diff --git a/soft/thermostat/src/settings.cpp b/soft/thermostat/src/settings.cpp
index 72a59c8..c5e6ec8 100644
--- a/soft/thermostat/src/settings.cpp
+++ b/soft/thermostat/src/settings.cpp
@@ -124,7 +124,7 @@ void Settings::setRoomDefaultTemperature(int idx, double temperature)
 		return;
 	}
 
-	this->beginWriteArray("rooms");
+	this->beginWriteArray("rooms", nbZones());
 	this->setArrayIndex(idx);
 	this->setValue("default_temperature", temperature);
 	this->endArray();
@@ -138,7 +138,7 @@ void Settings::setRoomPrograms(int idx, QVector<struct Program> &progs)
 		return;
 	}
 
-	this->beginWriteArray("rooms");
+	this->beginWriteArray("rooms", nbZones());
 
 	this->setArrayIndex(idx);
 	this->remove("temperature_schedule");