Window air conditioner has ice or frost on the coil: A DIY troubleshooting guide

Ice or frost buildup on air conditioner coils is a common issue, but the good news is that it’s usually a manageable problem if you know what to look for. Stick with us to learn how you can get your window unit back in tip-top shape.

If you find out that you need any replacement parts for your air conditioner while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The troubleshooting information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

What you need

• Screwdrivers
• Vacuum cleaner
• Soft-bristle brush

Important: The specific tools required may vary depending on the model of your appliance and the type of fasteners used on it. Always consult the user manual or refer to any specific instructions provided by the manufacturer for the recommended tools for your appliance model.

Read more: How to get better air quality from your window air conditioner  

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind:

• Always power off and unplug your appliance or switch off the circuit breaker before you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock.
• If the appliance has recently been used, give it plenty of time to cool down before working on it.
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part.
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Consider wearing safety glasses and/or a dust mask when working with chemicals, dust or a large amount of debris to prevent irritation or injury.

Read more: How to troubleshoot & fix common window air conditioner problems

How to troubleshoot a window AC with an ice-covered coil

If the entire evaporator coil is covered in ice, it suggests that the outside temperature is too low for the air conditioner to operate correctly. Window air conditioners are designed to operate in warmer outdoor temperatures, typically above 65°F (18°C). If the outside temperature drops below this threshold, then the AC’s compressor may not be able to maintain the necessary pressure and temperature differential to keep the evaporator coil from freezing.

If the evaporator coil is completely covered with ice, you should turn off the air conditioner and allow the ice to melt naturally. Once the ice has fully melted, you can try operating the air conditioner again, but be prepared to turn it off if the icing issue persists.

How to troubleshoot a window AC with a partially frosted coil

Inspect the evaporator coil, which is usually located behind the front panel of the air conditioner. If the evaporator coil is partially or unevenly frosted, it means that the system is low on refrigerant. An ice ball on the refrigerant lines can indicate that there’s a restriction in the system.

To confirm this, use a refrigerant leak detector or have a professional HVAC technician check the refrigerant level. If the refrigerant level is low, then a licensed HVAC technician will need to recharge the system with the proper refrigerant type and amount.

Read more: How to Clean Your Air Conditioner the Easy Way  

Additional information

Thank you for reading! We hope this guide helped you get your window air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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