diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/CurtainsController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/CurtainsController.java
index 4065f12..9fbf704 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/CurtainsController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/CurtainsController.java
@@ -64,8 +64,8 @@ public class CurtainsController {
                         .findByIdAndUsername(deviceId, principal.getName())
                         .orElseThrow(NotFoundException::new);
         State<? extends Dimmable> s = c.cloneState();
-        sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
-        s.setSceneId(sceneId);
+        final Scene sc = sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
+        s.setSceneId(sc.getId());
         if (stateRepository.countByDeviceIdAndSceneId(deviceId, sceneId) > 0)
             throw new DuplicateStateException();
         return stateRepository.save(s);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DeviceController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DeviceController.java
index b53b0af..1221043 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DeviceController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DeviceController.java
@@ -5,6 +5,7 @@ import ch.usi.inf.sa4.sanmarinoes.smarthut.error.BadDataException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.error.NotFoundException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.Device;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.DeviceRepository;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.Room;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.RoomRepository;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.service.DeviceService;
 import java.security.Principal;
@@ -40,11 +41,12 @@ public class DeviceController {
                         .orElseThrow(NotFoundException::new);
 
         // check if roomId is valid
-        roomRepository
-                .findByIdAndUsername(deviceSaveRequest.getRoomId(), principal.getName())
-                .orElseThrow(() -> new BadDataException("roomId is not a valid room id"));
+        final Room r =
+                roomRepository
+                        .findByIdAndUsername(deviceSaveRequest.getRoomId(), principal.getName())
+                        .orElseThrow(() -> new BadDataException("roomId is not a valid room id"));
 
-        d.setRoomId(deviceSaveRequest.getRoomId());
+        d.setRoomId(r.getId());
         d.setName(deviceSaveRequest.getName());
 
         deviceService.saveAsOwner(d, principal.getName());
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DimmableLightController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DimmableLightController.java
index 28648c1..e315ff1 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DimmableLightController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/DimmableLightController.java
@@ -98,8 +98,8 @@ public class DimmableLightController extends GuestEnabledController<DimmableLigh
                         .findByIdAndUsername(deviceId, principal.getName())
                         .orElseThrow(NotFoundException::new);
         State<? extends Dimmable> s = d.cloneState();
-        sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
-        s.setSceneId(sceneId);
+        final Scene sc = sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
+        s.setSceneId(sc.getId());
         if (stateRepository.countByDeviceIdAndSceneId(deviceId, sceneId) > 0)
             throw new DuplicateStateException();
         return stateRepository.save(s);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/RegularLightController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/RegularLightController.java
index 145aa04..3768cb4 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/RegularLightController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/RegularLightController.java
@@ -110,8 +110,8 @@ public class RegularLightController extends GuestEnabledController<RegularLight>
                         .findByIdAndUsername(deviceId, principal.getName())
                         .orElseThrow(NotFoundException::new);
         State<? extends Switchable> s = d.cloneState();
-        sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
-        s.setSceneId(sceneId);
+        final Scene sc = sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
+        s.setSceneId(sc.getId());
         if (stateRepository.countByDeviceIdAndSceneId(deviceId, sceneId) > 0)
             throw new DuplicateStateException();
         return stateRepository.save(s);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/SmartPlugController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/SmartPlugController.java
index 790aee2..88a78f6 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/SmartPlugController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/SmartPlugController.java
@@ -78,8 +78,8 @@ public class SmartPlugController {
                         .findByIdAndUsername(deviceId, principal.getName())
                         .orElseThrow(NotFoundException::new);
         State<? extends Switchable> s = d.cloneState();
-        sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
-        s.setSceneId(sceneId);
+        final Scene sc = sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
+        s.setSceneId(sc.getId());
         if (stateRepository.countByDeviceIdAndSceneId(deviceId, sceneId) > 0)
             throw new DuplicateStateException();
         return stateRepository.save(s);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/ThermostatController.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/ThermostatController.java
index 49c31f2..8ab96f5 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/ThermostatController.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/ThermostatController.java
@@ -75,8 +75,8 @@ public class ThermostatController {
                         .findByIdAndUsername(deviceId, principal.getName())
                         .orElseThrow(NotFoundException::new);
         State<? extends Switchable> s = d.cloneState();
-        sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
-        s.setSceneId(sceneId);
+        final Scene sc = sceneRepository.findById(sceneId).orElseThrow(NotFoundException::new);
+        s.setSceneId(sc.getId());
         if (stateRepository.countByDeviceIdAndSceneId(deviceId, sceneId) > 0)
             throw new DuplicateStateException();
         return stateRepository.save(s);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Device.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Device.java
index d2231d8..aa88d09 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Device.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Device.java
@@ -7,7 +7,6 @@ import io.swagger.annotations.ApiModelProperty;
 import java.util.HashSet;
 import java.util.Set;
 import javax.persistence.*;
-import javax.validation.constraints.NotNull;
 
 /** Generic abstraction for a smart home device */
 @Entity
@@ -46,11 +45,9 @@ public abstract class Device {
      * a REST call.
      */
     @Column(name = "room_id", nullable = false)
-    @NotNull
     private Long roomId;
 
     /** The name of the device as assigned by the user (e.g. 'Master bedroom light') */
-    @NotNull
     @Column(nullable = false)
     private String name;
 
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/RangeTrigger.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/RangeTrigger.java
index 19e179c..5fdc119 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/RangeTrigger.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/RangeTrigger.java
@@ -43,7 +43,6 @@ public class RangeTrigger<D extends Device & RangeTriggerable> extends Trigger<D
         GREATER_EQUAL
     }
 
-    @NotNull
     @Column(nullable = false)
     private Operator operator;
 
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Sensor.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Sensor.java
index 0124016..58aa7f9 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Sensor.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Sensor.java
@@ -7,7 +7,6 @@ import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.EnumType;
 import javax.persistence.Enumerated;
-import javax.validation.constraints.NotNull;
 
 /** A sensor input device that measures a quantity in a continuous scale (e.g. temperature) */
 @Entity
@@ -45,7 +44,6 @@ public class Sensor extends InputDevice implements RangeTriggerable {
 
     /** The type of this sensor */
     @Column(nullable = false)
-    @NotNull
     @Enumerated(value = EnumType.STRING)
     private SensorType sensor;
 
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/SmartPlug.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/SmartPlug.java
index 77f6c3d..10fcacf 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/SmartPlug.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/SmartPlug.java
@@ -1,6 +1,5 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
 
-
 import java.math.BigDecimal;
 import javax.persistence.Column;
 import javax.persistence.Entity;
@@ -20,7 +19,6 @@ public class SmartPlug extends Switchable implements BooleanTriggerable {
 
     /** Whether the smart plug is on */
     @Column(name = "smart_plug_on", nullable = false)
-    @NotNull
     private boolean on;
 
     public BigDecimal getTotalConsumption() {
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Thermostat.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Thermostat.java
index b6caf72..abcc1cb 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Thermostat.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Thermostat.java
@@ -64,7 +64,7 @@ public class Thermostat extends Switchable implements BooleanTriggerable {
     }
 
     /** Temperature to be reached */
-    @Column @NotNull private BigDecimal targetTemperature;
+    @Column private BigDecimal targetTemperature;
 
     /** The temperature detected by the embedded sensor */
     @Column(nullable = false, precision = 4, scale = 1)
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/ThermostatRepository.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/ThermostatRepository.java
index 896e0ad..290ebf5 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/ThermostatRepository.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/ThermostatRepository.java
@@ -25,6 +25,6 @@ public interface ThermostatRepository extends DeviceRepository<Thermostat> {
      * @return an optional big decimal, empty if none found
      */
     @Query(
-            "SELECT AVG(s.value) FROM Sensor s JOIN s.room r WHERE s.sensor = 'TEMPERATURE' AND r.id = ?1")
-    Optional<BigDecimal> getAverageTemperature(Long thermostatRoomId);
+            "SELECT AVG(s.value) FROM Sensor s JOIN s.room r WHERE s.sensor = ?2 AND r.id = ?1")
+    Optional<BigDecimal> getAverageTemperature(Long thermostatRoomId, Sensor.SensorType sensorType);
 }
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Trigger.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Trigger.java
index 77010c6..9b7f990 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Trigger.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Trigger.java
@@ -37,7 +37,6 @@ public abstract class Trigger<D extends Device> {
      * from a REST call.
      */
     @Column(name = "device_id", nullable = false)
-    @NotNull
     private Long deviceId;
 
     @ManyToOne
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/DeviceService.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/DeviceService.java
index b1a9c9e..bf16b88 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/DeviceService.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/DeviceService.java
@@ -48,7 +48,11 @@ public class DeviceService {
     }
 
     public void throwIfRoomNotOwned(Long roomId, String username) throws NotFoundException {
-        roomRepository.findByIdAndUsername(roomId, username).orElseThrow(NotFoundException::new);
+        final Room r =
+                roomRepository
+                        .findByIdAndUsername(roomId, username)
+                        .orElseThrow(NotFoundException::new);
+        if (!r.getId().equals(roomId)) throw new IllegalStateException();
     }
 
     private void triggerTriggers(Device device, final String username) {
@@ -140,9 +144,7 @@ public class DeviceService {
         User host = null;
         if (hostId == null) {
             if (roomId != null) {
-                roomRepository
-                        .findByIdAndUsername(roomId, username)
-                        .orElseThrow(NotFoundException::new);
+                throwIfRoomNotOwned(roomId, username);
                 devices = deviceRepository.findByRoomId(roomId);
             } else {
                 devices = deviceRepository.findAllByUsername(username);
diff --git a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/ThermostatService.java b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/ThermostatService.java
index 5cdee37..100d77d 100644
--- a/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/ThermostatService.java
+++ b/src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/ThermostatService.java
@@ -77,7 +77,8 @@ public class ThermostatService {
         Optional<BigDecimal> average;
 
         if (thermostat.isUseExternalSensors()) {
-            average = thermostatRepository.getAverageTemperature(thermostat.getRoomId());
+            average = thermostatRepository.getAverageTemperature(thermostat.getRoomId(), Sensor.SensorType.TEMPERATURE);
+
         } else {
             return thermostat.getInternalSensorTemperature();
         }