Measurement of heat transfer holds significant importance in the construction industry, especially with new regulations aimed at reducing energy consumption. Various types of measurements are required to assess the thermal performance of walls. Among the most common is the HFM method, based on the measurement of heat flow using heat flow sensors (HFS). New insulation materials used in construction are often highly hygroscopic, or at least vapor permeable, which means that heat transfer through these materials also involves simultaneous mass transfer. Using heat flow sensors can locally alter this mass transfer, sometimes acting as a vapor barrier: this alters local moisture transfer and the associated latent heat flux. In this study, the aim is to gain a better understanding of the latent heat flow associated with these transfers. For this purpose, the focus is on developing a new method for measuring heat transfer, using solid (vapor tight) and perforated flow sensors, the latter allowing mass diffusion through materials. A test bench is set up incorporating a heated plate. This approach is applied to vapor-open insulation materials, such as mineral wools with large or low mass transfer.