How Dirty Coils Impact Your AC’s Performance

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What Are AC Coils and What Do They Do?

Your air conditioner relies on two main coils to move heat from inside your home to the outdoors:

• Evaporator Coil: Located inside your indoor air handler, this coil pulls heat and humidity from the air in your home.
  
• Condenser Coil: Located in the outdoor unit, it releases the absorbed heat into the outside air.
  

For your system to work efficiently, air needs to pass over these coils freely. When they’re covered in dust, grime, pet hair, or even grass clippings, that airflow gets restricted, and the whole system starts to struggle.

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How Dirty Coils Affect Your AC’s Performance

Let’s talk about what happens when those coils get dirty:

1. Reduced Cooling Efficiency

The biggest problem is reduced heat transfer. Dirty coils act like insulation. They trap heat instead of moving it. That means your AC has to work harder and run longer to hit the thermostat setting.

More run time = higher energy bills.

2. Increased Wear and Tear

When your system is constantly running to make up for poor airflow, it puts stress on all components — especially the compressor. Over time, this can shorten the lifespan of your equipment.

3. Frozen Evaporator Coils

You’d think dirty coils would lead to overheating, right? Ironically, a dirty evaporator coil can cause the system to freeze up. Restricted airflow means refrigerant doesn’t evaporate properly, and the moisture on the coil turns to ice.

Now you’ve got no airflow and a frozen system that can’t cool at all.

4. Overheating and System Shutdown

When the condenser coil is dirty, your outdoor unit can overheat. The system’s safety mechanisms may trigger a shutdown to prevent damage, leaving you without cooling when you need it most — often in the middle of a Las Vegas summer.

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Real-World Symptoms of Dirty AC Coils

So how do you know if your coils might be the problem?

Here are a few red flags we look for during an inspection:

• Warm air coming from vents, even when the AC is running
  
• Longer cooling cycles (it takes forever to cool down)
  
• Higher energy bills without any change in usage
  
• Ice on refrigerant lines or around the coil
  
• Frequent system short cycling or shutdowns
  
• Unusual smells — especially musty or burning odors
  

If you’re noticing any of these, it’s a good time to schedule an AC Maintenance or AC Repair visit with us.

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What Causes Coils to Get Dirty?

You might be wondering, “Why do coils get dirty in the first place?”

Here are the usual suspects:

• Lack of filter changes: If your air filter is clogged or missing, dirt will bypass it and settle right on the coils.
  
• Dusty home or construction nearby: Airborne particles make their way into your system and cling to moisture on the coils.
  
• Outdoor debris: Your condenser coil is exposed to the elements. Grass, leaves, and pollutants from the street can build up fast.
  
• Pets and indoor air pollutants: Pet hair, dander, and even candles can leave residue behind on indoor coils.
  

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The Fix: Coil Cleaning and Preventive Maintenance

Regular AC Maintenance is your best defense.

Here’s what our coil cleaning process includes:

Indoor Coil (Evaporator):

• Inspection and access through the plenum or coil cabinet
  
• Safe removal of buildup using coil-safe cleaning solutions
  
• Drain pan cleaning to avoid mold and mildew
  
• Inspection of blower components and refrigerant lines
  

Outdoor Coil (Condenser):

• Removal of surface debris by hand or soft brush
  
• Gentle rinse or use of foam cleaner to remove dirt
  
• Check for bent fins or signs of corrosion
  
• Clearance of obstructions around the unit
  

This is all part of our standard tune-up, and it makes a big difference.

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How Often Should AC Coils Be Cleaned?

In our climate, we recommend cleaning your coils at least once a year — especially before peak cooling season.

That may need to be more frequent if:

• You have pets
  
• You’re near a construction site or high-traffic area
  
• You notice dust or allergy flare-ups inside
  

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Coil Maintenance vs. Coil Replacement

In most cases, coils just need to be cleaned — not replaced. But there are exceptions:

• Corrosion: Over time, coils can corrode and start leaking refrigerant. If you’ve got a leak, it may be more cost-effective to replace the coil or even the whole system depending on age.
  
• Severe clogging or damage: If the fins are flattened or the buildup is excessive, replacement may be the only option.
  

We always give you an honest assessment. If a repair makes sense, we’ll recommend it. If it doesn’t, we’ll walk you through your options for upgrading your AC — like AC Installation.

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Want to Learn More?

If you’re weighing whether to repair your current system or start fresh, check out our blog on When to Repair or Replace Your Air Conditioner.

Or, if you’re considering a switch from central air, we break it all down in Mini Split vs. Central Air: What’s Right for Your Home?

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Final Thoughts from the Field

Dirty coils are like clogged arteries for your HVAC system. Left unchecked, they silently reduce performance, increase your energy use, and eventually break your system down. But with a little preventive care, you can keep things running efficiently and avoid major issues.

If you haven’t had your system checked in the last year, now’s the time. At Eco Friendly Air Conditioning & Heating, we’ll inspect your coils, clean them the right way, and help your system breathe again.