Efficient air-conditioners (ACs) may well be a misnomer, according to a recent study by the Centre for Science and Environment (CSE). An AC with energy ratings of five-stars performs like one with two-stars when the temperature soars to 40ºC. The performance further dips to a one-star level by the time the mercury touches 45ºC, results of CSE’s lab showed. In peak summers, when temperatures are in the 40-50ºC range, a five-star room AC can start consuming 10-28 per cent more power than its declared capacity, thus adding to the peak load demand on the electricity grid, noted the study, which tested ACs under normal as well as extremely high temperatures. CSE conducted the tests on three popular split AC models from Voltas, LG and Godrej, and all the three failed the tests at higher temperatures. While Voltas and LG ACs performed optimally at 35ºC, the Godrej AC’s energy efficiency ratio (EER) dropped to four-star levels. The LG AC performed better than the other two at 40ºC and 45ºC at three-star and one-star level, respectively, against two-star and zero-star for the other two companies. At 50ºC, all the three dropped to zero-star levels, as per the study. It is estimated that ACs account for as much as 28 per cent of the total monthly electricity consumption in Delhi. The think-tank estimates that room ACs might be consuming about 96 billion units of electricity if they function at their declared ratings. On an average, there is a 2.5 per cent dip (in efficiency) for every degree rise in external ambient temperature above 35ºC. This means a five-star rated room AC performs worse than a one-star rated room AC when the external temperature reaches 45ºC. At an extreme 50ºC, the average EER was at a level which has been outlawed by the BEE (Bureau of Energy Efficiency) way back in 2010, the study mentioned. The study finds a resultant increase in power consumption at an average rate of 1.9 per cent for every degree rise in external temperature above 35ºC. The test results were in line with earlier findings of the BEE, which had published names of the companies whose models failed its random sampling in 2014 and 2015. Some of the companies that failed the compliance tests were Samsung, Godrej, Panasonic, O General, Whirlpool, IFB and Videocon. CSE explained that these companies had countered the BEE’s findings with claims that the named models were discontinued before the results came out. It has been noted that companies periodically change the model names by modifying any minor feature, thus escaping BEE scrutiny, CSE said as reported. Further, Vijay Babu, Business Head-RAC, LG Electronics India, reportedly said that all electronic goods from reputed companies are developed and tested as per the standards set up by relevant authorities, adding that ACs too follow the IS-1391 (part 2) laid down by the Bureau of Indian Standards and energy-efficiency norms laid down by BEE. As reported, he added that the study by CSE states there is reduction in energy-efficiency at higher temperatures, which is due to the very nature of the product and is not specific to any particular brand of AC. The same is also mentioned in the study which says, ‘CSE researchers point out that it is not unusual for RACs (rooms ACs) to consume more power to cool and suffer energy-efficiency loss under climatic stress.’