<p>In manual picking warehouses, the indispensable role of human involvement cannot be overstated. Tasked with repetitive duties, order pickers often grapple with fatigue and physical discomfort. It becomes imperative, therefore, to meticulously address ergonomic concerns when devising the blueprint and functionality of warehouses. This study introduces novel assignment strategies hinging on product attributes like weight, diameter, and cluster-based categorization, subsequently evaluating their impact on the energy consumption of order pickers. The outcomes, achieved by adjusting pivotal warehouse parameters, are meticulously compared against an exact solution method. Additionally, a multi-objective model is proposed, encompassing both economic and ergonomic considerations, scrutinized through the lens of the Pareto frontier. Noteworthy results reveal that the modified Cube order index stands out, exhibiting the lowest energy consumption for order pickers. This model emerges as a valuable tool for warehouse managers, furnishing insights to optimize item assignments and alleviate ergonomic stress on order pickers.</p>