To maintain a stable room temperature throughout the seasons, more air conditioners are equipped with both cooling and heating functions. The Consumer Council tested 12 models of “2 horsepower (HP)” inverter split-type air conditioners, 5 of which were reverse cycle air conditioners (RCAC). Although all models had Grade 1 energy labels for both cooling and heating, the test results revealed that the actual energy efficiency varied considerably. Based on the Cooling Seasonal Performance Factor (CSPF), the model with the highest cooling energy efficiency saved 27.4% more energy annually than the least energy-efficient model in the same group. In terms of heating, upon comparing the Heating Seasonal Performance Factor (HSPF) among the 5 RCACs, the model with the highest HSPF was found to save 10% more energy than the one with the lowest HSPF. In addition, the cooling capacity or heating capacity of 4 models did not meet their claimed levels, with the greatest variance being 2.6% for cooling and 1.4% for heating, though still within the 10% tolerance range allowed under the local Mandatory Energy Efficiency Labelling Scheme (MEELS) and common international practice. The Council anticipates manufacturers to strengthen quality control and recommends the Electrical and Mechanical Services Department (EMSD) to review current energy label grading standards, which could motivate the industry to enhance the energy efficiency of their products and introduce more energy-saving options to help consumers achieve sustainable consumption.
Of the 12 models of “2 HP” inverter split-type air conditioners tested, 5 were RCACs priced between $9,980 and $20,580, while the remaining 7 were cooling-only models priced from $9,888 to $12,840. The claimed cooling capacity of these 12 models ranged from 5.000kW to 5.310kW, while the claimed heating capacity of the 5 RCAC models ranged from 5.334kW to 6.000kW. In terms of design, 10 models were of regular split-type design, while the remaining 2 were of “slim-type” or “window-type” outdoor unit design respectively. The tests were conducted by an independent laboratory in Hong Kong with reference to international standards. Test items included the cooling capacity, heating capacity[1], energy efficiency, noise level, air flow rate, dehumidifying performance, safety level, and ease of use.
8 Models Had Cooling and Heating Capacity as Claimed
Yet 4 Models Slightly Lower than Claimed
The cooling and heating capacities are among the most critical considerations for consumers when purchasing air conditioners. The cooling capacities of the 12 models measured at maximum load ranged from 5.078kW to 5.526kW. 10 of the models scored 5 points, with measured values ranging from 1.5% to 5.8% higher than claimed. However, the cooling capacities of 2 models were 2.4% and 2.6% lower than their claimed capacities thus scored 4 points. As for heating, the measured heating capacities of the 5 RCAC models ranged from 5.271kW to 6.163kW, of which 3 exceeded claimed values by 1.0% to 2.7%, scoring 5 points, while the other 2 were 1.2% and 1.4% lower than claimed, scoring 4 points. Although the discrepancies between the claimed and measured cooling or heating capacities of these 4 models fell within the 10% acceptable tolerance range under the MEELS and common international practice, their performance was inferior to other tested models. The Council reminds the concerned manufacturers to step up quality control to ensure that products perform as claimed.
Energy Efficiency Varied by up to 27.4% for Cooling and 10% for Heating
Among Models with Same Grade 1 Rating
The CSPF of an air conditioner indicates its cooling energy efficiency, the higher the value, the more energy efficient it is. The 12 tested models covered both RCAC as well as cooling-only units, with the 7 cooling-only models classified into 3 sub-categories according to different outdoor unit designs. However, even after considering major differences in function and design, the CSPF values of models within the same group varied significantly, the highest being 6.535 and the lowest being 4.746. The model with the highest cooling energy efficiency could save up to 27.4%[2] more energy annually compared to the lowest performer per year, and both models were in the same cooling-only (non-slim-type/window-type outdoor unit) group.
For heating, higher HSPF values indicate greater heating energy efficiency. The HSPF values of the 5 RCAC models ranged from 4.722 to 5.247, with the highest heating energy efficiency model saving 10.0% more than the lowest performing model[3] annually.
With reference to the international standard method of calculating electricity consumption, the temperature and time distribution data adopted by the MEELS, and the current test results, based on the cost of $1.7 per kWh, the estimated annual electricity cost for cooling is $1,184 to $1,630 assuming operation for 12 hours per day for 180 days a year; and that for heating (for RCACs only) is about $100 to $117 per year assuming operation of 12 hours per day for 25 days a year.
Urging for Further Tightening Energy Label Grading Standards for
Air Conditioners
All tested models received Grade 1 energy labels. However, test results showed that even among models in the same group, there were significant variances in cooling or heating energy efficiency, reflecting that manufacturers possess the technical capabilities and room to design products with higher energy efficiency and cost-effectiveness. Under the current MEELS, as at mid-March this year, 78% split-type models were awarded Grade 1 energy efficiency in cooling (versus only 30% of window-type units), and 99% split-type RCAC models were awarded Grade 1 energy efficiency in heating. The Council recommends the EMSD to explore the possibility of further upgrading energy label grading standards for air conditioners, to encourage suppliers to introduce more energy-efficient products. This would help consumers to save energy, reduce carbon emission, and promote sustainable consumption.
Use of “Dry” Mode May Help Enhance Dehumidifying Performance
According to test results conducted in the standard environment, in “cooling” mode with the highest fan speed setting, the 5 RCAC models utilised 18% to 31% of the cooling capacity for dehumidification operating at maximum load, while that of the 7 cooling-only models ranged from 15% to 24%. When operating at half load, 2% to 8% of the cooling capacity of the 5 RCAC models was used for dehumidification, while that of the 7 cooling-only models ranged from less than 1% to 4%. Consumers needing dehumidification may consider using the “dry” mode or lowering the fan speed setting, which can aid in condensing moisture in the air into water droplets inside the air conditioner unit and improve the dehumidifying performance.
Basic safety tests were also conducted with reference to international standards. The power cord of 3 models were displaced after 25 pulls at a force of 100N, failing to comply with the standard requirement, while the remaining models all passed the safety test. The EMSD expressed that despite the models failing to fully comply with safety standards, they would not pose safety concerns under normal use.
Shortest Warranty Period at 1 Year Only
Industry Urged to Extend Coverage to Minimise Waste
As air conditioners are durable goods, careful consideration should be given to the maintenance arrangements and warranty renewal costs. The 12 models provided full machine warranty periods from 1 to 3 years for new units, with 7 offering only 1-year full machine warranty. For the more durable compressors inside the units, the warranty period was generally 5 years, except for 2 models which only provided 1-year warranty. During the warranty period, all models covered free on-site basic inspection service in urban areas, and labour and spare parts charges were generally waived for damages not caused by human factors. However, beyond the warranty period, on-site inspection in urban areas would cost between $410 and $950. As for warranty renewal, except for 1 model which did not offer such service, the annual fee for the remaining models ranged from $680 to $1,650, a difference of over 1.4 times. Furthermore, if repair of a split-type outdoor unit involves scaffolding, the relevant cost is usually borne by the consumer. Consumers may consider supplementary scaffolding fee supporting plans offered by some suppliers at an additional charge, and they should understand the details before committing. The Council calls on suppliers to offer longer warranty periods and cheaper annual renewal and maintenance fees, so as to encourage consumers to repair products that can still be used, thereby reducing waste and contributing to environment protection.
Compared with heaters or fan heaters which could be easily obstructed or tripped over, RCACs are generally safer and more space-saving because they are installed in higher positions. They are also more energy-efficient, saving electricity in the long run. However, as RCACs are generally more expensive and require professional installation, consumers should choose the right heating appliances according to their home environment and needs. Consumers may also refer to the following tips for use and maintenance:
- Set cooling at 24°C to 26°C and heating at 16°C to 18°C to save energy. In the summer, close curtains to block direct sunlight, and keep windows and doors closed to maintain the room temperature;
- Electric fans consume much less electricity than air conditioners. By using a fan alongside the cooling function, the air conditioner can be set at a higher temperature to reduce electricity consumption;
- Utilise the timer function to preset switch-off time to avoid prolonged operation or forgetting to switch off; do not switch it on again immediately after turning it off;
- Clean the dust filter, air inlet and outlet about every 2 weeks during summer to prevent airflow obstruction which affects performance; while deep cleaning of the air conditioner involves disassembling and reassembling parts, it is recommended to engage the servicing agent of the air conditioner or a professional air conditioner cleaning company.
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[1] The cooling and heating tests were conducted with reference to international standards, with the cooling test set at an indoor temperature of 27°C and a relative humidity of 48%, and an outdoor temperature of 35°C and a relative humidity of 41%; the heating test was set at an indoor temperature of 20°C and a relative humidity of 58%, and an outdoor temperature of 7°C and a relative humidity of 87%, with test conditions identical or very close to air conditioner testing standards in most advanced regions or the energy efficiency labelling schemes for air conditioners in those regions.
[2] Assuming total amount of heat extracted from the room is the same for each model throughout the year.
[3] Assuming total amount of heat brought indoors from outside is the same for each model throughout the year.