diff --git a/software/README.md b/software/README.md
index 4a386c1..8f7b2a0 100644
--- a/software/README.md
+++ b/software/README.md
@@ -184,6 +184,14 @@ For smaller intervals it is 10 minutes.
 Calibration parameters are stored in the sensor itself and not in the ESP.
 Therefore even after powerloss or flashing of new software no recalibration is needed.
 
+No manual calibration is needed if you operate the sensor in an environment with constant support of fresh air.
+The sensor datasheet explains this further:
+
+> The correct application of ASC requires the SCD30 to be regularly exposed to air with CO2 concentration = 400 ppm,
+> as is the case in well ventilated buildings over night without human presence.
+
+This `ASC` mode can be enabled by changing the parameter to the call of `setAutoSelfCalibration` to `true` (`src/sensors/scd30.cpp`).
+
 
 
 Development