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How to Clean Your Air Conditioner Coils

Updated on July 15, 2022 by Joseph D. Nielson

Table of Contents

Air condenser units after a thorough AC coil cleaning

Summer is right around the corner, which is both a cause for celebration and a shot of encouragement for DIYers to finish their spring maintenance projects. Once the hot weather hits, the last thing you want is to be inside tinkering with appliances.

But where to start? What appliances and home systems should you prioritize ahead of the summer months?

Arguably, the single most important appliance during the summer months is your AC system. If your AC malfunctions or works inefficiently, you can count on sweaty days and sleepless nights. It is your first, and sometimes only, defense against sweltering temperatures – transforming a humid home into a breezy, relaxing respite.  

Now, let’s take it a step further: what’s the most important component of your AC? For our money, it’s the coils. Your air conditioner coils (often called the evaporator and condenser coils) are the unsung heroes of your HVAC system, bullishly exchanging the hot air in your home for a cooler climate. Take care of these coils, and you can take care of your summer comfort.

In this post, let’s explore the humble air conditioner coil. What is it? Why should you routinely clean it? And what simple steps can you follow to refresh these all-important home-cooling components?  

What Are Air Conditioner Coils? And What Are They for, Exactly?

When you hear an HVAC professional or home expert talk about “air conditioner coils,” chances are they’re talking about two mechanisms at once: the evaporator coil and the condenser coil. Occasionally, people use the term “air conditioner coil” to refer to the evaporator exclusively – but more often than not, we refer to both coils when using the term.

Simply put, your evaporator coil captures indoor heat, and your condenser coil releases that heat into the outdoors. It’s a split-system mechanism that ensures warm indoor air is fully displaced by cool air.

The evaporator coil essentially facilitates refrigerant flow, acting as a heat sink for a home’s warm air. Water vapor in a warm house hits the coils, condenses, and then drips down to the condensate pan. As such, your evaporator coil pulls double-duty in the summer as a dehumidifier. If you own a humidifier for small rooms, consider shutting it off for the summer to avoid overworking your evaporator coil.

The condenser takes the low-pressure, gaseous and warm refrigerant created by the evaporator, pressurizes it, and releases it back into the outdoors via the condenser coils.

Both of these coils need to be working in tip-top shape for your AC system to effectively cool your home. If one – or both – isn’t working properly, the whole system fails to displace warm air.

A young family happily goofs around on the couch in an air-conditioned home

Why Clean Your Air Conditioning Coils?

You might wonder: Why do we have to clean our air conditioning coils? A refrigerator doesn’t stop working just because it’s dirty, right? Surely dirty air conditioning coils still cool down your house somewhat!

Firstly, that’s simply not true. And secondly, there are reasons other than efficacy to maintain your AC system. Here are a few compelling reasons to clean your air conditioning coils:

  • Let’s start with the obvious: A clean AC system works better to cool down your home. Clean coils capture, transfer and release heat better than dirty coils.
  • Dirty coils waste energy. According to the US Department of Energy, dirty air conditioner coils increase energy consumption by 30-40%. In other words, you pay a hefty monthly price on your utility bills by putting off coil cleaning.
  • Dirty coils do not properly dehumidify your home. If coils can’t effectively pull warm moisture from the air, your home will become damper and more humid. The EPA cautions that high humidity levels caused by inefficient AC systems can lead to mould and mildew growth – posing a danger to inhabitants.
  • Dirty coils reduce the functional lifespan of your AC unit. Air conditioning systems aren’t cheap! Think of cleaning your coils like changing the oil in your car – it’s a small investment in prolonging its lifespan.  

Now that you know why we clean our air conditioning coils, we can move on to how to clean our coils.

DIY Air Conditioner Coil Cleaning Versus Calling in the Pros

You have two options for cleaning your coils: do it yourself, or call a professional HVAC maintenance team. As with any home maintenance project, you have to weigh your options according to personal preference.

If you have the budget to call professionals, and don’t necessarily want to get your hands dirty, call in the HVAC maintenance. If you’d rather save money, and you feel fine dedicating a couple of weekend hours to scrubbing some dirty coils, take the DIY route.

We encourage most homeowners to give DIYing a try. Best case scenario, you complete the job with ease – saving money and enjoying a rejuvenated AC system. Worst case scenario, you get partway through before realizing that the scope of the job is beyond your “pay grade,” at which point you can call professionals. 

How to Clean Your Air Conditioner Coils, Step by Step

In this section, we’ll begin by discussing how to clean coils without removing them – a process that should work for a majority of homeowners. That said, depending on the age and wear of your unit, you may need to execute a more detailed cleaning that involves disassembling the unit, which we will briefly touch on below.  

Before you begin cleaning, we recommend running an air quality monitor and air purifier to ensure that you breathe easy while working. Cleaning dirty coils can sometimes kick up dust and mould, so it’s wise to observe some purification protocols. You can read Fresh Home Guide’s air purifier and humidifier reviews, as well as our article on the benefits of an air quality monitor.

What You’ll Need:

  • A tight-fitting mask: a ventilator mask, dust mask or standard-issue medical mask (which most people have lying around post-COVID) should do the trick.
  • A screwdriver: panel removal varies by manufacturer and model. Take a moment to determine what kind of head you will need.
  • Compressed air and vacuum: Air duster cans or rechargeable dusters both work well. A shop vac works best for removing material, but a regular vacuum hose will also do the trick.
  • An old toothbrush: Any garden variety brush will work, but we prefer using a cheap toothbrush to get in the crevices of the coils.
  • Mild detergent, vinegar or foaming HVAC coil cleaner: The choice is yours!
  • A spray bottle and cloth: To get every last iota of gunk from your coils, have a spray bottle and microfibre cloth on hand alongside your cleaner of choice.
  • The number of a professional AC cleaner – just in case!

Once you’ve rounded up all the essentials – including a couple of air purifiers for large rooms for good measure – it’s time to get started.

A woman carries a pink bucket filled with various cleaning products and supplies

Disconnect Power and Remove the Access Panels on Your Evaporator and Condenser Coils

Arguably the most important aspect of any DIY project is safety. Before you attempt any kind of maintenance on an electrical appliance – including your AC system – cut the power on your breaker. Some people maintain that turning off your AC at the thermostat is enough, but why risk it? Introducing liquid to a running electrical product can be a fire and smoke hazard that even the best air purifier for smoke can’t manage.

Remember, you are essentially doing two jobs in one day: cleaning the indoor evaporator and the outdoor condenser. Follow these steps for each process.

Remove the access panel from the evaporator/condenser according to the manual. Set the panel aside. If the panel looks grimy, give it a good scrub with your toothbrush and a spray bottle.

Use Compressed Air for Loose Material

Sometimes, compressed air is all you need. Coils with recent or light buildup may only require a few blasts with compressed air. At any rate, start with your compressed air before you move onto more labour-intensive cleaning procedures, just to wrestle some of the larger chunks of debris from the coils.

Have a household vacuum hose or (preferably) a shop vac in the other hand to clear away debris.

Use an Old Toothbrush to Work More Stubborn Dirt

Once you’ve removed the loose material, you can turn your attention to the stubborn buildup. We recommend using an old toothbrush for this – they’re cheap, easily manoeuvrable, and almost everyone has one lying around!

If you want a more dedicated tool, we recommend getting a “coil brush” or condenser fin brush from your local hardware store or Amazon.

Use a Spray Bottle and Mild Detergent

If you still see bits of gunk and grime on your air conditioning coils after compressed air and brushing, use a spray bottle and cloth to polish the coil.

Fill the spray bottle with a diluted mixture of warm water and mild detergent. Spray the coils, and walk away for ten or fifteen minutes. (This is a good time to check to see that your air purifier is doing its job!) When you return, wipe the coils thoroughly with your cloth. If you see any leftover soap residue, repeat this process with water exclusively.

Cleaning Air Conditioning Coils with Vinegar

Some people prefer to use vinegar instead of detergent to clean their AC coils. Both options work like a charm – it all boils down to your personal preference.

If you’d rather use vinegar, simply repeat the process from the step above using a spray bottle filled with white distilled vinegar. (Save your fancy vinegars for salads!)

Using Foaming HVAC Coil Cleaner

Some people swear by HVAC coil cleaner once a year to keep their air conditioning coils in peak condition. Those people aren’t wrong; this dedicated product does a fantastic job cleaning evaporator and condenser coils.

If you can get your hands on foaming HVAC coil cleaner, we recommend it. But it shouldn’t be a barrier to entry. If you can’t find coil cleaner, the above two methods work very well also.

When to Call an HVAC Technician or AC Maintenance

In some cases, an air conditioning system that’s been neglected for a long time will feature heavily soiled coils. You can try to get it all off with a brush and cleaner, but nothing seems to work. In these cases, you may need to disassemble the unit for a deep cleaning.

While it’s possible for home DIYers to disassemble and deep clean an AC system, it’s not always advisable. In these cases, we recommend erring on the side of surety – just call a professional.

Hopefully, this article has primed you for the summer. Now you know the importance of keeping your air conditioning coils clean, as well as a few tried-and-tested methods for getting the job done. Here’s to a breezy, cool summer from everyone at Fresh Home Guide!

About Joseph D. Nielson

Former journalist and editor for various press groups, I now dedicate my time to reviewing products for the home and family life. When I get time to myself, I enjoy rock climbing, taking my dirt bike for a rip, and most importantly providing my family with the best home possible!