The roll-out of the new-generation smart meter with artificial intelligence (AI)-based data mining algorithms causes serious privacy issues for consumers. By detecting appliance usages, an adversary can easily monitor the behavior patterns of residents. In this paper, a privacy-preserving smart metering model is proposed; the system utilizes a data aggregator to aggregate the readings of neighboring smart meters and a data down-sampler to reduce the sensitive information in the load profiles. An AI-based adversary is introduced to simulate the adversarial process. Four state-of-the-art deep learning/machine learning algorithms (convolutional neural network-long short-term memory (CNN-LSTM), gated recurrent unit (GRU), k-nearest neighbors (KNN), and CNN are employed as data mining algorithms. By tuning the variables (aggregation size α and interval resolution σ), the detectability boundaries of particular appliances are evaluated. Based on the appliance detectability, a three-level privacy boundary (real-time surveillance, presence/absence detection, and complete protection) is obtained. The result shows that to achieve complete data protection, the aggregation size should exceed 40, and the interval resolution should exceed 8 hours.