With the approach of summer, we may need an air conditioner to keep us cool and comfortable during the hot summer days. Air conditioners account for 30% of household electricity consumption, making it the highest energy consuming household electrical appliance. So a smart consumer should always bear in mind the idea of energy efficiency when buying a new air conditioner.
The Consumer Council has recently conducted a test on 15 models of window-type room air conditioners, with claimed cooling capacities of 5.0kW to 5.3kW (or "2 horsepower"), and prices ranging from HK$3,298 to $5,990. The results revealed that some models with the higher prices do not translate into higher energy efficiency.
For cooling capacity, two thirds of the samples (10) were found to fall below their own claims, with the largest difference at about 5.1%. The Electrical and Mechanical Services Department (EMSD) said such variations are within the tolerance level of the Mandatory Energy Efficiency Labelling Scheme (MEELS) and overseas practices.
Apart from cooling capacity, energy efficiency is another important consideration when choosing an air conditioner. The lower the energy efficiency, the more energy the air conditioner consumes to produce the same cooling capacity. The Coefficient of Performance (COP), a measurement of cooling capacity produced by 1 kilowatt of energy consumption, is an indication of the energy efficiency performance of an air conditioner. According to the Council's test results, there is a difference of about 25% among the samples with highest and lowest energy efficiency. In terms of annual running cost of electricity, the samples varied from HK$2,228 to $2,968, a difference of HK$740 (about 25%) per year.
In addition, 3 samples were found to have energy efficiency grades lower than that indicated on their energy labels. The EMSD said the Council's test results of these 3 samples comply with the requirements of the MEELS as their calculated COPs for determining the energy efficiency grades are within the tolerance level of the MEELS and overseas practices.
All tested samples passed a series of basic safety tests (with reference to IEC 60335-2-40) including leakage of current, earthing continuity, etc.
The May issue of CHOICE offers useful tips for energy saving when using air conditioners:
- Do not set the air conditioner at too low a temperature.
- Use curtains to block direct sunlight into the room in order to reduce the room temperature.
- Clean the air filters regularly to maintain the efficiency of the machine.
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