Why does my AC keep Freezing up at Night? Reasons and Troubleshooting Tips

In summer we mostly use air conditioning to provide a comfortable and cool environment. But this does not happen when the air conditioner is facing some technical faults or not working well. The very common problem with with AC unit is freezing up. We can find this when there is frost on the copper tubing of ac unit or other parts of ac. Here we will discuss the main reasons for AC freezing up and learn how to solve this issue. So let’s get started with why my AC keeps Freezing up at Night.

What are the Signs of AC Freezing Up? 

  1. The basic indication of AC freezing up is ic on your refrigerant line set pipe. just check the outdoor AC unit and home external all that there is ac line frozen.
  2. There can be a frozen evaporator coil. It is not easy to check. There is a need to open a panel on the indoor unit for inspection.
  3. Another sign is AC is not sending cool air back into the house.
  4. There is condensation created on the indoor unit and external side of the condensate drain

Why Is My Air Conditioner Freezing Up?

AN ac freezes up when there is ice created on the unit, the frozen AC line, or when ice is made on the evaporator coil. The first two causes can be found with a visual check. But finding either evaporator coil is frozen is a sticky process and needs an expert. Here the main causes of conditioner freezing up explained

The Air Filter is Dirty

The main function of the air filter is to get air pollutants like dust, dirt, and mold and put them away from ac ducts. The constant airflow maintains the evaporator coil free from humidity. The filter comes with a porous structure for good filtration operation. The creation of dust particles on the surface can restrict and affect airflow to the HVAC system, help humidity, and cause freezing to build up.


Many engineers suggest changing the air filter after 3 to 4 months. But for changing the filter first of all check the air filter type, number of people living, smoke in the room, duration of AC use, and people that have health issues like COPD, allergies, or heart disease. The main method to check that an air filter is needed is to check whether that light shines through a filter or not.

 Low Refrigerant

The low refrigerant level is a very common problem. The ac features to sustain consistent temperature are based on refrigerant. Mostly refrigerant leaks are not known for longer duration and are found in refrigerant lines, compressors, or evaporator coils. Low refrigerant levels affect the working of the evaporator coil causing moisture accumulation. With time it causes the coil to freeze up. Delay in restoring needed refrigerant levels can result in harsh effects on compressors and replacing or chain-affected compressors can be a costly process.


If there is a freon leak off the air conditioner instantly.  Get the services of an HVAC professional to find leakage

Faulty Air Duct 

Ducts are paths for providing and removing air from the HVAC system. The normal flow of air is impeded by leaks and obstacles, which keeps warm air from reaching the coils and freezing them.


  • Check dust particles and hurdles like curtains, air vents
  • Ensure that you are doing regular maintenance
  • Contact with an HVAC technician

 Dirty and Clogged Coils

Evaporated coils get heat from the air in the homes and convert heat into cool air. Another means its main function is to exchange heat. Since the coil is damaged it gets dust particles easily and direct coils affect the airflow.

First of all off the ac to avoid more damage. When it cleans dirty evaporator coils ask the technician to check it

 Thermostat Levels

In some AC units, there is a predetermined temperature range and they do not work if the external temperature is less than 60°F. So there are freezing issues due to low evening temperature which prevents air conditioning from operating well. it also reduces pressures in AC and causes freezing

  • off the unit and make it thaw
  • Not use AC unit in complete night
  • Put the thermostat at a low level in heat waves
  • if issues still exist get the services of experts

 Blower Fan Damaged

Drawing warm air in ducts and circulation of cool air through the house is the main operation of the blower fan. But this heat transfer process cam affected of blower fan is not working accurately. Without enough airflow coils and refrigerant lines can freeze.


Get the services of an HVAC technician to find the age and overall condition of the blower fan and motor. it must check fan rotation speed and power output to ensure sure best operation. Based on damage it can be changed or repaired

Blocked Vent Returns and Registers

HVAC vents and registers are made for pul in warm conditions, and humid air, and carry to handle where it gets cooled and dehumidified. Many people do not know that vent blockages or many vents closed off can cause an AC to freeze. If not enough air circulates through the coil moisture condenses and freezes.

off the thermostat or fan position and allow it to thaw.
Not closing more than two to three supply vents

How Do I Keep My Air Conditioner From Freezing Up?

  1. The main step is to avoid frozen air conditions by varying filters. In other words from four to twelve times in year based on air filters and people living under unit
  2. Do the HVAC professional check of your AC system in spring. AC unit service can stop frozen air conditioners and other AC faults and also increase the operating life of the system.
  3. Ask the technician to check the air filter for dirt, coil for grime, refrigerant level, drain blockage, and blower fan for accurate rotation and speed.
  4. HVAC pro checks the air ducts for accurate airflow. In some cases, it is difficult to do due to complications and difficulty in getting an air ductwork system.

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