How to Rejuvenate a Box Fan





Introduction: How to Rejuvenate a Box Fan

Many people throw fairly new box fans out well before their time. Like most small appliances, people don't take the time to clean them, even though it will make them last much longer. I guess it is easier to put it out for the trash and spend another $20-$30. Whenever I see the towers of box fans for sale, I always wonder what happened to the ones people bought the year before.

After only one season a fan may be covered in enough gunk to give the illusion that the 'motor' is worn out, when really all that is needed is a good cleaning to keep it running for a lot more hours. I have often picked these up on trash day, and gotten years of use from them. Rarely I may have to replace a knob, but usually they are functioning, but the blade speed is about half of normal.

Step 1: Tools

Just a few tools, though you can use many more for cleaning depending on the gunk level.

Screw driver
Paper towel
Dusting Brush
All Purpose Cleaner/degreaser
Finger Nail Brush
green kitchen scrubbies
steel wool

Step 2: Remove Front and Back Grills

These screws are usually very small. put them in your pocket or somewhere SAFE.
Sometimes a few can be missing OR the hole has grown too large to reseat tightly.

Yes, you can skip a few, usually you can leave off a side screw without TOO much noise factor.
but you NEED the top and bottom tightly screwed down of the vibration will make a hell of a racket.
scout around for replacements - you want short and fat threads.

Step 3: Remove Grill and Fit

You may have to unhook the power cord collar and remove the feet.
if the feet are missing you will have to dummy a replacement, or just make sure the fan is propped up, like in a window. Vibration at high speeds will make the fan walk and possibly fall.

Step 4: Brush the Motor

Remove all the material surrounding the motor, avoid spraying it with any cleaners.
Use a brush to remove the hair and gunk.
also wipe the struts.

Step 5: Wash Blades

Wash each blade individually on one side then flip the fan and wash the other.
I find that some blades resist degunking and a scrubbie pad is useful to remove the stuck on gunk.

If you leave it gunked and only remove the visual material, new stuff will quickly latch on and you will be just as bad off. You want to end up with smooth clean plastic blades, where things slide off.

Step 6: Clean Fan Grills

This is tedious and you will feel like cutting corners. If you have more than one fan to do, leave the 2nd until the next day. Use a brush for the solid matter. then spray with a degreaser/cleaner and then scrub with a nail brush or other firm bristle brush. Then wipe with paper towels.

The grids are NOT straight but beveled, and may appear clean if you look at them straight on, look at them from an angle and you will see they have four sides, you don't need it spotless, but get the area in front of the blades reasonable clean. You CAN do these in the shower, and use a long handled scrub brush, but you will still need to use paper towels to get in some crevasses.

Step 7: Reassemble the Fan.

Wipe the whole thing down inside and out.
Reattach the grills, the feet and align the power cord collar.
Turn it on, if the fan was not old to begin with you will find a world of difference between the speed of the fan blades before and after the cleaning.

I do this every season to my own fans and these $20 box fans last a lot longer then the manufacturers want them too.

2 People Made This Project!


  • Space Challenge

    Space Challenge
  • Microcontroller Contest

    Microcontroller Contest
  • Spotless Contest

    Spotless Contest

We have a be nice policy.
Please be positive and constructive.




That's how to clean a fan - no rejuvenate.


Cleaning it DOES rejuvenate it

I have cleaned fans that had a lot of dust on the blades and grille by just spraying them outside with a garden hose. No disassmbly, left the motor in. I let it dry several days in the sun outside before using. I was concerrned about water in the motor but no problems years later.

I have a fan that the fuse blew on the plug how can i replace that

Does anybody know the customer service number for cool master box fan?

I have a new fan that is very noisy. Is there any way to make it quieter?

Thank you!

Is your fan a small 8-inch desktop? Most of the time it is a result of lousy bearings with so much play that the shaft rattles. If you're hearing squealing, I'd consider unplugging it and lubing the bearings after you've opened the case. There are several very small coarse-thread screws from the back that hold the front to the back half. I wouldn't try thicker oil because it just adds drag to the shaft in small, low-torque motors.

Returning it to the store or manufacturer will make it a lot quieter.

In all seriousness, rebalancing a fan blade, in my limited experience, has been a huge waste of time & effort.

Fan noise usually comes from vibration. Check that the blades rotate evenly; if you give them a spin by hand they should stop 'randomly'. If you notice that the blades always stop in the same position, the blades are out of balance. Try to clean them, look for small breaks in the plastic, etc. You *can* counterweight them with small pieces of tape, but once they are out of balance its almost impossible to rebalance them. Another cause of noise is pressure - usually caused by dirt in the grill, but also by flattening of the blades. Look for evenness doing the spin test.