Cleaning your air conditioner is an essential part of keeping it running efficiently, but did you know that improper cleaning can do more harm than good?

Many homeowners make simple mistakes − like using the wrong cleaning products or forgetting to turn off the power − that can damage the unit or reduce its performance. A poorly maintained air conditioner not only struggles to cool your home but can also drive up energy bills and lead to costly repairs.

To keep your system in top shape, it’s important to know what not to do when cleaning your window air conditioner, split system, ducted system or any other type of AC.

In this guide, we’ll cover the most common cleaning mistakes and how to avoid them, so you can maintain your air conditioner safely and effectively. By following the right steps, you’ll enjoy better cooling, improved energy efficiency and a longer-lasting unit.

Forgetting to Turn Off the Power

One of the biggest mistakes people make when cleaning their air conditioner is forgetting to turn off the power. It might seem like a small oversight, but it can be dangerous.

Air conditioners are electrical appliances, and attempting to clean them while they’re still powered can put you at risk of electric shock. Plus, moving parts like the fan blades can cause injury if they suddenly start spinning.

To stay safe, always switch off your AC at the thermostat and the main power source before cleaning. This ensures that no electricity is flowing to the unit while you’re working on it.

Taking this simple precaution can prevent accidents and protect both you and your air conditioner from unnecessary damage. A few extra seconds to turn off the power is well worth the safety it provides.

Using the Wrong Cleaning Products

Cleaning your air conditioner is important, but using the wrong products can do more harm than good. Harsh chemicals and abrasive cleaners can damage delicate components, leading to costly repairs.

Here’s what to avoid and what to use instead:

What Not to Use:

• Bleach or ammonia-based cleaners – These can corrode coils and damage filters.
• High-pressure sprays – Can bend the fins on the condenser and evaporator coils.
• Abrasive sponges or brushes – Can scratch and weaken sensitive parts.

What to Use Instead:

• Mild soap and warm water – Safe for cleaning plastic and metal components.
• Coil cleaner spray – Specifically designed to remove dirt without harming the coils.
• A soft brush or cloth – Ideal for gently wiping away dust.

Using the right products keeps your AC clean without causing damage.

Not Cleaning or Replacing the Air Filter

One of the most common and costly mistakes people make when cleaning their air conditioner is neglecting the air filter. The filter’s job is to trap dust, dirt, and allergens, keeping the air in your home clean.

But over time, it gets clogged, restricting airflow and making your AC work much harder than it should. This not only reduces cooling efficiency but also increases your energy bills and can even lead to system breakdowns.

To avoid these issues, check your filter at least once a month. If it’s reusable, give it a thorough clean with water and let it dry completely before reinstalling. If it’s disposable, replace it as recommended by the manufacturer. A clean filter means better air quality, improved efficiency, and a longer-lasting air conditioner.

Neglecting the Evaporator and Condenser Coils

Your air conditioner’s evaporator and condenser coils play a key role in cooling your home. If they’re covered in dirt and dust, your AC has to work much harder, leading to reduced efficiency, higher energy bills, and potential system breakdowns.

Unfortunately, many homeowners overlook these coils during cleaning.

Why You Should Clean the Coils:

• Dirty coils reduce cooling efficiency – Less heat is absorbed and released, making your AC struggle.
• Increased energy consumption – A clogged system runs longer, raising electricity costs.
• Risk of freezing or overheating – Poor airflow can cause ice buildup or overheating.

How to Clean Them Safely:

• Turn off the power before cleaning.
• Use a soft brush or coil cleaner spray to remove dirt.
• Check regularly and clean at least once a year.

Keeping your coils clean ensures better performance and a longer-lasting AC.

Ignoring the Drain Line

Your air conditioner’s drain line plays a crucial role in removing excess moisture from the system. But if it gets clogged with dirt, dust or algae, water can back up into the unit, leading to leaks, water damage and even mould growth. Unfortunately, many homeowners overlook this small but essential component when cleaning their AC.

To prevent issues, check the drain line regularly and clear any blockages. A simple way to keep it clean is by pouring a mixture of warm water and vinegar through the pipe every few months.

If you notice standing water around your unit or musty odours, a clogged drain line could be the culprit. Keeping it clear ensures your AC runs efficiently, prevents costly water damage and helps maintain good indoor air quality.

Using High-Pressure Water on Delicate Components

When cleaning your air conditioner, using a pressure washer or a strong water spray might seem like a good idea − but it can actually cause serious damage.

Delicate components like the evaporator and condenser coils, as well as the aluminum fins, can bend or break under high pressure, reducing your AC’s efficiency.

Why High-Pressure Water is a Bad Idea:

• Can bend the aluminum fins – This restricts airflow and reduces cooling performance.
• May force water into electrical components – Leading to short circuits or system failure.
• Can dislodge important parts – Small screws or delicate pieces may get knocked loose.

How to Clean Safely:

• Use a garden hose with gentle pressure to rinse the coils.
• Use a soft brush or vacuum to remove dust.
• Apply a coil cleaner spray for deeper cleaning.

A gentle approach keeps your AC in top shape without causing costly damage.

Not Checking and Cleaning the Outdoor Unit

Many people focus on cleaning the indoor components of their air conditioner but forget about the outdoor unit.

Since it sits outside, it’s constantly exposed to dirt, leaves, and other debris, which can block airflow and make your system work harder than necessary. A clogged outdoor unit reduces cooling efficiency, increases energy consumption, and can even lead to overheating.

To keep your AC running smoothly, regularly check the outdoor unit for buildup. Use a garden hose to gently rinse off dirt, but avoid high-pressure sprays that could bend the delicate fins. Trim back any nearby plants or weeds to ensure proper airflow.

A little routine maintenance on the outdoor unit goes a long way in keeping your air conditioner efficient, reducing strain on the system, and preventing costly repairs.

Skipping Professional Maintenance

While regular DIY cleaning helps keep your air conditioner running smoothly, skipping professional maintenance is a big mistake. Some issues, like refrigerant leaks, electrical faults or internal wear and tear, require expert attention.

Without professional servicing, your AC might not perform at its best, leading to higher energy bills and costly breakdowns.

Why Professional Maintenance is Essential:

• Experts spot hidden problems – Technicians can detect issues before they turn into major repairs.
• Ensures optimal efficiency – A well-maintained AC uses less energy and cools more effectively.
• Extends the lifespan of your unit – Regular servicing prevents premature wear and tear.

How Often Should You Schedule a Service?

• At least once a year – Ideally before peak summer months.
• More frequently if you notice issues – Like weak airflow, strange noises, or higher energy bills.

Investing in professional maintenance keeps your AC reliable and running efficiently for years to come.

Clean Your AC and Keep Your Cool

Cleaning your air conditioner is essential for keeping it efficient and long-lasting, but avoiding common mistakes is just as important.

Simple errors – like using the wrong cleaning products, ignoring the drain line or skipping professional maintenance – can lead to costly repairs and reduced performance.

By taking the right approach, such as regularly replacing the air filter, gently cleaning the coils, and checking the outdoor unit, you can keep your AC running smoothly.

A little care and attention go a long way in improving cooling efficiency and lowering energy bills. Follow these tips and your air conditioner will thank you.