diff --git a/src/main/java/homecontrol/impl/hwep1/HWEP1Client.java b/src/main/java/homecontrol/impl/hwep1/HWEP1Client.java
index bbeaec8..169ba43 100644
--- a/src/main/java/homecontrol/impl/hwep1/HWEP1Client.java
+++ b/src/main/java/homecontrol/impl/hwep1/HWEP1Client.java
@@ -27,6 +27,13 @@ public class HWEP1Client {
     @ConfigProperty(name = "EVCHARGING_HWEP1_IP")
     String ip;
 
+    @ConfigProperty(name = "HAS_GAS", defaultValue = "true")
+    String hasGas;
+
+    boolean hasGas() {
+        return Boolean.valueOf(hasGas);
+    }
+
     @CacheResult(cacheName = "hwep1-data")
     JsonObject getJsonData() throws IOException {
         LOGGER.fine("Requesting data from HWEP1");
@@ -93,7 +100,7 @@ Telegram parseTelegram(String body) {
         if (gas != null && gas.size() > 1) {
             telegram.setTotal_gas_m3(new BigDecimal(parseValue(gas.get(1))));
         }
-        telegram.setTotal_gas_m3(new BigDecimal(parseValue(map.get("0-1:24.2.3").get(1))));
+        if (hasGas()) telegram.setTotal_gas_m3(new BigDecimal(parseValue(map.get("0-1:24.2.3").get(1))));
         telegram.setActive_power_average_w(new BigDecimal(parseValue(map.get("1-0:1.4.0").get(0))).multiply(new BigDecimal(1000)).intValue());
         telegram.setActive_power_import_w(new BigDecimal(parseValue(map.get("1-0:1.7.0").get(0))).multiply(new BigDecimal(1000)).intValue());
         telegram.setActive_power_export_w(new BigDecimal(parseValue(map.get("1-0:2.7.0").get(0))).multiply(new BigDecimal(1000)).intValue());
diff --git a/src/main/java/homecontrol/impl/slack/SlackService.java b/src/main/java/homecontrol/impl/slack/SlackService.java
index fb0cb7d..fc9f2bf 100644
--- a/src/main/java/homecontrol/impl/slack/SlackService.java
+++ b/src/main/java/homecontrol/impl/slack/SlackService.java
@@ -18,9 +18,9 @@
 
 @ApplicationScoped
 public class SlackService implements NotificationService {
-    @ConfigProperty(name = "EVCHARGING_SLACK_URL")
+    @ConfigProperty(name = "EVCHARGING_SLACK_URL", defaultValue="NONE")
     String slackUrl;
-    @ConfigProperty(name = "EVCHARGING_SLACK_CHANNEL")
+    @ConfigProperty(name = "EVCHARGING_SLACK_CHANNEL", defaultValue="NONE")
     String channel;
 
     @Inject
diff --git a/src/main/java/homecontrol/impl/sma/SMACharger.java b/src/main/java/homecontrol/impl/sma/SMACharger.java
index cfc2583..dd1f6b0 100644
--- a/src/main/java/homecontrol/impl/sma/SMACharger.java
+++ b/src/main/java/homecontrol/impl/sma/SMACharger.java
@@ -19,7 +19,7 @@
 @ApplicationScoped
 public class SMACharger implements Charger {
 
-    @ConfigProperty(name = "EVCHARGING_CHARGER_IP")
+    @ConfigProperty(name = "EVCHARGING_CHARGER_IP", defaultValue="NONE")
     String chargerIp;
     @ConfigProperty(name = "EVCHARGING_CHARGER_USERNAME")
     String chargerUserName;
@@ -53,6 +53,7 @@ public State getCurrentState(StateRefresh stateRefresh) {
     @Asynchronous
     @Retry(maxRetries = 3, delay = 2, delayUnit = ChronoUnit.SECONDS)
     public Uni<Integer> getActivePower() {
+        if (isDisabled()) return Uni.createFrom().item(0);
         int activePower = (int) getLivePowerMeterReading();
         return Uni.createFrom().item(activePower);
     }
@@ -64,6 +65,7 @@ public int getChargingMeterReading() {
     }
 
     public State getStateInternal() {
+        if (isDisabled()) return State.NotConnected;
         try {
             if (token == null) {
                 token = authenticate();
@@ -204,4 +206,7 @@ private String authenticate() {
         }
     }
 
+    boolean isDisabled() {
+        return "NONE".equals(chargerIp);
+    }
 }
diff --git a/src/main/java/homecontrol/impl/sma/SMAInverter.java b/src/main/java/homecontrol/impl/sma/SMAInverter.java
index 823ad7e..8d52f40 100644
--- a/src/main/java/homecontrol/impl/sma/SMAInverter.java
+++ b/src/main/java/homecontrol/impl/sma/SMAInverter.java
@@ -27,9 +27,9 @@
 @ApplicationScoped
 public class SMAInverter implements Inverter {
     public static final Logger LOGGER = Logger.getLogger(SMAInverter.class.getName());
-    @ConfigProperty(name = "EVCHARGING_INVERTER_IP")
+    @ConfigProperty(name = "EVCHARGING_INVERTER_IP", defaultValue="NONE")
     String inverterIp;
-    @ConfigProperty(name = "EVCHARGING_INVERTER_PASSWORD")
+    @ConfigProperty(name = "EVCHARGING_INVERTER_PASSWORD", defaultValue="NONE")
     String inverterPassword;
 
     String sid;
@@ -38,6 +38,7 @@ public class SMAInverter implements Inverter {
     @Retry(maxRetries = 3, delay = 2, delayUnit = ChronoUnit.SECONDS)
     @Asynchronous
     public Uni<Integer> getCurrentYield() {
+        if (isDisabled()) return Uni.createFrom().item(0);
         return Uni.createFrom().item(getLiveSMAPowerDataInternal());
     }
 
@@ -184,4 +185,8 @@ private void logout() {
             }
         }
     }
+
+    boolean isDisabled() {
+        return "NONE".equals(inverterIp);
+    }
 }