Can Dirty Coils in Mini Split Cause No Cold Air?

Dirty coils in a mini-split system can indeed cause the unit to blow warm or no air. When the coils become dirty, they can’t effectively remove heat from the refrigerant, which can lead to a decrease in cooling performance. This issue can be caused by a lack of regular maintenance or cleaning of the system.

Identifying the Problem

The first step in addressing this issue is to identify the problem. If your mini-split system is not blowing cold air, it’s essential to inspect the coils for any signs of dirt or debris buildup. You can do this by turning off the unit and removing the front panel to access the coils.

Look for the following signs that the coils may be dirty:
– Visible dirt or dust buildup on the coils
– Ice formation on the coils
– Reduced airflow from the unit

If you notice any of these signs, it’s likely that the dirty coils are causing the lack of cold air.

Cleaning the Coils

can dirty coils in mini split cause no cold airImage source: Flickr

Once you’ve identified the problem, the next step is to clean the coils. Here’s a step-by-step guide on how to do it:

  1. Turn off the unit and disconnect it from the power source: Before you start, it’s essential to turn off the mini-split system and disconnect it from the power source to ensure your safety.

  2. Allow the ice to melt or gently remove it: If there is ice formation on the coils, you’ll need to allow it to melt or gently remove it. Avoid using sharp objects or excessive force, as this can damage the coils.

  3. Wipe down the coils: Once the ice has melted, use a dry cloth to wipe down the coils. Be gentle and avoid applying too much pressure, as this can also damage the coils.

  4. Ensure the system is dry: After cleaning the coils, make sure that all the moisture has been removed from the system before reconnecting it to the power source.

  5. Check the refrigerant level: If the coils were heavily soiled, it’s possible that the refrigerant level may have been affected. Use a refrigerant gauge to check the level and add more refrigerant if necessary.

  6. Clean or replace the air filter: In addition to cleaning the coils, it’s also essential to clean or replace the air filter regularly. A dirty air filter can restrict airflow and cause the unit to work harder, which can lead to decreased cooling performance.

Maintaining the System

To prevent the coils from becoming dirty in the future, it’s essential to maintain the mini-split system regularly. Here are some tips:

  • Clean the coils every 6-12 months: Depending on the environment and usage, the coils may need to be cleaned more or less frequently. It’s a good idea to schedule regular maintenance checks to ensure the system is running efficiently.

  • Replace the air filter regularly: Most manufacturers recommend replacing the air filter every 3-6 months, or more frequently if the system is used heavily.

  • Keep the outdoor unit clean: The outdoor unit of a mini-split system can also accumulate dirt and debris, which can affect the system’s performance. Regularly clean the outdoor unit to ensure proper airflow.

  • Consider professional maintenance: If you’re not comfortable performing the maintenance tasks yourself, consider hiring a professional HVAC technician to service your mini-split system. They can ensure that the system is running at its optimal performance and identify any potential issues before they become a problem.

By following these steps and maintaining your mini-split system regularly, you can ensure that it continues to blow cold air and operate efficiently.


Dirty coils in a mini-split system can indeed cause the unit to blow warm or no air. By identifying the problem, cleaning the coils, and maintaining the system regularly, you can ensure that your mini-split system continues to provide reliable and efficient cooling.

Remember, if you’re not comfortable performing the maintenance tasks yourself, it’s always best to consult with a professional HVAC technician to ensure the safety and proper operation of your mini-split system.