The feasibility of using neural networks (NNs) for optimizing air conditioning (AC) setback scheduling in public buildings was investigated. The main focus is on optimizing the network architecture in order to achieve best performance.To save energy, the temperature inside public buildings is allowed to rise after business hours by setting back the thermostat. The objective is to predict the time of the end of thermostat setback (EoS) such that the design temperature inside the building is restored in time for the start of business hours.State of the art building simulation software, ESP-r, was used to generate a database that covered the years 1995-1999. The software was used to calculate the EoS for two office buildings using the climate records in Kuwait. The EoS data for 1995 and 1996 were used for training and testing the NNs. The robustness of the trained NN was tested by applying them to a "production" data set (1997-1999), which the networks have never "seen" before.For each of the six different NN architectures evaluated, parametric studies were performed to determine the network parameters that best predict the EoS. External hourly temperature readings were used as network inputs, and the thermostat end of setback (EoS) is the output. The NN predictions were improved by developing a neural control scheme (NC). This scheme is based on using the temperature readings as they become available. For each NN architecture considered, six NNs were designed and trained for this purpose. The performance of the NN analysis was evaluated using a statistical indicator (the coefficient of multiple determination) and by statistical analysis of the error patterns, including ANOVA (analysis of variance).The results show that the NC, when used with a properly designed NN, is a powerful instrument for optimizing AC setback scheduling based only on external temperature records. (C) 2003 Elsevier Ltd. All rights reserved.