Do I Need a Replacement Evaporator Coil or a Whole New AC?

Most homeowners in Georgia rely on their AC to keep them cool during the blazing summer. There’s nothing worse than coming home after a long day to discover your AC isn’t working. A common point of failure in older AC models is the evaporator coil, which controls the cooling capability of the entire AC unit. If it’s broken, your air conditioner won’t work.

While it may be tempting to simply replace the coil, you may need to replace the entire AC unit for reasons we’ll get into here in just a moment. But before you start contemplating potential fixes for your broken AC, it’s good to know exactly what your evaporator does in your HVAC system.

Evaporator Coils: What Do They Do?

Your AC’s evaporator coil is the component responsible for removing heat and moisture from the air. The coil contains a refrigerant, which is a chemical that’s very good at absorbing heat. As warm air passes over the coil, the refrigerant absorbs heat from it, resulting in the cold air that’s pushed through the rest of your home.

The refrigerant can only absorb a certain amount of heat before it turns into a gas. Then, it moves out of the evaporator unit into your HVAC outdoor unit, where it releases the heat into the outside air, turning the refrigerant back into a liquid.

The refrigerant cycles between the inside coil and outside condenser, constantly transferring heat and keeping your home cool.

When Does an Evaporator Coil Need Replacing?

Just like every other component of an AC unit, evaporator coils experience constant wear and tear. While no mechanical parts rub against each other, the coils still experience erosion. As the refrigerant passes through the coils, it can gradually wear down the inner lining. Some evaporator coil cleaners also use harsh chemicals that can corrode the outer lining of the evaporator coil.

This constant erosion will eventually weaken the AC coils and potentially lead to cracking. These cracks cause refrigerant leaks, which makes the unit less effective and may even present a health hazard.

If the leak continues unaddressed, your entire AC unit will eventually run out of refrigerant and stop working completely. Adding more refrigerant is a temporary fix, but you’ll continue to see poor air conditioning efficiency until you fix the underlying problem.

In most cases, it’s more cost-effective to get a new coil than repair an old one. The only question remaining is whether you should replace the coil or replace the entire AC unit.

There are many factors to consider that will affect your eventual decision.

Replacing the Evaporator Coil vs. the Whole AC Unit

While it may seem cheaper to replace just the evaporator coil, there are many cases where it’s better to replace the entire unit. The main reason for this is that most air conditioner systems have two coils that work together.

The first is the inside coil—the evaporator that cools the air down. The second is the outside coil—the condenser that dumps excess heat outdoors. These separate components work together to create a system that cools air effectively. Both occupy the same AC unit, and replacing one without considering the other can lead to disaster.

A common issue when you replace just the evaporator coil is that you have a condenser and evaporator mismatch, resulting in a whole host of problems for the AC unit and your air conditioner system as a whole.

When to Replace the Entire Unit

Your Air Conditioning Unit is Over Eight Years Old

Most AC units have a lifespan of between 10 and 12 years if maintained correctly. As the unit ages, all its components will become less efficient, especially when compared to a new AC system.

Putting a new, efficient coil into an older AC is like putting a brand-new engine into a car from the 70s—you simply won’t get the performance you expect from the evaporator coil replacement. Since the new coil has to take up the slack of the old condenser coil, it will experience a lot more stress than it should, which could cause premature failure.

Trying to replace coils or other components in an aging AC system isn’t cost-effective. You’ll spend more time and effort trying to repair the system than it would cost you to replace it.

Replacing the Old Coil Will Result in a SEER Mismatch

Every air conditioning system has a seasonal energy efficiency ratio (SEER) rating that determines how efficient it is—the higher the rating, the more efficient the unit. The SEER rating applies to the whole unit as well as the separate components inside.

Federal regulations control the minimum SEER ratings for air conditioners, and modern units have to have a rating of 14 or more in northern United States and 15 SEER for the south. However, old coils may have much lower SEER ratings which are impossible to find on the market today.

Trying to pair a modern evaporator coil with a higher SEER rating with a low-SEER outdoor coil will result in the whole AC unit becoming more inefficient as the indoor coil has to pick up the slack of the low-SEER outside unit.

You're Still Using R-22 Refrigerant

Older ACs use a refrigerant known as R-22, which is toxic and harmful to the environment. An R-22 refrigerant leak is a serious issue and can lead to potential health concerns. Since manufacturers stopped producing this refrigerant type, replacing R-22 is becoming increasingly expensive and difficult.

In this case, replacing the coil will only add to your expenses, and it will likely be a better option to scrap the existing unit and switch to a modern AC.  

When to Replace Just the Evaporator Coil

However, there are cases where replacing the evaporator coil is the more cost-effective option. If you have a relatively new AC unit, and you can get a replacement coil that ensures your two coils work well together, you’ll likely find the evaporator coil replacement cost more affordable than replacing the whole unit.

Signs You Need to Check Your Evaporator Coil

There are plenty of reasons your AC may stop working that don’t involve the AC’s evaporator coil. For example, clogged filters or damaged vents can affect the quality and quantity of the air produced by your AC.

However, there are some signs that you should take a look at your coils as the culprit. These include:

Both the indoor coil and outdoor coil can leak. These refrigerant leaks can affect the processing quality of the entire unit. It’s a good idea to check both coils to narrow down the problem and either replace the entire unit or the leaky coils.

Proper Evaporator Coil/ Condenser Coil Maintenance

Like every other part of your AC, regular maintenance on your coils can prevent issues in the future. Most technicians will do a thorough examination of your indoor and outdoor unit, which includes checking the integrity and performance of the coils.

Regular maintenance can dramatically extend the lifespan of the entire unit and prevent unwanted high energy bills or unexpected cooling failures in the middle of summer.

If you suspect you have an issue with your evaporator or condenser coil, don’t hesitate to get in touch with Service Emperor. Call us at (912) 231-5430 to schedule an appointment today!

Service Emperor is a family-owned and operated company that has been supplying quality HVAC services in the Savannah area for 15 years.

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Tersh Blissett

CEO of Service Emperor and part-time HVAC Guru

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