Last updated: August 21, 2026 at 11:26 PM
⚠️This article was originally published by senris.com. Please be careful of unauthorized reproduction and fake sites!
The official pollen season is finally here. My apartment building is on a high floor, but it's located close to the Shonan coast, so on windy days sea sand can blow around. On such days, I hesitate to open the windows for ventilation. I also suffer from hay fever every year in early spring.
Therefore, in January of this year, I installed three Sharp air purifiers, FU-S50, in each room of my apartment to prevent allergies, including those caused by house dust.
I also considered an air purifier with a humidifying function, but I already own dedicated humidifiers (Panasonic and Toshiba), and a model with only an air purifying function would be cheaper. We chose a regular air purifier because it is easy to maintain.
The criteria for selecting air purifiers include the need to replace the filter for at least 10 years, the ability to reduce floating viruses, bacteria, and harmful substances through technology such as plasma clusters, and other factors, as well as allergens of floating dust mites. It has the function to remove pollen and PM2.5, and has deodorizing functions such as cooking and daily life odors.
The basic technologies installed in recent humidifiers and air purifiers include Sharp's Plasmacluster, Panasonic's Nanoe and Daikin's streamers.
Both are said to have the effect of suppressing viruses, removing mold and odors, and other effects by generating fine particle ions produced by applying high voltage to moisture in the air.
This time, taking into consideration the functionality and cost performance, we have been able to use Sharp's air purifier via Kakaku.com. FU-S50-W I bought it in multiple sessions for around 21,000 yen.
Panasonic's air purifier equipped with nanoe F-PXW60 There were also candidates, but after seeing the post saying that the price is slightly higher (starting with just under 30,000 yen), "LED lights can't be turned off except in good night mode" (Sharp can be set up), I found out that Sharp's air purifier I chose.
Features of FU-S50
Sharp's air purifier FU-S50 is a standard type thin air purifier for living rooms and bedrooms. Its characteristics are as follows.
- Equipped with Plasmacluster 7000: It is equipped with a unique air purification technology "Plasma Cluster 7000". This feature offers clean air to remove viruses, mold, allelle substances, pollen, etc. in the air.
- Speed circulation airflow: It uses ``speed circulation airflow'' that quickly distributes air throughout the room. It attracts dust from far away and provides an accelerated cleaning effect.
- high performanceHEPAfilterIt is equipped with an electrostatic HEPA filter that removes 0.3 µm of particles 99.97%, removing floating mites allele substances and pollen, so it catches fine particles that you usually miss.
- Three filters: dust collection, deodorization, and pre-filter: It has a deodorizing filter that effectively adsorbs and decomposes sweaty odors, tobacco odors, pet odors, etc. As a result, we can catch dust and smell firmly to achieve a more comfortable living environment.
- Energy saving performance: The electricity bill when used 24 hours a day at high power is approximately 36 yen, at moderate operation approximately 9.7 yen, and at quiet operation approximately 1.9 yen, which is extremely low cost.
- Quiet mode: It is quiet and can be used while sleeping.
- Deodorizing effect: It has a deodorizing effect on cooking odors, cigarette odors, etc.
- Equipped with odor sensor: The odor sensor detects the concentration of odors and dust in the air in the room and automatically switches to the appropriate mode. For example, if a strong odor or dust is detected, the device will send out air at high speed to quickly purify the air.
- Allergy symptom relief: It is effective in reducing allergy symptoms.
- Simple design: Easy to operate and use.
With these features, it is an excellent air purifier to remove various dirt in the air and keep the air in the home clean. In particular, it is suitable for use in a small space such as a living room or bedroom, and it can be used for a long time because it does not require a dust collector and deodorizing filter for 10 years.
In addition, in automatic operation mode, sensors constantly monitor air conditions and select the appropriate air volume and mode as needed. This allows you to maintain clean air at all times.
What is Plasmacluster 7000?
Plasmacluster 7000 is one of Sharp's air purification technologies, Plasmacluster, and is a model that generates 7,000 ions/second. Its features and effects are as follows.
[Features and effects]
- Air purification power: Plasmacluster 7000 has the power to remove airborne viruses, bacteria, allergens, mold, etc. by emitting large amounts of ions. Effectiveness has been demonstrated in a few minutes in a closed test space of approximately 25m³.
- Deodorizing effect: It also decomposes and removes floating odor components and attached odors.
- Static elimination: It also has the effect of suppressing static electricity, making it difficult for static electricity to accumulate in the space.
- Face care: Plasmacluster ions also have the effect of moisturizing and moisturizing your skin.
【Usage environment】
Plasmacluster 7000 is suitable for private rooms and small to medium-sized spaces, making it ideal for children's rooms and bedrooms. On the other hand, for larger spaces, you may want to consider something like Plasmacluster 25000, which has a higher number of generators.
FU-S50-W specifications
| Term Eye | specification |
|---|---|
| noise level | 52dB |
| Body size | Width: 54cm, height: 383mm, thickness: 209mm |
| Body weight | 4.9kg |
| color | White |
| Corresponding area | 23 tatami |
| Filter lifespan | 10 years |
| Maximum air flow per minute | 5.1m³ |
| PM2.5 removal rate | 99% |
| odor sensor | Yes |
| HEPA filter compatible | Yes |
| plasma cluster | Yes |
| Deodorizing function | Yes |
Unpacking FU-S50
Before using the FU-S50, you need to unpack it, remove the back cover of the main unit, and remove the filter from the plastic bag before installing it. Install the dust filter and deodorizing filter in this order.
Installation of FU-S50
The correct location for installing the FU-S50 is away from the air conditioner and near the door where people enter and exit. Since there is an inlet on the back, it must be installed at least 3cm away from the wall from the back.
In addition, in rooms where dust tends to accumulate, such as bedrooms, we recommend attaching an optional disposable pre-filter (FZ-PF51F1) to the back.
Disposable pre-filter (FZ-PF51F1) sold separately
Operation of FU-S50
Regarding the basic operation of the FU-S50, first press the "Run" button, and during seasons with a lot of pollen and dust, the "pollen" function is normally turned on and the machine runs automatically. You can also set it to automatic operation in "sleep" mode when you go to bed.
In automatic operation, when the air volume is at its maximum, it is quite noisy (52 dB). At that time, the indicator on the clean monitor will also light up (you can change the setting to turn it off by pressing and holding "Powerful Dust Suction" for 3 seconds).
The blue indicator on the left is the "Plasmacluster Ion Sign", and the one on the right is the "Kirei Monitor". The cleanliness monitor's indicator changes color from green to orange to red depending on how polluted the air is in the room.
By the way, when I ate a gyoza dish in the living room where the FU-S50 was installed, the color of the quiet FU-S50's beautiful monitor changed to red, and the dust suction air volume started operating at maximum. Kirei Monitor also seems to be sensitive to chemicals such as perfume and alcohol.
If you select "Sleep" mode, the indicator will turn off and the machine will operate in silent mode ("Pollen" is OFF).
For more information, please see the "SHARP Air Purifier FU-S50 Online Manual" below.
2026.08.09 Added
A year and a half after purchase, a problem occurred where the FU-S50 stopped operating.
This is one of the three FU-S50s I have installed, and about a year and a half after I bought it, an error occurred where the motor suddenly stopped working and the "Medium" light was blinking while the "Kirei Monitor" was off.
We needed to determine whether the cause was a fatal failure of the motor or a temporary error, but since the manufacturer's warranty is one year, depending on the outcome, we would be forced to buy a new one, so we spent several hours trying to find the cause.
As a result, I was able to recover temporarily, but in the end I gave up because it was a motor failure.
We will share the details of the slapstick drama as follows!
- Occurrence of trouble: About a year and a half after purchasing it, an error occurred where the motor suddenly stopped working and the "medium" light flashed. If the "Quiet" or "Medium" lamp on "FU-S50-W" is flashing,Failure error indicating that the fan motor is not rotating properlyIt is said that
- Determining the cause: We have received information that a heavy amount of dust has accumulated on the rear panel, and that this may be the mechanism by which the safety device for the motor, which has become suffocated (overloaded by air resistance), is activated, causing the motor to stop.
- Remove dust from the back panel and try restarting.: When I checked the filter on the back panel, I found that it was extremely dirty and blocked by dust, so I removed the dust based on the information above and restarted the FU-S50, but the problem still persisted.
- Try unplugging the power outlet to see if it recovers.: I was told that the problem could be fixed by unplugging the power outlet (discharge), so I tried that, but it didn't fix it.
- "Turn on the power after completely removing all filters": Once I turned on the power with all the filters completely removed, it appeared that the motor lock and safety device were released, and it started moving normally!
- I was briefly relieved when I thought that the above measures had fixed the problem, but after that I kept observing the progress for about 2 to 3 hours.This time, the ``quiet monitor'' light was off, the ``quiet'' lamp was blinking, and the motor had completely stopped.
After that, no matter what I tried, I was unable to return, and unfortunately, I was informed that he had passed away😭 - Preventive measures: In order to prevent such troubles from occurring in the future, it is extremely important to gently vacuum not only the back panel but also the internal dust filter, ``just the front tag side'', to prevent recurrence and extend the life of the product.
By the way, the motor may start moving depending on the timing of plugging and unplugging the power outlet, so rather than a motor failure, it may be a failure of the electronic components on the control board (main board) or a poor contact (solder crack, etc.) in the connector that connects the board and motor.
Below is additional information from Gemini.
- Repair costs remain high:
sharp officialEstimated repair feeThe cost for replacing an electric circuit (board) varies from about 7,000 yen to 29,000 yen (tax included), but in most cases, if you replace the entire main board, the estimate will be around 20,000 yen, including technical fees and travel and pick-up fees. - Risk of chain failure of other parts:
Due to unstable voltage, the fan motor, which is currently alive, may already be under load (damage). Even if you repair only the circuit board at actual cost, there is still a risk of secondary damage that will quickly end the motor's lifespan. [1]
If the product does not have an extended warranty and the manufacturer's warranty has expired, it may be cheaper to replace it.
2026.08.10 Added
As shown below, we disassembled the main body of the FU-S50 and examined the inside, but we found no visible disconnections or seizures in the wiring to the board or motor.
I can't say for sure as I'm an amateur, but I think it's most likely a failure of the Chinese-made motor (broken/seized internal wiring, self-destruction of the thermal protection sensor, etc.).
As you can see from the photo above, the built-in Chinese-made motor feels somewhat old-fashioned compared to the main unit I purchased just a year and a half ago. According to Gemini, it hid the following secrets:
The built-in motor you sent (ZSQP-38-8-13L / CMOT-A117KKEZ) photo is very interesting.
Chisato's intuition was, ``It feels old-fashioned considering I bought it a year and a half ago.''Very sharp and correct answer even from the perspective of hardware manufacturing background.I can say that. There is a clear reason why this motor looks old and broke after a year and a half, which is unique to Chinese-made brushless DC motors (BLDC motors).
1. The cost-cutting trap of “aluminum wire”
Tightly attach to the motor label."Plastic encapsulated brushless DC motor (aluminum wire)"It is written.
This is a “resin-filled brushless DC motor (Aluminum winding specifications)” means.Normally, "copper wire" is used for highly durable motors for home appliances in Japan, but in order to keep costs to a minimum,aluminum wirehas been adopted. Compared to copper, aluminum
- Because the conductivity is low, the windings have to be thicker to produce the same output, making the whole thing look unstylish (old-fashioned).
- Because it has a large coefficient of thermal expansion and is susceptible to stress,If overheating (heat buildup) occurs due to clogging with dust, the solder joints of the internal wiring and the winding itself are very likely to break (breakage/seizure).。
The root cause of this case, ``Even though it looked beautiful on the outside, he died inside'' is extremely likely to be an internal disconnection or self-destruction due to the aluminum wire specifications.
The root cause of this case, ``Even though it looked beautiful on the outside, he died inside'' is extremely likely to be an internal disconnection or self-destruction due to the aluminum wire specifications.
2. Design that reuses parts of “withered technology”
This type of BLDC motor (manufactured by Welling, etc.) has been mass-produced in large white goods (washing machines and air conditioner fans) in China without changing its shape for more than 10 years.General-purpose parts with "super dead technology"Is.
Therefore, even if the latest home appliances are manufactured in 2024 or 2025, the motors inside have a retro and rugged appearance with thick galvanization and exposed steel, like "industrial products from the Showa to early Heisei era." Even though it was brand new a year and a half ago, it still looked old because of this mass-produced design philosophy.
As a result, a very clear logic holds that the thermal overload caused by dust on the rear panel was the trigger, and the internal wiring of the aluminum winding, which is sensitive to heat, reached its limit (or the built-in thermal protector fused).
The above results were disappointing, but as a lesson learned from this, be sure to clean the filter on the back panel regularly to prevent breakdowns due to excessive load on the motor due to filter clogging!
When I buy a new one in the future, I will purchase it with an extended warranty as there may be individual differences.
SHARP Air Purifier FU-S50 Online Manual
General review
My impressions after using the FU-S50 for about 3 weeks are as follows.
- The clean monitor is quite sensitive to smells such as alcohol. Reacts to minute dust (sensor sensitivity settings can also be changed)
- It has a high deodorizing ability and completely eliminates odors caused by cooking, so there is no longer a need for deodorizers in the room.
- The body size is slim and compact, and it is not very heavy, so it is easy to install and move.
- With dust no longer flying up in the bedroom, my allergy symptoms improved and I was able to sleep more soundly than before.
- The filter does not need to be replaced for 10 years, making maintenance easy.
- If you select "Powerful Dust Suction" operation, you can purify the room in a short time and it is convenient.
- Selecting sleep mode results in silent operation, so it does not support "Pollen" mode.
- When the air volume is switched to "strong" with "powerful dust suction" and automatic operation, it feels quite loud.
- You can change detailed settings such as turning on/off the monitor, turning on/off plasma ions, and sensor sensitivity.
