diff --git a/src/graphEntry.ts b/src/graphEntry.ts
index 8aa5bff..9ed6f2f 100644
--- a/src/graphEntry.ts
+++ b/src/graphEntry.ts
@@ -245,16 +245,32 @@ export default class GraphEntry {
       );
 
       // if data in cache, get data from last data's time + 1ms
-      const fetchStart = usableCache
+      let fetchStart = usableCache
         ? // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
           new Date(history!.data[history!.data.length - 1][0] + 1)
-        : new Date(startHistory.getTime() + (this._config.group_by.func !== 'raw' ? 0 : -1));
+        : new Date(startHistory.getTime() 
+            + (this._config.group_by.func !== 'raw' ? 0 : -1));
       const fetchEnd = end;
 
       let newStateHistory: EntityCachePoints = [];
       let updateGraphHistory = false;
 
       if (this._config.statistics) {
+
+        // console.log(start, end)
+        // console.log(fetchStart, JSON.stringify(this._config))
+        if (this._config.statistics.type === "diff") {
+          if (this._config.statistics.period === '5minute') {
+            fetchStart = new Date(fetchStart.getTime() - 450000); // 2min30s
+          } else if (!this._config.statistics?.period || this._config.statistics.period === 'hour') {
+            fetchStart = new Date(fetchStart.getTime() - 5400000); // 30min
+          } else if (this._config.statistics.period === 'day') {
+            fetchStart = new Date(fetchStart.getTime() - 100400000); // 12h
+          } else {
+            fetchStart = new Date(fetchStart.getTime() - 3888000000); // 15d
+          }
+        }
+        
         const newHistory = await this._fetchStatistics(fetchStart, fetchEnd, this._config.statistics.period);
         if (newHistory && newHistory.length > 0) {
           updateGraphHistory = true;
@@ -264,11 +280,17 @@ export default class GraphEntry {
           }
           newStateHistory = newHistory.map((item) => {
             let stateParsed: number | null = null;
-            [lastNonNull, stateParsed] = this._transformAndFill(
-              item[this._config.statistics?.type || DEFAULT_STATISTICS_TYPE],
-              item,
-              lastNonNull,
-            );
+            if (this._config.statistics?.type === "diff") {
+              stateParsed = (item["sum"]  ?? 0) - (lastNonNull ?? 0);
+              lastNonNull = item["sum"]
+              // console.log(new Date(item.start), item["sum"], lastNonNull, stateParsed)
+            } else {
+              [lastNonNull, stateParsed] = this._transformAndFill(
+                item[this._config.statistics?.type || DEFAULT_STATISTICS_TYPE],
+                item,
+                lastNonNull,
+              );
+            }
 
             let displayDate: Date | null = null;
             const startDate = new Date(item.start);
diff --git a/src/types-config-ti.ts b/src/types-config-ti.ts
index 9eb302a..ffd63b4 100644
--- a/src/types-config-ti.ts
+++ b/src/types-config-ti.ts
@@ -77,7 +77,7 @@ export const ChartCardAllSeriesExternalConfig = t.iface([], {
   "invert": t.opt("boolean"),
   "data_generator": t.opt("string"),
   "statistics": t.opt(t.iface([], {
-    "type": t.opt(t.union(t.lit('mean'), t.lit('max'), t.lit('min'), t.lit('sum'), t.lit('state'))),
+    "type": t.opt(t.union(t.lit('mean'), t.lit('max'), t.lit('min'), t.lit('sum'), t.lit('state'), t.lit('diff'))),
     "period": t.opt("StatisticsPeriod"),
     "align": t.opt(t.union(t.lit('start'), t.lit('end'), t.lit('middle'))),
   })),
diff --git a/src/types-config.ts b/src/types-config.ts
index 9bc7b13..9c6f52c 100644
--- a/src/types-config.ts
+++ b/src/types-config.ts
@@ -77,7 +77,7 @@ export interface ChartCardAllSeriesExternalConfig {
   invert?: boolean;
   data_generator?: string;
   statistics?: {
-    type?: 'mean' | 'max' | 'min' | 'sum' | 'state';
+    type?: 'mean' | 'max' | 'min' | 'sum' | 'state' | 'diff';
     period?: StatisticsPeriod;
     align?: 'start' | 'end' | 'middle';
   };