diff --git a/nymea-app/main.cpp b/nymea-app/main.cpp
index ceead76b..2b9590c3 100644
--- a/nymea-app/main.cpp
+++ b/nymea-app/main.cpp
@@ -36,6 +36,7 @@
 #include <QSysInfo>
 #include <QCommandLineParser>
 #include <QCommandLineOption>
+#include "utils/qhashqml.h"
 
 #include "libnymea-app-core.h"
 #include "libnymea-app-airconditioning.h"
@@ -183,6 +184,7 @@ int main(int argc, char *argv[])
     qmlRegisterUncreatableType<DashboardWebViewItem>("Nymea", 1, 0, "DashboardWebViewItem", "");
 
     qmlRegisterSingletonType<PrivacyPolicyHelper>("NymeaApp.Utils", 1, 0, "PrivacyPolicyHelper", PrivacyPolicyHelper::qmlProvider);
+    qmlRegisterType<QHashQml>("NymeaApp.Utils", 1, 0, "QHash");
 
     qmlRegisterType<MouseObserver>("Nymea", 1, 0, "MouseObserver");
 
diff --git a/nymea-app/nymea-app.pro b/nymea-app/nymea-app.pro
index 173e6334..05cf702b 100644
--- a/nymea-app/nymea-app.pro
+++ b/nymea-app/nymea-app.pro
@@ -42,7 +42,8 @@ HEADERS += \
     pushnotifications.h \
     platformhelper.h \
     ruletemplates/messages.h \
-    utils/privacypolicyhelper.h
+    utils/privacypolicyhelper.h \
+    utils/qhashqml.h
 
 SOURCES += main.cpp \
     configuredhostsmodel.cpp \
@@ -56,7 +57,8 @@ SOURCES += main.cpp \
     pushnotifications.cpp \
     platformhelper.cpp \
     platformintegration/generic/screenhelper.cpp \
-    utils/privacypolicyhelper.cpp
+    utils/privacypolicyhelper.cpp \
+    utils/qhashqml.cpp
 
 RESOURCES += resources.qrc \
     ruletemplates.qrc \
diff --git a/nymea-app/ui/mainviews/energy/ConsumersHistory.qml b/nymea-app/ui/mainviews/energy/ConsumersHistory.qml
index 3f3ed05c..c233cc98 100644
--- a/nymea-app/ui/mainviews/energy/ConsumersHistory.qml
+++ b/nymea-app/ui/mainviews/energy/ConsumersHistory.qml
@@ -375,6 +375,8 @@ Item {
                         readonly property Thing thing: consumers.get(index)
                         property AreaSeries series: null
 
+                        property QHash valueCache: QHash {}
+
                         function calculateBaseValue(timestamp) {
                             if (index > 0) {
                                 return consumersRepeater.itemAt(index - 1).calculateValue(timestamp)
@@ -383,6 +385,12 @@ Item {
                         }
 
                         function calculateValue(timestamp) {
+                            var cached = valueCache.value(timestamp)
+//                            print("ached:", cached)
+                            if (cached !== undefined) {
+                                return cached//valueCache.value(timestamp)
+                            }
+
                             var ret = calculateBaseValue(timestamp)
 
                             var entry = logs.find(timestamp)
@@ -390,6 +398,7 @@ Item {
                                 ret += entry.currentPower;
                             }
 
+                            valueCache.insert(timestamp, ret);
 //                            print("calculating value for", thing.name, timestamp, ret)
                             return ret
                         }
@@ -408,11 +417,21 @@ Item {
                             series.lowerSeries.removePoints(0, 1);
                             series.upperSeries.removePoints(0, 1);
 
+                            var oldestTimestamp = null
+                            var newestTimestamp = null
+
                             for (var i = 0; i < count; i++) {
                                 var entry = logs.get(index + i)
 //                                    print("got thing entry", thing.name, entry.timestamp, entry.currentPower, index + i)
 
-                                zeroSeries.ensureValue(entry.timestamp)
+//                                zeroSeries.ensureValue(entry.timestamp)
+                                if (oldestTimestamp == null || entry.timestamp < oldestTimestamp) {
+                                    oldestTimestamp = entry.timestamp;
+                                }
+                                if (newestTimestamp == null || entry.timestamp > newestTimestamp) {
+                                    newestTimestamp = entry.timestamp;
+                                }
+
                                 valueAxis.adjustMax(entry.currentPower)
 
                                 insertEntry(index + i, entry)
@@ -421,6 +440,9 @@ Item {
                                 }
                             }
 
+                            zeroSeries.ensureValue(oldestTimestamp)
+                            zeroSeries.ensureValue(newestTimestamp)
+
                             // Add the leading 0-value entry back
                             series.lowerSeries.insert(0, series.upperSeries.at(0).x, 0)
                             series.upperSeries.insert(0, series.upperSeries.at(0).x, 0)
diff --git a/nymea-app/utils/qhashqml.cpp b/nymea-app/utils/qhashqml.cpp
new file mode 100644
index 00000000..64d200a0
--- /dev/null
+++ b/nymea-app/utils/qhashqml.cpp
@@ -0,0 +1,22 @@
+#include "qhashqml.h"
+
+QHashQml::QHashQml(QObject *parent)
+    : QObject{parent}
+{
+
+}
+
+void QHashQml::insert(int key, const QVariant &value)
+{
+    m_hash.insert(key, value);
+}
+
+bool QHashQml::contains(int key)
+{
+    return m_hash.contains(key);
+}
+
+QVariant QHashQml::value(int key)
+{
+    return m_hash.value(key);
+}
diff --git a/nymea-app/utils/qhashqml.h b/nymea-app/utils/qhashqml.h
new file mode 100644
index 00000000..b46a2821
--- /dev/null
+++ b/nymea-app/utils/qhashqml.h
@@ -0,0 +1,23 @@
+#ifndef QHASHQML_H
+#define QHASHQML_H
+
+#include <QObject>
+#include <QHash>
+#include <QVariant>
+
+class QHashQml : public QObject
+{
+    Q_OBJECT
+public:
+    explicit QHashQml(QObject *parent = nullptr);
+
+    Q_INVOKABLE void insert(int key, const QVariant &value);
+    Q_INVOKABLE bool contains(int key);
+    Q_INVOKABLE QVariant value(int key);
+
+
+private:
+    QHash<int, QVariant> m_hash;
+};
+
+#endif // QHASHQML_H