In 2021, a significant update was made to the household appliance classification system in Europe with the introduction of a new energy-efficient label (EE). This update is a step towards achieving the Sustainable Development Goal 7 of the United Nations, which focuses on sustainable energy. The EE label is an effective tool for reducing overall energy consumption. However, its success relies on the awareness and decision making of consumers when making purchases. During the purchase phase, shop assistants have the potential to play a crucial role in promoting energy-efficient choices. Surprisingly, this aspect has been largely overlooked in previous research. In an attempt to fill this gap, we conducted an exploratory study employing a mixed-method approach, encompassing 22 in-depth interviews and questionnaires administered to shop assistants from various appliance stores. Our findings revealed that shop assistants face challenges in promoting energy-efficient choices, particularly after the introduction of the new EE label, due to a lack of training. This may result in incorrect advice that could impact consumer purchases and their daily energy consumption. Our study emphasises the need to support shop assistants in promoting energy-efficient purchases, to enhance their training, and to incorporate tools such as augmented reality to foster energy-efficient-orientated purchases.