When you turn on your air conditioner or heat pump and notice a musty smell, dark spots, or stale air, the problem may be more than just a dirty filter. We often find that moisture, dust and poor ventilation can create conditions where mold and microbial growth develop inside ductless air-conditioning equipment. A ductless mini-split can be particularly susceptible because the indoor unit contains a cold coil, drain pan and blower wheel where moisture and dust can accumulate.

During cooling, warm indoor air passes over the cold evaporator coil. Moisture in the air condenses on the coil and drains away. That moisture is necessary for the air conditioner to remove humidity but it also means the inside of the indoor head can become cool and damp. If moisture remains, microbial growth can develop. The EPA notes that moisture and dirt in HVAC systems increase the potential for biological growth, and that controlling moisture is one of the most important ways to prevent mold growth.

A musty or dirty-sock smell when the unit starts is one warning sign that the indoor unit should be inspected and possibly professionally cleaned. Ductless systems have washable filters, but those filters don't necessarily remove everything from the air. These units generally are designed to protect the equipment from larger particles rather than filter fine airborne particles. This means a homeowner can regularly wash the filters and still have dust and buildup deeper inside the indoor unit, particularly around the blower wheel and coil. John's Home Comfort, HVAC professional can inspect and clean the areas that aren't easily visible during normal filter maintenance.

Don't forget the outdoor condenser coil

The outdoor portion of your air-conditioning or heat-pump system needs attention too. Leaves, grass, dirt, and other debris can become trapped between the outdoor condenser coils. A dirty condenser coil has a harder time releasing heat to the outdoors. This can cause the system to work harder and may reduce cooling performance and efficiency.

Does the outdoor condenser coil need to be cleaned every year? It should be inspected every year, but it doesn't necessarily need a deep cleaning every year.

If the coil is visibly dirty or restricted with debris, it should be cleaned. Homes surrounded by trees, gardens, construction dust or other sources of debris may require more frequent cleaning. We recommends periodically inspecting the outdoor unit, removing leaves and debris, keeping vegetation away from the unit and checking the coil for dirt between the fins.

John's Home Comfort can perform yearly maintenance visit that includes inspection of both the indoor and outdoor HVAC systems. Call today! 416.881.5425