How to Defrost an Air Conditioner. Step by Step

How to Defrost an Air Conditioner. Step by Step

AC Frozen How to defrost your ac unit safely

You are finally home after a hot, bustling day and turn on your AC just to find out that it is blasting hot air! If your AC unit’s cooling capacity reduces, you should first check if the system is frozen before troubleshooting it further or calling a technician.

A frozen air conditioner in the middle of the sweltering summer heat can be an absolute pesky and frustrating inconvenience. What then is the solution? How do you unfreeze an air conditioner? Here’s a sneak peek look at how to defrost AC unit and get it up and running without calling for an AC repair:

  • Turn off the thermostat
  • Switch the fan ON
  • Dry up the AC coils after thawing
  • Check the air filter
  • Check that there are no blockages on the air vents
  • Switch the system on
  • Keep a close eye on the unit and call a professional if you notice any thawing

But before we get into the details of how to unfreeze an air conditioner, let’s first get a few things out of the way.

Is My Air Conditioner Frozen?

Keeping a frozen air conditioner running could easily damage your compressor, which is extremely expensive and exhausting to repair. But how can you tell is your AC frozen in the first place?

Here are a few telltale signs of a frozen unit:

  • Your AC system isn’t reaching the desired thermostat setting
  • The air blasting from the air registers feels warm
  • Your electric bill is higher than usual
  • Water leaking around the AC
  • Hissing or bubbling noise
  • Condensation and moisture around the air handler
  • AC coils are encased in ice
  • Ice is visible outside the AC unit

Why Is My Air Conditioner Frozen?

Your air conditioner can freeze up for a variety of reasons. Let’s look at some of the most probable cause of a frozen AC.

  • Poor Airflow In Your AC’s Evaporator Coil

Lack of proper airflow to keep the air conditioning coil warm can lead to ac frozen. Warm air from the surroundings of the ac is used to keep the air above the freezing point to avoid the condensed water from freezing on the coil.

Air registers can get clogged or blocked, leading to insufficient airflow over the AC’s evaporator coil. A dirty air filter can also cause a constricted airflow within the AC unit. This can hamper the active heat exchange in the unit leading to a consistent drop in temperature. Without proper airflow, the temperate in the coils will drop below freezing, and any humidity in the air will collect on them and freeze.

Besides blocked air registers, there are other causes of insufficient airflow that may require professional attention. These include:

  • Tight or improperly sized filter
  • Blower motor (or fan) isn’t working correctly
  • Dirty heat pump and air handler
  • Blocked return grills and closed vents
  • Undersized or damaged ductwork
  • Damaged Blower Fan

The blower fan helps to ensure balanced air circulation within the air conditioning unit. Typically, as the air cools inside the AC unit, it becomes denser and doesn’t circulate well within the house. The blower fan pushes hot air from your space, allowing the cooler denser air to circulate freely within the room.

If the fan gets damaged, the entire air circulation system inside the AC and in your house is messed up, causing the refrigerant line to freeze.

  • Low Refrigerant

Refrigerant leaks or low levels of refrigerant can lead to a frozen AC. The refrigerant is built to collect heat from your house and conduct it outside. It is then sent through the compression and condenser, converting it from liquid to gas repeatedly. This helps the AC to maintain low, comfortable temperatures within the house.

However, when your unit has low refrigerant, the air pressure inside the unit is decreased, and the air-to-liquid cycle is not reached efficiently. As a result, the refrigerant’s temperature falls below 32 degrees F, causing the evaporator coil to get too cold. This makes the air moisture to freeze and accumulate on the coil.

How To Unfreeze an Air Conditioning Unit

The buildup of ice and frost on your AC unit is a surefire sign that your air conditioner is not operating correctly. A frozen unit should be defrosted immediately to prevent damage to the compressor unit that may cost your time and money. Let’s get into the details of how you can defrost the AC unit.

  • Turn off the thermostat

When the AC unit starts to freeze, it means that the refrigerant’s temperature is lower than usual. A functional AC unit works by sending superheated refrigerant gas to the compressor and not liquid.

Turning off the power and switching off the circuit breaker ensures that the cold fluid does not flow to the compressor and possibly cause damage that can cost your hundreds of dollars to repair. It is also important to switch off the power to protect yourself and the equipment while you work on identifying the root cause problem of the frozen AC unit.

  • Switch the fan ON and wait for the AC unit to thaw completely

The second step is to turn your fan to ON. This ensures that the fan blows warm air over the AC’s coils to hasten the defrosting process.

How Long Does it Take to Defrost My AC Unit?

A common question among many people experiencing a frozen AC issue is: How long does it take to thaw a frozen air conditioner? Well, the thawing process could take up to 24 hours depending on the size of your unit, the extent of the ice buildup, and the efficiency of your blower fan. If the freezing on your AC unit was just starting, it could clear up faster in an hour or two.

While you wait for the AC to that, it is crucial that you keep an eye on the drain pan and the condensate pan. As the ice thaws, it will melt and collect on the drain pan, which then directs the water to the condensate pan draining it outside.

When dealing with huge ice accumulation, it may melt very fast, leading to an overflow in the drain pan. Having some towels around the pan can prevent water spillage around the house in case of an overflow. It’s important to periodically check for water that might have collected under your evaporator coil and mop it up.

An overflowing drain pan can also be a red flag of another concealed problem—a Clogged condensate drain. The condensate drain collects melted ice from the drain pan and directs it outside. Sometimes, ice can form inside the pipe leading to a blockage. Dirt and debris could also collect inside the condensate drain, leading to a blockage over time.

If you have a clogged condensate drain, there are a few things you can do to clear it up.

  • Get out your wet/dry vacuum
  • Find the main drain line outside of your home
  • Connect the vacuum hose to the main drain line, ensuring a secure seal
  • Turn the vacuum on and let it run for 3 minutes to clear off any blockages

IMPORTANT: You should never attempt to scrape off the ice on the AC unit as this could damage the coils and possibly damage your unit permanently. Always let the ice thaw naturally.

  • Dry up the AC coils after thawing

Where possible, you can wipe off any excess water on your evaporator coils with a soft cloth to ensure that the unit does not freeze up again. A soft wipe on the coils will also prevent odors from building up.

  • Check the air filter

A dirty filter can cause a constrained airflow in the AC, leading to ice buildup on your system. It could be the underlying cause of this sweaty debacle you now find yourself in.

To fix it, you need to locate your AC’s return vent and unscrew its cover to get to the filter. Slide-out your filter and check for any damage. If none is found, clean it with a dry piece of cloth or slightly moist and slide it right back.

If the air filter is found to be dirty or damaged, replace it with a new one and slide the new filter right back – any home improvement store will have the required filter.

Ensure that you put the filter correctly, through the right side, and not backward. Away from the return duct and towards the air handler, there is always an arrow to point you in the right direction.

  • Check that there are no blockages on the air vents

For the AC unit to work effectively without freezing up, the air needs to be able to enter freely and disperse itself accordingly. Ensure that all air vents and registers around the house are open and not blocked by furniture. If there are any blockages, clear them up to ensure unobstructed airflow in the home.

  • Switch the system on

Once the AC unit has thawed completely, and you’ve done a check on the filters and the air registers. It is now time to fire the system on. Switch ON the thermostat and set it at COOL. If the AC is working correctly, the air registers should blow cold air into the room.

It is crucial that you keep a close eye on the system to ensure that the system is in its best shape, and there are no other underlying issues. If the system keeps freezing, that’s usually a sign that something is wrong.

Frozen AC Professionals in San Antonio and Houston, TX

The following steps on how to unfreeze air conditioner should help you thaw your AC unit without a hassle. However, if you continue experiencing the freezing on the unit, you should call a professional to have it checked up.

At Texas Air Repair, we pride ourselves on being the best air conditioning company  in San Antonio, Houston, and all of the areas in between. If your AC is frozen even after following this “how to defrost ac unit” guide, we can send a tech over to your house to get run a check on your system. In addition to repair services, we also provide preventative maintenance services to ensure that your AC unit functions optimally through the hot season.

Even if your air conditioning or heating system goes down when you need it most, you can always count on us to provide you with a solution.

Call (210) 380-8000 or contact us online to speak with a frozen AC repair expert.

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Texas Air Repair offers air conditioning, heating, and indoor air quality services to residential and commercial customers in San Antonio, TX & the surrounding areas with their 25+ years of experience.

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About Us

Texas Air Repair offers air conditioning, heating, and indoor air quality services to residential and commercial customers in San Antonio, TX & the surrounding areas with their 25+ years of experience.