[api] Split process_batch_ to reduce stack on single-message hot path

Clamp buffer pre-allocation to MAX_BATCH_PACKET_SIZE.

esphome/components/api/api.proto

@@ -1155,9 +1155,11 @@ enum WaterHeaterCommandHasField {
   WATER_HEATER_COMMAND_HAS_NONE = 0;
   WATER_HEATER_COMMAND_HAS_MODE = 1;
   WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE = 2;
-  WATER_HEATER_COMMAND_HAS_STATE = 4;
+  WATER_HEATER_COMMAND_HAS_STATE = 4 [deprecated=true];
   WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_LOW = 8;
   WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_HIGH = 16;
+  WATER_HEATER_COMMAND_HAS_ON_STATE = 32;
+  WATER_HEATER_COMMAND_HAS_AWAY_STATE = 64;
 }
 
 message WaterHeaterCommandRequest {

esphome/components/api/api_connection.cpp

@@ -1343,8 +1343,12 @@ void APIConnection::on_water_heater_command_request(const WaterHeaterCommandRequ
     call.set_target_temperature_low(msg.target_temperature_low);
   if (msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_HIGH)
     call.set_target_temperature_high(msg.target_temperature_high);
-  if (msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_STATE) {
+  if ((msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_AWAY_STATE) ||
+      (msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_STATE)) {
     call.set_away((msg.state & water_heater::WATER_HEATER_STATE_AWAY) != 0);
+  }
+  if ((msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_ON_STATE) ||
+      (msg.has_fields & enums::WATER_HEATER_COMMAND_HAS_STATE)) {
     call.set_on((msg.state & water_heater::WATER_HEATER_STATE_ON) != 0);
   }
   call.perform();
@@ -1895,10 +1899,6 @@ bool APIConnection::schedule_batch_() {
 }
 
 void APIConnection::process_batch_() {
-  // Ensure MessageInfo remains trivially destructible for our placement new approach
-  static_assert(std::is_trivially_destructible<MessageInfo>::value,
-                "MessageInfo must remain trivially destructible with this placement-new approach");
-
   if (this->deferred_batch_.empty()) {
     this->flags_.batch_scheduled = false;
     return;
@@ -1923,6 +1923,10 @@ void APIConnection::process_batch_() {
   for (size_t i = 0; i < num_items; i++) {
     total_estimated_size += this->deferred_batch_[i].estimated_size;
   }
+  // Clamp to MAX_BATCH_PACKET_SIZE — we won't send more than that per batch
+  if (total_estimated_size > MAX_BATCH_PACKET_SIZE) {
+    total_estimated_size = MAX_BATCH_PACKET_SIZE;
+  }
 
   this->prepare_first_message_buffer(shared_buf, header_padding, total_estimated_size);
 
@@ -1946,7 +1950,20 @@ void APIConnection::process_batch_() {
     return;
   }
 
-  size_t messages_to_process = std::min(num_items, MAX_MESSAGES_PER_BATCH);
+  // Multi-message path — heavy stack frame isolated in separate noinline function
+  this->process_batch_multi_(shared_buf, num_items, header_padding, footer_size);
+}
+
+// Separated from process_batch_() so the single-message fast path gets a minimal
+// stack frame without the MAX_MESSAGES_PER_BATCH * sizeof(MessageInfo) array.
+void APIConnection::process_batch_multi_(std::vector<uint8_t> &shared_buf, size_t num_items, uint8_t header_padding,
+                                         uint8_t footer_size) {
+  // Ensure MessageInfo remains trivially destructible for our placement new approach
+  static_assert(std::is_trivially_destructible<MessageInfo>::value,
+                "MessageInfo must remain trivially destructible with this placement-new approach");
+
+  const size_t messages_to_process = std::min(num_items, MAX_MESSAGES_PER_BATCH);
+  const uint8_t frame_overhead = header_padding + footer_size;
 
   // Stack-allocated array for message info
   alignas(MessageInfo) char message_info_storage[MAX_MESSAGES_PER_BATCH * sizeof(MessageInfo)];
@@ -1973,7 +1990,7 @@ void APIConnection::process_batch_() {
 
     // Message was encoded successfully
     // payload_size is header_padding + actual payload size + footer_size
-    uint16_t proto_payload_size = payload_size - header_padding - footer_size;
+    uint16_t proto_payload_size = payload_size - frame_overhead;
     // Use placement new to construct MessageInfo in pre-allocated stack array
     // This avoids default-constructing all MAX_MESSAGES_PER_BATCH elements
     // Explicit destruction is not needed because MessageInfo is trivially destructible,
@@ -1989,42 +2006,38 @@ void APIConnection::process_batch_() {
     current_offset = shared_buf.size() + footer_size;
   }
 
-  if (items_processed == 0) {
-    this->deferred_batch_.clear();
-    return;
-  }
+  if (items_processed > 0) {
+    // Add footer space for the last message (for Noise protocol MAC)
+    if (footer_size > 0) {
+      shared_buf.resize(shared_buf.size() + footer_size);
+    }
 
-  // Add footer space for the last message (for Noise protocol MAC)
-  if (footer_size > 0) {
-    shared_buf.resize(shared_buf.size() + footer_size);
-  }
-
-  // Send all collected messages
-  APIError err = this->helper_->write_protobuf_messages(ProtoWriteBuffer{&shared_buf},
-                                                        std::span<const MessageInfo>(message_info, items_processed));
-  if (err != APIError::OK && err != APIError::WOULD_BLOCK) {
-    this->fatal_error_with_log_(LOG_STR("Batch write failed"), err);
-  }
+    // Send all collected messages
+    APIError err = this->helper_->write_protobuf_messages(ProtoWriteBuffer{&shared_buf},
+                                                          std::span<const MessageInfo>(message_info, items_processed));
+    if (err != APIError::OK && err != APIError::WOULD_BLOCK) {
+      this->fatal_error_with_log_(LOG_STR("Batch write failed"), err);
+    }
 
 #ifdef HAS_PROTO_MESSAGE_DUMP
-  // Log messages after send attempt for VV debugging
-  // It's safe to use the buffer for logging at this point regardless of send result
-  for (size_t i = 0; i < items_processed; i++) {
-    const auto &item = this->deferred_batch_[i];
-    this->log_batch_item_(item);
-  }
+    // Log messages after send attempt for VV debugging
+    // It's safe to use the buffer for logging at this point regardless of send result
+    for (size_t i = 0; i < items_processed; i++) {
+      const auto &item = this->deferred_batch_[i];
+      this->log_batch_item_(item);
+    }
 #endif
 
-  // Handle remaining items more efficiently
-  if (items_processed < this->deferred_batch_.size()) {
-    // Remove processed items from the beginning
-    this->deferred_batch_.remove_front(items_processed);
-    // Reschedule for remaining items
-    this->schedule_batch_();
-  } else {
-    // All items processed
-    this->clear_batch_();
+    // Partial batch — remove processed items and reschedule
+    if (items_processed < this->deferred_batch_.size()) {
+      this->deferred_batch_.remove_front(items_processed);
+      this->schedule_batch_();
+      return;
+    }
   }
+
+  // All items processed (or none could be processed)
+  this->clear_batch_();
 }
 
 // Dispatch message encoding based on message_type

esphome/components/api/api_connection.h

@@ -549,8 +549,8 @@ class APIConnection final : public APIServerConnectionBase {
       batch_start_time = 0;
     }
 
-    // Remove processed items from the front
-    void remove_front(size_t count) { items.erase(items.begin(), items.begin() + count); }
+    // Remove processed items from the front — noinline to keep memmove out of warm callers
+    void remove_front(size_t count) __attribute__((noinline)) { items.erase(items.begin(), items.begin() + count); }
 
     bool empty() const { return items.empty(); }
     size_t size() const { return items.size(); }
@@ -622,6 +622,8 @@ class APIConnection final : public APIServerConnectionBase {
 
   bool schedule_batch_();
   void process_batch_();
+  void process_batch_multi_(std::vector<uint8_t> &shared_buf, size_t num_items, uint8_t header_padding,
+                            uint8_t footer_size) __attribute__((noinline));
   void clear_batch_() {
     this->deferred_batch_.clear();
     this->flags_.batch_scheduled = false;

esphome/components/api/api_pb2.h

@@ -147,6 +147,8 @@ enum WaterHeaterCommandHasField : uint32_t {
   WATER_HEATER_COMMAND_HAS_STATE = 4,
   WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_LOW = 8,
   WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_HIGH = 16,
+  WATER_HEATER_COMMAND_HAS_ON_STATE = 32,
+  WATER_HEATER_COMMAND_HAS_AWAY_STATE = 64,
 };
 #ifdef USE_NUMBER
 enum NumberMode : uint32_t {

esphome/components/api/api_pb2_dump.cpp

@@ -385,6 +385,10 @@ const char *proto_enum_to_string<enums::WaterHeaterCommandHasField>(enums::Water
       return "WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_LOW";
     case enums::WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_HIGH:
       return "WATER_HEATER_COMMAND_HAS_TARGET_TEMPERATURE_HIGH";
+    case enums::WATER_HEATER_COMMAND_HAS_ON_STATE:
+      return "WATER_HEATER_COMMAND_HAS_ON_STATE";
+    case enums::WATER_HEATER_COMMAND_HAS_AWAY_STATE:
+      return "WATER_HEATER_COMMAND_HAS_AWAY_STATE";
     default:
       return "UNKNOWN";
   }

esphome/components/ld2450/__init__.py

@@ -1,7 +1,8 @@
+from esphome import automation
 import esphome.codegen as cg
 from esphome.components import uart
 import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_THROTTLE
+from esphome.const import CONF_ID, CONF_ON_DATA, CONF_THROTTLE, CONF_TRIGGER_ID
 
 AUTO_LOAD = ["ld24xx"]
 DEPENDENCIES = ["uart"]
@@ -11,6 +12,8 @@ MULTI_CONF = True
 ld2450_ns = cg.esphome_ns.namespace("ld2450")
 LD2450Component = ld2450_ns.class_("LD2450Component", cg.Component, uart.UARTDevice)
 
+LD2450DataTrigger = ld2450_ns.class_("LD2450DataTrigger", automation.Trigger.template())
+
 CONF_LD2450_ID = "ld2450_id"
 
 CONFIG_SCHEMA = cv.All(
@@ -20,6 +23,11 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_THROTTLE): cv.invalid(
                 f"{CONF_THROTTLE} has been removed; use per-sensor filters, instead"
             ),
+            cv.Optional(CONF_ON_DATA): automation.validate_automation(
+                {
+                    cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(LD2450DataTrigger),
+                }
+            ),
         }
     )
     .extend(uart.UART_DEVICE_SCHEMA)
@@ -45,3 +53,6 @@ async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     await uart.register_uart_device(var, config)
+    for conf in config.get(CONF_ON_DATA, []):
+        trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
+        await automation.build_automation(trigger, [], conf)

esphome/components/ld2450/ld2450.cpp

@@ -413,6 +413,10 @@ void LD2450Component::restart_and_read_all_info() {
   this->set_timeout(1500, [this]() { this->read_all_info(); });
 }
 
+void LD2450Component::add_on_data_callback(std::function<void()> &&callback) {
+  this->data_callback_.add(std::move(callback));
+}
+
 // Send command with values to LD2450
 void LD2450Component::send_command_(uint8_t command, const uint8_t *command_value, uint8_t command_value_len) {
   ESP_LOGV(TAG, "Sending COMMAND %02X", command);
@@ -613,6 +617,8 @@ void LD2450Component::handle_periodic_data_() {
     this->still_presence_millis_ = App.get_loop_component_start_time();
   }
 #endif
+
+  this->data_callback_.call();
 }
 
 bool LD2450Component::handle_ack_data_() {

esphome/components/ld2450/ld2450.h

@@ -141,6 +141,9 @@ class LD2450Component : public Component, public uart::UARTDevice {
                       int32_t zone2_x1, int32_t zone2_y1, int32_t zone2_x2, int32_t zone2_y2, int32_t zone3_x1,
                       int32_t zone3_y1, int32_t zone3_x2, int32_t zone3_y2);
 
+  /// Add a callback that will be called after each successfully processed periodic data frame.
+  void add_on_data_callback(std::function<void()> &&callback);
+
  protected:
   void send_command_(uint8_t command_str, const uint8_t *command_value, uint8_t command_value_len);
   void set_config_mode_(bool enable);
@@ -190,6 +193,15 @@ class LD2450Component : public Component, public uart::UARTDevice {
 #ifdef USE_TEXT_SENSOR
   std::array<text_sensor::TextSensor *, 3> direction_text_sensors_{};
 #endif
+
+  LazyCallbackManager<void()> data_callback_;
+};
+
+class LD2450DataTrigger : public Trigger<> {
+ public:
+  explicit LD2450DataTrigger(LD2450Component *parent) {
+    parent->add_on_data_callback([this]() { this->trigger(); });
+  }
 };
 
 }  // namespace esphome::ld2450

esphome/components/template/water_heater/__init__.py

@@ -3,6 +3,7 @@ import esphome.codegen as cg
 from esphome.components import water_heater
 import esphome.config_validation as cv
 from esphome.const import (
+    CONF_AWAY,
     CONF_ID,
     CONF_MODE,
     CONF_OPTIMISTIC,
@@ -18,6 +19,7 @@ from esphome.types import ConfigType
 from .. import template_ns
 
 CONF_CURRENT_TEMPERATURE = "current_temperature"
+CONF_IS_ON = "is_on"
 
 TemplateWaterHeater = template_ns.class_(
     "TemplateWaterHeater", cg.Component, water_heater.WaterHeater
@@ -51,6 +53,8 @@ CONFIG_SCHEMA = (
             cv.Optional(CONF_SUPPORTED_MODES): cv.ensure_list(
                 water_heater.validate_water_heater_mode
             ),
+            cv.Optional(CONF_AWAY): cv.returning_lambda,
+            cv.Optional(CONF_IS_ON): cv.returning_lambda,
         }
     )
     .extend(cv.COMPONENT_SCHEMA)
@@ -98,6 +102,22 @@ async def to_code(config: ConfigType) -> None:
     if CONF_SUPPORTED_MODES in config:
         cg.add(var.set_supported_modes(config[CONF_SUPPORTED_MODES]))
 
+    if CONF_AWAY in config:
+        template_ = await cg.process_lambda(
+            config[CONF_AWAY],
+            [],
+            return_type=cg.optional.template(bool),
+        )
+        cg.add(var.set_away_lambda(template_))
+
+    if CONF_IS_ON in config:
+        template_ = await cg.process_lambda(
+            config[CONF_IS_ON],
+            [],
+            return_type=cg.optional.template(bool),
+        )
+        cg.add(var.set_is_on_lambda(template_))
+
 
 @automation.register_action(
     "water_heater.template.publish",
@@ -110,6 +130,8 @@ async def to_code(config: ConfigType) -> None:
             cv.Optional(CONF_MODE): cv.templatable(
                 water_heater.validate_water_heater_mode
             ),
+            cv.Optional(CONF_AWAY): cv.templatable(cv.boolean),
+            cv.Optional(CONF_IS_ON): cv.templatable(cv.boolean),
         }
     ),
 )
@@ -134,4 +156,12 @@ async def water_heater_template_publish_to_code(
         template_ = await cg.templatable(mode, args, water_heater.WaterHeaterMode)
         cg.add(var.set_mode(template_))
 
+    if CONF_AWAY in config:
+        template_ = await cg.templatable(config[CONF_AWAY], args, bool)
+        cg.add(var.set_away(template_))
+
+    if CONF_IS_ON in config:
+        template_ = await cg.templatable(config[CONF_IS_ON], args, bool)
+        cg.add(var.set_is_on(template_))
+
     return var

esphome/components/template/water_heater/automation.h

@@ -11,12 +11,15 @@ class TemplateWaterHeaterPublishAction : public Action<Ts...>, public Parented<T
   TEMPLATABLE_VALUE(float, current_temperature)
   TEMPLATABLE_VALUE(float, target_temperature)
   TEMPLATABLE_VALUE(water_heater::WaterHeaterMode, mode)
+  TEMPLATABLE_VALUE(bool, away)
+  TEMPLATABLE_VALUE(bool, is_on)
 
   void play(const Ts &...x) override {
     if (this->current_temperature_.has_value()) {
       this->parent_->set_current_temperature(this->current_temperature_.value(x...));
     }
-    bool needs_call = this->target_temperature_.has_value() || this->mode_.has_value();
+    bool needs_call = this->target_temperature_.has_value() || this->mode_.has_value() || this->away_.has_value() ||
+                      this->is_on_.has_value();
     if (needs_call) {
       auto call = this->parent_->make_call();
       if (this->target_temperature_.has_value()) {
@@ -25,6 +28,12 @@ class TemplateWaterHeaterPublishAction : public Action<Ts...>, public Parented<T
       if (this->mode_.has_value()) {
         call.set_mode(this->mode_.value(x...));
       }
+      if (this->away_.has_value()) {
+        call.set_away(this->away_.value(x...));
+      }
+      if (this->is_on_.has_value()) {
+        call.set_on(this->is_on_.value(x...));
+      }
       call.perform();
     } else {
       this->parent_->publish_state();

esphome/components/template/water_heater/template_water_heater.cpp

@@ -17,7 +17,7 @@ void TemplateWaterHeater::setup() {
     }
   }
   if (!this->current_temperature_f_.has_value() && !this->target_temperature_f_.has_value() &&
-      !this->mode_f_.has_value())
+      !this->mode_f_.has_value() && !this->away_f_.has_value() && !this->is_on_f_.has_value())
     this->disable_loop();
 }
 
@@ -32,6 +32,12 @@ water_heater::WaterHeaterTraits TemplateWaterHeater::traits() {
   if (this->target_temperature_f_.has_value()) {
     traits.add_feature_flags(water_heater::WATER_HEATER_SUPPORTS_TARGET_TEMPERATURE);
   }
+  if (this->away_f_.has_value()) {
+    traits.set_supports_away_mode(true);
+  }
+  if (this->is_on_f_.has_value()) {
+    traits.add_feature_flags(water_heater::WATER_HEATER_SUPPORTS_ON_OFF);
+  }
   return traits;
 }
 
@@ -62,6 +68,22 @@ void TemplateWaterHeater::loop() {
     }
   }
 
+  auto away = this->away_f_.call();
+  if (away.has_value()) {
+    if (*away != this->is_away()) {
+      this->set_state_flag_(water_heater::WATER_HEATER_STATE_AWAY, *away);
+      changed = true;
+    }
+  }
+
+  auto is_on = this->is_on_f_.call();
+  if (is_on.has_value()) {
+    if (*is_on != this->is_on()) {
+      this->set_state_flag_(water_heater::WATER_HEATER_STATE_ON, *is_on);
+      changed = true;
+    }
+  }
+
   if (changed) {
     this->publish_state();
   }
@@ -90,6 +112,17 @@ void TemplateWaterHeater::control(const water_heater::WaterHeaterCall &call) {
     }
   }
 
+  if (call.get_away().has_value()) {
+    if (this->optimistic_) {
+      this->set_state_flag_(water_heater::WATER_HEATER_STATE_AWAY, *call.get_away());
+    }
+  }
+  if (call.get_on().has_value()) {
+    if (this->optimistic_) {
+      this->set_state_flag_(water_heater::WATER_HEATER_STATE_ON, *call.get_on());
+    }
+  }
+
   this->set_trigger_.trigger();
 
   if (this->optimistic_) {

esphome/components/template/water_heater/template_water_heater.h

@@ -24,6 +24,8 @@ class TemplateWaterHeater : public Component, public water_heater::WaterHeater {
     this->target_temperature_f_.set(std::forward<F>(f));
   }
   template<typename F> void set_mode_lambda(F &&f) { this->mode_f_.set(std::forward<F>(f)); }
+  template<typename F> void set_away_lambda(F &&f) { this->away_f_.set(std::forward<F>(f)); }
+  template<typename F> void set_is_on_lambda(F &&f) { this->is_on_f_.set(std::forward<F>(f)); }
 
   void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
   void set_restore_mode(TemplateWaterHeaterRestoreMode restore_mode) { this->restore_mode_ = restore_mode; }
@@ -49,6 +51,8 @@ class TemplateWaterHeater : public Component, public water_heater::WaterHeater {
   TemplateLambda<float> current_temperature_f_;
   TemplateLambda<float> target_temperature_f_;
   TemplateLambda<water_heater::WaterHeaterMode> mode_f_;
+  TemplateLambda<bool> away_f_;
+  TemplateLambda<bool> is_on_f_;
   TemplateWaterHeaterRestoreMode restore_mode_{WATER_HEATER_NO_RESTORE};
   water_heater::WaterHeaterModeMask supported_modes_;
   bool optimistic_{true};

requirements.txt

@@ -11,8 +11,8 @@ pyserial==3.5
 platformio==6.1.19
 esptool==5.1.0
 click==8.1.7
-esphome-dashboard==20260110.0
-aioesphomeapi==43.14.0
+esphome-dashboard==20260210.0
+aioesphomeapi==44.0.0
 zeroconf==0.148.0
 puremagic==1.30
 ruamel.yaml==0.19.1 # dashboard_import

tests/components/ld2450/common.yaml

@@ -1,5 +1,8 @@
 ld2450:
   - id: ld2450_radar
+    on_data:
+      then:
+        - logger.log: "LD2450 Radar Data Received"
 
 button:
   - platform: ld2450

tests/components/template/common-base.yaml

@@ -13,6 +13,8 @@ esphome:
         id: template_water_heater
         target_temperature: 50.0
         mode: ECO
+        away: false
+        is_on: true
 
     # Templated
     - water_heater.template.publish:
@@ -20,6 +22,8 @@ esphome:
         current_temperature: !lambda "return 45.0;"
         target_temperature: !lambda "return 55.0;"
         mode: !lambda "return water_heater::WATER_HEATER_MODE_GAS;"
+        away: !lambda "return true;"
+        is_on: !lambda "return false;"
 
     # Test C++ API: set_template() with stateless lambda (no captures)
     # NOTE: set_template() is not intended to be a public API, but we test it to ensure it doesn't break.
@@ -414,6 +418,8 @@ water_heater:
     current_temperature: !lambda "return 42.0f;"
     target_temperature: !lambda "return 60.0f;"
     mode: !lambda "return water_heater::WATER_HEATER_MODE_ECO;"
+    away: !lambda "return false;"
+    is_on: !lambda "return true;"
     supported_modes:
       - "OFF"
       - ECO

tests/integration/fixtures/water_heater_template.yaml

@@ -4,6 +4,14 @@ host:
 api:
 logger:
 
+globals:
+  - id: global_away
+    type: bool
+    initial_value: "false"
+  - id: global_is_on
+    type: bool
+    initial_value: "true"
+
 water_heater:
   - platform: template
     id: test_boiler
@@ -11,6 +19,8 @@ water_heater:
     optimistic: true
     current_temperature: !lambda "return 45.0f;"
     target_temperature: !lambda "return 60.0f;"
+    away: !lambda "return id(global_away);"
+    is_on: !lambda "return id(global_is_on);"
     # Note: No mode lambda - we want optimistic mode changes to stick
     # A mode lambda would override mode changes in loop()
     supported_modes:
@@ -22,3 +32,8 @@ water_heater:
       min_temperature: 30.0
       max_temperature: 85.0
       target_temperature_step: 0.5
+    set_action:
+      - lambda: |-
+          // Sync optimistic state back to globals so lambdas reflect the change
+          id(global_away) = id(test_boiler).is_away();
+          id(global_is_on) = id(test_boiler).is_on();

tests/integration/test_water_heater_template.py

@@ -5,7 +5,13 @@ from __future__ import annotations
 import asyncio
 
 import aioesphomeapi
-from aioesphomeapi import WaterHeaterInfo, WaterHeaterMode, WaterHeaterState
+from aioesphomeapi import (
+    WaterHeaterFeature,
+    WaterHeaterInfo,
+    WaterHeaterMode,
+    WaterHeaterState,
+    WaterHeaterStateFlag,
+)
 import pytest
 
 from .state_utils import InitialStateHelper
@@ -22,18 +28,25 @@ async def test_water_heater_template(
     loop = asyncio.get_running_loop()
     async with run_compiled(yaml_config), api_client_connected() as client:
         states: dict[int, aioesphomeapi.EntityState] = {}
-        gas_mode_future: asyncio.Future[WaterHeaterState] = loop.create_future()
-        eco_mode_future: asyncio.Future[WaterHeaterState] = loop.create_future()
+        state_future: asyncio.Future[WaterHeaterState] | None = None
 
         def on_state(state: aioesphomeapi.EntityState) -> None:
             states[state.key] = state
-            if isinstance(state, WaterHeaterState):
-                # Wait for GAS mode
-                if state.mode == WaterHeaterMode.GAS and not gas_mode_future.done():
-                    gas_mode_future.set_result(state)
-                # Wait for ECO mode (we start at OFF, so test transitioning to ECO)
-                elif state.mode == WaterHeaterMode.ECO and not eco_mode_future.done():
-                    eco_mode_future.set_result(state)
+            if (
+                isinstance(state, WaterHeaterState)
+                and state_future is not None
+                and not state_future.done()
+            ):
+                state_future.set_result(state)
+
+        async def wait_for_state(timeout: float = 5.0) -> WaterHeaterState:
+            """Wait for next water heater state change."""
+            nonlocal state_future
+            state_future = loop.create_future()
+            try:
+                return await asyncio.wait_for(state_future, timeout)
+            finally:
+                state_future = None
 
         # Get entities and set up state synchronization
         entities, services = await client.list_entities_services()
@@ -89,24 +102,52 @@ async def test_water_heater_template(
             f"Expected target temp 60.0, got {initial_state.target_temperature}"
         )
 
+        # Verify supported features: away mode and on/off (fixture has away + is_on lambdas)
+        assert (
+            test_water_heater.supported_features & WaterHeaterFeature.SUPPORTS_AWAY_MODE
+        ) != 0, "Expected SUPPORTS_AWAY_MODE in supported_features"
+        assert (
+            test_water_heater.supported_features & WaterHeaterFeature.SUPPORTS_ON_OFF
+        ) != 0, "Expected SUPPORTS_ON_OFF in supported_features"
+
+        # Verify initial state: on (is_on lambda returns true), not away (away lambda returns false)
+        assert (initial_state.state & WaterHeaterStateFlag.ON) != 0, (
+            "Expected initial state to include ON flag"
+        )
+        assert (initial_state.state & WaterHeaterStateFlag.AWAY) == 0, (
+            "Expected initial state to not include AWAY flag"
+        )
+
+        # Test turning on away mode
+        client.water_heater_command(test_water_heater.key, away=True)
+        away_on_state = await wait_for_state()
+        assert (away_on_state.state & WaterHeaterStateFlag.AWAY) != 0
+        # ON flag should still be set (is_on lambda returns true)
+        assert (away_on_state.state & WaterHeaterStateFlag.ON) != 0
+
+        # Test turning off away mode
+        client.water_heater_command(test_water_heater.key, away=False)
+        away_off_state = await wait_for_state()
+        assert (away_off_state.state & WaterHeaterStateFlag.AWAY) == 0
+        assert (away_off_state.state & WaterHeaterStateFlag.ON) != 0
+
+        # Test turning off (on=False)
+        client.water_heater_command(test_water_heater.key, on=False)
+        off_state = await wait_for_state()
+        assert (off_state.state & WaterHeaterStateFlag.ON) == 0
+        assert (off_state.state & WaterHeaterStateFlag.AWAY) == 0
+
+        # Test turning back on (on=True)
+        client.water_heater_command(test_water_heater.key, on=True)
+        on_state = await wait_for_state()
+        assert (on_state.state & WaterHeaterStateFlag.ON) != 0
+
         # Test changing to GAS mode
         client.water_heater_command(test_water_heater.key, mode=WaterHeaterMode.GAS)
-
-        try:
-            gas_state = await asyncio.wait_for(gas_mode_future, timeout=5.0)
-        except TimeoutError:
-            pytest.fail("GAS mode change not received within 5 seconds")
-
-        assert isinstance(gas_state, WaterHeaterState)
+        gas_state = await wait_for_state()
         assert gas_state.mode == WaterHeaterMode.GAS
 
         # Test changing to ECO mode (from GAS)
         client.water_heater_command(test_water_heater.key, mode=WaterHeaterMode.ECO)
-
-        try:
-            eco_state = await asyncio.wait_for(eco_mode_future, timeout=5.0)
-        except TimeoutError:
-            pytest.fail("ECO mode change not received within 5 seconds")
-
-        assert isinstance(eco_state, WaterHeaterState)
+        eco_state = await wait_for_state()
         assert eco_state.mode == WaterHeaterMode.ECO