The interferometric modeling of temperature fields allows to visualize clearly the distribution of temperatures in typical centres of ventilated and warm air heated spaces and spaces heated using radiators and walls. For the visualization the Mach-Zehnder interferometer is applied and the research is realized on diminished models by means of the similarity theory application. This contribution contains some examples of visualized non-isothermal jets flowing into free space, visualized flow around some obstacles and visualized temperature fields in heated rooms at heating start and in a stable state. The visualization results comprise temperature fields pictures which provide both qualitative and quantitative information. From interferometric researches the conclusions for further investigation of monitored processes are deduced either using experimental or computer modeling methods. The results of the visualization contribute to an optimum solution of above ventilation and heating problems.