This code presents a simplified heat transfer model based on zonal approach. It allows the temperature prediction (air and product) inside an insulated box with PCM (Phase Change Material as cold source) to maintain product at low temperature during food transport to assure its quality. The model involves airflow, conduction, convection and radiation. The studied geometry is a rectangular insulated box, with PCM on a sidewall and loaded with test product. The code requires a short calculation time and can be useful to researchers and stakeholders to study the effect of box design, PCM/product properties and mass and ambient temperature.