hi, don't know why but if you set that line n°31 in comment, it seems to work "# tvoc0.set_iaq_baseline(35187, 35502) while True: you may try to use the sample loop that you find in UIflow_Unit TVOC. As you can see on the picture below, TOVC/eCO2 can be use in a classroom context and it works fine I initialized it outside the window and came inside after