Why Does My AC Stop Working at Night?

Updated: Feb 15, 2024 5:03 PM


Even if you have a top-tier AC unit, you may eventually encounter a frozen air conditioner at night. This air conditioning issue can be stressful as your home struggles to reach a comfortable temperature at night, especially during the summer heat. Moreover, an air conditioner might stop working at night because the electricity is being overused, the air filter is dirty, or an AC component is broken. Sometimes, the thermostat might not be working correctly.

Key Takeaways_

  • If the temperature drops quickly at nighttime, the pressure change can negatively affect your AC system.
  • Low refrigerant and poor airflow can cause the evaporator coils to freeze, leading to diminished cooling power.
  • If your AC contactor breaks, your unit cannot turn off or on without changing a circuit breaker switch.

If you’re still asking, “Why does my AC stop working at night?” keep reading. You may have a frozen evaporator coil whenever your central or window air conditioning unit stops working. In addition, if your AC isn’t cooling, it could be insufficient airflow. Unfortunately, air conditioning repair hacks won’t work without studying the potential causes of the problem. In either case, it’s good to know what’s happening before you call an air conditioning service.

insider tip

You need a licensed HVAC professional to diagnose and treat a Freon leak because unlicensed people cannot legally handle air conditioning refrigerants.

Why an Air Conditioner Freezes at Night

Losing air conditioning efficiency at nighttime is a common problem for AC users, indicating a fault somewhere in the system. In addition to increased electricity consumption, your AC system may cause damage to your home from water or refrigerant leaks. Luckily, proper maintenance and preventative inspections can help mitigate severe problems.

Poor Air Flow

Dirty air filters, clogged vents, and damaged AC ducts can negatively impact the airflow in your air conditioner. Unless you clean your ventilation system regularly, the dirt and dust can prevent your AC from cooling your home. Additionally, if you’re looking for the best portable AC for an RV, it’s important to look at the energy efficiency rating and noise level before making a purchase.

Low Refrigerant

If your AC stops working, the issue could be a refrigerant leak. You should look into how to fix a portable Air conditioner. Low refrigerant levels cause the evaporator coils to get too cold, leading to frozen coils.

Outside Air Temperature

As the temperature drops at night, the pressure in the AC system will drop. If the outside temperature drops too quickly, your air conditioner may lose its cooling ability.

STAT: According to a 2020 US EIA (Energy Information Agency) survey, 42% of Americans have a programmable thermostat temperature. (source)

Defective Blower Motor

If your blower motor isn’t working, your air conditioner cannot pull air from your home to complete the heat exchange process. Fortunately, a broken blower motor is easy to spot. If the outdoor unit is running, but the indoor unit isn’t, the blower motor is faulty.


A dirty air filter in an AC unit will lead to insufficient airflow, warm indoor temperatures, and higher energy bills.

Bad Contactor

An AC contactor passes electricity from your home to the air conditioner’s components. The contactor can get stuck, leading to an AC unit that won’t shut down or turn on.

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