Air conditioner owners are often confused as to why ice forms on the evaporator coils of their cooling systems, even when it is boiling outside. An air conditioner is a complex HVAC appliance, but through attention to some minor details, air conditioner owners can understand it easily.

Before you call a mechanic for AC repair in Phoenix, you should know the reasons that lead to ice formation. Knowing these reasons can help you avoid them in the future and save you money. Here are the most common reasons for ice on the coils:

Airflow Problems Due To Dirty Air Filters

Air filters not only purify your indoor air and keep it free of bacteria and viruses but also maintain smooth airflow within the air conditioner. Without air filters, the internal part of your air conditioner will be full of dirt and dust.

Sometimes, the airflow does not remain smooth due to dirty air filters, and dust enters the system. This dust settles on the evaporator coils, due to which the refrigerant will not absorb any heat from the indoor air, decreasing the temperature to the extent that ice forms on the coils. Keep your air filters clean to avoid this problem.

Less Refrigerant

Several reasons can lead to less refrigerant in the evaporator coils, like excessive usage and leakages. Irrespective of the reason, the consequence is the same. When the refrigerant is insufficient, it will expand more, and the temperature around the coils will decrease, leading to ice formation.

Some signs of less refrigerant are inefficient cooling and hot and cold pockets in the house. If you notice such signs often in your home, you should contact a technician for HVAC repair in Phoenix .

Mechanical Faults

An air conditioner has numerous parts that may malfunction due to numerous reasons. Components like fans and condenser coils can also lead to ice formation on the evaporator coils.

Air conditioner owners can not possibly know about all these components in detail and fix them themselves. In such cases, air conditioner owners should schedule regular maintenance and service schedules for their cooling systems. In these schedules, the technicians will thoroughly inspect the whole system for faults and damages that may trouble you in the future and repair them.

Outside Temperature

An air conditioner has a fixed outside temperature range at which it works efficiently. If the outside temperature is above or below that range, it will not perform at its highest efficiency levels.

Let us assume that the outside temperature is not as hot as it feels and is below the fixed temperature range. In this case, if you continue using your air conditioner, the refrigerant in the evaporator coils will continue expanding as there is no heat to absorb from the indoor air, leading to ice formation on the surface.


LJ Refrigeration Co, Inc. is one of the best HVAC companies in Phoenix and has years of experience dealing with air conditioners and other appliances.

Contact us at  (480)-948-5004  or email us at [email protected]. to know more about our services.