As Hong Kong summers are hot and humid, many households turn air conditioners on to keep their homes dry and comfortable. However, as air conditioners are high electricity consumption appliances which consume more electricity when set at lower temperatures, electricity expenses are bound to increase. According to the Electrical and Mechanical Services Department, generally speaking, for every 1°C increase in temperature setting, the reduction of electricity consumption in the air conditioning equipment is about 3%. To enjoy air conditioning with less electricity consumption, there is no better way than assisting by a fan, which consumes far less power than an air conditioner, to evenly distribute cool air to every corner of the room. As such, in recent years many consumers opt for air circulator fans that are generally smaller in size and more convenient for placement and storage. The Consumer Council tested the safety and performance of 12 air circulator fan models, among which 8 models failed some of the safety test items, including 4 models found with insufficient insulation distances, which may increase the risk of electric shock; the materials of 2 models did not comply with the standard for resistance to fire; while 1 model posed risks of catching children’s fingers. On the other hand, the airflow rates among models could vary by up to over 50%, and the maximum difference in energy efficiency even reached 67%. Even tiny sums add up in the long run, so the Council reminds consumers to compare the price, electricity consumption, as well as features and design among different models before purchase.
Air circulator fans, also known as convection fans, are generally smaller in size than traditional floor or table fans, and the shape of the fan head is generally cylindrical. Some models claimed to be able to accelerate indoor air convection, facilitating more even room temperature when used alongside air conditioners or heaters, in turn allowing the temperature setting of air conditioners or heaters to be adjusted correspondingly to save electricity. Among the 12 models tested by the Council, 8 models had larger fan blades ranging from 18cm to 21cm in diameter, while the remaining 4 models had fan blades ranging from 14cm to 16cm in diameter. Test items included the safety, airflow rate, energy-saving performance, noise level, and ease of use. 4 models received the highest overall rating of 4.5 points, with prices ranging from $459 to $798, while the highest priced model ($1,149) scored slightly lower (overall rating 4 points). Consumers should compare more when making a selection.
8 Models Failed Some Safety Test Items
Air circulator fans may be used for longer periods, even overnight during sleep, so the safety level must not be neglected. In this test, 1 model passed all safety test items and performed satisfactorily, while 3 other models only had deficiencies in instructions, so these 4 models received an overall rating of 4.5 points. The remaining 8 models failed some safety test items, of which 1 model had insufficient insulation distance between individual live parts on the internal circuit board, which was 1mm less than the required insulation distance (2mm) in the standard. This model and 3 other models had insufficient insulation distances between an individual internal live part and the motor shaft which could be accessible to the user after removing the fan guard and/or fan blade, ranging from 2.8mm to 4.3mm less than the standard required insulation distance (8mm). If users removed the fan guards and/or fan blades without disconnecting the power supply beforehand, the risk of electric shock would increase. In addition, when 1 model was oscillating in the up-down direction during operation, a test finger simulating a child’s finger could be caught in the gap between the fan head and the base, and the force exerted when caught (16N) exceeded the standard upper limit (15N), which may put children at risk of injury if they accidentally put their fingers into the gap.
The test also found that the resistance to fire of 2 models’ materials did not meet standard requirement, with 1 model’s internal plastic component and the exterior casing plastic material of the other model both failing the needle-flame test as they did not self-extinguish within 30 seconds after catching fire. Furthermore, when 1 model operated at a higher voltage, the temperature rise of its motor winding was measured at 93.1K (1K is 1°C), which exceeded the standard maximum limit (90K) by 3.1K.
Maximum Variation in Airflow Rate and Energy Efficiency Recorded Over 50% and 67% Respectively
The airflow rate directly affects the sensation of coolness. The model with the highest airflow rate in the test (fan blade diameter 21cm) delivered 21.2m³ of air per minute, while the model with the lowest airflow rate (fan blade diameter 18cm) delivered 10.1m³ of air per minute, a difference of 52%. According to the results, the airflow rate of the models with a larger fan blade diameter (18cm to 21cm) ranged from 10.1m³ to 21.2m³ of air per minute, while that for models with a smaller fan blade diameter (14cm to 16cm) was between 10.3m³ to 13.3m³ of air per minute. Generally, the larger the fan blade diameter, the higher the airflow rate.
As for energy-saving performance, 3 models had an input power (i.e. electricity consumption) of less than 20W when operating at their highest wind speed settings and maximum auto-oscillation angles, which means that by estimation, they would consume less than 0.2kWh of electricity for 10 hours of operation. As for the model with the highest input power of 45.9W, its estimated power consumption was about 0.5kWh for 10 hours of operation, which was more than double the one with the lowest power consumption. As the airflow rate varied among models, the energy efficiency of each model was expressed in terms of airflow rate per watt of input power, with a higher value representing a higher energy efficiency. The airflow rate per watt produced by the 12 models ranged from 0.4m³/min to 1.2m³/min, with a maximum difference of 67%. Overall, the energy efficiency of the 5 models with DC motor-driven fan blades was better than the 7 models with conventional AC motor-driven fan blades.
High power consumption when appliances are on standby is quite wasteful of energy. The input power of the 12 models in standby mode ranged from 0.1W to 1.5W. The model with the highest standby power consumption was estimated to consume around 1.1 kWh of electricity if kept on standby for 30 consecutive days, which was equivalent to this model being turned on for almost 40 hours. The Council recommends that if consumers are not using a fan for a long period, they should unplug the power supply, or use an independent switch on the outlet to cut off power to avoid wasting electricity.
One would naturally expect fans to be as quiet as possible, especially while sleeping, yet the test found that the noise levels of the models vastly varied. The measured noise levels of 1 model were relatively low, both at the lowest wind speed setting with the auto-oscillation function set at stationary, and at the highest wind speed setting with the auto-oscillation function activated. 2 models produced higher noise levels during operation that were approximately equivalent to the level of street noise, which were 66 decibels and 73 decibels respectively when set to the highest wind speed with the auto-oscillation function activated, and measured at a distance of 0.5m from the model. The only way for consumers to reduce the noise would be to lower the wind speed.
Some tips for consumers when using a fan:
- If the fan is equipped with a pre-set start timer function, it can be used in conjunction with the timer shut-off function of air conditioners. For example, before going to bed, pre-setting the air conditioner to turn off automatically after a certain period of time while pre-setting the fan to start automatically afterwards could shorten the usage time of the air conditioner, as a result saving electricity;
- Place the fan on a level surface where it will not easily trip people over, and leave space for the fan to oscillate and dissipate heat;
- Fans with plastic cases should not be exposed to direct sunlight for long periods of time to prevent the case from becoming brittle and deteriorating;
- Do not allow children to stick their fingers or other objects into fan guards or gaps, do not run the fan unattended, and do not allow objects such as paper or clothing to be sucked into the fan;
- Unplug the fan before moving or cleaning. Unplug it if it will not be used for a long period of time;
If the fan emits unusual sounds or odours, or if the casing is broken, stop using immediately, unplug it, and arrange for inspection and repair.
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