What are variable speed compressors or inverter drives?
Variable speed compressors are a new technology that improves the efficiency of air conditioners. Unfortunately the contribution of variable speed compressors (or inverter drives) is not well measured by the energy star rating. This rating is based on the maximum output, which may not necessarily be the operating output. Therefore, an air conditioner with a 4-5 star rating and a variable speed compressor might outperform a 6 star rated machine without a variable compressor.
