Step-by-Step Guide: How To Replace an Evaporator Coil

Your home’s heating, ventilation, and air conditioning (HVAC) system works tirelessly to ensure a comfortable living environment. The evaporator coil plays a crucial role in this system by absorbing heat from the surrounding air and transferring it outside, ensuring cool and comfortable indoor temperatures. However, like any other component in the HVAC system, the evaporator coil can deteriorate over time, necessitating a replacement. This step-by-step guide simplifies the process of replacing an evaporator coil for homeowners and DIY enthusiasts.

Before diving into the replacement process, it’s important to understand the signs that indicate a failing evaporator coil. Common symptoms include a decrease in cooling efficiency, frost or ice buildup on the coil, unusual noises from the air handler or furnace unit, and increased utility bills despite normal usage. By identifying these early warning signs, you can prevent further damage to your HVAC system and avoid the hefty repair costs involved.

When it comes to replacing the evaporator coil, there are several factors to consider, such as the type of coil and compatibility with your HVAC system. This guide will provide insight into the different types of evaporator coils and offer expert advice on choosing the right one for your specific needs.

Equipped with a list of essential tools and materials, you’ll be well-prepared to tackle the replacement task without any hiccups. It’s crucial to follow safety precautions when working with electrical components, and our guide will highlight vital safety guidelines to ensure a hazard-free experience.

Featuring detailed step-by-step instructions, Stiles Services, a leading HVAC contractor in Georgia, will guide you through the process of replacing an evaporator coil, from opening the air handler or furnace unit to installing the new coil and sealing the system. Furthermore, we’ll discuss troubleshooting common issues that may arise during the replacement process and provide expert tips on maintaining your evaporator coil for long-lasting performance.

Incorporating visuals and diagrams for clarity, this comprehensive guide is your ultimate resource for replacing an evaporator coil and keeping your HVAC system working efficiently.

Signs That Your Evaporator Coil Needs Replacement

Identifying the early signs of a failing evaporator coil can save you time, money, and headaches. A damaged coil may result in reduced cooling efficiency and potentially costly damage to your HVAC system. Here are some common signs that your evaporator coil needs replacement:

  1. Reduced Cooling Efficiency: If your home struggles to stay cool despite the air conditioner working at full blast, the evaporator coil could be the culprit. An inefficient coil can’t absorb heat properly, leading to poor temperature regulation.
  2. Frost or Ice Buildup: A malfunctioning evaporator coil can result in frost or ice forming on its surface, impeding heat transfer. This problem not only affects overall system performance but could also potentially cause a complete breakdown.
  3. Unusual Noises: If you hear strange sounds emanating from your air handler or furnace unit, it may indicate coil problems. These noises could be caused by a refrigerant leak or other issues within the system.
  4. Increased Utility Bills: If your energy bills are on the rise despite regular usage patterns, a faulty evaporator coil could be to blame. Inefficient heat transfer forces your HVAC system to work harder, consuming more energy in the process.

Understanding Types of Evaporator Coils and Replacement Considerations

There are two primary types of evaporator coils: A-coils and N-coils. A-coils are shaped like an “A” and are typically found in an air handler or furnace unit. N-coils resemble a capital “N” and are commonly found in split-system units. When selecting a replacement evaporator coil, consider the following factors:

  1. Compatibility: Choose a coil that’s compatible with your HVAC system. Consult your system’s documentation or seek professional advice to ensure proper matching.
  2. Size: Select a coil with the right size to ensure efficient heat transfer and overall system performance. An oversized or undersized coil could negatively impact your HVAC system.
  3. Material: Evaporator coils are available in various materials, such as aluminum, copper, and a combination of both. Each material has its pros and cons, so evaluate these factors before making a decision.
  4. Warranty: Look for a replacement coil with a solid warranty, as this can provide peace of mind and added protection should any issues arise.

Gathering Necessary Tools and Materials

Before starting the replacement process, make sure to gather the necessary tools and materials. Here are some items you’ll need for a successful replacement:

  1. Screwdrivers (Phillips and flathead)
  2. Wrench set
  3. Pliers
  4. Pipe cutter
  5. Brazing torch
  6. Vacuum pump
  7. Refrigerant scales
  8. Safety glasses
  9. Gloves

Don’t forget to consult your system’s instruction manual for any additional tools or materials specific to your model.

Safety Precautions for Evaporator Coil Replacement

Safety should be a top priority when working with electrical components and refrigerants. Follow these precautions to ensure a safe evaporator coil replacement process:

  1. Disconnect Power: To prevent electrical hazards, disconnect power to your HVAC system by turning off the circuit breaker or removing the fuse.
  2. Wear Protective Gear: Always wear safety glasses and gloves to protect yourself from potential injuries while handling tools, components, and refrigerants.
  3. Store Refrigerants Safely: If you need to remove refrigerants from the system, ensure proper storage and disposal following the Environmental Protection Agency (EPA) guidelines.
  4. Ventilate the Workspace: When working with refrigerants, ensure adequate ventilation to prevent inhalation of harmful fumes.

Step-by-Step Instructions for Replacing the Evaporator Coil

Now that you’re well-prepared let’s dive into the step-by-step process of replacing the evaporator coil:

Step 1: Turn Off the Power

Ensure the power to your HVAC system is disconnected by turning off the designated circuit breaker or removing the fuse. Confirm power disconnection before proceeding.

Step 2: Open the Air Handler or Furnace Unit

Locate and remove the access panel(s) to gain entry to the evaporator coil. This may require unscrewing or unfastening bolts or clips.

Step 3: Locate and Remove the Old Evaporator Coil

Carefully locate the evaporator coil. Disconnect any attached electrical wires or refrigerant lines. Use the pipe cutter to sever the copper tubing connecting the Evaporator Coil to the system and simply unscrew the coil from its mounting.

Step 4: Install the New Evaporator Coil

Secure the new evaporator coil in place by following your system’s specific guidelines. Reconnect any electrical connections and refrigerant lines. Use your brazing torch to reattach the copper tubing you previously severed. Ensure all connections are secure and properly seated.

Step 5: Seal the Air Handler or Furnace Unit

With your new coil in place, reinstall the access panels and ensure proper sealing to maintain system efficiency and prevent air leaks.

Step 6: Restore Power and Test the System

Turn the power back on and test your HVAC system. Monitor the system’s performance to ensure proper operation and troubleshoot any issues that arise.


Replacing an evaporator coil is a challenging yet doable task for determined homeowners and DIYers. This step-by-step guide provides all the necessary information for a successful replacement process. However, always remember that if you are feeling uncomfortable or unsure about any step of the process, don’t hesitate to consult our professional HVAC technicians at Stiles Services. With our top-notch HVAC services in Georgia, you can ensure optimal system performance and a comfortable home environment for years to come.

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