Let me say this upfront:
Dirty coils are the silent killer of otherwise good HVAC systems.
I’ve seen perfectly solid Goodman air conditioners lose efficiency, spike electric bills, and even burn out compressors — not because they were old, but because the coils were neglected.
The good news?
You don’t need to be an HVAC technician to clean your coils properly.
You just need to know what to clean, how to clean it, and what mistakes to avoid.
This guide is the exact process I’d walk a homeowner through if I wanted them to save money without wrecking their system.
🧠 Why Coil Cleaning Is Non-Negotiable
Your AC has one job: move heat.
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The indoor coil absorbs heat from your home
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The outdoor coil dumps that heat outside
When either coil gets dirty, heat transfer drops — and your system has to work longer, harder, and hotter to do the same job.
According to the U.S. Department of Energy, dirty coils can reduce AC efficiency by up to 30% over time.
👉 https://www.energy.gov/energysaver/air-conditioner-maintenance
That’s not a small loss. That’s real money.
🧰 Tools You’ll Need (No Gimmicks)
You don’t need a truck full of gear. Just the right basics.
🧰 Coil Cleaning Kit
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Non-acidic foaming coil cleaner
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Garden hose with spray nozzle
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Soft coil brush or fin comb
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Screwdriver or nut driver
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Gloves & safety glasses
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Shop towels
🚫 What NOT to Use
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Pressure washer
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Acid-based cleaners
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Household degreasers
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Wire brushes
Those destroy fins, coatings, and warranties.
The EPA specifically warns against harsh chemicals that damage HVAC components and reduce lifespan.
👉 https://www.epa.gov/indoor-air-quality-iaq
⚠️ Step Zero: Safety First (Always)
Before touching anything:
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Turn off power at the disconnect (outdoor unit)
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Confirm the system is completely off
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Wear gloves and eye protection
You’re cleaning — not rushing to the ER.
🌬️ Part 1: Cleaning the Outdoor Condenser Coil (The Big One)
This coil handles heat rejection — and it gets filthy fast.
🔍 What You’re Looking For
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Grass clippings
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Pollen
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Dust
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Cottonwood fuzz
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Dirt packed between fins
Note: If it looks clean from the outside, it’s usually dirtier inside.
🛠️ Step-by-Step Outdoor Coil Cleaning
1️⃣ Remove the Top or Side Panels
Use a nut driver or screwdriver. Set screws aside.
2️⃣ Clear Debris by Hand
Leaves, sticks, dead bugs — get them out first.
3️⃣ Rinse from the Inside Out
This is critical.
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Spray from inside the unit outward
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Gentle water pressure only
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Let dirt wash out, not deeper in
4️⃣ Apply Foaming Coil Cleaner
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Spray evenly
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Let it foam and lift grime
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Follow label dwell time
5️⃣ Final Rinse
Rinse thoroughly until runoff is clean.
🧠 Tony’s Pro Tip
If water beads up instead of flowing through the fins, the coil is still dirty.
❄️ Part 2: Cleaning the Indoor Evaporator Coil (More Delicate)
Your indoor coil lives in a dark, damp environment — perfect for dust and bio-growth.
⚠️ When to Be Careful
If the coil is buried deep or hard to access, stop. Some layouts are not DIY-friendly.
🛠️ Indoor Coil Cleaning Steps
1️⃣ Remove Access Panel
Shut off power at the breaker first.
2️⃣ Inspect the Coil Face
Light dust = DIY-safe
Thick buildup = slow and gentle
3️⃣ Apply No-Rinse Coil Cleaner
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Spray lightly
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Let foam break down dirt
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Do NOT rinse unless instructions say so
4️⃣ Wipe Surrounding Surfaces
Drain pan, cabinet walls, nearby insulation.
The CDC emphasizes moisture control as critical to preventing mold growth in HVAC systems.
👉 https://www.cdc.gov/mold
💧 Don’t Forget the Drain Line (Seriously)
A clean coil means nothing if the drain is clogged.
Drain Line Maintenance
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Flush with distilled vinegar or approved cleaner
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Use a wet/dry vac on the outlet if needed
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Check for standing water in the pan
Clogged drains cause:
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Water damage
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Mold
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System shutdowns via float switches
🌀 Coil Fins: Straighten, Don’t Flatten
Bent fins block airflow.
Use a Fin Comb If:
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You see crushed or folded sections
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Airflow looks uneven
Be gentle. Fins are aluminum — not armor.
📅 How Often Should You Clean Coils?
Typical Schedule
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Outdoor coil: Once per year (twice if dusty area)
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Indoor coil: Every 1–2 years (inspect annually)
ENERGY STAR confirms routine coil cleaning improves efficiency and system longevity.
👉 https://www.energystar.gov/saveathome/heating-cooling/maintenance-checklist
🚫 Common DIY Coil Cleaning Mistakes
Let’s save you from expensive lessons.
❌ Pressure washing
❌ Using bleach or degreasers
❌ Ignoring airflow direction
❌ Bending fins “flat”
❌ Skipping power shutoff
Any one of these can turn a $0 cleaning into a $1,500 repair.
🧠 Signs Your Coils Are Already Dirty
Watch for:
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Higher electric bills
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Longer cooling cycles
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Warm air from vents
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Ice forming on lines or coil
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Loud condenser operation
If you see ice, stop cleaning and let it thaw before continuing.
🧾 Warranty Reality Check
Manufacturers like Goodman expect reasonable maintenance.
Failing to maintain coils can:
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Void warranty claims
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Shorten compressor life
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Reduce SEER2 performance permanently
☎️ When to Call a Pro Instead
Call a licensed tech if:
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Coils are inaccessible
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Refrigerant lines are iced
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You see oil residue (possible leak)
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Electrical components are corroded
EPA rules strictly regulate refrigerant handling — DIY is illegal and unsafe.
👉 https://www.epa.gov/section608
🏁 Final Word from Tony
Cleaning your Goodman AC’s coils isn’t about perfection.
It’s about restoring airflow, protecting efficiency, and reducing strain on the most expensive parts of your system.
Do it right, once a year, and you’ll:
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Lower energy bills
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Avoid breakdowns
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Extend system life
Skip it, and your AC will collect payment later — with interest.
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In the next topic we will know more about: The Seasonal Maintenance Dance: What To Do Each Quarter for Peak Performance
