How to clean an AC unit

November 28, 2023
A man cleaning an AC unit

Maintaining your air conditioning unit isn’t just a task; it’s an investment in comfort, efficiency, and the system’s longevity. Regular AC maintenance ensures that your unit operates at peak performance, especially when you need it most. Keeping your AC clean fosters a healthier living environment by improving air quality and ensuring that your unit is both eco-friendly and economically beneficial. Let’s dive into AC maintenance and uncover the secrets to a cooler, more comfortable home.

Pre-Cleaning Checklist

Begin by disconnecting the power to the unit. This means unplugging the window and portable units from the electrical outlet. For central systems, switch off the circuit breaker or the external safety switch to prevent electrical hazards.

Equipping yourself with the right tools and materials is the next step. Gather a screwdriver, soft brushes, a fin comb, cleaning sprays or solutions recommended for AC units, gloves, and protective eyewear. A garden hose might be necessary for outdoor units, while a vacuum with a brush attachment is ideal for indoor components.

Lastly, identify the type of your AC unit—window, split, central, or portable—as this will determine the specific cleaning protocol. Each type has unique access points and components requiring particular attention during cleaning.

Step-by-Step Cleaning Guide

For Window and Portable AC Units

Filter Maintenance

The filter in your AC unit is crucial for trapping dust, pollen, and other airborne particles. Check your user manual to locate and remove the filter, as the position can vary. Typically, it’s found in the front panel or the bottom of a window unit and in a designated slot for portable ones. Gently slide or pop it out.

Once removed, assess whether the filter needs cleaning or replacing. If washable, rinse it with warm water and mild detergent, then let it air dry completely before reinserting. Non-washable filters should be replaced when they become visibly dirty or at least every three months. However, monthly checks are advisable in homes with pets or high dust levels.

Coil Cleaning

The evaporator and condenser coils are vital for heat exchange. In window units, the evaporator coils are behind the front panel, while the condenser coils are on the backside. Portable units typically have both coils within the interior compartment.

To clean the coils, first, use a soft brush to remove loose debris gently. Then, apply a no-rinse coil cleaner, which is available at most hardware stores, following the instructions on the label. A mild soap and water solution can work for a DIY approach but ensure no electrical components get wet.

Fin Care

The fins on the coils can bend easily, obstructing airflow. To straighten them, use a fin comb designed for AC units. Gently run the comb along the fins to realign them without damaging the delicate metal.

Unit Interior

Open the unit as per the manual’s instructions to access the interior. Clean out any dust or debris with a soft brush attachment to your vacuum. Check for signs of mold or mildew, especially on the interior surfaces and near the drain pan. If present, use a solution of equal parts water and vinegar to clean the area thoroughly, ensuring all parts are dry before reassembling the unit.

For Central AC Units

Filter Maintenance

Central AC filters are typically located along the return duct’s length or in walls, ceilings, or the unit itself. Replace disposable or clean washable filters every 1-3 months, depending on usage and household conditions. Ensure the replacement filter matches the size and type specified for your system.

Condenser Unit Care

The outdoor condenser unit requires periodic cleaning to function efficiently. After shutting off the power, remove the fan cage or grill on top of the condenser unit. Use a refrigerator coil brush to clean the fins gently, then rinse them with a gentle water stream from a hose. Check for any debris, such as leaves or twigs, in the unit and remove them.

Evaporator Coil Access

Inside your home, the evaporator coil is usually found in the air handler. Carefully remove the access panel and remove any dust or buildup using a soft brush. Use a specialized evaporator coil cleaner to thoroughly clean and follow the instructions carefully. To prevent mold growth in the drip pans, clean them with a bleach and water solution and ensure they drain properly.

Regular maintenance of your AC unit’s filters, coils, fins, and interior ensures efficient operation and improves the air quality in your home. By following these steps, you can extend the life of your unit and avoid the discomfort of unexpected breakdowns.

Seasonal Maintenance Tips

As the seasons change, so should your approach to AC maintenance. Before the summer heat peaks, ensure your unit is primed for performance with a thorough clean. This includes checking coolant levels, verifying the system’s operation, and cleaning or replacing filters. Post-summer, as the unit winds down from heavy use, inspect and clean the coils and fins and cover the outdoor unit to protect it from falling leaves and debris.

To shield your external unit from harsh weather elements, use a breathable, waterproof cover that fits snugly, preventing moisture accumulation while keeping out ice, snow, and dirt. This helps avoid rust and damage to the internal components.

Additionally, inspect any exposed ductwork for leaks or poor insulation before the cooling season begins. Properly insulated ducts maintain cool airflow and efficiency, preventing energy loss and ensuring your home stays comfortable when temperatures soar.

Troubleshooting Common Issues

Recognizing the signs of a dirty AC unit is key to preventing more significant issues. If you notice reduced airflow, increased dust around your home, or a spike in energy bills, it might be time for a cleaning. Unusual noises, such as rattling, buzzing, or leaks around the unit, indicate that your AC requires attention.

A DIY approach is often sufficient for basic maintenance like cleaning or replacing filters, straightening fins, and clearing minor blockages. However, if the problems persist or you encounter complex issues like coolant leaks, electrical faults, or deep-set mold, it’s time to call a professional (like us here at Carney and Son). HVAC technicians have the expertise to diagnose and resolve issues beyond surface-level maintenance, ensuring your unit operates safely and efficiently. Remember, timely intervention can save you from costly repairs down the line.

Advanced Maintenance Tips

Advanced maintenance steps are crucial to maximize the efficiency of your AC system. Sealing and insulating ductwork is one of them. Leaky ducts can lose up to 20% of cooled air, so use mastic sealant or metal tape to seal all joints and seams. Then, insulate ducts running through unconditioned spaces to keep the air within your desired temperature.

Coolant levels are vital for your AC’s performance but are best checked by professionals due to the complexity and safety concerns. Incorrect coolant levels can cause your system to work harder, increasing energy costs and reducing lifespan.

Integrating energy-saving settings through a smart thermostat can lead to significant savings. Smart thermostats can learn your schedule and adjust temperatures accordingly, ensuring your AC only works when needed. They also provide valuable insights into your energy consumption, helping you make informed decisions about your AC usage.

Final Thoughts on AC Unit Cleaning

Regular AC unit maintenance is not just a chore—it’s an essential practice ensuring your AC covers the square footage it’s capable of. By keeping up with the simple tasks of cleaning filters, coils, and fins and scheduling professional check-ups for the more intricate systems, you can significantly extend the life of your unit, improve air quality, and reduce energy costs. 

Embrace these maintenance rituals as part of your routine for a healthier home environment. Remember, a well-maintained AC unit is the heartbeat of a cool, inviting home, and with these tips, you’re well-equipped to keep the air flowing smoothly all year round.

Carney & Son Air Conditioning and Heating

Carney & Son, 72 Degrees

We are a family Owned & Operated HVAC Services in Charleston, SC, proudly serving the Charleston community for 39 years.

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