When summer heat hits St. Albert, homeowners rely on air conditioners to keep indoor spaces cool and comfortable. But what happens when turning on the AC leaves your home smelling musty instead of fresh? That earthy, damp smell is more than just unpleasant — it can be a sign that something is not working properly inside your cooling system or ductwork.
Ignoring this problem can make it worse over time. Musty smells usually do not go away on their own, and they often point to moisture buildup or airflow issues that impact your indoor air quality. A home that smells like mildew every time the AC runs can become uncomfortable quickly, especially for anyone with allergies. If you are noticing the smell every time your system turns on, it is time to take a closer look at what might be causing it.
Common Causes Of Musty Smells After Running The AC
A properly functioning AC system should cool your home without any unpleasant odours. When a musty smell comes through the vents, it means something is wrong behind the scenes. Here are the most common reasons this smell can occur when running your AC during the summer in St. Albert:
1. Mold or Mildew Growth
Moisture and darkness create an ideal environment for mold and mildew. If condensation remains inside your system too long — such as on coils or in ductwork — it can start to grow. Once mold develops, spores may be pushed through the vents, causing that unmistakable musty smell to spread throughout your home.
2. Clogged or Dirty Filters
If your air filters are overdue for a replacement or cleaning, they can restrict airflow and trap moisture. This not only makes the AC work harder but also gives dust and organic matter a chance to cling to the damp surface, which can feed mold or mildew. Musty smells are often a side effect of neglected filters.
3. Drainage Issues
Your air conditioner removes humidity from the air as part of the cooling process. That moisture typically flows through a drain line that leads outside. If the line becomes clogged or partially blocked, water collects inside the unit, where it can stagnate and start producing odours.
4. Stagnant Water in the Condensate Pan
A full or cracked condensate pan can allow standing water to sit inside the system. If the water remains there and does not drain properly, bacteria and mold can begin to grow. Every time the AC runs, the air passing through picks up that odour and carries it into your living space.
5. Dirty Evaporator Coils
Evaporator coils sit inside your indoor unit and are responsible for chilling the air. Over time, they collect dust, hair, and moisture. This grime creates ideal conditions for mold growth. If these coils are not cleaned during maintenance visits, the odour can start to flow through your ductwork.
A homeowner in St. Albert once contacted us with a persistent musty smell that had lasted for weeks. After a detailed inspection, we found a clogged drain line and a very dirty filter. Once those issues were resolved, the musty smell disappeared. This shows how small issues, if ignored, can become bigger problems.
Steps to Identify and Address Musty Smells
When you first notice a musty smell after turning on the AC, it is important to investigate the issue right away. Acting early can prevent airflow problems or worsening air quality in your home. These practical steps can help identify the source of the smell and begin resolving it:
1. Inspect and clean your air filters
If the filters look dirty or clogged, they could be restricting airflow and trapping moisture. Replace them with good-quality filters, and consider checking them more frequently during the summer.
2. Check for visible mold or mildew
Examine the vents, return ducts, and around the indoor unit for signs of mold growth. Look for black, green, or grey build-up, and contact a licensed HVAC technician for removal.
3. Ensure water can drain properly
If you have access to your AC’s drainage line or pan, inspect them for blockages. Standing water in the drainage system can be a major source of stale smells.
4. Clean or flush the condensate pan
If the condensate pan is full or dirty, it may need cleaning or flushing. In some cases, a technician may need to remove and clean the pan thoroughly to restore proper drainage.
5. Schedule a deep cleaning of the evaporator coils
These coils are hard to reach and often overlooked, but they are a common source of odours. A professional cleaning can remove the buildup that leads to mold and improve airflow efficiency.
A homeowner in St. Albert recently noticed a persistent odour in the hallway every time the AC turned on. The air filter was clean, so another issue had to be the cause. Upon inspection, our technician discovered a partially clogged drain line that caused moisture to build up near the coil. As soon as the obstruction was removed and the area dried and cleaned, the smell faded in less than a day.
Preventive Measures To Keep Your AC Smell-Free
Once your AC system is back to smelling clean, regular upkeep can help stop musty odours from returning. Taking preventive steps ensures more comfortable air and helps reduce allergy risks in your home.
To help keep your AC in St. Albert free from musty smells, consider the following habits:
1. Schedule regular maintenance checks with our professionals
A professional inspection can find and address minor problems before they become major repairs.
2. Use high-quality air filters
Low-quality filters clog faster and allow more moisture and dust into the system. Upgrading your filters and changing them often leads to better airflow and reduced chance of odour.
3. Keep the area around your indoor unit clean and dry
Avoid storing items near your AC unit, and check for any signs of leaks or excess moisture in the area.
4. Monitor indoor humidity levels
In humid summers, extra moisture can linger indoors. Use a dehumidifier if needed to keep levels in a comfortable range.
5. Book professional duct cleaning services when appropriate
Dust and mold hidden inside ducts can affect the air coming through your vents. Routine duct cleaning can improve system performance and remove lingering odours.
These small efforts have a major impact on indoor comfort. A clean AC system not only improves how your home smells but also allows the system to run more efficiently.
In St. Albert, summer air tends to carry extra humidity. If that moisture hugs your ductwork and filters, it triggers conditions for mildew and odours. By reducing moisture, keeping airflow steady, and booking cleanings on time, you limit the risk of unwanted smells.
Maintaining a Fresh and Comfortable Home Environment
A musty-smelling home can quickly affect your comfort and peace of mind during hot summer months. These smells usually signal trapped moisture or a blocked airflow within your AC system. Cleaning and maintenance are the most effective ways to fix the problem before it becomes more widespread.
Ignoring the smell leads to reduced air quality and more stress on your AC system. Whether your home has had the issue for a few days, or it has lasted throughout the season, it is worth having it inspected properly. Our technicians can identify the exact cause and restore fresh airflow.
Regular maintenance and attention to problem areas like the drain line and filters help protect your air quality and comfort long term. With consistent care, homes in St. Albert can stay fresh and cool all summer.
If you are dealing with persistent musty odours and suspect hidden issues with your cooling system, trust the team at Acclaimed! Heating, Cooling & Furnace Cleaning for dependable AC service in St. Albert to keep your home comfortable all summer long. For a quick estimate or to book a service visit, please contact us today.
