Add parent device to entity context

Fix energy period rollover overnight and in the first hour (#53717 )
* Fix energy dashboard staying on yesterday after midnight. * Catch up the energy live day before subscribe fetches. * Keep energy day math in the server timezone so DST cannot skip a live day. Browser-local addDays can jump a calendar day on a 23-hour DST fallback. Assert against tz-internal endOfDay/addDays under Europe/Berlin so UTC CI catches a regression, and prove the 01:00 timer and catch-up refresh fetch the live day rather than only updating collection.start. * Don't follow the live day from midnightRollover alone. A stored non-today preset would otherwise be discarded on the first subscribe. Drop tautological UTC DST tests that cannot fail.
2026-08-24 15:50:05 +00:00 · 2026-08-24 15:59:53 +02:00 · 2026-08-24 10:16:00 +02:00
30 changed files with 1121 additions and 217 deletions
@@ -12,13 +12,24 @@ import { getEntityContext } from "./context/get_entity_context";
 const DEFAULT_SEPARATOR = " ";

 export const DEFAULT_ENTITY_NAME = [
+  { type: "parent_device" },
  { type: "device" },
  { type: "entity" },
 ] satisfies EntityNameItem[];

+export const ENTITY_NAME_TYPES = [
+  "entity",
+  "device",
+  "parent_device",
+  "area",
+  "floor",
+] as const;
+
+export type EntityNameType = (typeof ENTITY_NAME_TYPES)[number];
+
 export type EntityNameItem =
  | {
-      type: "entity" | "device" | "area" | "floor";
+      type: EntityNameType;
    }
  | {
      type: "text";
@@ -91,7 +102,7 @@ export const computeEntityNameList = (
  areas: HomeAssistant["areas"],
  floors: HomeAssistant["floors"]
 ): (string | undefined)[] => {
-  const { device, area, floor } = getEntityContext(
+  const { device, parentDevice, area, floor } = getEntityContext(
    stateObj,
    entities,
    devices,
@@ -105,6 +116,8 @@ export const computeEntityNameList = (
        return computeEntityName(stateObj, entities, devices);
      case "device":
        return device ? computeDeviceName(device) : undefined;
+      case "parent_device":
+        return parentDevice ? computeDeviceName(parentDevice) : undefined;
      case "area":
        return area ? computeAreaName(area) : undefined;
      case "floor":
@@ -136,14 +149,20 @@ export const computeEntityPickerDisplay = (
  >,
  stateObj: HassEntity
 ): EntityPickerDisplay => {
-  const [entityName, deviceName, areaName] = computeEntityNameList(
-    stateObj,
-    [{ type: "entity" }, { type: "device" }, { type: "area" }],
-    hass.entities,
-    hass.devices,
-    hass.areas,
-    hass.floors
-  );
+  const [entityName, deviceName, parentDeviceName, areaName] =
+    computeEntityNameList(
+      stateObj,
+      [
+        { type: "entity" },
+        { type: "device" },
+        { type: "parent_device" },
+        { type: "area" },
+      ],
+      hass.entities,
+      hass.devices,
+      hass.areas,
+      hass.floors
+    );

  const isRTL = computeRTL(
    hass.language,
@@ -152,7 +171,7 @@ export const computeEntityPickerDisplay = (

  const primary = entityName || deviceName || stateObj.entity_id;
  const secondary =
-    [areaName, entityName ? deviceName : undefined]
+    [areaName, parentDeviceName, entityName ? deviceName : undefined]
      .filter(Boolean)
      .join(isRTL ? " ◂ " : " ▸ ") || undefined;

@@ -13,6 +13,7 @@ import { getDeviceAreaId } from "./get_device_context";
 interface EntityContext {
  entity: EntityRegistryDisplayEntry | null;
  device: DeviceRegistryEntry | null;
+  parentDevice: DeviceRegistryEntry | null;
  area: AreaRegistryEntry | null;
  floor: FloorRegistryEntry | null;
 }
@@ -31,6 +32,7 @@ export const getEntityContext = (
    return {
      entity: null,
      device: null,
+      parentDevice: null,
      area: null,
      floor: null,
    };
@@ -65,6 +67,9 @@ export const getEntityEntryContext = (
  const entity = entities[entry.entity_id];
  const deviceId = entry?.device_id;
  const device = deviceId ? devices[deviceId] : undefined;
+  const parentDevice = device?.parent_device_id
+    ? devices[device.parent_device_id]
+    : undefined;
  const areaId =
    entry?.area_id || (device ? getDeviceAreaId(device, devices) : undefined);
  const area = areaId ? areas[areaId] : undefined;
@@ -74,6 +79,7 @@ export const getEntityEntryContext = (
  return {
    entity: entity,
    device: device || null,
+    parentDevice: parentDevice || null,
    area: area || null,
    floor: floor || null,
  };
@@ -31,8 +31,6 @@ export type FormatEntityAttributeNameFunc = (
  attribute: string
 ) => string;

-export type EntityNameType = "entity" | "device" | "area" | "floor";
-
 export type FormatEntityNameFunc = (
  stateObj: HassEntity,
  name: EntityNameItem | EntityNameItem[],
@@ -7,9 +7,12 @@ import { repeat } from "lit/directives/repeat";
 import memoizeOne from "memoize-one";
 import { ensureArray } from "../../common/array/ensure-array";
 import { fireEvent } from "../../common/dom/fire_event";
-import type { EntityNameItem } from "../../common/entity/compute_entity_name_display";
+import {
+  ENTITY_NAME_TYPES,
+  type EntityNameItem,
+  type EntityNameType,
+} from "../../common/entity/compute_entity_name_display";
 import { getEntityContext } from "../../common/entity/context/get_entity_context";
-import type { EntityNameType } from "../../common/translations/entity-state";
 import type { LocalizeKeys } from "../../common/translations/localize";
 import type { HomeAssistant, ValueChangedEvent } from "../../types";
 import "../chips/ha-assist-chip";
@@ -35,9 +38,7 @@ const rowRenderer: RenderItemFunction<PickerComboBoxItem> = (item) => html`
  </ha-combo-box-item>
 `;

-const KNOWN_TYPES = new Set(["entity", "device", "area", "floor"]);
-
-const UNIQUE_TYPES = new Set(["entity", "device", "area", "floor"]);
+const KNOWN_TYPES = new Set<string>(ENTITY_NAME_TYPES);

 const formatOptionValue = (item: EntityNameItem) => {
  if (item.type === "text" && item.text) {
@@ -387,6 +388,7 @@ export class HaEntityNamePicker extends LitElement {
    );

    if (context.device) options.add("device");
+    if (context.parentDevice) options.add("parent_device");
    if (context.area) options.add("area");
    if (context.floor) options.add("floor");
    return options;
@@ -399,9 +401,7 @@ export class HaEntityNamePicker extends LitElement {

    const types = this._validTypes(entityId);

-    const items = (
-      ["entity", "device", "area", "floor"] as const
-    ).map<PickerComboBoxItem>((name) => {
+    const items = ENTITY_NAME_TYPES.map<PickerComboBoxItem>((name) => {
      const stateObj = this.hass.states[entityId];
      const isValid = types.has(name);
      const primary = this.hass.localize(
@@ -464,7 +464,7 @@ export class HaEntityNamePicker extends LitElement {

    const excludedValues = new Set(
      this._items
-        .filter((item) => UNIQUE_TYPES.has(item.type))
+        .filter((item) => KNOWN_TYPES.has(item.type))
        .map((item) => formatOptionValue(item))
    );

@@ -178,6 +178,17 @@ export class HaStateContentPicker extends LitElement {
                  ),
                });
              }
+              if (context.parentDevice) {
+                contextItems.push({
+                  id: "parent_device_name",
+                  primary: this.hass.localize(
+                    "ui.components.state-content-picker.parent_device_name"
+                  ),
+                  sorting_label: this.hass.localize(
+                    "ui.components.state-content-picker.parent_device_name"
+                  ),
+                });
+              }
              if (context.area) {
                contextItems.push({
                  id: "area_name",
@@ -52,6 +52,7 @@ const SEARCH_KEYS = [
  { name: "search_labels.entityName", weight: 10 },
  { name: "search_labels.friendlyName", weight: 9 },
  { name: "search_labels.deviceName", weight: 8 },
+  { name: "search_labels.parentDeviceName", weight: 6 },
  { name: "search_labels.areaName", weight: 6 },
  { name: "search_labels.domainName", weight: 4 },
  { name: "statisticId", weight: 3 },
@@ -292,17 +293,27 @@ export class HaStatisticPicker extends LitElement {

        const friendlyName = computeStateName(stateObj); // Keep this for search

-        const [entityName, deviceName, areaName] = computeEntityNameList(
-          stateObj,
-          [{ type: "entity" }, { type: "device" }, { type: "area" }],
-          hass.entities,
-          hass.devices,
-          hass.areas,
-          hass.floors
-        );
+        const [entityName, deviceName, parentDeviceName, areaName] =
+          computeEntityNameList(
+            stateObj,
+            [
+              { type: "entity" },
+              { type: "device" },
+              { type: "parent_device" },
+              { type: "area" },
+            ],
+            hass.entities,
+            hass.devices,
+            hass.areas,
+            hass.floors
+          );

        const primary = entityName || deviceName || id;
-        const secondary = [areaName, entityName ? deviceName : undefined]
+        const secondary = [
+          areaName,
+          parentDeviceName,
+          entityName ? deviceName : undefined,
+        ]
          .filter(Boolean)
          .join(isRTL ? " ◂ " : " ▸ ");

@@ -318,6 +329,7 @@ export class HaStatisticPicker extends LitElement {
          search_labels: {
            entityName: entityName || null,
            deviceName: deviceName || null,
+            parentDeviceName: parentDeviceName || null,
            areaName: areaName || null,
            friendlyName,
          },
@@ -395,14 +407,20 @@ export class HaStatisticPicker extends LitElement {
    const stateObj = this.hass.states[statisticId];

    if (stateObj) {
-      const [entityName, deviceName, areaName] = computeEntityNameList(
-        stateObj,
-        [{ type: "entity" }, { type: "device" }, { type: "area" }],
-        this.hass.entities,
-        this.hass.devices,
-        this.hass.areas,
-        this.hass.floors
-      );
+      const [entityName, deviceName, parentDeviceName, areaName] =
+        computeEntityNameList(
+          stateObj,
+          [
+            { type: "entity" },
+            { type: "device" },
+            { type: "parent_device" },
+            { type: "area" },
+          ],
+          this.hass.entities,
+          this.hass.devices,
+          this.hass.areas,
+          this.hass.floors
+        );

      const isRTL = computeRTL(
        this.hass.language,
@@ -410,7 +428,11 @@ export class HaStatisticPicker extends LitElement {
      );

      const primary = entityName || deviceName || statisticId;
-      const secondary = [areaName, entityName ? deviceName : undefined]
+      const secondary = [
+        areaName,
+        parentDeviceName,
+        entityName ? deviceName : undefined,
+      ]
        .filter(Boolean)
        .join(isRTL ? " ◂ " : " ▸ ");
      const friendlyName = computeStateName(stateObj); // Keep this for search
@@ -427,6 +449,7 @@ export class HaStatisticPicker extends LitElement {
        search_labels: {
          entityName: entityName || null,
          deviceName: deviceName || null,
+          parentDeviceName: parentDeviceName || null,
          areaName: areaName || null,
          friendlyName,
          statisticId,
@@ -197,17 +197,27 @@ export class HaAreaControlsPicker extends LitElement {
              return;
            }

-            const [entityName, deviceName, areaName] = computeEntityNameList(
-              stateObj,
-              [{ type: "entity" }, { type: "device" }, { type: "area" }],
-              this.hass!.entities,
-              this.hass!.devices,
-              this.hass!.areas,
-              this.hass!.floors
-            );
+            const [entityName, deviceName, parentDeviceName, areaName] =
+              computeEntityNameList(
+                stateObj,
+                [
+                  { type: "entity" },
+                  { type: "device" },
+                  { type: "parent_device" },
+                  { type: "area" },
+                ],
+                this.hass!.entities,
+                this.hass!.devices,
+                this.hass!.areas,
+                this.hass!.floors
+              );

            const primary = entityName || deviceName || entityId;
-            const secondary = [areaName, entityName ? deviceName : undefined]
+            const secondary = [
+              areaName,
+              parentDeviceName,
+              entityName ? deviceName : undefined,
+            ]
              .filter(Boolean)
              .join(isRTL ? " ◂ " : " ▸ ");

@@ -761,6 +761,9 @@ export class HaCodeEditor extends ReactiveElement {
    const deviceName = context.device
      ? computeDeviceName(context.device)
      : undefined;
+    const parentDeviceName = context.parentDevice
+      ? computeDeviceName(context.parentDevice)
+      : undefined;
    const areaName = context.area ? computeAreaName(context.area) : undefined;
    const floorName = context.floor
      ? computeFloorName(context.floor)
@@ -788,6 +791,15 @@ export class HaCodeEditor extends ReactiveElement {
      });
    }

+    if (parentDeviceName) {
+      completionItems.push({
+        label: this._i18n!.localize(
+          "ui.components.device-picker.parent_device"
+        ),
+        value: parentDeviceName,
+      });
+    }
+
    if (deviceName) {
      completionItems.push({
        label: this._i18n!.localize("ui.components.device-picker.device"),
@@ -129,21 +129,31 @@ export class HaMediaPlayerPicker extends LitElement {
        .filter(this._filterPlayerEntities)
        .map<MediaPlayerComboBoxItem>((stateObj) => {
          const friendlyName = computeStateName(stateObj);
-          const [entityName, deviceName, areaName] = computeEntityNameList(
-            stateObj,
-            [{ type: "entity" }, { type: "device" }, { type: "area" }],
-            this._entities,
-            this._devices,
-            this._areas,
-            this._floors
-          );
+          const [entityName, deviceName, parentDeviceName, areaName] =
+            computeEntityNameList(
+              stateObj,
+              [
+                { type: "entity" },
+                { type: "device" },
+                { type: "parent_device" },
+                { type: "area" },
+              ],
+              this._entities,
+              this._devices,
+              this._areas,
+              this._floors
+            );
          const entityId = stateObj.entity_id;
          const domainName = domainToName(
            this._i18n.localize,
            computeDomain(entityId)
          );
          const primary = entityName || deviceName || entityId;
-          const secondary = [areaName, entityName ? deviceName : undefined]
+          const secondary = [
+            areaName,
+            parentDeviceName,
+            entityName ? deviceName : undefined,
+          ]
            .filter(Boolean)
            .join(isRTL ? " ◂ " : " ▸ ");

@@ -157,6 +167,7 @@ export class HaMediaPlayerPicker extends LitElement {
            search_labels: {
              entityName: entityName || null,
              deviceName: deviceName || null,
+              parentDeviceName: parentDeviceName || null,
              areaName: areaName || null,
              domainName: domainName || null,
              friendlyName: friendlyName || null,
@@ -62,17 +62,27 @@ class HaMediaPlayerToggle extends LitElement {
      isRTL: boolean,
      stateObj: HassEntity
    ) => {
-      const [entityName, deviceName, areaName] = computeEntityNameList(
-        stateObj,
-        [{ type: "entity" }, { type: "device" }, { type: "area" }],
-        entities,
-        devices,
-        areas,
-        floors
-      );
+      const [entityName, deviceName, parentDeviceName, areaName] =
+        computeEntityNameList(
+          stateObj,
+          [
+            { type: "entity" },
+            { type: "device" },
+            { type: "parent_device" },
+            { type: "area" },
+          ],
+          entities,
+          devices,
+          areas,
+          floors
+        );

      const primary = entityName || deviceName || entityId;
-      const secondary = [areaName, entityName ? deviceName : undefined]
+      const secondary = [
+        areaName,
+        parentDeviceName,
+        entityName ? deviceName : undefined,
+      ]
        .filter(Boolean)
        .join(isRTL ? " ◂ " : " ▸ ");

@@ -683,7 +683,7 @@ export class HaTargetPickerItemRow extends LitElement {
      const entityName = stateObject
        ? computeEntityName(stateObject, this.hass.entities, this.hass.devices)
        : item;
-      const { area, device } = stateObject
+      const { area, device, parentDevice } = stateObject
        ? getEntityContext(
            stateObject,
            this.hass.entities,
@@ -691,10 +691,17 @@ export class HaTargetPickerItemRow extends LitElement {
            this.hass.areas,
            this.hass.floors
          )
-        : { area: undefined, device: undefined };
+        : { area: undefined, device: undefined, parentDevice: undefined };
      const deviceName = device ? computeDeviceName(device) : undefined;
+      const parentDeviceName = parentDevice
+        ? computeDeviceName(parentDevice)
+        : undefined;
      const areaName = area ? computeAreaName(area) : undefined;
-      const context = [areaName, entityName ? deviceName : undefined]
+      const context = [
+        areaName,
+        parentDeviceName,
+        entityName ? deviceName : undefined,
+      ]
        .filter(Boolean)
        .join(
          computeRTL(
@@ -21,7 +21,6 @@ import {
 } from "../common/datetime/calc_date";
 import type { DateRange } from "../common/datetime/calc_date_range";
 import { calcDateRange } from "../common/datetime/calc_date_range";
-import { formatTime24h } from "../common/datetime/format_time";
 import { DEFAULT_ENTITY_NAME } from "../common/entity/compute_entity_name_display";
 import { formatNumber } from "../common/number/format_number";
 import { normalizeValueBySIPrefix } from "../common/number/normalize-by-si-prefix";
@@ -799,8 +798,8 @@ const clearEnergyCollectionPreferences = (hass: HomeAssistant) => {
 };

 const scheduleHourlyRefresh = (collection: EnergyCollection) => {
-  if (collection._refreshTimeout) {
-    clearTimeout(collection._refreshTimeout);
+  if (collection._refreshTimeout !== undefined) {
+    window.clearTimeout(collection._refreshTimeout);
  }

  if (collection._active && (!collection.end || collection.end > new Date())) {
@@ -859,18 +858,92 @@ export const getEnergyDefaultPeriodStorageKey = (
  return `energy-default-period-${key}`;
 };

-// When does the collection's day period need to roll over to the next day?
-// With `midnightRollover` (the real-time "Now" view) it rolls over right at
-// midnight. Otherwise it waits an hour, until the new day's first hourly
-// statistic exists — rolling over at midnight would show an empty graph.
-export const getNextEnergyPeriodStart = (
+// When today's first hourly statistic becomes available (01:00 in the
+// configured timezone). Rolling the statistics view over at midnight would
+// show an empty graph.
+export const getEnergyFirstStatisticAt = (
+  now: Date,
+  locale: HomeAssistant["locale"],
+  config: HomeAssistant["config"]
+): Date => addHours(calcDate(now, startOfDay, locale, config), 1);
+
+// The statistics Energy view shows yesterday until 01:00 so the graph is not
+// empty. The real-time "Now" view never does this — it has live data.
+export const shouldFallbackEnergyPeriodToYesterday = (
  midnightRollover: boolean,
  now: Date,
  locale: HomeAssistant["locale"],
  config: HomeAssistant["config"]
+): boolean =>
+  !midnightRollover &&
+  now.getTime() < getEnergyFirstStatisticAt(now, locale, config).getTime();
+
+// Live day used while a rollover timer is scheduled (today, or the hour-0
+// yesterday fallback). Custom dates do not use this. If the user already
+// picked today during hour 0, keep today rather than snapping back.
+export const getEnergyLiveDayPeriod = (
+  midnightRollover: boolean,
+  now: Date,
+  locale: HomeAssistant["locale"],
+  config: HomeAssistant["config"],
+  currentStart: Date
+): { start: Date; end: Date } => {
+  const todayStart = calcDate(now, startOfDay, locale, config);
+  if (
+    shouldFallbackEnergyPeriodToYesterday(
+      midnightRollover,
+      now,
+      locale,
+      config
+    ) &&
+    currentStart.getTime() !== todayStart.getTime()
+  ) {
+    const yesterday = calcDate(now, addDays, locale, config, -1);
+    return {
+      start: calcDate(yesterday, startOfDay, locale, config),
+      end: calcDate(yesterday, endOfDay, locale, config),
+    };
+  }
+  return {
+    start: todayStart,
+    end: calcDate(now, endOfDay, locale, config),
+  };
+};
+
+// When does the collection's day period need to roll over to the next day?
+// With `midnightRollover` (the real-time "Now" view) it rolls over right at
+// midnight. Otherwise it waits an hour, until the new day's first hourly
+// statistic exists — rolling over at midnight would show an empty graph.
+// Pass `periodStart` when the collection is on a specific day: hour-0
+// yesterday (and any older stale live day) must wake at today 01:00, not
+// tomorrow 01:00. Keep tomorrow 01:00 only when the user already picked today.
+export const getNextEnergyPeriodStart = (
+  midnightRollover: boolean,
+  now: Date,
+  locale: HomeAssistant["locale"],
+  config: HomeAssistant["config"],
+  periodStart?: Date
 ): Date => {
-  const dayEnd = calcDate(now, endOfDay, locale, config);
-  return midnightRollover ? addMilliseconds(dayEnd, 1) : addHours(dayEnd, 1);
+  const todayStart = calcDate(now, startOfDay, locale, config);
+  if (
+    periodStart &&
+    shouldFallbackEnergyPeriodToYesterday(
+      midnightRollover,
+      now,
+      locale,
+      config
+    ) &&
+    periodStart.getTime() !== todayStart.getTime()
+  ) {
+    return getEnergyFirstStatisticAt(now, locale, config);
+  }
+  // Next midnight in the configured zone, not browser-local addDays, so a
+  // DST transition cannot skip a server-tz day.
+  const nextMidnight = addMilliseconds(
+    calcDate(now, endOfDay, locale, config),
+    1
+  );
+  return midnightRollover ? nextMidnight : addHours(nextMidnight, 1);
 };

 export const getEnergyDataCollection = (
@@ -929,12 +1002,80 @@ export const getEnergyDataCollection = (
    }
  ) as EnergyCollection;

+  collection._active = 0;
+  collection.prefs = options.prefs;
+
+  // True while the collection is tracking the rolling "today" (or hour-0
+  // yesterday) day. Cleared when the user picks a custom range.
+  let followLiveDay = false;
+
+  const applyLiveDayPeriod = (now: Date): boolean => {
+    const live = getEnergyLiveDayPeriod(
+      midnightRollover,
+      now,
+      hass.locale,
+      hass.config,
+      collection.start
+    );
+    const changed =
+      collection.start.getTime() !== live.start.getTime() ||
+      collection.end?.getTime() !== live.end.getTime();
+    collection.start = live.start;
+    collection.end = live.end;
+    return changed;
+  };
+
+  const clearUpdatePeriodTimeout = () => {
+    if (collection._updatePeriodTimeout !== undefined) {
+      window.clearTimeout(collection._updatePeriodTimeout);
+      collection._updatePeriodTimeout = undefined;
+    }
+  };
+
+  const scheduleUpdatePeriod = () => {
+    clearUpdatePeriodTimeout();
+    const scheduledAt = new Date();
+    collection._updatePeriodTimeout = window.setTimeout(
+      () => {
+        if (applyLiveDayPeriod(new Date())) {
+          collection.refresh();
+        }
+        scheduleUpdatePeriod();
+      },
+      Math.max(
+        0,
+        getNextEnergyPeriodStart(
+          midnightRollover,
+          scheduledAt,
+          hass.locale,
+          hass.config,
+          collection.start
+        ).getTime() - scheduledAt.getTime()
+      )
+    );
+  };
+
  const origSubscribe = collection.subscribe;

  collection.subscribe = (subscriber: (data: EnergyData) => void) => {
+    // Catch up before origSubscribe so the first fetch uses the live day.
+    // Refresh only when state already exists: cold subscribe fetches via
+    // origSubscribe; a re-subscribe inside the 5s unsub grace does not.
+    const needsRefresh =
+      followLiveDay &&
+      applyLiveDayPeriod(new Date()) &&
+      collection.state !== undefined;
+    if (followLiveDay) {
+      scheduleUpdatePeriod();
+    }
+
    const unsub = origSubscribe(subscriber);
    collection._active++;

+    if (needsRefresh) {
+      collection.refresh();
+    }
+
    if (collection._refreshTimeout === undefined) {
      scheduleHourlyRefresh(collection);
    }
@@ -942,79 +1083,55 @@ export const getEnergyDataCollection = (
    return () => {
      collection._active--;
      if (collection._active < 1) {
-        clearTimeout(collection._refreshTimeout);
-        collection._refreshTimeout = undefined;
+        if (collection._refreshTimeout !== undefined) {
+          window.clearTimeout(collection._refreshTimeout);
+          collection._refreshTimeout = undefined;
+        }
+        clearUpdatePeriodTimeout();
      }
      unsub();
    };
  };

-  collection._active = 0;
-  collection.prefs = options.prefs;
-
-  const now = new Date();
-  const hour = formatTime24h(now, hass.locale, hass.config).split(":")[0];
  // Set start to start of today if we have data for today, otherwise yesterday.
  // The real-time "Now" view always tracks today; it shows live data even
  // before today's first statistic exists, so it never falls back to yesterday.
+  const now = new Date();
  const preferredPeriod =
    (localStorage.getItem(
      getEnergyDefaultPeriodStorageKey(hass, options.key)
    ) as DateRange) || "today";
  const period =
-    preferredPeriod === "today" && hour === "0" && !midnightRollover
+    preferredPeriod === "today" &&
+    shouldFallbackEnergyPeriodToYesterday(
+      midnightRollover,
+      now,
+      hass.locale,
+      hass.config
+    )
      ? "yesterday"
      : preferredPeriod;

  const [start, end] = calcDateRange(hass.locale, hass.config, period);
  collection.start = calcDate(start, startOfDay, hass.locale, hass.config);
  collection.end = calcDate(end, endOfDay, hass.locale, hass.config);
-
-  const scheduleUpdatePeriod = () => {
-    collection._updatePeriodTimeout = window.setTimeout(
-      () => {
-        collection.start = calcDate(
-          new Date(),
-          startOfDay,
-          hass.locale,
-          hass.config
-        );
-        collection.end = calcDate(
-          new Date(),
-          endOfDay,
-          hass.locale,
-          hass.config
-        );
-        collection.refresh();
-        scheduleUpdatePeriod();
-      },
-      getNextEnergyPeriodStart(
-        midnightRollover,
-        new Date(),
-        hass.locale,
-        hass.config
-      ).getTime() - Date.now()
-    );
-  };
-  scheduleUpdatePeriod();
+  followLiveDay = preferredPeriod === "today";

  collection.isActive = () => !!collection._active;
  collection.clearPrefs = () => {
    collection.prefs = undefined;
  };
  collection.setPeriod = (newStart: Date, newEnd?: Date) => {
-    if (collection._updatePeriodTimeout) {
-      clearTimeout(collection._updatePeriodTimeout);
-      collection._updatePeriodTimeout = undefined;
-    }
+    clearUpdatePeriodTimeout();
    collection.start = newStart;
    collection.end = newEnd;
-    if (
+    const periodNow = new Date();
+    followLiveDay =
      collection.start.getTime() ===
-        calcDate(new Date(), startOfDay, hass.locale, hass.config).getTime() &&
+        calcDate(periodNow, startOfDay, hass.locale, hass.config).getTime() &&
      collection.end?.getTime() ===
-        calcDate(new Date(), endOfDay, hass.locale, hass.config).getTime()
-    ) {
+        calcDate(periodNow, endOfDay, hass.locale, hass.config).getTime();
+    if (followLiveDay) {
      scheduleUpdatePeriod();
    }
  };
@@ -31,6 +31,10 @@ export const entityComboBoxKeys: FuseWeightedKey[] = [
    name: "search_labels.deviceName",
    weight: 7,
  },
+  {
+    name: "search_labels.parentDeviceName",
+    weight: 6,
+  },
  {
    name: "search_labels.areaName",
    weight: 6,
@@ -129,14 +133,20 @@ export const getEntities = (
    const stateObj = hass.states[entityId];

    const friendlyName = computeStateName(stateObj); // Keep this for search
-    const [entityName, deviceName, areaName] = computeEntityNameList(
-      stateObj,
-      [{ type: "entity" }, { type: "device" }, { type: "area" }],
-      hass.entities,
-      hass.devices,
-      hass.areas,
-      hass.floors
-    );
+    const [entityName, deviceName, parentDeviceName, areaName] =
+      computeEntityNameList(
+        stateObj,
+        [
+          { type: "entity" },
+          { type: "device" },
+          { type: "parent_device" },
+          { type: "area" },
+        ],
+        hass.entities,
+        hass.devices,
+        hass.areas,
+        hass.floors
+      );

    const domain = computeDomain(entityId);
    let domainName = domainNames.get(domain);
@@ -146,7 +156,11 @@ export const getEntities = (
    }

    const primary = entityName || deviceName || entityId;
-    const secondary = [areaName, entityName ? deviceName : undefined]
+    const secondary = [
+      areaName,
+      parentDeviceName,
+      entityName ? deviceName : undefined,
+    ]
      .filter(Boolean)
      .join(isRTL ? " ◂ " : " ▸ ");

@@ -159,6 +173,7 @@ export const getEntities = (
      search_labels: {
        entityName: entityName || null,
        deviceName: deviceName || null,
+        parentDeviceName: parentDeviceName || null,
        areaName: areaName || null,
        domainName: domainName || null,
        friendlyName: friendlyName || null,
@@ -1,5 +1,6 @@
 import { ensureArray } from "../../common/array/ensure-array";
 import { computeAreaName } from "../../common/entity/compute_area_name";
+import { DEFAULT_ENTITY_NAME } from "../../common/entity/compute_entity_name_display";
 import { blankBeforeUnit } from "../../common/translations/blank_before_unit";
 import type { HomeAssistant } from "../../types";
 import type { Selector } from "../selector";
@@ -82,10 +83,7 @@ export const formatSelectorValue = (
        if (!stateObj) {
          return entityId;
        }
-        const name = hass.formatEntityName(stateObj, [
-          { type: "device" },
-          { type: "entity" },
-        ]);
+        const name = hass.formatEntityName(stateObj, DEFAULT_ENTITY_NAME);
        return name || entityId;
      })
      .join(", ");
@@ -74,7 +74,7 @@ class HaMoreInfoDetails extends LitElement {
      attributes,
      yamlData: stateYamlData,
    } = this._getDetailData(this._stateObj);
-    const { floor, area, device } = getEntityContext(
+    const { floor, area, device, parentDevice } = getEntityContext(
      this._stateObj,
      this.hass.entities,
      this.hass.devices,
@@ -83,6 +83,13 @@ class HaMoreInfoDetails extends LitElement {
    );
    const floorName = floor ? computeFloorName(floor) : undefined;
    const areaName = area ? (computeAreaName(area) ?? area.area_id) : undefined;
+    const parentDeviceName = parentDevice
+      ? computeDeviceNameDisplay(
+          parentDevice,
+          this.hass.localize,
+          this.hass.states
+        )
+      : undefined;
    const deviceName = device
      ? computeDeviceNameDisplay(device, this.hass.localize, this.hass.states)
      : undefined;
@@ -112,6 +119,13 @@ class HaMoreInfoDetails extends LitElement {
        href: `/config/areas/area/${area.area_id}`,
      });
    }
+    if (parentDevice && parentDeviceName) {
+      contextEntries.push({
+        translationKey: "ui.dialogs.more_info_control.parent_device",
+        value: parentDeviceName,
+        href: `/config/devices/device/${parentDevice.id}`,
+      });
+    }
    if (device && deviceName) {
      contextEntries.push({
        translationKey: "ui.components.related-items.device",
@@ -145,6 +159,7 @@ class HaMoreInfoDetails extends LitElement {
            context: {
              ...(floorName ? { floor: floorName } : {}),
              ...(areaName ? { area: areaName } : {}),
+              ...(parentDeviceName ? { parent_device: parentDeviceName } : {}),
              ...(deviceName ? { device: deviceName } : {}),
              ...(integrationName ? { integration: integrationName } : {}),
            },
@@ -615,11 +615,17 @@ export class MoreInfoDialog extends DirtyStateProviderMixin<
    const deviceName = context?.device
      ? computeDeviceName(context.device)
      : undefined;
+    const parentDeviceName = context?.parentDevice
+      ? computeDeviceName(context.parentDevice)
+      : undefined;
    const areaName = context?.area ? computeAreaName(context.area) : undefined;

-    const breadcrumb = [areaName, deviceName, entityName].filter(
-      (v): v is string => Boolean(v)
-    );
+    const breadcrumb = [
+      areaName,
+      parentDeviceName,
+      deviceName,
+      entityName,
+    ].filter((v): v is string => Boolean(v));
    const defaultTitle = breadcrumb.pop() || entityId;
    const addToTitle = this.hass.localize(
      "ui.dialogs.more_info_control.add_to.title",
@@ -977,16 +977,26 @@ class DialogAddAutomationElement
            );
          } else {
            const stateObj = this.hass.states[targetId];
-            const [entityName, deviceName, areaName] = computeEntityNameList(
-              stateObj,
-              [{ type: "entity" }, { type: "device" }, { type: "area" }],
-              this.hass.entities,
-              this.hass.devices,
-              this.hass.areas,
-              this.hass.floors
-            );
+            const [entityName, deviceName, parentDeviceName, areaName] =
+              computeEntityNameList(
+                stateObj,
+                [
+                  { type: "entity" },
+                  { type: "device" },
+                  { type: "parent_device" },
+                  { type: "area" },
+                ],
+                this.hass.entities,
+                this.hass.devices,
+                this.hass.areas,
+                this.hass.floors
+              );

-            subtitle = [areaName, entityName ? deviceName : undefined]
+            subtitle = [
+              areaName,
+              parentDeviceName,
+              entityName ? deviceName : undefined,
+            ]
              .filter(Boolean)
              .join(
                computeRTL(
@@ -31,6 +31,7 @@ const SEARCH_KEYS = [
  { name: "search_labels.entityName", weight: 10 },
  { name: "search_labels.friendlyName", weight: 9 },
  { name: "search_labels.deviceName", weight: 8 },
+  { name: "search_labels.parentDeviceName", weight: 6 },
  { name: "search_labels.areaName", weight: 6 },
  { name: "search_labels.domainName", weight: 4 },
  { name: "id", weight: 2 },
@@ -64,14 +65,20 @@ export class HaEnergyUpstreamDevicePicker extends LitElement {
    const stateObj = this.hass.states[statisticId];

    if (stateObj) {
-      const [entityName, deviceName, areaName] = computeEntityNameList(
-        stateObj,
-        [{ type: "entity" }, { type: "device" }, { type: "area" }],
-        this.hass.entities,
-        this.hass.devices,
-        this.hass.areas,
-        this.hass.floors
-      );
+      const [entityName, deviceName, parentDeviceName, areaName] =
+        computeEntityNameList(
+          stateObj,
+          [
+            { type: "entity" },
+            { type: "device" },
+            { type: "parent_device" },
+            { type: "area" },
+          ],
+          this.hass.entities,
+          this.hass.devices,
+          this.hass.areas,
+          this.hass.floors
+        );

      const friendlyName = computeStateName(stateObj); // Keep this for search

@@ -89,6 +96,7 @@ export class HaEnergyUpstreamDevicePicker extends LitElement {
        search_labels: {
          entityName: entityName || null,
          deviceName: deviceName || null,
+          parentDeviceName: parentDeviceName || null,
          areaName: areaName || null,
          friendlyName,
        },
@@ -160,11 +160,17 @@ export class DialogVacuumSegmentMapping
    const deviceName = context?.device
      ? computeDeviceName(context.device)
      : undefined;
+    const parentDeviceName = context?.parentDevice
+      ? computeDeviceName(context.parentDevice)
+      : undefined;
    const areaName = context?.area ? computeAreaName(context.area) : undefined;

-    const breadcrumb = [areaName, deviceName, entityName].filter(
-      (v): v is string => Boolean(v)
-    );
+    const breadcrumb = [
+      areaName,
+      parentDeviceName,
+      deviceName,
+      entityName,
+    ].filter((v): v is string => Boolean(v));

    return html`
      <ha-dialog
@@ -195,7 +195,12 @@ class DialogExposeEntity extends DirtyStateProviderMixin<string[]>()(

        const nameList = computeEntityNameList(
          entity,
-          [{ type: "entity" }, { type: "device" }, { type: "area" }],
+          [
+            { type: "entity" },
+            { type: "device" },
+            { type: "parent_device" },
+            { type: "area" },
+          ],
          this._registries.entities,
          this._registries.devices,
          this._registries.areas,
@@ -218,13 +223,18 @@ class DialogExposeEntity extends DirtyStateProviderMixin<string[]>()(
          continue;
        }

-        const [, deviceName, areaName] = nameList;
+        const [, deviceName, parentDeviceName, areaName] = nameList;

        if (deviceName?.toLowerCase().includes(lowerFilter)) {
          result.push({ entity, nameList });
          continue;
        }

+        if (parentDeviceName?.toLowerCase().includes(lowerFilter)) {
+          result.push({ entity, nameList });
+          continue;
+        }
+
        if (areaName?.toLowerCase().includes(lowerFilter)) {
          result.push({ entity, nameList });
          continue;
@@ -237,14 +247,18 @@ class DialogExposeEntity extends DirtyStateProviderMixin<string[]>()(

  private _renderItem = (item: FilteredEntity) => {
    const { entity: entityState, nameList } = item;
-    const [entityName, deviceName, areaName] = nameList;
+    const [entityName, deviceName, parentDeviceName, areaName] = nameList;

    const isRTL = computeRTL(
      this._i18n.language,
      this._i18n.translationMetadata.translations
    );
    const primary = entityName || deviceName || entityState.entity_id;
-    const context = [areaName, entityName ? deviceName : undefined]
+    const context = [
+      areaName,
+      parentDeviceName,
+      entityName ? deviceName : undefined,
+    ]
      .filter(Boolean)
      .join(isRTL ? " ◂ " : " ▸ ");
    const showEntityId = this._config?.userData?.showEntityIdPicker;
@@ -63,8 +63,8 @@ export class HuiEntityEditor extends LitElement {
      this.hass.formatEntityName(
        stateObj,
        useDeviceName
-          ? [{ type: "area" }]
-          : [{ type: "area" }, { type: "device" }],
+          ? [{ type: "area" }, { type: "parent_device" }]
+          : [{ type: "area" }, { type: "parent_device" }, { type: "device" }],
        {
          separator: isRTL ? " ◂ " : " ▸ ",
        }
@@ -32,6 +32,7 @@ interface EntityPickerTableRowData extends DataTableRowData {
  name: string;
  entity_name?: string;
  device_name?: string;
+  parent_device_name?: string;
  area_name?: string;
  domain_name: string;
  last_changed: string;
@@ -60,14 +61,20 @@ export class HuiEntityPickerTable extends LitElement {
        (entity) => {
          const stateObj = this.hass.states[entity];

-          const [entityName, deviceName, areaName] = computeEntityNameList(
-            stateObj,
-            [{ type: "entity" }, { type: "device" }, { type: "area" }],
-            this.hass.entities,
-            this.hass.devices,
-            this.hass.areas,
-            this.hass.floors
-          );
+          const [entityName, deviceName, parentDeviceName, areaName] =
+            computeEntityNameList(
+              stateObj,
+              [
+                { type: "entity" },
+                { type: "device" },
+                { type: "parent_device" },
+                { type: "area" },
+              ],
+              this.hass.entities,
+              this.hass.devices,
+              this.hass.areas,
+              this.hass.floors
+            );
          const name = [deviceName, entityName].filter(Boolean).join(" ");
          const domain = computeDomain(entity);

@@ -78,6 +85,7 @@ export class HuiEntityPickerTable extends LitElement {
            name: name,
            entity_name: entityName,
            device_name: deviceName,
+            parent_device_name: parentDeviceName,
            area_name: areaName,
            domain_name: domainToName(localize, domain),
            last_changed: stateObj!.last_changed,
@@ -152,6 +160,7 @@ export class HuiEntityPickerTable extends LitElement {
              entity.entity_name || entity.device_name || entity.entity_id;
            const secondary = [
              entity.area_name,
+              entity.parent_device_name,
              entity.entity_name ? entity.device_name : undefined,
            ]
              .filter(Boolean)
@@ -191,6 +200,12 @@ export class HuiEntityPickerTable extends LitElement {
        hidden: true,
      };

+      columns.parent_device_name = {
+        title: "parent_device_name",
+        filterable: true,
+        hidden: true,
+      };
+
      columns.area_name = {
        title: "area_name",
        filterable: true,
@@ -172,14 +172,20 @@ export class HuiHeadingBadgesEditor extends LitElement {
      `;
    }

-    const [entityName, deviceName, areaName] = computeEntityNameList(
-      stateObj,
-      [{ type: "entity" }, { type: "device" }, { type: "area" }],
-      this.hass.entities,
-      this.hass.devices,
-      this.hass.areas,
-      this.hass.floors
-    );
+    const [entityName, deviceName, parentDeviceName, areaName] =
+      computeEntityNameList(
+        stateObj,
+        [
+          { type: "entity" },
+          { type: "device" },
+          { type: "parent_device" },
+          { type: "area" },
+        ],
+        this.hass.entities,
+        this.hass.devices,
+        this.hass.areas,
+        this.hass.floors
+      );

    const isRTL = computeRTL(
      this.hass.language,
@@ -187,7 +193,11 @@ export class HuiHeadingBadgesEditor extends LitElement {
    );

    const primary = entityName || deviceName || entityId;
-    const secondary = [entityName ? deviceName : undefined, areaName]
+    const secondary = [
+      entityName ? deviceName : undefined,
+      parentDeviceName,
+      areaName,
+    ]
      .filter(Boolean)
      .join(isRTL ? " ◂ " : " ▸ ");

@@ -1,4 +1,5 @@
-import { array, literal, object, string, union } from "superstruct";
+import { array, enums, literal, object, string, union } from "superstruct";
+import { ENTITY_NAME_TYPES } from "../../../../common/entity/compute_entity_name_display";

 const entityNameItemStruct = union([
  object({
@@ -6,12 +7,7 @@ const entityNameItemStruct = union([
    text: string(),
  }),
  object({
-    type: union([
-      literal("entity"),
-      literal("device"),
-      literal("area"),
-      literal("floor"),
-    ]),
+    type: enums(ENTITY_NAME_TYPES),
  }),
  string(),
 ]);
@@ -5,6 +5,7 @@ import { html, LitElement } from "lit";
 import { customElement, property } from "lit/decorators";
 import { join } from "lit/directives/join";
 import { ensureArray } from "../common/array/ensure-array";
+import type { EntityNameType } from "../common/entity/compute_entity_name_display";
 import { computeStateDomain } from "../common/entity/compute_state_domain";
 import {
  STRINGS_SEPARATOR_DOT,
@@ -56,6 +57,13 @@ export const DEFAULT_STATE_CONTENT_DOMAINS: Record<string, StateContent> = {
  valve: ["state", "current_position"],
 };

+const NAME_CONTENT_TYPES: Partial<Record<string, EntityNameType>> = {
+  device_name: "device",
+  parent_device_name: "parent_device",
+  area_name: "area",
+  floor_name: "floor",
+};
+
 const TIMESTAMP_STATE_PROPS = ["last_updated", "last_changed"];

 const TIMESTAMP_CONTENTS = [...TIMESTAMP_STATE_PROPS, "last_triggered"];
@@ -190,13 +198,11 @@ class StateDisplay extends LitElement {
    if (content === "entity-id") {
      return stateObj.entity_id;
    }
-    if (
-      content === "device_name" ||
-      content === "area_name" ||
-      content === "floor_name"
-    ) {
-      const type = content.replace("_name", "") as "device" | "area" | "floor";
-      return this.hass.formatEntityName(stateObj, { type }) || undefined;
+    const nameType = NAME_CONTENT_TYPES[content];
+    if (nameType) {
+      return (
+        this.hass.formatEntityName(stateObj, { type: nameType }) || undefined
+      );
    }

    let relativeDateTime: string | number | undefined;
@@ -764,10 +764,12 @@
          "types": {
            "floor": "Floor",
            "area": "Area",
+            "parent_device": "[%key:ui::components::device-picker::parent_device%]",
            "device": "Device",
            "entity": "Entity",
            "area_missing": "No area assigned",
            "floor_missing": "No floor assigned",
+            "parent_device_missing": "No parent device",
            "device_missing": "No related device"
          },
          "mode_composed": "Composed",
@@ -916,6 +918,7 @@
        "no_devices": "No devices available",
        "no_match": "No devices found for {term}",
        "device": "Device",
+        "parent_device": "Parent device",
        "unnamed_device": "Unnamed device",
        "no_area": "No area",
        "placeholder": "Select a device",
@@ -1446,6 +1449,7 @@
        "remaining_time": "Remaining time",
        "install_status": "Install status",
        "device_name": "Device name",
+        "parent_device_name": "Parent device name",
        "area_name": "Area name",
        "floor_name": "Floor name"
      },
@@ -1673,6 +1677,7 @@
        "context": "Context",
        "entity": "Entity",
        "floor": "Floor",
+        "parent_device": "[%key:ui::components::device-picker::parent_device%]",
        "entity_id": "Entity ID",
        "labels": "Labels",
        "toggle_yaml_mode": "Toggle YAML mode",
@@ -245,6 +245,43 @@ describe("computeEntityNameDisplay", () => {
    expect(result).toBe("Kitchen Smart Light");
  });

+  it("returns parent device name for an entity on a child device", () => {
+    const stateObj = mockStateObj({ entity_id: "switch.outlet_1" });
+    const hass = {
+      entities: {
+        "switch.outlet_1": mockEntity({
+          entity_id: "switch.outlet_1",
+          name: "Switch",
+          device_id: "child_1",
+        }),
+      },
+      devices: {
+        child_1: mockDevice({
+          id: "child_1",
+          name: "Outlet 1",
+          parent_device_id: "parent_1",
+        }),
+        parent_1: mockDevice({
+          id: "parent_1",
+          name: "Power strip",
+        }),
+      },
+      areas: {},
+      floors: {},
+    } as unknown as HomeAssistant;
+
+    const result = computeEntityNameDisplay(
+      stateObj,
+      [{ type: "parent_device" }, { type: "device" }, { type: "entity" }],
+      hass.entities,
+      hass.devices,
+      hass.areas,
+      hass.floors
+    );
+
+    expect(result).toBe("Power strip Outlet 1 Switch");
+  });
+
  it("returns floor name", () => {
    const stateObj = mockStateObj({ entity_id: "light.kitchen" });
    const hass = {
@@ -37,6 +37,7 @@ describe("getEntityContext", () => {
    expect(result).toEqual({
      entity,
      device: null,
+      parentDevice: null,
      area: null,
      floor: null,
    });
@@ -88,6 +89,7 @@ describe("getEntityContext", () => {
    expect(result).toEqual({
      entity,
      device,
+      parentDevice: null,
      area,
      floor,
    });
@@ -144,6 +146,7 @@ describe("getEntityContext", () => {
    expect(result).toEqual({
      entity,
      device: childDevice,
+      parentDevice,
      area,
      floor,
    });
@@ -184,6 +187,7 @@ describe("getEntityContext", () => {
    expect(result).toEqual({
      entity,
      device: null,
+      parentDevice: null,
      area,
      floor,
    });
@@ -223,8 +227,38 @@ describe("getEntityContext", () => {
    expect(result).toEqual({
      entity,
      device: null,
+      parentDevice: null,
      area,
      floor: null,
    });
  });
+
+  it("should not resolve a parent device for an entity on a main device", () => {
+    const entity = mockEntity({
+      entity_id: "switch.strip",
+      device_id: "parent_1",
+    });
+    const parentDevice = mockDevice({
+      id: "parent_1",
+    });
+    const stateObj = mockStateObj({
+      entity_id: "switch.strip",
+    });
+
+    const result = getEntityContext(
+      stateObj,
+      { "switch.strip": entity },
+      { parent_1: parentDevice },
+      {},
+      {}
+    );
+
+    expect(result).toEqual({
+      entity,
+      device: parentDevice,
+      parentDevice: null,
+      area: null,
+      floor: null,
+    });
+  });
 });
@@ -0,0 +1,116 @@
+import {
+  addDays,
+  addHours,
+  addMilliseconds,
+  endOfDay,
+  startOfDay,
+} from "date-fns";
+import type { HassConfig } from "home-assistant-js-websocket";
+import { afterAll, assert, beforeAll, describe, it } from "vitest";
+
+import { calcDate } from "../../src/common/datetime/calc_date";
+import {
+  type FrontendLocaleData,
+  NumberFormat,
+  TimeFormat,
+  FirstWeekday,
+  DateFormat,
+  TimeZone,
+} from "../../src/data/translation";
+import {
+  getEnergyFirstStatisticAt,
+  getEnergyLiveDayPeriod,
+  getNextEnergyPeriodStart,
+} from "../../src/data/energy";
+
+const locale: FrontendLocaleData = {
+  language: "en",
+  number_format: NumberFormat.language,
+  time_format: TimeFormat.language,
+  date_format: DateFormat.language,
+  time_zone: TimeZone.server,
+  first_weekday: FirstWeekday.language,
+};
+const tokyoConfig = { time_zone: "Asia/Tokyo" } as HassConfig;
+
+// Dedicated file so Europe/Berlin can be pinned without leaking into other
+// suites. Vitest's default TZ is Etc/UTC, where browser-local addDays and
+// server-zone math often agree — so UTC CI would miss this regression.
+describe("energy period DST (Europe/Berlin local TZ)", () => {
+  const originalTz = process.env.TZ;
+
+  beforeAll(() => {
+    process.env.TZ = "Europe/Berlin";
+  });
+
+  afterAll(() => {
+    process.env.TZ = originalTz;
+  });
+
+  it("uses a DST-fallback browser zone for this file", () => {
+    // 24 Oct 2026 is still CEST. If TZ pinning failed, offset is 0 (UTC).
+    assert.equal(
+      new Date("2026-10-24T14:30:00.000Z").getTimezoneOffset(),
+      -120
+    );
+  });
+
+  it("schedules tomorrow 01:00 in the server zone, not via browser-local addDays", () => {
+    // 23:30 JST on 24 Oct 2026. Europe/Berlin falls back on 25 Oct; local
+    // addDays(now, 1) then startOfDay in Tokyo skips to 26 Oct 01:00 JST.
+    const now = new Date("2026-10-24T14:30:00.000Z");
+
+    // Compare to the tz-internal formula rather than a hardcoded instant:
+    // the formula is the production invariant, and a pinned ISO string would
+    // not explain why UTC CI cannot catch a raw addDays(now, 1) regression.
+    const tzInternal = addHours(
+      addMilliseconds(calcDate(now, endOfDay, locale, tokyoConfig), 1),
+      1
+    );
+    const browserLocalAddDays = getEnergyFirstStatisticAt(
+      addDays(now, 1),
+      locale,
+      tokyoConfig
+    );
+    const actual = getNextEnergyPeriodStart(false, now, locale, tokyoConfig);
+
+    assert.equal(actual.getTime(), tzInternal.getTime());
+    assert.notEqual(actual.getTime(), browserLocalAddDays.getTime());
+    assert.equal(
+      actual.getTime(),
+      new Date("2026-10-24T16:00:00.000Z").getTime()
+    );
+    assert.equal(
+      browserLocalAddDays.getTime(),
+      new Date("2026-10-25T16:00:00.000Z").getTime()
+    );
+  });
+
+  it("resolves yesterday in the server zone, not via browser-local addDays", () => {
+    // 00:30 JST on 26 Oct 2026. Browser-local addDays can land two days back.
+    const now = new Date("2026-10-25T15:30:00.000Z");
+
+    const tzInternal = calcDate(
+      calcDate(now, addDays, locale, tokyoConfig, -1),
+      startOfDay,
+      locale,
+      tokyoConfig
+    );
+    const browserLocalAddDays = calcDate(
+      addDays(now, -1),
+      startOfDay,
+      locale,
+      tokyoConfig
+    );
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      locale,
+      tokyoConfig,
+      new Date(0)
+    );
+
+    assert.equal(live.start.getTime(), tzInternal.getTime());
+    assert.notEqual(live.start.getTime(), browserLocalAddDays.getTime());
+  });
+});
@@ -1,6 +1,6 @@
-import { startOfDay } from "date-fns";
+import { addDays, endOfDay, startOfDay } from "date-fns";
 import type { HassConfig } from "home-assistant-js-websocket";
-import { assert, describe, it } from "vitest";
+import { afterEach, assert, describe, it, vi } from "vitest";

 import { calcDate } from "../../src/common/datetime/calc_date";
 import {
@@ -20,6 +20,11 @@ import {
  formatPowerShort,
  getNextEnergyPeriodStart,
  getEnergyDefaultPeriodStorageKey,
+  getEnergyFirstStatisticAt,
+  getEnergyLiveDayPeriod,
+  shouldFallbackEnergyPeriodToYesterday,
+  getEnergyDataCollection,
+  EMPTY_PREFERENCES,
 } from "../../src/data/energy";
 import type { DeviceRegistryEntry } from "../../src/data/device/device_registry";
 import type { EntityRegistryDisplayEntry } from "../../src/data/entity/entity_registry";
@@ -866,27 +871,55 @@ describe("Self-consumed solar gauge tests", () => {
  });
 });

-describe("getNextEnergyPeriodStart", () => {
-  const locale: FrontendLocaleData = {
-    language: "en",
-    number_format: NumberFormat.language,
-    time_format: TimeFormat.language,
-    date_format: DateFormat.language,
-    time_zone: TimeZone.server,
-    first_weekday: FirstWeekday.language,
+// Pin the time zone (via TimeZone.server) so energy period tests do not
+// depend on the machine's local zone.
+const energyPeriodLocale: FrontendLocaleData = {
+  language: "en",
+  number_format: NumberFormat.language,
+  time_format: TimeFormat.language,
+  date_format: DateFormat.language,
+  time_zone: TimeZone.server,
+  first_weekday: FirstWeekday.language,
+};
+const energyPeriodConfig = { time_zone: "America/New_York" } as HassConfig;
+const energyPeriodDay = (now: Date, offset = 0) => {
+  const day = calcDate(
+    now,
+    addDays,
+    energyPeriodLocale,
+    energyPeriodConfig,
+    offset
+  );
+  return {
+    start: calcDate(day, startOfDay, energyPeriodLocale, energyPeriodConfig),
+    end: calcDate(day, endOfDay, energyPeriodLocale, energyPeriodConfig),
  };
-  // Pin the time zone (via TimeZone.server) so the test does not depend on the
-  // machine's local zone.
-  const config = { time_zone: "America/New_York" } as HassConfig;
+};

+describe("getNextEnergyPeriodStart", () => {
  const isMidnight = (date: Date) =>
-    calcDate(date, startOfDay, locale, config).getTime() === date.getTime();
+    calcDate(
+      date,
+      startOfDay,
+      energyPeriodLocale,
+      energyPeriodConfig
+    ).getTime() === date.getTime();

  it("rolls the real-time view over at midnight, statistics an hour later", () => {
    const now = new Date("2026-06-19T15:30:00-04:00");

-    const realTime = getNextEnergyPeriodStart(true, now, locale, config);
-    const statistics = getNextEnergyPeriodStart(false, now, locale, config);
+    const realTime = getNextEnergyPeriodStart(
+      true,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig
+    );
+    const statistics = getNextEnergyPeriodStart(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig
+    );

    // Real-time rolls over exactly at the next midnight.
    assert.isTrue(isMidnight(realTime));
@@ -896,9 +929,14 @@ describe("getNextEnergyPeriodStart", () => {
    );

    // Statistics roll over an hour after midnight, on the same day boundary.
-    assert.equal(statistics.getTime() - realTime.getTime(), 60 * 60 * 1000 - 1);
+    assert.equal(statistics.getTime() - realTime.getTime(), 60 * 60 * 1000);
    assert.equal(
-      calcDate(statistics, startOfDay, locale, config).getTime(),
+      calcDate(
+        statistics,
+        startOfDay,
+        energyPeriodLocale,
+        energyPeriodConfig
+      ).getTime(),
      realTime.getTime()
    );
  });
@@ -906,7 +944,12 @@ describe("getNextEnergyPeriodStart", () => {
  it("advances the real-time view to the next midnight when called after midnight", () => {
    const now = new Date("2026-06-20T00:30:00-04:00");

-    const realTime = getNextEnergyPeriodStart(true, now, locale, config);
+    const realTime = getNextEnergyPeriodStart(
+      true,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig
+    );

    assert.isTrue(isMidnight(realTime));
    // Next midnight is June 21, not the already-passed June 20 midnight.
@@ -915,6 +958,352 @@ describe("getNextEnergyPeriodStart", () => {
      new Date("2026-06-21T00:00:00-04:00").getTime()
    );
  });
+
+  it("wakes a non-today live day at today 01:00 during hour 0", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+    const todayOne = new Date("2026-06-20T01:00:00-04:00").getTime();
+
+    for (const offset of [-1, -2]) {
+      assert.equal(
+        getNextEnergyPeriodStart(
+          false,
+          now,
+          energyPeriodLocale,
+          energyPeriodConfig,
+          energyPeriodDay(now, offset).start
+        ).getTime(),
+        todayOne
+      );
+    }
+  });
+
+  it("keeps tomorrow 01:00 when statistics is already on today during hour 0", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+
+    assert.equal(
+      getNextEnergyPeriodStart(
+        false,
+        now,
+        energyPeriodLocale,
+        energyPeriodConfig,
+        energyPeriodDay(now).start
+      ).getTime(),
+      new Date("2026-06-21T01:00:00-04:00").getTime()
+    );
+  });
+});
+
+describe("shouldFallbackEnergyPeriodToYesterday", () => {
+  it("is true for the statistics view before 01:00", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+    assert.isTrue(
+      shouldFallbackEnergyPeriodToYesterday(
+        false,
+        now,
+        energyPeriodLocale,
+        energyPeriodConfig
+      )
+    );
+    assert.equal(
+      getEnergyFirstStatisticAt(
+        now,
+        energyPeriodLocale,
+        energyPeriodConfig
+      ).getTime(),
+      new Date("2026-06-20T01:00:00-04:00").getTime()
+    );
+  });
+
+  it("is false at 01:00 and for the real-time view", () => {
+    const atOne = new Date("2026-06-20T01:00:00-04:00");
+    const beforeOne = new Date("2026-06-20T00:30:00-04:00");
+    assert.isFalse(
+      shouldFallbackEnergyPeriodToYesterday(
+        false,
+        atOne,
+        energyPeriodLocale,
+        energyPeriodConfig
+      )
+    );
+    assert.isFalse(
+      shouldFallbackEnergyPeriodToYesterday(
+        true,
+        beforeOne,
+        energyPeriodLocale,
+        energyPeriodConfig
+      )
+    );
+  });
+});
+
+describe("getEnergyLiveDayPeriod", () => {
+  it("keeps yesterday during hour 0 when that is the current period", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+    const { start, end } = energyPeriodDay(now, -1);
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig,
+      start
+    );
+    assert.equal(live.start.getTime(), start.getTime());
+    assert.equal(live.end.getTime(), end.getTime());
+  });
+
+  it("keeps today during hour 0 when the user already picked today", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+    const { start, end } = energyPeriodDay(now);
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig,
+      start
+    );
+    assert.equal(live.start.getTime(), start.getTime());
+    assert.equal(live.end.getTime(), end.getTime());
+  });
+
+  it("advances a stale yesterday to today after 01:00", () => {
+    const now = new Date("2026-06-20T10:00:00-04:00");
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig,
+      energyPeriodDay(now, -1).start
+    );
+    const expected = energyPeriodDay(now);
+    assert.equal(live.start.getTime(), expected.start.getTime());
+    assert.equal(live.end.getTime(), expected.end.getTime());
+  });
+
+  it("advances a two-day-old live day to today", () => {
+    const now = new Date("2026-06-20T10:00:00-04:00");
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig,
+      energyPeriodDay(now, -2).start
+    );
+    const expected = energyPeriodDay(now);
+    assert.equal(live.start.getTime(), expected.start.getTime());
+    assert.equal(live.end.getTime(), expected.end.getTime());
+  });
+
+  it("falls back to yesterday for a stale live day during hour 0", () => {
+    const now = new Date("2026-06-20T00:30:00-04:00");
+    const live = getEnergyLiveDayPeriod(
+      false,
+      now,
+      energyPeriodLocale,
+      energyPeriodConfig,
+      energyPeriodDay(now, -2).start
+    );
+    const expected = energyPeriodDay(now, -1);
+    assert.equal(live.start.getTime(), expected.start.getTime());
+    assert.equal(live.end.getTime(), expected.end.getTime());
+  });
+});
+
+describe("getEnergyDataCollection live day", () => {
+  afterEach(() => {
+    localStorage.clear();
+    vi.useRealTimers();
+  });
+
+  const createCollection = (
+    key: string,
+    preset?: string,
+    midnightRollover = false
+  ) => {
+    const hass = createMockHass();
+    hass.locale = energyPeriodLocale;
+    hass.config = { ...hass.config, time_zone: "America/New_York" };
+    const callWS = vi.fn(async (msg: { type: string }) => {
+      if (msg.type === "energy/info") {
+        return { cost_sensors: {}, solar_forecast_domains: [] };
+      }
+      throw new Error(`unexpected ${msg.type}`);
+    });
+    Object.assign(hass, {
+      connection: {
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+        connected: true,
+      },
+      callWS,
+    });
+    if (preset) {
+      localStorage.setItem(getEnergyDefaultPeriodStorageKey(hass, key), preset);
+    }
+    return {
+      collection: getEnergyDataCollection(hass, {
+        key,
+        prefs: EMPTY_PREFERENCES,
+        midnightRollover,
+      }),
+      callWS,
+    };
+  };
+
+  const energyInfoFetches = (callWS: ReturnType<typeof vi.fn>) =>
+    callWS.mock.calls.filter((call) => call[0].type === "energy/info");
+
+  it("advances hour-0 yesterday to today at 01:00 and fetches the new day", async () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-20T00:30:00-04:00"));
+
+    const { collection, callWS } = createCollection("energy_timer");
+    const refresh = vi.spyOn(collection, "refresh");
+    const unsub = collection.subscribe(() => undefined);
+    await vi.advanceTimersByTimeAsync(0);
+    refresh.mockClear();
+    callWS.mockClear();
+
+    assert.equal(
+      collection.start.getTime(),
+      energyPeriodDay(new Date(), -1).start.getTime()
+    );
+
+    await vi.advanceTimersByTimeAsync(30 * 60 * 1000);
+
+    assert.equal(
+      collection.start.getTime(),
+      energyPeriodDay(new Date()).start.getTime()
+    );
+    // Cards render EnergyData from the websocket store, not collection.start.
+    // The 01:00 callback must refresh() so getEnergyData runs for today.
+    assert.equal(refresh.mock.calls.length, 1);
+    assert.equal(energyInfoFetches(callWS).length, 1);
+
+    unsub();
+  });
+
+  it("catches up a stale live day on resubscribe", async () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-18T15:00:00-04:00"));
+
+    const { collection, callWS } = createCollection("energy_catchup");
+    const refresh = vi.spyOn(collection, "refresh");
+    let unsub = collection.subscribe(() => undefined);
+    await vi.advanceTimersByTimeAsync(0);
+    refresh.mockClear();
+    callWS.mockClear();
+
+    unsub();
+    vi.setSystemTime(new Date("2026-06-20T10:00:00-04:00"));
+    unsub = collection.subscribe(() => undefined);
+    await vi.advanceTimersByTimeAsync(0);
+
+    assert.equal(
+      collection.start.getTime(),
+      energyPeriodDay(new Date()).start.getTime()
+    );
+    assert.equal(refresh.mock.calls.length, 1);
+    assert.equal(energyInfoFetches(callWS).length, 1);
+
+    unsub();
+  });
+
+  it("does not double-refresh on a cold subscribe after the unsub grace", async () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-18T15:00:00-04:00"));
+
+    const { collection, callWS } = createCollection("energy_cold_refresh");
+    const refresh = vi.spyOn(collection, "refresh");
+    let unsub = collection.subscribe(() => undefined);
+    await vi.advanceTimersByTimeAsync(0);
+    unsub();
+    await vi.advanceTimersByTimeAsync(5000);
+    refresh.mockClear();
+    callWS.mockClear();
+
+    vi.setSystemTime(new Date("2026-06-20T10:00:00-04:00"));
+    unsub = collection.subscribe(() => undefined);
+    await vi.advanceTimersByTimeAsync(0);
+
+    assert.equal(
+      collection.start.getTime(),
+      energyPeriodDay(new Date()).start.getTime()
+    );
+    // The library's first fetch is not collection.refresh(); this spy only
+    // sees the extra refresh used during the unsub-grace re-subscribe.
+    assert.equal(refresh.mock.calls.length, 0);
+    assert.equal(energyInfoFetches(callWS).length, 1);
+
+    unsub();
+  });
+
+  it("keeps a custom setPeriod range overnight", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-18T15:00:00-04:00"));
+
+    const { collection } = createCollection("energy_custom_period");
+    let unsub = collection.subscribe(() => undefined);
+    const custom = energyPeriodDay(new Date(), -5);
+    collection.setPeriod(custom.start, custom.end);
+    unsub();
+
+    vi.setSystemTime(new Date("2026-06-20T10:00:00-04:00"));
+    unsub = collection.subscribe(() => undefined);
+
+    assert.equal(collection.start.getTime(), custom.start.getTime());
+
+    unsub();
+  });
+
+  it("does not advance the period after the last subscriber leaves", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-20T00:30:00-04:00"));
+
+    const { collection } = createCollection("energy_unsub_timer");
+    const unsub = collection.subscribe(() => undefined);
+    const start = collection.start.getTime();
+    unsub();
+
+    vi.advanceTimersByTime(48 * 60 * 60 * 1000);
+
+    assert.equal(collection.start.getTime(), start);
+  });
+
+  it("does not roll a remembered week preset over to today", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-18T15:00:00-04:00"));
+
+    const { collection } = createCollection("energy_week_stored", "this_week");
+    const weekStart = collection.start.getTime();
+    const unsub = collection.subscribe(() => undefined);
+
+    vi.setSystemTime(new Date("2026-06-20T10:00:00-04:00"));
+    vi.advanceTimersByTime(48 * 60 * 60 * 1000);
+
+    assert.equal(collection.start.getTime(), weekStart);
+
+    unsub();
+  });
+
+  it("does not roll a remembered week preset over to today with midnightRollover", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-06-18T15:00:00-04:00"));
+
+    const { collection } = createCollection(
+      "energy_week_stored_now",
+      "this_week",
+      true
+    );
+    const weekStart = collection.start.getTime();
+    const unsub = collection.subscribe(() => undefined);
+
+    vi.setSystemTime(new Date("2026-06-20T10:00:00-04:00"));
+    vi.advanceTimersByTime(48 * 60 * 60 * 1000);
+
+    assert.equal(collection.start.getTime(), weekStart);
+
+    unsub();
+  });
 });

 describe("getEnergyDefaultPeriodStorageKey", () => {