From 81b78db887e67aab77ebbc5fece156c1657193bd Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Wed, 15 Apr 2026 13:34:28 +0200
Subject: [PATCH] Collect 15min energy metrics (#23185)

---
 assets/js/components/BottomTabs/MoreMenu.vue  |   5 +-
 assets/js/components/History/Chart.vue        | 177 ++++++++++++++
 assets/js/components/History/EnergyChart.vue  | 170 ++++++++++++++
 assets/js/components/Top/Navigation.vue       |   5 +
 assets/js/router.ts                           |   5 +
 assets/js/views/History.vue                   | 103 ++++++++
 core/meterenergy.go                           |  60 -----
 core/metrics/accumulator.go                   | 126 ++++++++++
 .../accumulator_test.go}                      |  24 +-
 core/metrics/collector.go                     | 126 ++++++++++
 core/metrics/collector_test.go                | 132 +++++++++++
 core/metrics/db.go                            | 220 ++++++++++++++++--
 core/metrics/db_test.go                       | 102 ++++++++
 core/site.go                                  |  81 +++----
 core/site_optimizer.go                        |   3 +-
 core/site_optimizer_test.go                   |  85 -------
 core/site_tariffs.go                          |  16 +-
 core/site_test.go                             |  35 ---
 server/http.go                                |   1 +
 server/http_history_handler.go                |  51 ++++
 tests/energy-history.spec.ts                  |  72 ++++++
 tests/energy-history.sql                      |  42 ++++
 22 files changed, 1375 insertions(+), 266 deletions(-)
 create mode 100644 assets/js/components/History/Chart.vue
 create mode 100644 assets/js/components/History/EnergyChart.vue
 create mode 100644 assets/js/views/History.vue
 delete mode 100644 core/meterenergy.go
 create mode 100644 core/metrics/accumulator.go
 rename core/{meterenergy_test.go => metrics/accumulator_test.go} (53%)
 create mode 100644 core/metrics/collector.go
 create mode 100644 core/metrics/collector_test.go
 create mode 100644 core/metrics/db_test.go
 create mode 100644 server/http_history_handler.go
 create mode 100644 tests/energy-history.spec.ts
 create mode 100644 tests/energy-history.sql

diff --git a/assets/js/components/BottomTabs/MoreMenu.vue b/assets/js/components/BottomTabs/MoreMenu.vue
index 53b374709..f27d2704d 100644
--- a/assets/js/components/BottomTabs/MoreMenu.vue
+++ b/assets/js/components/BottomTabs/MoreMenu.vue
@@ -55,7 +55,10 @@
 			to="/optimize"
 			active-class="active"
 		>
-			Optimize
+			Optimize 🧪
+		</router-link>
+		<router-link v-if="experimental" class="dropdown-item" to="/history" active-class="active">
+			History 🧪
 		</router-link>
 	</div>
 </template>
diff --git a/assets/js/components/History/Chart.vue b/assets/js/components/History/Chart.vue
new file mode 100644
index 000000000..874388cf4
--- /dev/null
+++ b/assets/js/components/History/Chart.vue
@@ -0,0 +1,177 @@
+<template>
+	<div class="mb-5">
+		<div class="chart-container my-3">
+			<Line ref="chartRef" :data="chartData" :options="chartOptions" :height="300" />
+		</div>
+		<LegendList :legends="legends" />
+	</div>
+</template>
+
+<script lang="ts">
+import { defineComponent, type PropType } from "vue";
+import {
+	Chart as ChartJS,
+	LinearScale,
+	TimeScale,
+	LineController,
+	LineElement,
+	PointElement,
+	Filler,
+	Tooltip,
+	type ChartData,
+	type ChartOptions,
+} from "chart.js";
+import "chartjs-adapter-dayjs-4/dist/chartjs-adapter-dayjs-4.esm";
+import { Line } from "vue-chartjs";
+import colors, { dimColor } from "@/colors";
+import { commonOptions } from "../Sessions/chartConfig";
+import LegendList from "../Sessions/LegendList.vue";
+import type { Legend } from "../Sessions/types";
+import formatter from "@/mixins/formatter";
+import { is12hFormat } from "@/units";
+
+ChartJS.register(
+	LinearScale,
+	TimeScale,
+	LineController,
+	LineElement,
+	PointElement,
+	Filler,
+	Tooltip
+);
+
+interface Slot {
+	start: string;
+	end: string;
+	import: number;
+	export: number;
+}
+
+export interface SeriesData {
+	name: string;
+	data: Slot[];
+}
+
+function slotPower(slot: Slot, field: "import" | "export"): number {
+	const hours = (new Date(slot.end).getTime() - new Date(slot.start).getTime()) / 3_600_000;
+	return hours > 0 ? slot[field] / hours : 0;
+}
+
+export default defineComponent({
+	name: "HistoryChart",
+	components: { Line, LegendList },
+	mixins: [formatter],
+	props: {
+		series: { type: Array as PropType<SeriesData[]>, default: () => [] },
+		from: { type: Date, required: true },
+		to: { type: Date, required: true },
+	},
+	computed: {
+		chartData(): ChartData<"line"> {
+			const datasets = this.series.map((s, i) => {
+				const color = colors.palette[i % colors.palette.length];
+				const fill = dimColor(color);
+
+				const points = s.data.map((slot) => ({
+					x: new Date(slot.start).getTime(),
+					y: slotPower(slot, "import") - slotPower(slot, "export"),
+				}));
+
+				return {
+					label: s.name,
+					data: points,
+					borderColor: color,
+					backgroundColor: fill,
+					fill: true,
+					pointRadius: 0,
+					borderWidth: 1.5,
+					tension: 0.3,
+				};
+			});
+
+			return { datasets } as ChartData<"line">;
+		},
+		chartOptions(): ChartOptions<"line"> {
+			const locale = this.$i18n?.locale;
+			const fmtTime = new Intl.DateTimeFormat(locale, {
+				hour: "2-digit",
+				minute: "2-digit",
+				hour12: is12hFormat(),
+			});
+			const fmtDayShort = new Intl.DateTimeFormat(locale, {
+				weekday: "short",
+				day: "numeric",
+			});
+			return {
+				...commonOptions,
+				scales: {
+					x: {
+						type: "time",
+						min: this.from.getTime(),
+						max: this.to.getTime(),
+						border: { display: false },
+						grid: { display: false },
+						ticks: {
+							maxTicksLimit: 12,
+							color: colors.muted || undefined,
+							autoSkip: true,
+							maxRotation: 0,
+							callback: (value: number | string) => {
+								const d = new Date(value);
+								if (d.getHours() === 0 && d.getMinutes() === 0) {
+									return [fmtTime.format(d), fmtDayShort.format(d)];
+								}
+								return fmtTime.format(d);
+							},
+						},
+					},
+					y: {
+						border: { display: false },
+						suggestedMin: 0,
+						title: {
+							display: true,
+							text: "kW",
+							color: colors.muted || undefined,
+						},
+						ticks: {
+							color: colors.muted || undefined,
+							callback: (value: number | string) => Number(value).toFixed(1),
+						},
+						grid: {
+							color: (ctx: { tick: { value: number } }) =>
+								ctx.tick.value === 0
+									? colors.muted || undefined
+									: colors.border || undefined,
+						},
+					},
+				},
+				plugins: {
+					...commonOptions.plugins,
+					tooltip: {
+						...commonOptions.plugins.tooltip,
+						callbacks: {
+							title: (items) => {
+								const val = items[0]?.parsed?.x ?? 0;
+								if (!val) return "";
+								const d = new Date(val);
+								return `${fmtDayShort.format(d)} ${fmtTime.format(d)}`;
+							},
+							label: (ctx) => {
+								const val = (ctx.parsed.y ?? 0).toFixed(1);
+								return `${ctx.dataset.label}: ${val} kW`;
+							},
+						},
+					},
+				},
+			} as ChartOptions<"line">;
+		},
+		legends(): Legend[] {
+			return this.series.map((s, i) => ({
+				label: s.name,
+				color: colors.palette[i % colors.palette.length],
+				value: "",
+			}));
+		},
+	},
+});
+</script>
diff --git a/assets/js/components/History/EnergyChart.vue b/assets/js/components/History/EnergyChart.vue
new file mode 100644
index 000000000..59705dc45
--- /dev/null
+++ b/assets/js/components/History/EnergyChart.vue
@@ -0,0 +1,170 @@
+<template>
+	<div class="mb-5">
+		<div class="chart-container my-3">
+			<Bar ref="chartRef" :data="chartData" :options="chartOptions" :height="300" />
+		</div>
+		<LegendList :legends="legends" />
+	</div>
+</template>
+
+<script lang="ts">
+import { defineComponent, type PropType } from "vue";
+import {
+	Chart as ChartJS,
+	CategoryScale,
+	LinearScale,
+	BarController,
+	BarElement,
+	Tooltip,
+	type ChartData,
+	type ChartOptions,
+} from "chart.js";
+import { Bar } from "vue-chartjs";
+import colors, { lighterColor } from "@/colors";
+import { commonOptions } from "../Sessions/chartConfig";
+import LegendList from "../Sessions/LegendList.vue";
+import type { Legend } from "../Sessions/types";
+import formatter from "@/mixins/formatter";
+import type { SeriesData } from "./Chart.vue";
+
+ChartJS.register(CategoryScale, LinearScale, BarController, BarElement, Tooltip);
+
+export default defineComponent({
+	name: "HistoryEnergyChart",
+	components: { Bar, LegendList },
+	mixins: [formatter],
+	props: {
+		series: { type: Array as PropType<SeriesData[]>, default: () => [] },
+		from: { type: Date, required: true },
+		days: { type: Number, default: 14 },
+	},
+	computed: {
+		dayDates(): Date[] {
+			const result: Date[] = [];
+			for (let i = 0; i < this.days; i++) {
+				const d = new Date(this.from);
+				d.setDate(d.getDate() + i);
+				result.push(d);
+			}
+			return result;
+		},
+		labels(): string[] {
+			const locale = this.$i18n?.locale;
+			const fmt = new Intl.DateTimeFormat(locale, {
+				weekday: "short",
+				day: "numeric",
+				month: "short",
+			});
+			return this.dayDates.map((d) => fmt.format(d));
+		},
+		chartData(): ChartData<"bar"> {
+			const datasets: ChartData<"bar">["datasets"] = [];
+			const dayKeys = this.dayDates.map(
+				(d) =>
+					`${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`
+			);
+
+			this.series.forEach((s, i) => {
+				const color = colors.palette[i % colors.palette.length];
+
+				// index data by day
+				const byDay: Record<string, { import: number; export: number }> = {};
+				s.data.forEach((slot) => {
+					const d = new Date(slot.start);
+					const key = `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`;
+					byDay[key] = { import: slot.import, export: slot.export };
+				});
+
+				const importData = dayKeys.map((key) => byDay[key]?.import ?? 0);
+				const exportData = dayKeys.map((key) => -(byDay[key]?.export ?? 0));
+				const hasExport = exportData.some((v) => v !== 0);
+
+				const importLabel = hasExport ? `${s.name} (import)` : s.name;
+
+				datasets.push({
+					label: importLabel,
+					data: importData,
+					backgroundColor: color,
+					stack: `s${i}`,
+				});
+
+				if (hasExport) {
+					datasets.push({
+						label: `${s.name} (export)`,
+						data: exportData,
+						backgroundColor: lighterColor(color),
+						stack: `s${i}`,
+					});
+				}
+			});
+
+			return { labels: this.labels, datasets };
+		},
+		chartOptions(): ChartOptions<"bar"> {
+			return {
+				...commonOptions,
+				scales: {
+					x: {
+						border: { display: false },
+						grid: { display: false },
+						ticks: {
+							color: colors.muted || undefined,
+							maxRotation: 0,
+						},
+					},
+					y: {
+						border: { display: false },
+						title: {
+							display: true,
+							text: "kWh",
+							color: colors.muted || undefined,
+						},
+						ticks: {
+							color: colors.muted || undefined,
+							callback: (value: number | string) => Number(value).toFixed(1),
+						},
+						grid: {
+							color: (ctx: { tick: { value: number } }) =>
+								ctx.tick.value === 0
+									? colors.muted || undefined
+									: colors.border || undefined,
+						},
+					},
+				},
+				plugins: {
+					...commonOptions.plugins,
+					tooltip: {
+						...commonOptions.plugins.tooltip,
+						callbacks: {
+							label: (ctx) => {
+								const val = ctx.parsed.y ?? 0;
+								const abs = Math.abs(val);
+								const label = ctx.dataset.label || "";
+								return `${label}: ${abs.toFixed(1)} kWh`;
+							},
+						},
+					},
+				},
+			} as ChartOptions<"bar">;
+		},
+		legends(): Legend[] {
+			const result: Legend[] = [];
+			this.series.forEach((s, i) => {
+				const color = colors.palette[i % colors.palette.length];
+				const hasExport = s.data.some((slot) => slot.export > 0);
+
+				const importLabel = hasExport ? `${s.name} (import)` : s.name;
+				result.push({ label: importLabel, color, value: "" });
+				if (hasExport) {
+					result.push({
+						label: `${s.name} (export)`,
+						color: lighterColor(color),
+						value: "",
+					});
+				}
+			});
+			return result;
+		},
+	},
+});
+</script>
diff --git a/assets/js/components/Top/Navigation.vue b/assets/js/components/Top/Navigation.vue
index 3db3845c3..11ddb133d 100644
--- a/assets/js/components/Top/Navigation.vue
+++ b/assets/js/components/Top/Navigation.vue
@@ -89,6 +89,11 @@
 					Optimize 🧪
 				</router-link>
 			</li>
+			<li v-if="experimental">
+				<router-link class="dropdown-item" to="/history" active-class="active">
+					History 🧪
+				</router-link>
+			</li>
 			<li><hr class="dropdown-divider" /></li>
 			<template v-if="authorizationRequired">
 				<li>
diff --git a/assets/js/router.ts b/assets/js/router.ts
index 5f099db0c..f55d4345d 100644
--- a/assets/js/router.ts
+++ b/assets/js/router.ts
@@ -120,6 +120,11 @@ export default function setupRouter(i18n: VueI18nInstance) {
         component: () => import("./views/Battery.vue"),
         props: true,
       },
+      {
+        path: "/history",
+        component: () => import("./views/History.vue"),
+        props: true,
+      },
       {
         path: "/optimize",
         component: () => import("./views/Optimize.vue"),
diff --git a/assets/js/views/History.vue b/assets/js/views/History.vue
new file mode 100644
index 000000000..4d818ebca
--- /dev/null
+++ b/assets/js/views/History.vue
@@ -0,0 +1,103 @@
+<template>
+	<div class="container px-4 safe-area-inset">
+		<TopHeader title="History" />
+		<div class="row">
+			<main class="col-12">
+				<div v-if="loading" class="my-5 text-center text-muted">loading...</div>
+				<template v-else>
+					<section v-if="powerSeries.length" class="mb-5">
+						<h3 class="fw-normal mb-3">Power <small class="ms-2">48 hours</small></h3>
+						<PowerChart :series="powerSeries" :from="powerFrom" :to="powerTo" />
+					</section>
+					<section v-if="energySeries.length" class="mb-5">
+						<h3 class="fw-normal mb-3">Energy <small class="ms-2">14 days</small></h3>
+						<EnergyChart :series="energySeries" :from="energyFrom" :days="14" />
+					</section>
+					<div
+						v-if="!powerSeries.length && !energySeries.length"
+						class="my-5 text-center text-muted"
+					>
+						no data
+					</div>
+				</template>
+			</main>
+		</div>
+	</div>
+</template>
+
+<script lang="ts">
+import { defineComponent } from "vue";
+import Header from "../components/Top/Header.vue";
+import PowerChart from "../components/History/Chart.vue";
+import EnergyChart from "../components/History/EnergyChart.vue";
+import api from "../api";
+
+export default defineComponent({
+	name: "History",
+	components: {
+		TopHeader: Header,
+		PowerChart,
+		EnergyChart,
+	},
+	data() {
+		return {
+			powerSeries: [] as any[],
+			energySeries: [] as any[],
+			powerFrom: new Date(),
+			powerTo: new Date(),
+			energyFrom: new Date(),
+			loading: true,
+			interval: null as ReturnType<typeof setInterval> | null,
+		};
+	},
+	head() {
+		return { title: "History" };
+	},
+	mounted() {
+		this.fetchData();
+		this.interval = setInterval(() => this.fetchData(), 15 * 60 * 1e3);
+	},
+	unmounted() {
+		if (this.interval) {
+			clearInterval(this.interval);
+		}
+	},
+	methods: {
+		async fetchData() {
+			try {
+				this.powerTo = new Date();
+				this.powerFrom = new Date();
+				this.powerFrom.setDate(this.powerFrom.getDate() - 2);
+				this.powerFrom.setHours(0, 0, 0, 0);
+
+				this.energyFrom = new Date();
+				this.energyFrom.setDate(this.energyFrom.getDate() - 13);
+				this.energyFrom.setHours(0, 0, 0, 0);
+
+				const [powerRes, energyRes] = await Promise.all([
+					api.get("history/energy", {
+						params: {
+							from: this.powerFrom.toISOString(),
+							to: this.powerTo.toISOString(),
+						},
+					}),
+					api.get("history/energy", {
+						params: {
+							from: this.energyFrom.toISOString(),
+							to: this.powerTo.toISOString(),
+							aggregate: "day",
+						},
+					}),
+				]);
+
+				this.powerSeries = powerRes.data || [];
+				this.energySeries = energyRes.data || [];
+			} catch (e) {
+				console.error("Failed to load energy history", e);
+			} finally {
+				this.loading = false;
+			}
+		},
+	},
+});
+</script>
diff --git a/core/meterenergy.go b/core/meterenergy.go
deleted file mode 100644
index 769834c37..000000000
--- a/core/meterenergy.go
+++ /dev/null
@@ -1,60 +0,0 @@
-package core
-
-import (
-	"bytes"
-	"fmt"
-	"time"
-
-	"github.com/benbjohnson/clock"
-)
-
-type meterEnergy struct {
-	clock       clock.Clock
-	updated     time.Time
-	meter       *float64 // kWh
-	Accumulated float64  `json:"accumulated"` // kWh
-}
-
-func (m *meterEnergy) String() string {
-	b := new(bytes.Buffer)
-	fmt.Fprintf(b, "Accumulated: %.3fkWh updated: %v", m.Accumulated, m.updated.Truncate(time.Second))
-	if m.meter != nil {
-		fmt.Fprintf(b, " meter: %.3fkWh", *m.meter)
-	}
-	return b.String()
-}
-
-// AccumulatedEnergy returns the accumulated energy in kWh
-func (m *meterEnergy) AccumulatedEnergy() float64 {
-	return m.Accumulated
-}
-
-// AddMeterTotal adds the difference to the last total meter value in kWh
-func (m *meterEnergy) AddMeterTotal(v float64) {
-	defer func() {
-		m.updated = m.clock.Now()
-		m.meter = new(v)
-	}()
-
-	if m.meter == nil {
-		return
-	}
-
-	m.Accumulated += v - *m.meter
-}
-
-// AddEnergy adds the given energy in kWh
-func (m *meterEnergy) AddEnergy(v float64) {
-	defer func() { m.updated = m.clock.Now() }()
-
-	if m.updated.IsZero() {
-		return
-	}
-
-	m.Accumulated += v
-}
-
-// AddPower adds the given power in W, calculating the energy based on the time since the last update
-func (m *meterEnergy) AddPower(v float64) {
-	m.AddEnergy(v * m.clock.Since(m.updated).Hours() / 1e3)
-}
diff --git a/core/metrics/accumulator.go b/core/metrics/accumulator.go
new file mode 100644
index 000000000..623d00e1d
--- /dev/null
+++ b/core/metrics/accumulator.go
@@ -0,0 +1,126 @@
+package metrics
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/benbjohnson/clock"
+	"github.com/samber/lo"
+)
+
+type Accumulator struct {
+	clock       clock.Clock
+	updated     time.Time
+	importMeter *float64 // kWh
+	exportMeter *float64 // kWh
+	Import      float64  `json:"import"` // kWh
+	Export      float64  `json:"export"` // kWh
+}
+
+func WithClock(clock clock.Clock) func(*Accumulator) {
+	return func(m *Accumulator) {
+		m.clock = clock
+	}
+}
+
+func NewAccumulator(opt ...func(*Accumulator)) *Accumulator {
+	m := &Accumulator{clock: clock.New()}
+	for _, o := range opt {
+		o(m)
+	}
+	return m
+}
+
+func (m *Accumulator) Updated() time.Time {
+	return m.updated
+}
+
+func (m *Accumulator) String() string {
+	b := new(bytes.Buffer)
+	fmt.Fprintf(b, "Accumulated: %.3fkWh pos, %.3fkWh neg, updated: %v", m.Import, m.Export, m.updated.Truncate(time.Second))
+	if m.importMeter != nil || m.exportMeter != nil {
+		fmt.Fprintf(b, " meter: ")
+		if m.importMeter != nil {
+			fmt.Fprintf(b, " %.3fkWh pos", *m.importMeter)
+		}
+		if m.exportMeter != nil {
+			fmt.Fprintf(b, " %.3fkWh pos", *m.exportMeter)
+		}
+	}
+	return b.String()
+}
+
+// Imported returns the accumulated import energy in kWh
+func (m *Accumulator) Imported() float64 {
+	return m.Import
+}
+
+// Exported returns the accumulated export energy in kWh
+func (m *Accumulator) Exported() float64 {
+	return m.Export
+}
+
+// SetImportMeterTotal adds the difference to the last total meter value in kWh
+func (m *Accumulator) SetImportMeterTotal(v float64) {
+	defer func() {
+		m.updated = m.clock.Now()
+		m.importMeter = lo.ToPtr(v)
+	}()
+
+	if m.importMeter == nil {
+		return
+	}
+
+	if v >= *m.importMeter {
+		m.Import += v - *m.importMeter
+	}
+}
+
+// SetExportMeterTotal adds the difference to the last total meter value in kWh
+func (m *Accumulator) SetExportMeterTotal(v float64) {
+	defer func() {
+		m.updated = m.clock.Now()
+		m.exportMeter = lo.ToPtr(v)
+	}()
+
+	if m.exportMeter == nil {
+		return
+	}
+
+	if v >= *m.exportMeter {
+		m.Export += v - *m.exportMeter
+	}
+}
+
+// AddImportEnergy adds the given energy in kWh to the positive meter
+func (m *Accumulator) AddImportEnergy(v float64) {
+	defer func() { m.updated = m.clock.Now() }()
+
+	if m.updated.IsZero() {
+		return
+	}
+
+	m.Import += v
+}
+
+// AddExportEnergy adds the given energy in kWh to the negative meter
+func (m *Accumulator) AddExportEnergy(v float64) {
+	defer func() { m.updated = m.clock.Now() }()
+
+	if m.updated.IsZero() {
+		return
+	}
+
+	m.Export += v
+}
+
+// AddPower adds the given power in W, calculating the energy based on the time since the last update
+func (m *Accumulator) AddPower(v float64) {
+	since := v * m.clock.Since(m.updated).Hours() / 1e3
+	if v >= 0 {
+		m.AddImportEnergy(since)
+	} else {
+		m.AddExportEnergy(-since)
+	}
+}
diff --git a/core/meterenergy_test.go b/core/metrics/accumulator_test.go
similarity index 53%
rename from core/meterenergy_test.go
rename to core/metrics/accumulator_test.go
index 3c0ae42e1..62b496214 100644
--- a/core/meterenergy_test.go
+++ b/core/metrics/accumulator_test.go
@@ -1,4 +1,4 @@
-package core
+package metrics
 
 import (
 	"testing"
@@ -13,31 +13,31 @@ func TestMeterEnergyMeterTotal(t *testing.T) {
 	clock := clock.NewMock()
 	clock.Set(now.BeginningOfDay())
 
-	me := &meterEnergy{clock: clock}
+	me := &Accumulator{clock: clock}
 
-	me.AddMeterTotal(10)
-	assert.Equal(t, 0.0, me.AccumulatedEnergy())
-	me.AddMeterTotal(11)
-	assert.Equal(t, 1.0, me.AccumulatedEnergy())
-	me.AddMeterTotal(11)
-	assert.Equal(t, 1.0, me.AccumulatedEnergy())
+	me.SetImportMeterTotal(10)
+	assert.Equal(t, 0.0, me.Imported())
+	me.SetImportMeterTotal(11)
+	assert.Equal(t, 1.0, me.Imported())
+	me.SetImportMeterTotal(11)
+	assert.Equal(t, 1.0, me.Imported())
 }
 
 func TestMeterEnergyAddPower(t *testing.T) {
 	clock := clock.NewMock()
 	clock.Set(now.BeginningOfDay())
 
-	me := &meterEnergy{clock: clock}
+	me := &Accumulator{clock: clock}
 
 	clock.Add(60 * time.Minute)
 	me.AddPower(1e3)
-	assert.Equal(t, 0.0, me.AccumulatedEnergy())
+	assert.Equal(t, 0.0, me.Imported())
 
 	clock.Add(60 * time.Minute)
 	me.AddPower(1e3)
-	assert.Equal(t, 1.0, me.AccumulatedEnergy())
+	assert.Equal(t, 1.0, me.Imported())
 
 	clock.Add(30 * time.Minute)
 	me.AddPower(1e3)
-	assert.Equal(t, 1.5, me.AccumulatedEnergy())
+	assert.Equal(t, 1.5, me.Imported())
 }
diff --git a/core/metrics/collector.go b/core/metrics/collector.go
new file mode 100644
index 000000000..5b412ae91
--- /dev/null
+++ b/core/metrics/collector.go
@@ -0,0 +1,126 @@
+package metrics
+
+import (
+	"time"
+
+	"github.com/evcc-io/evcc/server/db"
+	"github.com/evcc-io/evcc/tariff"
+)
+
+const (
+	// groups
+	Grid = "grid"
+	PV   = "pv"
+	Home = "home" // meter and group (virtual measurement)
+)
+
+type Collector struct {
+	entity  entity
+	accu    *Accumulator
+	started time.Time
+}
+
+func NewCollector(group, name string, opt ...func(*Accumulator)) (*Collector, error) {
+	entity, err := createEntity(group, name)
+	if err != nil {
+		return nil, err
+	}
+
+	c := &Collector{
+		entity: entity,
+		accu:   NewAccumulator(opt...),
+	}
+
+	return c, nil
+}
+
+func createEntity(group, name string) (entity, error) {
+	entity := entity{
+		Group: group,
+		Name:  name,
+	}
+
+	if err := db.Instance.Where(&entity).FirstOrCreate(&entity).Error; err != nil {
+		return entity, err
+	}
+
+	return entity, nil
+}
+
+func (c *Collector) process(fun func()) error {
+	now := c.accu.clock.Now()
+
+	fun()
+
+	if slotStart := now.Truncate(tariff.SlotDuration); slotStart.After(c.started) {
+		// skip incomplete first slot
+		if !c.started.IsZero() {
+			if err := c.persist(); err != nil {
+				return err
+			}
+		}
+
+		c.started = slotStart
+		c.accu.Import = 0
+		c.accu.Export = 0
+	}
+
+	return nil
+}
+
+func (c *Collector) persist() error {
+	return persist(c.entity, c.started, c.accu.Imported(), c.accu.Exported())
+}
+
+func (c *Collector) ImportProfile(from time.Time) (*[96]float64, error) {
+	return importProfile(c.entity, from)
+}
+
+func (c *Collector) AddImportEnergy(v float64) error {
+	return c.process(func() {
+		c.accu.AddImportEnergy(v)
+	})
+}
+
+func (c *Collector) AddExportEnergy(v float64) error {
+	return c.process(func() {
+		c.accu.AddExportEnergy(v)
+	})
+}
+
+func (c *Collector) SetImportMeterTotal(v float64) error {
+	return c.process(func() {
+		c.accu.SetImportMeterTotal(v)
+	})
+}
+
+func (c *Collector) SetExportMeterTotal(v float64) error {
+	return c.process(func() {
+		c.accu.SetExportMeterTotal(v)
+	})
+}
+
+// AddEnergy adds energy using meter totals if available, falling back to power integration.
+func (c *Collector) AddEnergy(importTotal, exportTotal *float64, power float64) error {
+	return c.process(func() {
+		switch {
+		case importTotal != nil && exportTotal != nil:
+			c.accu.SetImportMeterTotal(*importTotal)
+			c.accu.SetExportMeterTotal(*exportTotal)
+		case importTotal != nil:
+			// export via power integration (before meter updates clock)
+			if power < 0 {
+				c.accu.AddPower(power)
+			}
+			c.accu.SetImportMeterTotal(*importTotal)
+		case exportTotal != nil:
+			// import via power integration (before meter updates clock)
+			if power >= 0 {
+				c.accu.AddPower(power)
+			}
+			c.accu.SetExportMeterTotal(*exportTotal)
+		default:
+			c.accu.AddPower(power)
+		}
+	})
+}
diff --git a/core/metrics/collector_test.go b/core/metrics/collector_test.go
new file mode 100644
index 000000000..7e2e5bea7
--- /dev/null
+++ b/core/metrics/collector_test.go
@@ -0,0 +1,132 @@
+package metrics
+
+import (
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+	"github.com/evcc-io/evcc/server/db"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCollectorAddEnergy(t *testing.T) {
+	clock := clock.NewMock()
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	col, err := NewCollector("foo", "foo", WithClock(clock))
+	require.NoError(t, err)
+	require.True(t, col.accu.updated.IsZero())
+
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(nil, nil, 1e3))
+	require.False(t, col.accu.updated.IsZero())
+
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(nil, nil, 1e3))
+	require.Equal(t, 1e3*5/60/1e3, col.accu.Imported()) // kWh
+
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(nil, nil, 1e3))
+	require.Equal(t, 0.0, col.accu.Imported()) // accumulator reset after 15 minutes
+
+	clock.Add(15 * time.Minute)
+	require.NoError(t, col.AddEnergy(nil, nil, 1e3))
+	require.Equal(t, 0.0, col.accu.Imported()) // accumulator reset after 15 minutes
+}
+
+func f(v float64) *float64 { return &v }
+
+func TestCollectorAddEnergyWithImportMeter(t *testing.T) {
+	clock := clock.NewMock()
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	col, err := NewCollector("bar", "bar", WithClock(clock))
+	require.NoError(t, err)
+
+	// first call: seeds meter, no delta yet
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(50000), nil, 1e3))
+	require.Equal(t, 0.0, col.accu.Imported())
+
+	// second call: meter delta of 0.5 kWh, power ignored for import
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(50000.5), nil, 1e3))
+	require.Equal(t, 0.5, col.accu.Imported())
+
+	// implausible reading (decreased): ignored by guard
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(49000), nil, 1e3))
+	require.Equal(t, 0.0, col.accu.Imported()) // reset at slot boundary
+}
+
+func TestCollectorAddEnergyWithImportMeterAndExport(t *testing.T) {
+	clock := clock.NewMock()
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	col, err := NewCollector("baz", "baz", WithClock(clock))
+	require.NoError(t, err)
+
+	// seed import meter
+	clock.Add(3 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(1000), nil, 0))
+
+	// positive power: import via meter delta, no export
+	clock.Add(3 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(1000.3), nil, 500))
+	require.InDelta(t, 0.3, col.accu.Imported(), 1e-10)
+	require.Equal(t, 0.0, col.accu.Exported())
+
+	// negative power: import via meter (no change), export via power integration
+	clock.Add(3 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(1000.3), nil, -600))
+	require.InDelta(t, 0.3, col.accu.Imported(), 1e-10)
+	require.InDelta(t, 600.0*3/60/1e3, col.accu.Exported(), 1e-10) // 0.03 kWh
+}
+
+func TestCollectorAddEnergyWithBothMeters(t *testing.T) {
+	clock := clock.NewMock()
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	col, err := NewCollector("qux", "qux", WithClock(clock))
+	require.NoError(t, err)
+
+	// seed both meters
+	clock.Add(3 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(1000), f(2000), 0))
+
+	// both deltas used, power ignored
+	clock.Add(3 * time.Minute)
+	require.NoError(t, col.AddEnergy(f(1000.3), f(2000.7), 999))
+	require.InDelta(t, 0.3, col.accu.Imported(), 1e-10)
+	require.InDelta(t, 0.7, col.accu.Exported(), 1e-10)
+}
+
+func TestCollectorSetImportAndExportMeterTotal(t *testing.T) {
+	clock := clock.NewMock()
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	col, err := NewCollector("set", "set", WithClock(clock))
+	require.NoError(t, err)
+
+	// seed both import and export
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.SetImportMeterTotal(1000))
+	require.NoError(t, col.SetExportMeterTotal(2000))
+
+	// both deltas used
+	clock.Add(5 * time.Minute)
+	require.NoError(t, col.SetImportMeterTotal(1000.3))
+	require.NoError(t, col.SetExportMeterTotal(2000.7))
+	require.InDelta(t, 0.3, col.accu.Imported(), 1e-10)
+	require.InDelta(t, 0.7, col.accu.Exported(), 1e-10)
+}
diff --git a/core/metrics/db.go b/core/metrics/db.go
index 4520842bf..e1ef96150 100644
--- a/core/metrics/db.go
+++ b/core/metrics/db.go
@@ -10,42 +10,226 @@ import (
 )
 
 type meter struct {
-	Meter     int       `json:"meter" gorm:"column:meter;uniqueIndex:meter_ts"`
-	Timestamp time.Time `json:"ts" gorm:"column:ts;uniqueIndex:meter_ts"`
-	Value     float64   `json:"val" gorm:"column:val"`
+	Meter     int       `json:"meter" gorm:"column:meter;uniqueIndex:meters_meter_ts"`
+	Timestamp time.Time `json:"ts" gorm:"column:ts;uniqueIndex:meters_meter_ts"` // start of 15min slot
+	Entity    entity    `json:"-" gorm:"foreignkey:Meter;references:Id"`
+	Import    float64   `json:"import" gorm:"column:import"`
+	Export    float64   `json:"export" gorm:"column:export"`
+}
+
+type entity struct {
+	Id    int    `gorm:"column:id;primarykey"`
+	Group string `gorm:"column:group;uniqueIndex:entities_group_name"`
+	Name  string `gorm:"column:name;uniqueIndex:entities_group_name"`
 }
 
 var ErrIncomplete = errors.New("meter profile incomplete")
 
+// Slot represents an aggregated energy time slot
+type Slot struct {
+	Start  time.Time `json:"start"`
+	End    time.Time `json:"end"`
+	Import float64   `json:"import"`
+	Export float64   `json:"export"`
+}
+
+// Series represents a named series of energy slots
+type Series struct {
+	Name string `json:"name"`
+	Data []Slot `json:"data"`
+}
+
+var aggregateFormats = map[string]string{
+	"15m":   "%Y-%m-%d %H:%M",
+	"hour":  "%Y-%m-%d %H:00",
+	"day":   "%Y-%m-%d",
+	"month": "%Y-%m",
+}
+
+var aggregateGoFormats = map[string]string{
+	"15m":   "2006-01-02 15:04",
+	"hour":  "2006-01-02 15:00",
+	"day":   "2006-01-02",
+	"month": "2006-01",
+}
+
+var aggregateDurations = map[string]func(time.Time) time.Time{
+	"15m":   func(t time.Time) time.Time { return t.Add(15 * time.Minute) },
+	"hour":  func(t time.Time) time.Time { return t.Add(time.Hour) },
+	"day":   func(t time.Time) time.Time { return t.AddDate(0, 0, 1) },
+	"month": func(t time.Time) time.Time { return t.AddDate(0, 1, 0) },
+}
+
+// QueryImportEnergy returns aggregated import energy data from the meters table
+func QueryImportEnergy(from, to time.Time, aggregate string) ([]Series, error) {
+	format, ok := aggregateFormats[aggregate]
+	if !ok {
+		return nil, errors.New("invalid aggregate value")
+	}
+
+	addDuration := aggregateDurations[aggregate]
+
+	// use Go's tz offset instead of SQLite's 'localtime'
+	tz := time.Now().Format("-07:00")
+
+	tx := db.Instance.Table("meters m").
+		Select(`e.name AS label, strftime('` + format + `', m.ts, '` + tz + `') AS bucket,
+		COALESCE(SUM(m."import"), 0) AS import, COALESCE(SUM(m.export), 0) AS export`).
+		Joins("JOIN entities e ON m.meter = e.id").
+		Group("label, bucket").
+		Order("label, bucket")
+
+	if !from.IsZero() {
+		tx = tx.Where("m.ts >= ?", from)
+	}
+	if !to.IsZero() {
+		tx = tx.Where("m.ts < ?", to)
+	}
+
+	rows, err := tx.Rows()
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	seriesMap := make(map[string][]Slot)
+	var order []string
+
+	for rows.Next() {
+		var label, bucket string
+		var imp, exp float64
+
+		if err := rows.Scan(&label, &bucket, &imp, &exp); err != nil {
+			return nil, err
+		}
+
+		start, err := time.ParseInLocation(aggregateGoFormats[aggregate], bucket, time.Now().Location())
+		if err != nil {
+			return nil, err
+		}
+
+		if _, exists := seriesMap[label]; !exists {
+			order = append(order, label)
+		}
+
+		seriesMap[label] = append(seriesMap[label], Slot{
+			Start:  start,
+			End:    addDuration(start),
+			Import: imp,
+			Export: exp,
+		})
+	}
+
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	res := make([]Series, 0, len(order))
+	for _, name := range order {
+		res = append(res, Series{
+			Name: name,
+			Data: seriesMap[name],
+		})
+	}
+
+	return res, nil
+}
+
 func init() {
-	db.Register(func(db *gorm.DB) error {
-		return db.AutoMigrate(new(meter))
+	db.Register(func(_ *gorm.DB) error {
+		return SetupSchema()
 	})
 }
 
-// Persist stores 15min consumption in Wh
-func Persist(ts time.Time, value float64) error {
-	return db.Instance.Create(meter{
-		Meter:     1,
-		Timestamp: ts.Truncate(15 * time.Minute),
-		Value:     value,
+// SetupSchema is used for testing
+func SetupSchema() error {
+	m := db.Instance.Migrator()
+
+	// entites: create entity first to make sure foreign keys for existing data work
+	hasTable := m.HasTable(new(entity))
+	if err := db.Instance.AutoMigrate(new(entity)); err != nil {
+		return err
+	}
+
+	// entites: add entity id 1
+	if hasTable {
+		var res entity
+		if err := db.Instance.Where(&entity{Id: 1, Name: Home}).FirstOrCreate(&res).Error; err != nil {
+			return err
+		}
+
+		if res.Group == "" {
+			res.Group = Home
+			if err := db.Instance.Save(&res).Error; err != nil {
+				return err
+			}
+		}
+	}
+
+	// drop obsolete indexes
+	for _, idx := range []struct {
+		name string
+		obj  any
+	}{
+		{"name_idx", new(entity)},
+		{"group_name", new(entity)},
+		{"meter_ts", new(meter)},
+	} {
+		if m.HasIndex(idx.obj, idx.name) {
+			if err := m.DropIndex(idx.obj, idx.name); err != nil {
+				return err
+			}
+		}
+	}
+
+	// meter: split energy direction
+	if old := "val"; m.HasColumn(new(meter), old) {
+		if err := m.RenameColumn(new(meter), old, "import"); err != nil {
+			return err
+		}
+	}
+
+	// meter: split energy direction #2
+	if old := "pos"; m.HasColumn(new(meter), old) {
+		if err := m.RenameColumn(new(meter), old, "import"); err != nil {
+			return err
+		}
+	}
+	if old := "neg"; m.HasColumn(new(meter), old) {
+		if err := m.RenameColumn(new(meter), old, "export"); err != nil {
+			return err
+		}
+	}
+
+	return db.Instance.AutoMigrate(new(meter))
+}
+
+// persist stores 15min consumption in kWh
+func persist(entity entity, ts time.Time, imp, exp float64) error {
+	return db.Instance.Create(&meter{
+		Meter:     entity.Id,
+		Timestamp: ts.Truncate(tariff.SlotDuration),
+		Import:    imp,
+		Export:    exp,
 	}).Error
 }
 
-// Profile returns a 15min average meter profile in Wh.
-// Profile is sorted by timestamp starting at 00:00. It is guaranteed to contain 96 15min values.
-func Profile(from time.Time) (*[96]float64, error) {
+// importProfile returns a 15min average meter profile in Wh. The profile
+// is sorted by timestamp starting at 00:00. It is guaranteed to contain 96 15min values.
+func importProfile(entity entity, from time.Time) (*[96]float64, error) {
 	db, err := db.Instance.DB()
 	if err != nil {
 		return nil, err
 	}
 
-	// Use 'localtime' in strftime to fix https://github.com/evcc-io/evcc/discussions/23759
-	rows, err := db.Query(`SELECT min(ts) AS ts, avg(val) AS val
+	// use Go's tz offset instead of SQLite's 'localtime'
+	tz := from.Format("-07:00")
+
+	rows, err := db.Query(`SELECT min(ts) AS ts, avg(import) AS import
 		FROM meters
 		WHERE meter = ? AND ts >= ?
-		GROUP BY strftime("%H:%M", ts, 'localtime')
-		ORDER BY strftime("%H:%M", ts, 'localtime') ASC`, 1, from,
+		GROUP BY strftime("%H:%M", ts, '`+tz+`')
+		ORDER BY strftime("%H:%M", ts, '`+tz+`') ASC`, entity.Id, from,
 	)
 	if err != nil {
 		return nil, err
diff --git a/core/metrics/db_test.go b/core/metrics/db_test.go
new file mode 100644
index 000000000..e660395cd
--- /dev/null
+++ b/core/metrics/db_test.go
@@ -0,0 +1,102 @@
+package metrics
+
+import (
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+	"github.com/evcc-io/evcc/server/db"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSqliteTimestamp(t *testing.T) {
+	clock := clock.NewMock()
+	clock.Add(time.Hour)
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	entity := entity{Name: "foo"}
+	require.NoError(t, db.Instance.FirstOrCreate(&entity).Error)
+
+	persist(entity, clock.Now(), 0, 0)
+
+	db, err := db.Instance.DB()
+	require.NoError(t, err)
+
+	var (
+		ts  SqlTime
+		val float64
+	)
+
+	for _, sql := range []string{
+		`SELECT ts, import FROM meters`,
+		`SELECT min(ts), import FROM meters`,
+		`SELECT unixepoch(ts), import FROM meters`,
+		`SELECT unixepoch(min(ts)), import FROM meters`,
+		`SELECT min(ts) AS ts, avg(import) AS import
+			FROM meters
+			GROUP BY strftime("%H:%M", ts)
+			ORDER BY ts`,
+	} {
+		require.NoError(t, db.QueryRow(sql).Scan(&ts, &val))
+		require.True(t, clock.Now().Equal(time.Time(ts)), "expected %v, got %v", clock.Now().Local(), time.Time(ts).Local())
+	}
+
+	require.NoError(t, db.QueryRow(`SELECT ts, import FROM meters WHERE ts >= ?`, clock.Now()).Scan(&ts, &val))
+	require.True(t, clock.Now().Equal(time.Time(ts)), "expected %v, got %v", clock.Now().Local(), time.Time(ts).Local())
+}
+
+func TestUpdateProfile(t *testing.T) {
+	clock := clock.NewMock()
+
+	// adjust for 00:00 in local timezone
+	_, o := clock.Now().Zone()
+	clock.Add(-time.Duration(o) * time.Second)
+
+	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
+	require.NoError(t, SetupSchema())
+
+	entity := entity{Id: 2, Name: "foo"}
+	require.NoError(t, db.Instance.FirstOrCreate(&entity).Error)
+
+	// 2 days of data
+	// day 1:   0 ...  95
+	// day 2:  96 ... 181
+	for i := range 4 * 2 * 24 {
+		persist(entity, clock.Now(), float64(i), float64(i))
+		clock.Add(15 * time.Minute)
+	}
+
+	{
+		from := clock.Now().Local().AddDate(0, 0, -2).Add(12 * time.Hour) // 12:00 of day 0
+
+		prof, err := importProfile(entity, from)
+		require.NoError(t, err)
+
+		var expected [96]float64
+		for i := range expected {
+			if i < 48 {
+				expected[i] = float64(48+i+144+i) / 2
+				continue
+			}
+			expected[i] = float64(96 - 48 + i)
+		}
+
+		require.Equal(t, expected, *prof, "partial profile: expected %v, got %v", expected, *prof)
+	}
+
+	{
+		from := clock.Now().Local().AddDate(0, 0, -3).Add(12 * time.Hour) // 12:00 of day -1
+
+		prof, err := importProfile(entity, from)
+		require.NoError(t, err)
+
+		var expected [96]float64
+		for i := range expected {
+			expected[i] = float64(0+96+2*i) / 2
+		}
+
+		require.Equal(t, expected, *prof, "full profile: expected %v, got %v", expected, *prof)
+	}
+}
diff --git a/core/site.go b/core/site.go
index b4596dd8b..be816cfdc 100644
--- a/core/site.go
+++ b/core/site.go
@@ -11,7 +11,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benbjohnson/clock"
 	"github.com/cenkalti/backoff/v4"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/cmd/shutdown"
@@ -85,11 +84,10 @@ type Site struct {
 	coordinator *coordinator.Coordinator // Vehicles
 	prioritizer *prioritizer.Prioritizer // Power budgets
 	stats       *Stats                   // Stats
-	fcstEnergy  *meterEnergy
-	pvEnergy    map[string]*meterEnergy
+	fcstEnergy  *metrics.Accumulator
+	pvEnergy    map[string]*metrics.Accumulator
 
-	householdEnergy    *meterEnergy
-	householdSlotStart time.Time
+	homeEnergy, gridEnergy *metrics.Collector
 
 	// cached state
 	gridPower                float64            // Grid power
@@ -140,6 +138,12 @@ func (site *Site) Boot(log *util.Logger, loadpoints []*Loadpoint, tariffs *tarif
 	site.prioritizer = prioritizer.New(log)
 	site.stats = NewStats()
 
+	me, err := metrics.NewCollector(metrics.Home, metrics.Home)
+	if err != nil {
+		return err
+	}
+	site.homeEnergy = me
+
 	// upload telemetry on shutdown
 	if telemetry.Enabled() {
 		shutdown.Register(func() {
@@ -180,10 +184,17 @@ func (site *Site) Boot(log *util.Logger, loadpoints []*Loadpoint, tariffs *tarif
 		if err != nil {
 			return err
 		}
+
 		site.gridMeter = dev.Instance()
 		if site.gridMeter == nil {
 			return errors.New("missing grid meter instance")
 		}
+
+		me, err := metrics.NewCollector(metrics.Grid, site.Meters.GridMeterRef)
+		if err != nil {
+			return err
+		}
+		site.gridEnergy = me
 	}
 
 	// multiple pv
@@ -195,7 +206,7 @@ func (site *Site) Boot(log *util.Logger, loadpoints []*Loadpoint, tariffs *tarif
 		site.pvMeters = append(site.pvMeters, dev)
 
 		// accumulator
-		site.pvEnergy[ref] = &meterEnergy{clock: clock.New()}
+		site.pvEnergy[ref] = metrics.NewAccumulator()
 	}
 
 	// multiple batteries
@@ -240,11 +251,10 @@ func (site *Site) Boot(log *util.Logger, loadpoints []*Loadpoint, tariffs *tarif
 // NewSite creates a Site with sane defaults
 func NewSite() *Site {
 	site := &Site{
-		log:             util.NewLogger("site"),
-		Voltage:         230, // V
-		pvEnergy:        make(map[string]*meterEnergy),
-		fcstEnergy:      &meterEnergy{clock: clock.New()},
-		householdEnergy: &meterEnergy{clock: clock.New()},
+		log:        util.NewLogger("site"),
+		Voltage:    230, // V
+		pvEnergy:   make(map[string]*metrics.Accumulator),
+		fcstEnergy: metrics.NewAccumulator(),
 	}
 
 	return site
@@ -312,14 +322,14 @@ func (site *Site) restoreSettings() error {
 	}
 
 	// restore accumulated energy
-	pvEnergy := make(map[string]meterEnergy)
+	pvEnergy := make(map[string]metrics.Accumulator)
 	fcstEnergy, err := settings.Float(keys.SolarAccForecast)
 
 	if err == nil && settings.Json(keys.SolarAccYield, &pvEnergy) == nil {
 		var nok bool
 		for _, name := range site.Meters.PVMetersRef {
 			if fcst, ok := pvEnergy[name]; ok {
-				site.pvEnergy[name].Accumulated = fcst.Accumulated
+				site.pvEnergy[name].Import = fcst.Import
 			} else {
 				nok = true
 				site.log.WARN.Printf("accumulated solar yield: cannot restore %s", name)
@@ -327,7 +337,7 @@ func (site *Site) restoreSettings() error {
 		}
 
 		if !nok {
-			site.fcstEnergy.Accumulated = fcstEnergy
+			site.fcstEnergy.Import = fcstEnergy
 			site.log.DEBUG.Printf("accumulated solar yield: restored %.3fkWh forecasted, %+v produced", fcstEnergy, pvEnergy)
 		} else {
 			// reset metrics
@@ -337,7 +347,7 @@ func (site *Site) restoreSettings() error {
 			settings.Delete(keys.SolarAccYield)
 
 			for _, pe := range site.pvEnergy {
-				pe.Accumulated = 0
+				pe.Import = 0
 			}
 		}
 	}
@@ -580,15 +590,15 @@ func (site *Site) updatePvMeters() {
 		// use stored devices, not ui-updated instances!
 		name := dev.Config().Name
 
-		prev := site.pvEnergy[name].AccumulatedEnergy()
+		prev := site.pvEnergy[name].Imported()
 		if mm[i].Energy > 0 {
 			site.log.DEBUG.Printf("!! solar production: accumulate set %s %.3fkWh meter total (was: %s)", name, mm[i].Energy, site.pvEnergy[name])
-			site.pvEnergy[name].AddMeterTotal(mm[i].Energy)
+			site.pvEnergy[name].SetImportMeterTotal(mm[i].Energy)
 		} else {
 			site.log.DEBUG.Printf("!! solar production: accumulate add %s %.3fW power (was: %s)", name, mm[i].Energy, site.pvEnergy[name])
 			site.pvEnergy[name].AddPower(mm[i].Power)
 		}
-		site.log.DEBUG.Printf("!! solar production: accumulate moved %s from %.3f to %.3f", name, prev, site.pvEnergy[name].AccumulatedEnergy())
+		site.log.DEBUG.Printf("!! solar production: accumulate moved %s from %.3f to %.3f", name, prev, site.pvEnergy[name].Imported())
 	}
 
 	// store
@@ -751,14 +761,18 @@ func (site *Site) updateGridMeter() error {
 	}
 
 	// grid energy (import)
+	var importEnergy *float64
 	if energyMeter, ok := api.Cap[api.MeterEnergy](site.gridMeter); ok {
 		if f, err := energyMeter.TotalEnergy(); err == nil {
 			mm.Energy = f
+			importEnergy = &f
 		} else {
 			site.log.ERROR.Printf("grid energy: %v", err)
 		}
 	}
 
+	site.gridEnergy.AddEnergy(importEnergy, nil, mm.Power)
+
 	site.publish(keys.Grid, mm)
 
 	return nil
@@ -791,33 +805,6 @@ func optimizerEnabled() bool {
 	return exp && opt
 }
 
-func (site *Site) updateHomeConsumption(homePower float64) {
-	site.householdEnergy.AddPower(homePower)
-
-	now := site.householdEnergy.clock.Now()
-	if site.householdSlotStart.IsZero() {
-		site.householdSlotStart = now
-		return
-	}
-
-	slotDuration := 15 * time.Minute
-	slotStart := now.Truncate(slotDuration)
-
-	if slotStart.After(site.householdSlotStart) {
-		// next slot has started
-		if slotStart.Sub(site.householdSlotStart) >= slotDuration {
-			// more or less full slot
-			site.log.DEBUG.Printf("15min household consumption: %.0fWh", site.householdEnergy.Accumulated)
-			if err := metrics.Persist(site.householdSlotStart, site.householdEnergy.Accumulated); err != nil {
-				site.log.ERROR.Printf("persist household consumption: %v", err)
-			}
-		}
-
-		site.householdSlotStart = slotStart
-		site.householdEnergy.Accumulated = 0
-	}
-}
-
 // sitePower returns
 //   - the net power exported by the site minus a residual margin
 //     (negative values mean grid: export, battery: charging
@@ -963,7 +950,9 @@ func (site *Site) update(lp updater) {
 		site.publish(keys.HomePower, homePower)
 
 		if homePower > 0 {
-			site.updateHomeConsumption(homePower)
+			if err := site.homeEnergy.AddEnergy(nil, nil, homePower); err != nil {
+				site.log.ERROR.Printf("persist home consumption: %v", err)
+			}
 		}
 
 		// add battery charging power to homePower to ignore all consumption which does not occur on loadpoints
diff --git a/core/site_optimizer.go b/core/site_optimizer.go
index ab6da5d6d..fd5df9ee0 100644
--- a/core/site_optimizer.go
+++ b/core/site_optimizer.go
@@ -15,7 +15,6 @@ import (
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/keys"
 	"github.com/evcc-io/evcc/core/loadpoint"
-	"github.com/evcc-io/evcc/core/metrics"
 	"github.com/evcc-io/evcc/core/types"
 	"github.com/evcc-io/evcc/tariff"
 	"github.com/evcc-io/evcc/util/config"
@@ -533,7 +532,7 @@ func loadpointProfile(lp loadpoint.API, minLen int) []float64 {
 // homeProfile returns the home base load in Wh
 func (site *Site) homeProfile(minLen int) ([]float64, error) {
 	// kWh over last 30 days
-	profile, err := metrics.Profile(now.BeginningOfDay().AddDate(0, 0, -30))
+	profile, err := site.homeEnergy.ImportProfile(now.BeginningOfDay().AddDate(0, 0, -30))
 	if err != nil {
 		return nil, err
 	}
diff --git a/core/site_optimizer_test.go b/core/site_optimizer_test.go
index ca8e86146..42f17b521 100644
--- a/core/site_optimizer_test.go
+++ b/core/site_optimizer_test.go
@@ -4,99 +4,14 @@ import (
 	"testing"
 	"time"
 
-	"github.com/benbjohnson/clock"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/loadpoint"
-	"github.com/evcc-io/evcc/core/metrics"
-	"github.com/evcc-io/evcc/server/db"
 	optimizer "github.com/evcc-io/optimizer/client"
-	"github.com/jinzhu/now"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/mock/gomock"
 )
 
-func TestSqliteTimestamp(t *testing.T) {
-	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
-
-	clock := clock.NewMock()
-	clock.Add(time.Hour)
-	metrics.Persist(clock.Now(), 0)
-
-	db, err := db.Instance.DB()
-	require.NoError(t, err)
-
-	var (
-		ts  metrics.SqlTime
-		val float64
-	)
-
-	for _, sql := range []string{
-		`SELECT ts, val FROM meters`,
-		`SELECT min(ts), val FROM meters`,
-		`SELECT unixepoch(ts), val FROM meters`,
-		`SELECT unixepoch(min(ts)), val FROM meters`,
-		`SELECT min(ts) AS ts, avg(val) AS val
-			FROM meters
-			GROUP BY strftime("%H:%M", ts)
-			ORDER BY ts`,
-	} {
-		require.NoError(t, db.QueryRow(sql).Scan(&ts, &val))
-		require.True(t, clock.Now().Equal(time.Time(ts)), "expected %v, got %v", clock.Now().Local(), time.Time(ts).Local())
-	}
-
-	require.NoError(t, db.QueryRow(`SELECT ts, val FROM meters WHERE ts >= ?`, clock.Now()).Scan(&ts, &val))
-	require.True(t, clock.Now().Equal(time.Time(ts)), "expected %v, got %v", clock.Now().Local(), time.Time(ts).Local())
-}
-
-func TestUpdateHouseholdProfile(t *testing.T) {
-	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
-
-	// make sure test data added starting 00:00 local time
-	clock := clock.NewMock()
-	clock.Set(now.With(clock.Now()).BeginningOfDay())
-
-	// 2 days of data
-	// day 1:   0 ...  95
-	// day 2:  96 ... 181
-	for i := range 4 * 2 * 24 {
-		metrics.Persist(clock.Now(), float64(i))
-		clock.Add(15 * time.Minute)
-	}
-
-	{
-		from := clock.Now().Local().AddDate(0, 0, -2).Add(12 * time.Hour) // 12:00 of day 0
-
-		prof, err := metrics.Profile(from)
-		require.NoError(t, err)
-
-		var expected [96]float64
-		for i := range expected {
-			if i < 48 {
-				expected[i] = float64(48+i+144+i) / 2
-				continue
-			}
-			expected[i] = float64(96 - 48 + i)
-		}
-
-		require.Equal(t, expected, *prof, "partial profile: expected %v, got %v", expected, *prof)
-	}
-
-	{
-		from := clock.Now().Local().AddDate(0, 0, -3).Add(12 * time.Hour) // 12:00 of day -1
-
-		prof, err := metrics.Profile(from)
-		require.NoError(t, err)
-
-		var expected [96]float64
-		for i := range expected {
-			expected[i] = float64(0+96+2*i) / 2
-		}
-
-		require.Equal(t, expected, *prof, "full profile: expected %v, got %v", expected, *prof)
-	}
-}
-
 func TestLoadpointProfile(t *testing.T) {
 	ctrl := gomock.NewController(t)
 
diff --git a/core/site_tariffs.go b/core/site_tariffs.go
index 28372c618..5c95ec4be 100644
--- a/core/site_tariffs.go
+++ b/core/site_tariffs.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/keys"
+	"github.com/evcc-io/evcc/core/metrics"
 	"github.com/evcc-io/evcc/server/db/settings"
 	"github.com/evcc-io/evcc/tariff"
 	"github.com/evcc-io/evcc/util"
@@ -150,20 +151,21 @@ func (site *Site) solarDetails(solar api.Rates) solarDetails {
 	}
 
 	// accumulate forecasted energy since last update
-	energy := solarEnergy(solar, site.fcstEnergy.updated, time.Now()) / 1e3
+	fcstUpdated := site.fcstEnergy.Updated()
+	energy := solarEnergy(solar, fcstUpdated, time.Now()) / 1e3
 	site.log.DEBUG.Printf("solar forecast: accumulated %.3fWh from %v to %v",
-		energy, site.fcstEnergy.updated.Truncate(time.Second), time.Now().Truncate(time.Second),
+		energy, fcstUpdated.Truncate(time.Second), time.Now().Truncate(time.Second),
 	)
 
-	site.fcstEnergy.AddEnergy(energy)
-	settings.SetFloat(keys.SolarAccForecast, site.fcstEnergy.Accumulated)
+	site.fcstEnergy.AddImportEnergy(energy)
+	settings.SetFloat(keys.SolarAccForecast, site.fcstEnergy.Imported())
 
-	produced := lo.SumBy(slices.Collect(maps.Values(site.pvEnergy)), func(v *meterEnergy) float64 {
-		return v.AccumulatedEnergy()
+	produced := lo.SumBy(slices.Collect(maps.Values(site.pvEnergy)), func(v *metrics.Accumulator) float64 {
+		return v.Imported()
 	})
 	site.log.DEBUG.Printf("solar forecast: produced %.3f", produced)
 
-	if fcst := site.fcstEnergy.AccumulatedEnergy(); fcst > 0 {
+	if fcst := site.fcstEnergy.Imported(); fcst > 0 {
 		scale := produced / fcst
 		site.log.DEBUG.Printf("solar forecast: accumulated %.3fkWh, produced %.3fkWh, scale %.3f", fcst, produced, scale)
 
diff --git a/core/site_test.go b/core/site_test.go
index e12b1233f..a1ad32903 100644
--- a/core/site_test.go
+++ b/core/site_test.go
@@ -2,16 +2,11 @@ package core
 
 import (
 	"testing"
-	"time"
 
-	"github.com/benbjohnson/clock"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/types"
-	"github.com/evcc-io/evcc/server/db"
-	"github.com/evcc-io/evcc/util"
 	"github.com/evcc-io/evcc/util/config"
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func TestGreenShare(t *testing.T) {
@@ -163,33 +158,3 @@ func TestRequiredBatteryMode(t *testing.T) {
 		assert.Equal(t, tc.res, res, "expected %s, got %s", tc.res, res)
 	}
 }
-
-func TestUpdateHomeConsumption(t *testing.T) {
-	require.NoError(t, db.NewInstance("sqlite", ":memory:"))
-
-	clock := clock.NewMock()
-
-	s := &Site{
-		log:             util.NewLogger("foo"),
-		gridPower:       4e3,
-		householdEnergy: &meterEnergy{clock: clock},
-	}
-
-	require.True(t, s.householdEnergy.updated.IsZero())
-
-	clock.Add(5 * time.Minute)
-	s.updateHomeConsumption(1e3)
-	require.False(t, s.householdEnergy.updated.IsZero())
-
-	clock.Add(5 * time.Minute)
-	s.updateHomeConsumption(1e3)
-	require.Equal(t, 1e3*5/60/1e3, s.householdEnergy.AccumulatedEnergy()) // kWh
-
-	clock.Add(5 * time.Minute)
-	s.updateHomeConsumption(1e3)
-	require.Equal(t, 0.0, s.householdEnergy.AccumulatedEnergy()) // accumulator reset after 15 minutes
-
-	clock.Add(15 * time.Minute)
-	s.updateHomeConsumption(1e3)
-	require.Equal(t, 0.0, s.householdEnergy.AccumulatedEnergy()) // accumulator reset after 15 minutes
-}
diff --git a/server/http.go b/server/http.go
index a39d2d45a..e9b557a65 100644
--- a/server/http.go
+++ b/server/http.go
@@ -159,6 +159,7 @@ func (s *HTTPd) RegisterSiteHandlers(site site.API) {
 		"updatesession":           {"PUT", "/session/{id:[0-9]+}", updateSessionHandler},
 		"deletesession":           {"DELETE", "/session/{id:[0-9]+}", deleteSessionHandler},
 		"gridsessions":            {"GET", "/gridsessions", gridSessionsHandler},
+		"energyhistory":           {"GET", "/history/energy", energyHistoryHandler},
 		"telemetry2":              {"POST", "/settings/telemetry/{value:[01truefalse]+}", boolHandler(telemetry.Enable, telemetry.Enabled)},
 	}
 
diff --git a/server/http_history_handler.go b/server/http_history_handler.go
new file mode 100644
index 000000000..174e666e1
--- /dev/null
+++ b/server/http_history_handler.go
@@ -0,0 +1,51 @@
+package server
+
+import (
+	"errors"
+	"net/http"
+	"time"
+
+	"github.com/evcc-io/evcc/core/metrics"
+	"github.com/evcc-io/evcc/server/db"
+)
+
+// energyHistoryHandler returns aggregated energy history data
+func energyHistoryHandler(w http.ResponseWriter, r *http.Request) {
+	if db.Instance == nil {
+		jsonError(w, http.StatusBadRequest, errors.New("database offline"))
+		return
+	}
+
+	q := r.URL.Query()
+
+	var from, to time.Time
+
+	if s := q.Get("from"); s != "" {
+		var err error
+		if from, err = time.Parse(time.RFC3339, s); err != nil {
+			jsonError(w, http.StatusBadRequest, errors.New("invalid 'from' parameter"))
+			return
+		}
+	}
+
+	if s := q.Get("to"); s != "" {
+		var err error
+		if to, err = time.Parse(time.RFC3339, s); err != nil {
+			jsonError(w, http.StatusBadRequest, errors.New("invalid 'to' parameter"))
+			return
+		}
+	}
+
+	aggregate := q.Get("aggregate")
+	if aggregate == "" {
+		aggregate = "15m"
+	}
+
+	res, err := metrics.QueryImportEnergy(from, to, aggregate)
+	if err != nil {
+		jsonError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	jsonWrite(w, res)
+}
diff --git a/tests/energy-history.spec.ts b/tests/energy-history.spec.ts
new file mode 100644
index 000000000..662a5ffe0
--- /dev/null
+++ b/tests/energy-history.spec.ts
@@ -0,0 +1,72 @@
+import { test, expect } from "@playwright/test";
+import { start, stop, baseUrl } from "./evcc";
+
+test.use({ baseURL: baseUrl() });
+
+const from = "2026-03-24T21:00:00+01:00";
+const to = "2026-03-25T01:00:00+01:00";
+
+test.beforeAll(async () => {
+  await start(undefined, "energy-history.sql");
+});
+test.afterAll(async () => {
+  await stop();
+});
+
+test.describe("energy history API", () => {
+  test("15-minute resolution", async ({ request }) => {
+    const res = await request.get(`${baseUrl()}/api/history/energy`, {
+      params: { from, to },
+    });
+    expect(res.ok()).toBeTruthy();
+
+    const data = await res.json();
+    expect(data).toHaveLength(2);
+
+    const grid = data.find((s: any) => s.name === "grid");
+    const home = data.find((s: any) => s.name === "home");
+    expect(grid).toBeDefined();
+    expect(home).toBeDefined();
+
+    expect(grid.data).toHaveLength(6);
+    expect(home.data).toHaveLength(6);
+
+    expect(home.data[0].import).toBeCloseTo(0.1, 4);
+    expect(home.data[0].export).toBeCloseTo(0, 4);
+    expect(grid.data[0].import).toBeCloseTo(0.5, 4);
+    expect(grid.data[0].export).toBeCloseTo(0.1, 4);
+  });
+
+  test("day aggregation", async ({ request }) => {
+    const res = await request.get(`${baseUrl()}/api/history/energy`, {
+      params: { from, to, aggregate: "day" },
+    });
+    expect(res.ok()).toBeTruthy();
+
+    const data = await res.json();
+    expect(data).toHaveLength(2);
+
+    const grid = data.find((s: any) => s.name === "grid");
+    const home = data.find((s: any) => s.name === "home");
+    expect(grid).toBeDefined();
+    expect(home).toBeDefined();
+
+    expect(grid.data).toHaveLength(2);
+    expect(home.data).toHaveLength(2);
+
+    const [homeDay1, homeDay2] = home.data;
+    const [gridDay1, gridDay2] = grid.data;
+
+    // day 1 (2026-03-24): 4 slots
+    expect(homeDay1.import).toBeCloseTo(0.4, 4);
+    expect(homeDay1.export).toBeCloseTo(0, 4);
+    expect(gridDay1.import).toBeCloseTo(2.0, 4);
+    expect(gridDay1.export).toBeCloseTo(0.4, 4);
+
+    // day 2 (2026-03-25): 2 slots
+    expect(homeDay2.import).toBeCloseTo(0.2, 4);
+    expect(homeDay2.export).toBeCloseTo(0, 4);
+    expect(gridDay2.import).toBeCloseTo(1.0, 4);
+    expect(gridDay2.export).toBeCloseTo(0.2, 4);
+  });
+});
diff --git a/tests/energy-history.sql b/tests/energy-history.sql
new file mode 100644
index 000000000..b0aeb0f26
--- /dev/null
+++ b/tests/energy-history.sql
@@ -0,0 +1,42 @@
+DROP TABLE IF EXISTS `meters`;
+DROP TABLE IF EXISTS `entities`;
+
+CREATE TABLE `entities` (
+  `id` integer,
+  `group` text,
+  `name` text,
+  PRIMARY KEY (`id`)
+);
+CREATE UNIQUE INDEX `entities_group_name` ON `entities`(`group`, `name`);
+
+CREATE TABLE `meters` (
+  `meter` integer,
+  `ts` datetime,
+  `import` real,
+  `export` real
+);
+CREATE UNIQUE INDEX `meters_meter_ts` ON `meters`(`meter`, `ts`);
+
+-- entities
+INSERT INTO `entities` VALUES (1, 'virtual', 'home');
+INSERT INTO `entities` VALUES (2, 'grid', 'grid');
+
+-- meter data: 6 slots per entity spanning midnight (local time +01:00)
+-- 2026-03-24: 22:00, 22:15, 22:30, 22:45 (4 slots)
+-- 2026-03-25: 00:00, 00:15 (2 slots)
+
+-- home (id=1): import=0.1, export=0 per slot
+INSERT INTO `meters` VALUES (1, '2026-03-24 22:00:00+01:00', 0.1, 0);
+INSERT INTO `meters` VALUES (1, '2026-03-24 22:15:00+01:00', 0.1, 0);
+INSERT INTO `meters` VALUES (1, '2026-03-24 22:30:00+01:00', 0.1, 0);
+INSERT INTO `meters` VALUES (1, '2026-03-24 22:45:00+01:00', 0.1, 0);
+INSERT INTO `meters` VALUES (1, '2026-03-25 00:00:00+01:00', 0.1, 0);
+INSERT INTO `meters` VALUES (1, '2026-03-25 00:15:00+01:00', 0.1, 0);
+
+-- grid (id=2): import=0.5, export=0.1 per slot
+INSERT INTO `meters` VALUES (2, '2026-03-24 22:00:00+01:00', 0.5, 0.1);
+INSERT INTO `meters` VALUES (2, '2026-03-24 22:15:00+01:00', 0.5, 0.1);
+INSERT INTO `meters` VALUES (2, '2026-03-24 22:30:00+01:00', 0.5, 0.1);
+INSERT INTO `meters` VALUES (2, '2026-03-24 22:45:00+01:00', 0.5, 0.1);
+INSERT INTO `meters` VALUES (2, '2026-03-25 00:00:00+01:00', 0.5, 0.1);
+INSERT INTO `meters` VALUES (2, '2026-03-25 00:15:00+01:00', 0.5, 0.1);