The proliferation of purpose-built sensors and the advancement of predictive AI models have paved the way for the use of AI models in household appliances such as washing machines to improve energy efficiency as well as customer experience. Although there are plenty of sensors deployed in washing machines for monitoring, detection, and control purposes, there is no dedicated sensor to directly measure laundry weight due to cost inefficiency. To fill this gap, we researched machine learning-based soft sensors built on available sensor data. Our ANN-based soft sensor model achieved scores of 94.4% accuracy, 93.1% precision, 91.1% sensitivity, and 91.9% F1 score with crossvalidation in estimating laundry weight.