diff --git a/main/ZmqttDiscovery.ino b/main/ZmqttDiscovery.ino
index d262d6c2e4..80fe4a4475 100644
--- a/main/ZmqttDiscovery.ino
+++ b/main/ZmqttDiscovery.ino
@@ -254,6 +254,15 @@ void createDiscovery(const char* sensor_type,
     }
   }
 
+  // We check if the class belongs to HAAS class list
+  bool HASSUnit = false;
+  int num_units = sizeof(availableHASSUnits) / sizeof(availableHASSUnits[0]);
+  for (int i = 0; i < num_units; i++) { // see class list and size into config_mqttDiscovery.h
+    if (strcmp(availableHASSUnits[i], unit_of_meas) == 0) {
+      HASSUnit = true;
+    }
+  }
+
   sensor["name"] = s_name; //name
   sensor["uniq_id"] = unique_id; //unique_id
   if (retainCmd)
@@ -266,7 +275,7 @@ void createDiscovery(const char* sensor_type,
     sensor["pl_on"] = payload_on; // payload_on
   if (payload_off[0])
     sensor["pl_off"] = payload_off; //payload_off
-  if (unit_of_meas[0] && HASSClass)
+  if (unit_of_meas[0] && HASSUnit)
     sensor["unit_of_meas"] = unit_of_meas; //unit_of_measurement*/
   if (off_delay != 0)
     sensor["off_delay"] = off_delay; //off_delay
diff --git a/main/config_mqttDiscovery.h b/main/config_mqttDiscovery.h
index a6d9b1c306..8befac18a3 100644
--- a/main/config_mqttDiscovery.h
+++ b/main/config_mqttDiscovery.h
@@ -216,4 +216,24 @@ const char* availableHASSClasses[] = {"battery",
                                       "power_factor",
                                       "voltage"};
 
+// From https://github.com/home-assistant/core/blob/d7ac4bd65379e11461c7ce0893d3533d8d8b8cbf/homeassistant/const.py#L379
+// List of units available in Home Assistant
+const char* availableHASSUnits[] = {"W",
+                                    "kW",
+                                    "V",
+                                    "A",
+                                    "W",
+                                    "°C",
+                                    "°F",
+                                    "ms",
+                                    "s",
+                                    "hPa"
+                                    "kg",
+                                    "lb",
+                                    "µS/cm",
+                                    "lx",
+                                    "%",
+                                    "dB",
+                                    "B"};
+
 #endif