During the sweltering summer months, many consumers rely on portable fans to stay cool while commuting or working outdoors. The Consumer Council tested 18 models of rechargeable portable fans of various designs and found that among the lighter handheld models, the airflow rate at the highest fan speed setting could vary by over 1.5 times between the highest and lowest performing samples, while the variance among the heavier models could be more than 1.3 times. Some models with higher claimed battery capacities were found to store less energy and deliver less total airflow after a full charge than another model with lower claimed battery capacity. The performance in safety, noise level, energy efficiency and ease of use also varied among models.
The test covered 18 rechargeable portable fan models, including 16 handheld and 2 neck-mounted (neckband) designs. Among the 16 handheld models, some came with accessories including waist clips or neck straps. Designs ranged from traditional fan shapes to rectangular builds, all with delivering airflow for cooling as the main function. The handheld models were categorised into heavier (204g to 277g) and lighter (93g to 189g) groups based on the product weight (excluding accessories). Prices ranged from $58 to $339 for handheld models, and $99.9 and $239 respectively for the neckband models.
The Council commissioned an independent laboratory to conduct the tests, assessing the safety, airflow rate, charging efficiency, battery life (i.e. runtime), energy efficiency, noise level and ease of use. 6 handheld models received an overall rating of 4.5 stars, including the highest and lowest-priced models, as well as the heaviest and lightest ones, indicating that there are good options whether consumers prioritise portability or performance. The Council recommends consumers to compare comprehensively and select a model that suits their actual needs. Furthermore, all instruction manuals were found to be inadequate, such as failing to comply with the safety standard’s requirement to place safety instructions upfront in user manuals, or lacked warnings such as “Do not allow children to play with this product”. The Council urges relevant manufacturers to improve the content of user manuals and enhance safety guidance for consumers.
Airflow Rate Varied by over 1.5 Times Between Highest and Lowest Models
Fan Head Size Not Necessarily Correlated with Airflow Performance
The airflow rate directly affects the cooling sensation during use. With reference to the international standard[1], the tested models were first fully charged, then their airflow rates were measured at the highest fan speed setting, operating on battery power, and with the “cold compress” function (if any) disabled. Among the group with heavier handheld models, the measured airflow rate ranged from 1.25m3 to 2.98m3 per minute, with a difference of over 1.3 times between the highest and lowest models; while for the lighter handheld models, the airflow rate ranged from 0.91m3 to 2.34m3 per minute, a difference exceeding 1.5 times. The 2 neckband models delivered 1.32m3 and 1.55m3 per minute respectively.
It is worth noting that among models with similar fan head sizes, the airflow rate could still vary considerably. Taking for example the 3 handheld models with fan heads approximately 6cm in diameter, there was an almost onefold difference in airflow rate between the highest and lowest performing models. Consumers should not assess the airflow capability solely based on the fan head size.
Higher Battery Capacity Does Not Guarantee Longer Runtime
Battery Voltage Could Also Affect Energy Storage
When selecting rechargeable portable fans, consumers may assume that a higher claimed battery capacity means more stored energy and longer battery life. However, actual energy storage depends not only on the battery capacity (measured in milliampere-hours, mAh), but also on battery voltage (measured in volts, V). For instance, 1 model despite having a lower claimed battery capacity (2,200mAh), as it had a higher battery voltage (7.4V), it was able to store more energy, by calculation, than another model with a higher claimed battery capacity (3,600mAh) but lower battery voltage (3.7V).
Battery life is also influenced by a multitude of factors such as the fan speed setting and product design, etc. In the battery life test, the samples were fully charged and set to operate at the highest fan speed setting with the “cold compress” function (if any) disabled, and runtime was measured until battery depletion. 2 handheld models could operate continuously for over 3 hours.
However, since the primary function of a fan is to deliver airflow, solely measuring the runtime at the highest fan speed setting starting from a full charge may not entirely reflect its battery life. In view of this, the test also calculated the total volume of airflow delivered at the highest fan speed setting after a full charge as reference for the battery life. Results showed that shorter runtime did not always mean a lower airflow volume. For example, 1 handheld model in the heavier group operated for only about 1 hour and 52 minutes after a full charge, the second shortest among all handheld models, but delivered 334m3 of total airflow, second only to the model with the longest runtime (440m3). The Council recommends that consumers consider both the runtime after a full charge and the total airflow to select a model with more satisfactory battery life as needed.
Most Models Passed Safety Tests
1 Model’s Temperature Rise During Charging Non-compliant with Requirements
As rechargeable portable fans are often used close to the body, either handheld or hung around the neck, safety performance is critical. With reference to international safety standards, most models (17 models) passed basic safety tests, including overheating protection, overcharging protection, abnormal operation, mechanical strength, mechanical safety, and flame resistance. While the overall performance was satisfactory, 1 model showed room for improvement in overheating protection.
According to the latest 2020 version of the relevant standard[2], the maximum temperature rise of the battery surface during charging and operation should not exceed the battery manufacturer’s specified limit. As none of the models indicated relevant limits, the laboratory referred to the requirements from the previous version (2016 version) of the said standard, which stipulates that if no limit is specified, the maximum temperature rise of the battery surface should not exceed 20°C.
In a test environment at room temperature 25°C, 1 model recorded a highest temperature rise of 31.6°C during charging (i.e. reaching 56.6°C), and a 27.2°C rise during simultaneous charging and operation, both higher than that of the other 17 models (with temperature rise ranging from 0.3°C to 11.5°C and 0.3°C to 10.1°C respectively), and non-compliant with the requirements set out in the 2016 version of the standard. Experts have pointed out that while a battery surface temperature of around 57°C is unlikely to cause combustion or explosion, it may cause more side reactions in the battery and accelerate battery ageing. The Council recommends the relevant manufacturer to make improvements.
Additionally, all instruction manuals were found to be inadequate, with some failing to place safety instructions towards the front or missing warnings such as “Do not allow children to play with this product” as per the standard requirements. The Council urges relevant manufacturers to improve user manuals in accordance with the requirements of the standards to enhance consumer safety, and has referred the safety test results to the Customs and Excise Department for follow-up.
Noise Level, Energy Efficiency and Ease of Use Varied Across Models
Noise levels were measured in a soundproof room at 4 positions (front, back, left and right) 20cm from the sample, with fans operating at the highest fan speed setting. Some handheld models maintained low noise levels even at the highest fan speed, ranging from approximately 49 to 71 decibels, and thus received 4.5 points. Some others were noisier, ranging from about 69 to 98 decibels, and received only 3 points. The 2 neckband models recorded noise levels of approximately 53 and 59 decibels, and 59 and 64 decibels, receiving 4.5 and 4 points respectively.
Energy efficiency also varied significantly. The most energy-efficient handheld model required only 2.57Wh of electrical energy to deliver 100m3 of air, while the least energy-efficient consumed up to 14.63Wh, a difference of over 4.5 times. The neckband models consumed 5.98Wh and 9.16Wh respectively.
In terms of ease of use, 2 handheld models received full marks of 5 points for their compact size, clear button design and multiple fan speed settings. The 2 neckband models were heavier and offered fewer fan speed options, resulting in lower scores in this test item.
When purchasing and using portable fans, consumers should pay heed to the following:
- Children should use portable fans under adult supervision and should not be allowed to play with it. Neck straps, if any, may pose strangulation risks if misused;
- Lithium batteries should be kept at moderately charged levels as far as practicable. Avoid frequent full charges or charging only when the battery is nearly empty;
- If the fan will be idle for an extended period, discharge the lithium battery or charge it to a moderate level before switching off. Recharging the fan every few months to a moderately charged level helps maintain battery health;
- Select chargers manufactured by reputable brands. Keep the fan within sight when charging and refrain from charging without supervision or overnight while asleep. Unplug the charger after use;
- If the fan, battery, charger or cable shows signs of deformation, damage, overheating, or emits unusual sounds or smells during charging or operation, stop using it immediately and disconnect the power safely; and
- Avoid using the fan in damp environments to prevent water seepage, which may cause damage or hazards.
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