This paper presents an Multi Weights Neurons approach to determine the delay time for a heating, ventilating and airconditioning (HVAC) plan to respond to control actions. The Multi Weights Neurons is a fully connected four-layer network. An acceleration technique was used to improve the General Delta Rule for the learning process. Experimental data for heating and cooling modes were used with both the Multi Weights Neurons and a traditional mathematical method to determine the delay time. The results show that Multi Weights Neurons can be used effectively determining the delay time for HVAC systems.