How to Clean AC Coils Inside – A Complete Guide

Air conditioners are the silent champions of indoor comfort, especially during hot summers. However, many homeowners overlook one of the most essential maintenance tasks — cleaning the AC coils. Learning how to clean AC coils inside can make a huge difference in your system’s efficiency, lifespan, and energy bills. At The AC Genie, we specialize in helping you get the best out of your cooling systems, and this guide will walk you through everything you need to know about cleaning your indoor AC coils.

Why Cleaning AC Coils Is Important

Before diving into the steps, it's important to understand why this task matters. The evaporator coil (the one located inside your home, usually in the air handler or furnace) is responsible for absorbing heat from your indoor air. Over time, dirt, dust, and mold can build up on these coils, reducing heat transfer efficiency.

Here’s what can happen if you don’t clean your AC coils regularly:

Decreased cooling performance

Increased energy consumption

Overheating and potential system failure

Poor indoor air quality

Shorter system lifespan

Learning how to clean AC coils inside can prevent all of these issues and keep your AC system running like new.

Tools and Materials You’ll Need

Cleaning the AC coils inside your home isn’t complicated, but you do need the right tools and safety precautions. Here’s what you’ll need:

Screwdriver (to access the indoor unit)

Soft brush or coil cleaning brush

Compressed air (optional)

Fin comb (for realignment)

No-rinse coil cleaner or mild detergent solution

Spray bottle

Shop vacuum (optional)

Protective gloves and eyewear

Safety First

Before you begin any AC maintenance, safety must be your top priority. Follow these essential safety tips:

Turn off the power: Switch off your thermostat and shut down the power at the circuit breaker.

Wait for the coils to cool: If the unit was running, give it 30–60 minutes to cool down.

Wear safety gear: Use gloves and safety glasses to protect yourself from dirt and cleaner chemicals.

Step-by-Step Guide: How to Clean AC Coils Inside

Step 1: Locate the Indoor Unit and Access the Coils

Your evaporator coils are typically located inside the air handler or attached to your furnace. Remove the front panel using a screwdriver and set it aside. You may also need to remove additional screws or covers depending on your unit’s design.

Step 2: Inspect the Coils

Take a look at the coils. If they are lightly dusty, a quick brushing might be enough. If they are heavily soiled with grime or mold, you’ll need to use a cleaning spray and more thorough techniques.

Step 3: Dry Brush or Use Compressed Air

For coils with light dust, a soft brush can gently remove buildup. Brush in the direction of the fins to avoid bending them. Alternatively, you can use compressed air to blow off the debris — just make sure to do this outside or with proper ventilation.

Step 4: Apply Coil Cleaner

If the coils are sticky or grimy, use a no-rinse foaming coil cleaner. Spray it evenly over the coils and let the foam do the work. These cleaners are designed to break down dirt and evaporate safely into the drainage system. If you prefer a DIY approach, mix a mild detergent with water and spray it on the coils using a spray bottle.

Step 5: Rinse if Needed

Most no-rinse cleaners don’t require rinsing, but if you're using a homemade solution or if there’s stubborn gunk, you can use a damp cloth to gently wipe the coils. Avoid over-wetting as excess water can damage electrical components.

Step 6: Straighten Bent Fins

If any of the coil fins are bent, use a fin comb to gently straighten them. This helps maintain proper airflow and improves performance.

Step 7: Vacuum or Clean Surrounding Areas

While you’re in there, vacuum out any debris from the air handler and make sure the condensate drain is clear. This prevents blockages and water damage.

Step 8: Reassemble and Power On

Once everything is clean and dry, replace the access panels and screws. Restore power to the system at the breaker, and turn your thermostat back on. Your system should now run more efficiently and with improved airflow.

How Often Should You Clean Your AC Coils?

Now that you know how to clean AC coils inside, the next logical question is: how often should you do it?

The AC Genie recommends cleaning your indoor coils at least once a year, ideally during spring before the peak cooling season. However, you may need to clean more frequently if:

You have pets that shed

Your area has high pollen or dust

You smoke indoors

You run the AC for extended hours daily

Routine inspections every few months can also help you catch problems early.

Signs Your AC Coils Need Cleaning

Even if you forget your last maintenance date, your system will usually give you signs. Watch out for these indicators:

Warm air blowing from the vents

Reduced airflow

AC runs constantly without reaching the desired temperature

Higher electricity bills

Ice forming on the evaporator coil

When you notice any of these issues, it’s time to grab your tools or call The AC Genie for professional help.

Professional vs. DIY Coil Cleaning

While learning how to clean AC coils inside is a great way to save money and keep your system efficient, some situations require professional help. For instance:

If the coils are completely clogged

If there's mold or mildew spreading

If you’re not comfortable disassembling your unit

Professionals have industrial-grade cleaners, vacuums, and tools that ensure deeper cleaning. Annual tune-ups from HVAC pros can also include coil cleaning as part of a package.

Tips to Keep Coils Clean Longer

Want to reduce the frequency of deep cleanings? Follow these tips:

Change your air filters regularly (every 1–3 months)

Keep vents and ducts clean

Avoid blocking airflow with furniture

Use a programmable thermostat to prevent overuse

Maintain indoor air quality with proper humidity and air purifiers

The cleaner the air entering your system, the cleaner your coils will stay.

Conclusion

Knowing how to clean AC coils inside is a skill that pays off with better comfort, lower energy bills, and a longer-lasting HVAC system. With a few simple tools and some patience, you can keep your air conditioner running at peak performance all year long.

At The AC Genie, we’re all about making AC maintenance easier and more effective for homeowners. Whether you're a DIY enthusiast or prefer to leave it to the experts, don’t underestimate the power of clean coils. Contact us anytime for professional coil cleaning, system checkups, or full-service AC maintenance — we’re here to keep your cool!