Learn How to Clean Your Window Air Conditioner for Better Air Quality in Your Home

how to clean a window air
Image courtesy of Amazon

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Along with summer comes soaring temperatures and the need to cool your home using tower fans and home air conditioners. If you’re one of the lucky ones who has a window air conditioner unit instead of central air, you’ll know that they can be quite temperamental, at best. One day it works fine, and the next, you can’t get cold air whatsoever. And then there’s the dreaded air conditioner smell, which can ruin the simple pleasure of basking in the air-conditioned breeze. To avoid these annoyances, you need to ensure your window air conditioner stays in working order by cleaning it regularly.

And if you don’t know how to clean a window air conditioner, then keep reading. 

According to the Department of Energy, failing to clean a window air conditioner unit will lead to a steady decline in performance and an increase in energy use. In addition, a dirty air conditioner can impact the air quality in your home. But, regular cleaning can fix all these issues and extend the life of your air conditioner unit to boot. Remember, homes with central air conditioning need to change their air filter every few months, but many apartment dwellers will never even think about cleaning out their window AC unit.

In general, we recommend four types of cleaning:

  • Regular Cleaning – Each day, check your unit for signs of mildew and dust. If you see or smell it, spot clean the unit as laid out in steps one to three below.
  • Monthly Cleaning – Every month, you’ll need to clean the filter in your unit to ensure the air quality in your home stays high. See steps four and five.
  • Seasonal Cleaning – After summer is over, it’s important to clean both the inside and outside of your unit, and then store it properly (if necessary). We’ll cover the method for this in steps six to nine below.
  • Deep Cleaning – If you’ve just bought a second-hand window air conditioner or you’ve never cleaned yours before, you’ll need to deep clean it. See steps ten to twelve.

If you’re ready to learn how to clean a window air conditioner properly, read on for step-by-step instructions and cleaning products. You can also check out this great how-to video from Becky’s Homestead, which walks you through some of the more complicated steps.


1. Use a Hydrogen Peroxide Solution Regularly to Prevent Mildew

The easiest way to keep your window air conditioner in good working order is to clean it regularly. Throughout the summer, you should check your unit for signs of mildew growth, like the distinctive scent. Should you see or smell mildew, you need to be careful about the type of cleaner you use. Remember: alcohol or bleach-based cleaners can cause fires or toxic fumes. For that reason, stick to a 3% hydrogen peroxide solution.

how to clean a window air conditioner hydrogen peroxide Image courtesy of Amazon


2. Fill a Spray Bottle With the Solution

Once you have your cleaning solution in hand, fill a spray bottle, like these glass versions from Sally’s Organics, with the hydrogen peroxide. Then, turn your air conditioner off and spray down both the intake area of the unit and the outflow area with the peroxide solution. Allow the spray to dry before turning the air conditioner back on. Failure to do so may cause the spread of unwanted fumes, so please be careful!

how to clean a window air conditioner glass spray bottles Image courtesy of Amazon


3. Catch Drips in a Turkey Tray if a Deeper Clean is Required

Should you continue to smell mildew even after spraying the unit down, you’ll need to do a deeper clean. Turn the A/C off again and remove the filter, then spray the hydrogen peroxide further into your window unit. You’ll need to place a tray, like this one used for roasting turkeys, beneath the air conditioner to catch any drips of the hydrogen peroxide. Otherwise, you might end up with stained woodwork or carpet.

how to clean a window air conditioner turkey tray Image courtesy of Amazon


4. Clean the Filter Monthly

One of the most important parts of your air conditioner, and one that needs regular cleaning, is the air filter. This is especially true if you have pets or live in a particularly dusty environment, as the filter can become clogged causing your air conditioner to lose efficiency. To clean the filter, remove the front panel of your HVAC unit and pull the filter out of its slot. Rinse the filter with warm water or use a vacuum with a crevice tool attachment if there’s a lot of built-up dirt.

Don’t know how to access the filter in your window unit? Look for a model or brand name on the front or sides of the appliance. Most AC companies will have online manuals showing you exactly how to care for your model.

how to clean a window air conditioner crevice vacuum tool Image courtesy of Amazon


5. Replace the Filter Every Three Months

Even with monthly cleaning, your air filter won’t last forever. It will probably be worn out after approximately three months of use. For most air conditioners, you’ll need to find the model number of your filter and order a replacement online. But some filters feature universal foam filters. For those units, you can use a cut-to-fit air filter like this version from Vega AC, which comes in a pack of two.

how to clean a window air conditioner vega filter Image courtesy of Amazon


6. Comb the Fins Once a Season

Every six months if you live in a warm part of the country or at the end of the summer, you’ll need to give your window air conditioner unit a deeper clean. This might seem intimidating, but it’s a really straightforward process. First, remove the front panel of your unit. Then, using these made-for-purpose combs, remove all the dust and/or debris from the air conditioner’s fins. Be careful! The fins can be sharp.

how to clean a window air conditioner supco combs Image courtesy of Amazon


7. Also, Dust the Coils Every Season

While you have the unit open, you should use a can of compressed air, like this one from Dust-Off, to dust the coils. Simply spray the air at the fins and the coils in both the front and the back of the air conditioner. You can also “dust” the motor and the fan at the middle of the unit if you can easily reach them. Removing the dust from the inside of your air conditioner every three to six months will extend the life of your unit. Plus, watching all that accumulated dust fly away is extremely satisfying.

how to clean a window air conditioner dust off Image courtesy of Amazon


8. Then, Vacuum the Tray

In addition to cleaning the coils, you’ll also need to clean the tray or the base of your unit. That’s because this tray is attached to the drain, and if it’s not properly cleaned, it can cause blockages in the drain, leading to water damage inside the unit. To clean the tray, vacuum it out with a wet-dry vacuum, like this one from Stanley. Once the bigger debris is gone, spray it down with cleaner and wipe it down with a wet cloth. Let everything dry for several hours before putting your window air conditioner back together again.

how to clean a window air conditioner stanley shopvac wet dry vacuum Image courtesy of Amazon


9. Cover Your Air Conditioner When It’s Not in Use

One of the most important things you can do to keep your window air conditioner clean and in working order is to remove it from the window when it’s not needed. Store it inside in your garage or attic, and cover it with a cloth or a tarp. If, for some reason, you can’t take your unit out of the window, you’ll need to invest in a made-for-purpose window air conditioner cover, like this one from Jeacent. It slips over the unit and is secured in place by two buckled straps.

how to clean a window air conditioner cover Image courtesy of Amazon


10. To Deep Clean Air Conditioners, Use Coil Cleaner

Occasionally, you may need to give a window air conditioner the deepest clean possible. This may be the case if you’ve bought a second-hand unit, or you’ve never cleaned your air conditioner but now realize that you need to. The first step is to remove the air conditioner from the window and take off the front panel, the case and the fins that allow it to attach to the window. Spray these pieces down with an air conditioner coil cleaner, and then also spray the interior coils, the aluminum fins, the fan and the base of the unit. Let the cleaner sit on these parts for several minutes.

how to clean a window air conditioner foaming cleaner Image courtesy of Amazon


11. And, Scrub With a Soft Bristle Brush

Using a soft bristle brush, you can scrub everything down at this point. This includes both the case and the interior mechanics of the machine. However, you’ll need to be very careful when brushing the coil. Do so quite gently. If you happen across any stubborn dirt, simply spray it down with the cleaner again, let that sit for a few minutes and then brush it again. You may need to repeat these steps several times, depending on the severity of grime on your window air conditioner unit.

how to clean a window air conditioner oxo brushes Image courtesy of Amazon


12. Finally, Rinse With a Garden Hose

The last step in the deep clean process is to spray all the pieces down with your garden hose. Make sure to use the hose on the lowest pressure possible as you don’t want to damage the sensitive interior of the unit. First, spray off the casing and window fins, then move onto the fan, aluminum fins and coils. However, try to avoid spraying the control panel as water could damage the attached electronics. Once you are satisfied that everything looks spick and span, you’ll need to pick up one side of the air conditioner to allow all the excess water to drain out of the base.

Be very careful not to get the electronic components of your window air conditioner wet.

how to clean a window air conditioner garden hose Image courtesy of Amazon


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