Abstract Based on the network simulation method and using commercial computer codes, educational software has been developed for numerically solving and simulating lineal and non‐lineal problems of unsteady heat transfer in simple extended 1D surfaces, assuming convection and/or radiation as boundary conditions. Interface communication with the user is pleasant and immediate through the window ambient created in visual C++ source code. After introduction of the data, which includes reticulation parameters, a network model is generated whose finite difference differential equations are formally equivalent to those of the problem. Time remains a continuous variable in the model. The file is numerically run using a network simulation code, providing the transient temperature fields and heat fluxes in the whole medium. The results are shown by graphics or as tables. The program can be used as a low cost laboratory tool for teaching heat transfer or even for the design of simple fins. Students can easily determine the influence of physical parameters, such as thermal conductivity, specific heat, heat transfer coefficient, emissivity, reference temperatures, etc., in the problem. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 16: 72–82, 2008; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20159