Journal of Electronic Systems Hsing-Cheng Liu, Yao-Liang Chung 16 1 2026 https://doi.org/10.6025/jes/2026/16/1/31-43 https://www.dline.info/jes/fulltext/v16n1/jesv16n1_3.pdf The increasing penetration of high power residential appliances and renewable energy sources has intensified peak demand challenges in modern power systems. Demand Side Management (DSM), particularly through direct load control (DLC), is a key enabler of smart grids for mitigating peak loads while maintaining user comfort. This paper presents a fuzzy logic based Fuzzy Decision Maker (FDM) for optimal scheduling of timeshiftable residential loads. Unlike conventional approaches that rely solely on price signals or individual load characteristics, the proposed FDM jointly considers appliance demand power and the predicted aggregate residential load profile to determine an optimal delay time. The system emulates expert operator reasoning through interpretable linguistic rules and operates under a DLC paradigm with customer consent and incentives. Simulation results for a residential community demonstrate peak load reduction and a lower Peak to Average Ratio (PAR), thereby validating the effectiveness and scalability of the proposed approach for smart grid applications.