A clogged filter might seem like a minor issue, but it can lead to far greater financial and functional consequences than you’d expect. At AirGreen, we were recently called in to service an HVAC system in Montréal, where a clogged wall-mounted heat pump filter ended up causing a major breakdown—costing over $500 in repairs for a residential homeowner. This true story perfectly illustrates why regular HVAC maintenance is essential and highlights key mistakes to avoid in order to keep your system performing at its best for years to come.
A struggling Gree wall-mounted heat pump in Outremont
Our client, living in the Outremont neighbourhood of Montréal, owned a Gree Lomo 12,000 BTU wall-mounted heat pump, installed two years earlier by another contractor. For several weeks, the homeowner had noticed a drop in performance, unstable indoor temperatures, and a noticeable spike in their electric bill. They wrongly assumed the unit was near the end of its lifespan or that the compressor was failing.
After performing a full inspection, our technicians quickly discovered that the indoor filter was completely clogged with dust, pet hair, and fine particles. This lack of maintenance had blocked proper airflow and caused the compressor to run under heavy strain.
The result: $500 in repairs and a stressed compressor
Due to prolonged overheating, the system entered safety shutdown mode. Even worse, condensate had built up inside the indoor unit, overflowing and damaging the adjacent wall, which then required additional repair work. The client ended up paying for:
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A full cleaning of the indoor unit
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Replacement of a damaged temperature sensor
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Minor repairs to the wall damaged by moisture
Total bill: $527.
All of this could have been avoided with a simple $95 preventive maintenance service.
Why a clogged filter is your heat pump’s silent enemy
A clogged filter doesn’t just block airflow. It causes:
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Overload on the motor and compressor
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Higher energy consumption
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Drastically reduced lifespan of the unit
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Risk of condensate leaks and moisture damage in walls
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Heavily degraded indoor air quality
These issues are especially common in Montréal, Laval, Longueuil, the North Shore and the South Shore, particularly in winter when units run almost constantly.
Our advice to avoid costly breakdowns like this
At AirGreen, we recommend that all our clients:
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Clean or replace filters every 4 to 6 weeks
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Schedule annual professional HVAC maintenance, especially before winter
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Regularly check for strange noises or water droplets near the unit
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Watch for signs of underperformance: weak airflow, lukewarm air, rising energy use
We’ve set up flat-rate maintenance packages that help ensure optimal HVAC system performance and extend the lifespan of your equipment.
The AirGreen approach: vigilance, prevention, and expertise
Our certified technicians respond quickly across Montréal, Laval, Longueuil, the North Shore and South Shore, whether for a wall-mounted heat pump installation, emergency repair, or preventive maintenance. In the case of our Outremont client, not only did we repair the damage, but we also set up an automated maintenance schedule with reminders and yearly visits.
This kind of follow-up helps avoid costly surprises and ensures year-round comfort, winter and summer alike.
The key takeaway
A breakdown caused by a clogged filter can cost you up to five times more than a simple maintenance check. It can also jeopardize expensive components like the compressor or control board. Don’t let a forgotten little task turn into a big, expensive problem.
Trust AirGreen to care for your HVAC system with precision, transparency, and efficiency. Our clients choose us for our expertise, responsiveness, and our reliable, human-focused approach.