world conditions.
What you see in the photo: useful clues to guide the cleaning
Even before opening anything, the image gives us concrete points to address:
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The outer coil is visibly dulled by a film of dust (fins less “sharp”).
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Presence of a protective grid : good for safety, but it can also retain more debris if not cleaned properly.
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More pronounced deposits in the center/bottom : often where moisture and particles combine and create a stickier film.
Our AirGreen method: complete cleaning, without damaging the fins
Properly cleaning a Sharp heat pump isn't just a quick rinse. It requires removing deposits without bending the fins , without pushing the dirt deeper, and while protecting the electrical components.
1) Cleaning the outdoor unit (on the roof)
Our technicians proceeded as follows:
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Visual inspection of the coil, fixings, and the area around it (clearance, air circulation, traces of oil, vibrations).
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Protection of sensitive elements (if necessary): connections, electrical box, risk areas.
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Gentle cleaning of the coil :
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dislodge particles without aggressive high pressure;
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targeted treatment if the deposits are sticky;
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Controlled rinsing to restore airflow through the fins.
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General condition check:
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fins (slight straightening if necessary);
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base and lower area (where dust often accumulates);
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presence of debris likely to obstruct ventilation.
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Objective: to find a “breathing” heat exchanger, capable of transferring heat efficiently.
2) Cleaning the indoor unit (the part most closely linked to air quality)
Even though the photo shows the exterior, a proper maintenance includes the interior:
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Cleaning the filters (or replacing them if required).
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Cleaning the evaporator (internal coil) to reduce odors and improve efficiency.
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Cleaning the turbine/wheel (often responsible for odors and a decrease in airflow).
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Reasonable disinfection of internal surfaces when relevant (prevention of mold and biological deposits).
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Condensation tray and drain inspection:
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leak prevention;
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prevention of stagnant water odours;
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better humidity control.
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Inspections and commissioning: we validate, we don't "guess".
After cleaning, we carry out a structured recommissioning process:
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Checking ventilation and operating noise.
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Temperature control (inlet/outlet) and cycle stability.
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Inspection of basic points: fastening, clearance, vibrations, and consistency of operation.
These are the steps that transform a simple "wash" into a professional maintenance service .
Results: what the customer typically notices after a good cleaning
In this type of case (dirty outdoor coil on the roof), we frequently observe:
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Improved airflow and shorter cycles.
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A more stable feeling of comfort (fewer variations).
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Less risk of odors coming from the indoor unit.
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A machine that puts less strain on the machine, therefore better longevity in the medium term.
How often should I get my car serviced in Montreal?
For condos (Griffintown, Ville-Marie, Southwest, etc.), we generally recommend:
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Filters : every 4 to 8 weeks during periods of intensive use (heating/air conditioning).
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Complete cleaning (interior + exterior): 1 time per year , or 2 times if the unit is used a lot, if there are allergies, animals, significant dust, or if the outdoor unit is very exposed.