diff --git a/src/MqttHandleHass.cpp b/src/MqttHandleHass.cpp
index a2f38f0..9578daf 100644
--- a/src/MqttHandleHass.cpp
+++ b/src/MqttHandleHass.cpp
@@ -134,7 +134,7 @@ void MqttHandleHassClass::publishField(std::shared_ptr<InverterAbstract> inv, Ch
         createDeviceInfo(deviceObj, inv);
 
         if (Configuration.get().Mqtt_Hass_Expire) {
-            root["exp_aft"] = Hoymiles.getNumInverters() * Configuration.get().Mqtt_PublishInterval * 3;
+            root["exp_aft"] = Hoymiles.getNumInverters() * max<uint32_t>(Hoymiles.PollInterval(), Configuration.get().Mqtt_PublishInterval) * inv->getReachableThreshold();
         }
         if (devCls != 0) {
             root["dev_cla"] = devCls;