A botched installation in Longueuil: when a simple wall-mounted air conditioner causes an unexpected flood
At AirGreen, our mission is to step in when others fall short. That’s exactly what happened during an urgent service call in Longueuil, where a distressed homeowner contacted us after their newly installed wall-mounted air conditioner literally flooded their living room. What should have been a straightforward comfort upgrade turned into a nightmare due to a poorly executed HVAC installation by an inexperienced company.
In this article, we’re sharing this true story with precise technical details, practical advice, and a clear demonstration of our HVAC expertise in Longueuil and on the South Shore.
The context: a satisfied homeowner… until the deluge
It involved a couple who had recently moved into a newly renovated bungalow in a quiet residential neighbourhood in Longueuil. Wanting to improve their summer comfort, they chose a 12,000 BTU wall-mounted air conditioner from a generic brand, sold with included installation by a newly launched local company.
During the first few weeks, everything seemed to work fine. Until one evening, after a particularly hot and humid day, they heard a concerning gurgling sound in the living room. Within minutes, water started running down the wall, flooding the newly installed floating floors.
AirGreen’s diagnosis: a critical installation error
When we were contacted, our team responded quickly, equipped with all the necessary diagnostic tools. Here’s what we discovered:
1. Improper drainage connection
The drain hose for the wall-mounted unit had not been properly sloped downward toward the exterior. Worse still, it was connected against the direction of gravity, which caused condensate backup inside the indoor unit.
2. Missing condensate pump
In setups where the wall unit is installed below the potential exit point for the drain hose (a common scenario in split-level homes), a condensate pump is essential. In this case, nothing had been planned, despite a clearly unfavourable slope.
3. Improper mounting on the wall
The unit was not properly sealed to the interior wall, allowing warm, humid air to leak in. This led to condensation buildup, which had nowhere to go.
Our intervention: a tailored and lasting solution
Once the root of the problem was identified, we performed a complete uninstall of the incorrectly mounted unit. Here’s how we secured and optimized the installation:
1. Replacement with a reliable unit
We recommended a trusted model: the FUJITSU KZAS 12,000 BTU wall-mounted heat pump, equipped with an intelligent drainage system, known for its reliability, energy efficiency, and compatibility with available rebate programs.
2. Installation of a secure condensate pump
Our team installed a condensate pump discreetly hidden behind the indoor unit, ensuring constant evacuation of condensation, regardless of the home’s layout.
3. Full testing and calibration
Before leaving, we conducted a prolonged drainage test, pressure checks on the refrigerant lines, and airflow calibration tailored to the room’s dimensions.
Lessons learned: what every homeowner should always check
Here are the mistakes to avoid to ensure your wall-mounted air conditioner doesn’t become a source of damage:
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Always ask for proof of certification from the installer (especially RBQ certification in Québec).
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Make sure the drainage system follows proper standards (with slope or pump as needed).
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Avoid low-end models that lack built-in overflow protection.
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Go for trusted brands like Fujitsu, Gree, Sharp, or Bosch.
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Work with a company that offers a comprehensive installation warranty.
Why choose AirGreen for your wall-mounted air conditioners in Longueuil?
Our on-the-ground experience, combined with deep HVAC expertise, allows us to handle even the most complex situations. In Longueuil, and throughout the South Shore, we offer:
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A free technical evaluation on-site.
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Custom recommendations based on your home’s layout.
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Access to LogisVert grants and other government incentives.
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A satisfaction guarantee and fast, local after-sales service.
More successful installations by AirGreen
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Brossard: installed a Gree Lomo 18,000 BTU wall-mounted air conditioner with condensate pump in a triplex.
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Saint-Lambert: replaced an old unit with a Fujitsu KZAH wall-mounted heat pump, eligible for a $1,704 Hydro-Québec grant.
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Chambly: installed in an unconventional glass sunroom layout, requiring a custom airflow deflector and hidden vertical drainage solution.
Conclusion: an avoidable mistake, an irreplaceable expertise
A poorly installed wall-mounted air conditioner can cause far more than just discomfort — it can damage your home. In Longueuil, this true story illustrates the risks of careless work. Fortunately, with AirGreen, you get HVAC solutions installed with precision, transparency, and know-how.
Make the right choice—trust local expertise. Whether it’s a new installation, maintenance, or replacement of a wall-mounted air conditioner, we’re here to guide you — from diagnosis to complete satisfaction.