HVAC Evaporator Coil Replacement: The Comprehensive Guide

The evaporator coil is a fundamental component of your home's heating, ventilation, and air conditioning (HVAC) system. Located inside the air handler, it's responsible for extracting heat from your home's air, thus cooling it before redistribution. Over time, the coil may become damaged or fail due to wear and tear, requiring replacement to ensure your HVAC system functions optimally.

Although it can be tempting to replace a broken coil yourself, we strongly recommend that you don't. Performing this procedure requires a professional HVAC technician, replacing an evaporator coil is not a DiY job.

Before you begin, understand that this guide is general and not tailored for a specific HVAC model. Always refer to your manufacturer's manual for model-specific instructions.

First we must define what an evaporator coil even is. Another thing to note is that your ac unit contains more than one coil. The evaporator coil is located in the indoor unit and takes in heat from indoor air. Once the hot air moves through the indoor coil, the coil refrigerant takes the heat and converts it from a liquid form to a gas. This process sends cool air through the ac system and into the home using the internal fan of the unit.

However, the condenser coil is housed in the outdoor unit, also known as the compressor. The condenser coil releases the heat the evaporator coil absorbs. The condenser coil passes the refrigerant through the coil which changes it back to a liquid form. The process of condensing the refrigerant releases the absorbed warm air from inside the home, then uses its internal fan to dissipate the heat.

There are several hints that you might need to replace your evaporator coil. Signs that you might need a replacement include:

• Reduced airflow: If you notice the HVAC system airflow is weak, this could indicate that your coil needs to be cleaned, is blocked, or needs to be replaced.
• Less Effective Cooling: If you notice that the building takes longer to cool or does not cool at all, it could mean that the ac evaporator coil does not work.
• Higher Energy Costs: Higher power bills could indicate that your coil is inefficient. This means that it is working harder to cool effectively, which increases your power bills.
• Refrigerant Leaks: Seeing refrigerant leaks from your ac unit might indicated that your coil is damaged and in need of repair or replacement.
• Strange Noise: If your AC unit starts to make strange rattling sounds during operation, it could come from a number of sources. Check the unit to confirm if the sound is coming from the evaporator coil.

An average evaporator coil can last from 10 to 15 years. The real lifespan of your evaporator coil can vary depending on several important factors. If you conduct regular maintenance with a properly installed unit, your evaporator coil can operate even longer.

Factors that affect an evaporator coil lifespan include:

• How Much it's Used: Coils that cycle continuously wear down faster than coils that are operated less frequently. How often you use the coil can affect how long it lasts.
• Maintenance Level: If you perform regular maintenance on the evaporator coil, you can prolong its lifespan. Regular inspection and cleaning of the coil can catch potential damage early.
• Quality of the Coil: The quality of the coil can impact how long it lasts. Coil made from high-quality, durable materials, tend to last long longer than lower-quality coils made from cheap materials.
• Environmental Conditions: Environmental conditions can also impact the livelihood of your coil. For example, a coil left in dirty or cluttered conditions is likely to break faster than a coil in a clean environment. This is a result of increased dust and clutter to clog the HVAC unit.
• Refrigerant Type Used: Refrigerants have different rates of corrosion which can affect the lifespan of your coil. Refrigerants with higher rates of corrosion have a shorter lifespan than those that don't.

To stop premature failure of your evaporator coil, we recommend hiring an HVAC technician to conduct annual maintenance. If the air conditioning unit works in a dusty or cluttered space, it will require maintenance more frequently.

Preventative maintenance for your air conditioning system can include:

• Inspect: Taking a look at your coils to check for corrosive damage, refrigerant leaks, or physical damage to catch issues early. This is a practice that doesn’t require a technician.
• Cleaning: The technician can clean the evaporator coils of dirt, debris, and dust that can tank the coils’ efficiency. Removing the debris prevents hazardous buildup that lowers energy efficiency, as it forces the system to work harder. It can also prevent dust buildup in the heat pump or air filter because dust can clog the entire system.
• Secure Wire Connections: A hired HVAC professional checks the connections of the air conditioning system. If anything is loose, the technician will tighten those connections to prevent malfunction during operation.
• Remove Condensation on Coil: Remove excess water from the ac unit’s drain pan and drain line. The drain pan and drain lines remove excess condensation forming on the air handler coil. If there is condensation present then something is wrong with your coil or ac unit.
• Balance Refrigerant Charge: The technician will measure refrigerant charge in the coil. Refrigerant charge describes the quantity of refrigerant remaining in the coil. Coils that are under or overcharged can damage your system, so it is important that a technician balances the charge.

Only a licensed HVAC technician can replace your evaporator coil. Since the process involves handling refrigerant, it is not a DIY project.

If you attempt to perform HVAC repair yourself, you run the risk of voiding your warranty policy with the HVAC company, damaging the unit, and yourself.

Even though you cannot perform the replacement of the coil alone, it is important to understand the process a repairman follows.

1. Turn off the Power: The technician will start by turning off the circuit breaker that powers your HVAC system. This will ensure your safety while working on the unit.
2. Access the Evaporator Coil: The HVAC professional will remove the access panel on your air handler to reach the coil. This usually involves unscrewing a few screws on the panel's edge.
3. Disconnect the Coil: After accessing the evaporator coil, The HVAC tech will remove the old coil from inside the air handler. Because this process involves unscrewing and detaching the refrigerant lines, it must be done by a licensed professional. Only a certified person should handle the refrigerant.
4. Clean the Area: Before installing the new coil, the HVAC technician will clean the area inside the air handler with a coil cleaner. This is to ensure dust and debris aren't in the system before installing the replacement part.

If fins were bent during the removal process, the repairman will use a tool called a fin comb to straighten them.

5. Install the New Coil: Once the old part is removed, the repairman will place the new evaporator coil into the air handler. This involves reconnecting the refrigerant lines and securing them into place. Proper installation prevents refrigerant leaks.

Then the technician will reattach the access panel and screw it back into place.

6. Restore Power and Check Operation: After replacing the evaporator coil, the technician will turn the power back on and run the system. They will ensure the system works properly, by checking for unusual sounds or refrigerant leaks.

The cost to replace and install an evaporator coil in an HVAC system can vary depending on several factors. The average cost of the coil itself can range from $180 to $1,500, but higher-end models or specialized coils may cost more. The installation cost typically includes labor costs, refrigerant, and any additional materials required, and can range from $1,000 to $3,000. However, keep in mind that these are general estimates, and the final cost can be influenced by factors such as the size and complexity of the system, accessibility of the coil, regional pricing variations, and any additional repairs or modifications needed during the installation process. It is always recommended to obtain quotes from qualified HVAC professionals to get an accurate cost estimate for your specific situation.

An AC evaporator coil can be an A-coil, N or Z-coil, or slab unit type. Each type of coil varies in pricing and affects the total cost of the replacement.

A-Coils: A-coils are the most common type and are used in systems using vertical airflow. A-coil get the name from its shape, as it is in the triangular shape of the letter A. Depending on the brand, A-coils can cost around $1300.

N-Coil: Also known as Z-Coils typically costs more than A-types, averaging around $1500 per ac coil. N-Coils are compatible in vertical and horizontal airflow ac systems.

Slab Units / Horizontal Units: Horizontal units are only compatible with horizontal airflow but they are the cheapest on average. The average cost of a slab unit sits around $1200.

The style of coil needed is based on the HVAC system you have and the price of the individual coil can decrease or increase based on the brand. Be mindful of your budget when purchasing a coil.

Labor

Labor costs for ac evaporator coil replacement can range from $400 to $1000. This range varies depending on location of the job and the amount of work required. An HVAC contractor typically charges $75-$125 per hour for work. This means, the longer the job, the more you pay to cover labor costs. In most cases, the replacement can be completed in 2 to 4 hours. The hourly rate ultimately depends on the area you live in and the time of year.

• Type of Refrigerant: A new coil needs to be charged with new refrigerant. However, not all refrigerants cost the same. In fact, refrigerants can cost anywhere between $100 to $350.
• SEER Rating: SEER, or seasonal energy efficiency rating, measures the efficiency of an air conditioner unit. The higher the SEER rating, the more energy efficient the unit is. Higher efficiency ratings also increase the cost of the evaporator coil for purchase.
• Time of Year: If you can control it, try to avoid replacing or repairing an evaporator coil in the summer. Prices for labor tend to increase during the busy summer months for AC repair costs. Additional charges appear if repair is on an urgent service basis.
• Home Warranty Policy: If you have a home warranty, the provider may cover the replacement and labor costs to install a new ac coil. Check the terms of your home policy to confirm what is and is not covered by your warranty.
• AC Unit Type: Every type of HVAC system is different. For example, mini-splits, ductless AC units, packaged units, and geothermal heat pumps use different evaporator coils and each has different replacement costs.
• Location of the AC unit: Difficulty to access the air conditioner can increase costs if the technician needs special equipment to do the job. It can also extend the length of time it takes to finish the replacement which increases labor costs.

Replacing an evaporator coil can be a daunting task, especially for homeowners without prior HVAC experience. However, with the right knowledge, it's achievable. Always remember to let HVAC technicians handle refrigerants and the process of installation, no matter the circumstances.

Don't hesitate to contact an HVAC professional to handle it. They have the training, experience, and certification to manage any challenges that may arise during the process.