A Step By Step Guide on How to Defrost Outside AC Unit in winter 

An outside AC covered in snow.

The winter weather might cause your outside AC unit to freeze and catch you unprepared, wrecking the comfort of your home. You can leverage the situation if only you know how to defrost your unit. Whatever you do, do not attempt to use your AC as long as it has frost.

You can keep your air conditioner from freezing by having technicians get your HVAC ready for winter. However, all is not lost, as you can learn how to defrost an outside air conditioning unit. If you are lucky, you can find a technician to help you defrost the air conditioner.

How to Defrost Outside AC Unit in winter

You have alternatives when looking for a suitable way to defrost your outside air conditioner. Every choice has its advantages and disadvantages. The four options you can choose when defrosting vary in speed. The best thing to do is to consult an AC expert.

Here are some activities to help you defrost your AC unit.

  • Defrost your outside unit naturally- With this alternative, you won’t have to do anything to the unit. Instead, you leave it for an entire day to thaw itself. It’s an alternative that is as effective as it will test your patience.
  • Use a hair dryer- Using a hair dryer is an option you can explore if you are in a hurry. All you have to do is ensure you don’t set the temperature too high. Defrosting an AC unit with a hairdryer only takes about an hour.
  • Using heat- You may use a blow torch to defrost your unit, but you risk cracking the evaporator coils. Hot water could also work, although it could also damage your AC unit.
  • Use fan-only mode- Turn off the AC unit and run the fan. The fan will push warm air throughout your AC unit, and you must wait a maximum of two hours.

You have to be careful when settling for an alternative. This article will show you how to handle a frosted outside AC unit when you can’t get in touch with your technician.

Let’s look at the step-by-step process of naturally defrosting an outside AC unit and using the fan-only mode in winter that will get your air conditioner up and running.

Step 1: Turn Your AC Unit Off Beforehand

A running AC that keeps your house comfortable to spend time is almost mandatory while staying indoors for long periods of time. By turning off your AC before defrosting, it’ll go a long way towards preventing short circuiting and potential electrical damage to the unit. Turning the system off will also prevent having to pay to replace the compressor.

After turning off the device, it’s also best to switch the thermostat settings from COOL to OFF.

Step 2: Switch Fan Settings to On

The fan will start blowing warm air over frozen coils, which hastens to defrost. Ensure you set it to ON and not AUTO since automatic settings cause the system to short cycle. Leaving the settings on ON delivers continuous airflow to the frozen parts of the system.

Step 3: Look for Whatever Caused Behind the Frost

The third step requires you to do some inspection of the air conditioner. First, you have to know what parts to examine. They include:

  • The air filter: A clogged air filter essentially suffocates the AC system. Typically warm air circulates through the system after coming through the air filets. Lack of warm air supply allows ice to form on coils. Replace an air filter and try to do it every month.
  • Evaporators Coil: Check if the evaporator coils are dirty—dirt and grime on the coil restrict air from circulating through the unit. Clean the dirt and grime to keep your outside air conditioner from freezing.
  • Refrigerant Leaks: Looking for refrigerant leaks should be the first thing you do to figure out how to defrost your outside AC unit. Refrigerant leaks reduce the refrigerant pressure and allow the moisture in the air to freeze on the coils.

The refrigerant is supposed to remain at the levels the manufacturer put it. It’s never supposed to evaporate. So a reduction in refrigerant levels indicates a leak.

A technician has the skills to fix refrigerant leaks. However, attempting to repair a refrigerant exposes you to harm, as refrigerants are hazardous.

  • Other broken-down components: A malfunctioning component in an air conditioner could be why it has frost. There are secondary components in an AC, such as valves and ducts. A closed valve could cause frost on an outside air conditioning unit. Let a qualified technician find the solution for such a problem is best.

Step 4:  Watch Your Air Conditioner

After following all the steps from the first one to the third one, the next step is to watch how the system behaves. Wait for your AC to thaw out. A lot of water will likely start flowing from the unit, causing an overflow in the drain pan.

You can run the unit once again after it dries up. Then, listen to it and monitor it more over the next few hours. Take note of any abnormalities and make a point of contacting a technician.

Step 5: Perform Preventive Maintenance and Inspection

If you did all the steps above yourself, the next step is to call your technician to schedule preventive maintenance and inspection on the system. Again, please do this even though your unit seems to run as it should.

Preventive maintenance allows you to catch issues quickly before they become major problems. Unfortunately, the number of things you can do as an unskilled homeowner in an attempt to defrost your AC is limited. You need an expert eye to spot what you might have missed.


It’s essential to remain calm when you find your outside AC unit covered first for you to devise a rational defrosting plan. Ensure you set the thermostat to where it’s supposed to be to initiate defrosting without risking damage to delicate parts in the unit.

AC experts are probably overwhelmed during the winter season. Still, all technicians will look at your unit if you don’t trust your skills. So let a trained technician look at your unit even if you succeed in defrosting your outside AC unit.

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