diff --git a/esphome/components/ade7880/ade7880.cpp b/esphome/components/ade7880/ade7880.cpp
index 55f834bf86a..fd560e06766 100644
--- a/esphome/components/ade7880/ade7880.cpp
+++ b/esphome/components/ade7880/ade7880.cpp
@@ -113,7 +113,7 @@ void ADE7880::update() {
   if (this->channel_a_ != nullptr) {
     auto *chan = this->channel_a_;
     this->update_sensor_from_s24zp_register16_(chan->current, AIRMS, [](float val) { return val / 100000.0f; });
-    this->update_sensor_from_s24zp_register16_(chan->voltage, BVRMS, [](float val) { return val / 10000.0f; });
+    this->update_sensor_from_s24zp_register16_(chan->voltage, AVRMS, [](float val) { return val / 10000.0f; });
     this->update_sensor_from_s24zp_register16_(chan->active_power, AWATT, [](float val) { return val / 100.0f; });
     this->update_sensor_from_s24zp_register16_(chan->apparent_power, AVA, [](float val) { return val / 100.0f; });
     this->update_sensor_from_s16_register16_(chan->power_factor, APF,
diff --git a/esphome/components/as7341/sensor.py b/esphome/components/as7341/sensor.py
index 2832b7c3df6..fa51a1cdfa4 100644
--- a/esphome/components/as7341/sensor.py
+++ b/esphome/components/as7341/sensor.py
@@ -2,6 +2,7 @@ import esphome.codegen as cg
 from esphome.components import i2c, sensor
 import esphome.config_validation as cv
 from esphome.const import (
+    CONF_CLEAR,
     CONF_GAIN,
     CONF_ID,
     DEVICE_CLASS_ILLUMINANCE,
@@ -29,7 +30,6 @@ CONF_F5 = "f5"
 CONF_F6 = "f6"
 CONF_F7 = "f7"
 CONF_F8 = "f8"
-CONF_CLEAR = "clear"
 CONF_NIR = "nir"
 
 UNIT_COUNTS = "#"
diff --git a/esphome/components/ethernet/__init__.py b/esphome/components/ethernet/__init__.py
index a26238553c5..151da7d0e5d 100644
--- a/esphome/components/ethernet/__init__.py
+++ b/esphome/components/ethernet/__init__.py
@@ -77,6 +77,13 @@ ETHERNET_TYPES = {
     "DM9051": EthernetType.ETHERNET_TYPE_DM9051,
 }
 
+# PHY types that need compile-time defines for conditional compilation
+_PHY_TYPE_TO_DEFINE = {
+    "KSZ8081": "USE_ETHERNET_KSZ8081",
+    "KSZ8081RNA": "USE_ETHERNET_KSZ8081",
+    # Add other PHY types here only if they need conditional compilation
+}
+
 SPI_ETHERNET_TYPES = ["W5500", "DM9051"]
 SPI_ETHERNET_DEFAULT_POLLING_INTERVAL = TimePeriodMilliseconds(milliseconds=10)
 
@@ -345,6 +352,10 @@ async def to_code(config):
     if CONF_MANUAL_IP in config:
         cg.add(var.set_manual_ip(manual_ip(config[CONF_MANUAL_IP])))
 
+    # Add compile-time define for PHY types with specific code
+    if phy_define := _PHY_TYPE_TO_DEFINE.get(config[CONF_TYPE]):
+        cg.add_define(phy_define)
+
     cg.add_define("USE_ETHERNET")
 
     # Disable WiFi when using Ethernet to save memory
diff --git a/esphome/components/ethernet/ethernet_component.cpp b/esphome/components/ethernet/ethernet_component.cpp
index a48fd27383f..ff14d194277 100644
--- a/esphome/components/ethernet/ethernet_component.cpp
+++ b/esphome/components/ethernet/ethernet_component.cpp
@@ -229,10 +229,12 @@ void EthernetComponent::setup() {
   ESPHL_ERROR_CHECK(err, "ETH driver install error");
 
 #ifndef USE_ETHERNET_SPI
+#ifdef USE_ETHERNET_KSZ8081
   if (this->type_ == ETHERNET_TYPE_KSZ8081RNA && this->clk_mode_ == EMAC_CLK_OUT) {
     // KSZ8081RNA default is incorrect. It expects a 25MHz clock instead of the 50MHz we provide.
     this->ksz8081_set_clock_reference_(mac);
   }
+#endif  // USE_ETHERNET_KSZ8081
 
   for (const auto &phy_register : this->phy_registers_) {
     this->write_phy_register_(mac, phy_register);
@@ -721,6 +723,7 @@ bool EthernetComponent::powerdown() {
 
 #ifndef USE_ETHERNET_SPI
 
+#ifdef USE_ETHERNET_KSZ8081
 constexpr uint8_t KSZ80XX_PC2R_REG_ADDR = 0x1F;
 
 void EthernetComponent::ksz8081_set_clock_reference_(esp_eth_mac_t *mac) {
@@ -749,6 +752,7 @@ void EthernetComponent::ksz8081_set_clock_reference_(esp_eth_mac_t *mac) {
     ESP_LOGVV(TAG, "KSZ8081 PHY Control 2: %s", format_hex_pretty((u_int8_t *) &phy_control_2, 2).c_str());
   }
 }
+#endif  // USE_ETHERNET_KSZ8081
 
 void EthernetComponent::write_phy_register_(esp_eth_mac_t *mac, PHYRegister register_data) {
   esp_err_t err;
diff --git a/esphome/components/ethernet/ethernet_component.h b/esphome/components/ethernet/ethernet_component.h
index 3d2713ee5cc..bbb9d7fb608 100644
--- a/esphome/components/ethernet/ethernet_component.h
+++ b/esphome/components/ethernet/ethernet_component.h
@@ -104,8 +104,10 @@ class EthernetComponent : public Component {
   void start_connect_();
   void finish_connect_();
   void dump_connect_params_();
+#ifdef USE_ETHERNET_KSZ8081
   /// @brief Set `RMII Reference Clock Select` bit for KSZ8081.
   void ksz8081_set_clock_reference_(esp_eth_mac_t *mac);
+#endif
   /// @brief Set arbitratry PHY registers from config.
   void write_phy_register_(esp_eth_mac_t *mac, PHYRegister register_data);
 
diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index 7675280f1af..7ab6efd1a12 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -491,7 +491,7 @@ bool MQTTClientComponent::publish(const std::string &topic, const std::string &p
 
 bool MQTTClientComponent::publish(const std::string &topic, const char *payload, size_t payload_length, uint8_t qos,
                                   bool retain) {
-  return publish({.topic = topic, .payload = payload, .qos = qos, .retain = retain});
+  return publish({.topic = topic, .payload = std::string(payload, payload_length), .qos = qos, .retain = retain});
 }
 
 bool MQTTClientComponent::publish(const MQTTMessage &message) {
diff --git a/esphome/const.py b/esphome/const.py
index 677b9173ec1..c91c81f484f 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -186,6 +186,7 @@ CONF_CHARACTERISTIC_UUID = "characteristic_uuid"
 CONF_CHECK = "check"
 CONF_CHIPSET = "chipset"
 CONF_CLEAN_SESSION = "clean_session"
+CONF_CLEAR = "clear"
 CONF_CLEAR_IMPEDANCE = "clear_impedance"
 CONF_CLIENT_CERTIFICATE = "client_certificate"
 CONF_CLIENT_CERTIFICATE_KEY = "client_certificate_key"
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 9a7e090b833..6e8d5ed74c5 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -175,6 +175,7 @@
 #ifdef USE_ARDUINO
 #define USE_ARDUINO_VERSION_CODE VERSION_CODE(3, 2, 1)
 #define USE_ETHERNET
+#define USE_ETHERNET_KSZ8081
 #endif
 
 #ifdef USE_ESP_IDF
diff --git a/esphome/wizard.py b/esphome/wizard.py
index cb599df59a1..3edf519816e 100644
--- a/esphome/wizard.py
+++ b/esphome/wizard.py
@@ -1,6 +1,7 @@
 import os
 import random
 import string
+from typing import Literal, NotRequired, TypedDict, Unpack
 import unicodedata
 
 import voluptuous as vol
@@ -103,11 +104,25 @@ HARDWARE_BASE_CONFIGS = {
 }
 
 
-def sanitize_double_quotes(value):
+def sanitize_double_quotes(value: str) -> str:
     return value.replace("\\", "\\\\").replace('"', '\\"')
 
 
-def wizard_file(**kwargs):
+class WizardFileKwargs(TypedDict):
+    """Keyword arguments for wizard_file function."""
+
+    name: str
+    platform: Literal["ESP8266", "ESP32", "RP2040", "BK72XX", "LN882X", "RTL87XX"]
+    board: str
+    ssid: NotRequired[str]
+    psk: NotRequired[str]
+    password: NotRequired[str]
+    ota_password: NotRequired[str]
+    api_encryption_key: NotRequired[str]
+    friendly_name: NotRequired[str]
+
+
+def wizard_file(**kwargs: Unpack[WizardFileKwargs]) -> str:
     letters = string.ascii_letters + string.digits
     ap_name_base = kwargs["name"].replace("_", " ").title()
     ap_name = f"{ap_name_base} Fallback Hotspot"
@@ -180,7 +195,25 @@ captive_portal:
     return config
 
 
-def wizard_write(path, **kwargs):
+class WizardWriteKwargs(TypedDict):
+    """Keyword arguments for wizard_write function."""
+
+    name: str
+    type: Literal["basic", "empty", "upload"]
+    # Required for "basic" type
+    board: NotRequired[str]
+    platform: NotRequired[str]
+    ssid: NotRequired[str]
+    psk: NotRequired[str]
+    password: NotRequired[str]
+    ota_password: NotRequired[str]
+    api_encryption_key: NotRequired[str]
+    friendly_name: NotRequired[str]
+    # Required for "upload" type
+    file_text: NotRequired[str]
+
+
+def wizard_write(path: str, **kwargs: Unpack[WizardWriteKwargs]) -> bool:
     from esphome.components.bk72xx import boards as bk72xx_boards
     from esphome.components.esp32 import boards as esp32_boards
     from esphome.components.esp8266 import boards as esp8266_boards
@@ -237,14 +270,14 @@ def wizard_write(path, **kwargs):
 
 if get_bool_env(ENV_QUICKWIZARD):
 
-    def sleep(time):
+    def sleep(time: float) -> None:
         pass
 
 else:
     from time import sleep
 
 
-def safe_print_step(step, big):
+def safe_print_step(step: int, big: str) -> None:
     safe_print()
     safe_print()
     safe_print(f"============= STEP {step} =============")
@@ -253,14 +286,14 @@ def safe_print_step(step, big):
     sleep(0.25)
 
 
-def default_input(text, default):
+def default_input(text: str, default: str) -> str:
     safe_print()
     safe_print(f"Press ENTER for default ({default})")
     return safe_input(text.format(default)) or default
 
 
 # From https://stackoverflow.com/a/518232/8924614
-def strip_accents(value):
+def strip_accents(value: str) -> str:
     return "".join(
         c
         for c in unicodedata.normalize("NFD", str(value))
@@ -268,7 +301,7 @@ def strip_accents(value):
     )
 
 
-def wizard(path):
+def wizard(path: str) -> int:
     from esphome.components.bk72xx import boards as bk72xx_boards
     from esphome.components.esp32 import boards as esp32_boards
     from esphome.components.esp8266 import boards as esp8266_boards
@@ -509,6 +542,7 @@ def wizard(path):
         ssid=ssid,
         psk=psk,
         password=password,
+        type="basic",
     ):
         return 1
 
diff --git a/esphome/writer.py b/esphome/writer.py
index b8fe44abdd8..2a9c6a770db 100644
--- a/esphome/writer.py
+++ b/esphome/writer.py
@@ -315,6 +315,19 @@ def clean_build():
         _LOGGER.info("Deleting %s", dependencies_lock)
         os.remove(dependencies_lock)
 
+    # Clean PlatformIO cache to resolve CMake compiler detection issues
+    # This helps when toolchain paths change or get corrupted
+    try:
+        from platformio.project.helpers import get_project_cache_dir
+    except ImportError:
+        # PlatformIO is not available, skip cache cleaning
+        pass
+    else:
+        cache_dir = get_project_cache_dir()
+        if cache_dir and cache_dir.strip() and os.path.isdir(cache_dir):
+            _LOGGER.info("Deleting PlatformIO cache %s", cache_dir)
+            shutil.rmtree(cache_dir)
+
 
 GITIGNORE_CONTENT = """# Gitignore settings for ESPHome
 # This is an example and may include too much for your use-case.
diff --git a/requirements_test.txt b/requirements_test.txt
index 5ec9c984081..2e2f8a1c0d2 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -7,7 +7,7 @@ pre-commit
 # Unit tests
 pytest==8.4.2
 pytest-cov==7.0.0
-pytest-mock==3.15.0
+pytest-mock==3.15.1
 pytest-asyncio==1.2.0
 pytest-xdist==3.8.0
 asyncmock==0.4.2
diff --git a/tests/unit_tests/test_wizard.py b/tests/unit_tests/test_wizard.py
index fea2fb5558e..7af4db813a0 100644
--- a/tests/unit_tests/test_wizard.py
+++ b/tests/unit_tests/test_wizard.py
@@ -1,9 +1,12 @@
 """Tests for the wizard.py file."""
 
 import os
+from pathlib import Path
+from typing import Any
 from unittest.mock import MagicMock
 
 import pytest
+from pytest import MonkeyPatch
 
 from esphome.components.bk72xx.boards import BK72XX_BOARD_PINS
 from esphome.components.esp32.boards import ESP32_BOARD_PINS
@@ -15,7 +18,7 @@ import esphome.wizard as wz
 
 
 @pytest.fixture
-def default_config():
+def default_config() -> dict[str, Any]:
     return {
         "type": "basic",
         "name": "test-name",
@@ -28,7 +31,7 @@ def default_config():
 
 
 @pytest.fixture
-def wizard_answers():
+def wizard_answers() -> list[str]:
     return [
         "test-node",  # Name of the node
         "ESP8266",  # platform
@@ -53,7 +56,9 @@ def test_sanitize_quotes_replaces_with_escaped_char():
     assert output_str == '\\"key\\": \\"value\\"'
 
 
-def test_config_file_fallback_ap_includes_descriptive_name(default_config):
+def test_config_file_fallback_ap_includes_descriptive_name(
+    default_config: dict[str, Any],
+):
     """
     The fallback AP should include the node and a descriptive name
     """
@@ -67,7 +72,9 @@ def test_config_file_fallback_ap_includes_descriptive_name(default_config):
     assert 'ssid: "Test Node Fallback Hotspot"' in config
 
 
-def test_config_file_fallback_ap_name_less_than_32_chars(default_config):
+def test_config_file_fallback_ap_name_less_than_32_chars(
+    default_config: dict[str, Any],
+):
     """
     The fallback AP name must be less than 32 chars.
     Since it is composed of the node name and "Fallback Hotspot" this can be too long and needs truncating
@@ -82,7 +89,7 @@ def test_config_file_fallback_ap_name_less_than_32_chars(default_config):
     assert 'ssid: "A Very Long Name For This Node"' in config
 
 
-def test_config_file_should_include_ota(default_config):
+def test_config_file_should_include_ota(default_config: dict[str, Any]):
     """
     The Over-The-Air update should be enabled by default
     """
@@ -95,7 +102,9 @@ def test_config_file_should_include_ota(default_config):
     assert "ota:" in config
 
 
-def test_config_file_should_include_ota_when_password_set(default_config):
+def test_config_file_should_include_ota_when_password_set(
+    default_config: dict[str, Any],
+):
     """
     The Over-The-Air update should be enabled when a password is set
     """
@@ -109,7 +118,9 @@ def test_config_file_should_include_ota_when_password_set(default_config):
     assert "ota:" in config
 
 
-def test_wizard_write_sets_platform(default_config, tmp_path, monkeypatch):
+def test_wizard_write_sets_platform(
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
+):
     """
     If the platform is not explicitly set, use "ESP8266" if the board is one of the ESP8266 boards
     """
@@ -126,7 +137,7 @@ def test_wizard_write_sets_platform(default_config, tmp_path, monkeypatch):
     assert "esp8266:" in generated_config
 
 
-def test_wizard_empty_config(tmp_path, monkeypatch):
+def test_wizard_empty_config(tmp_path: Path, monkeypatch: MonkeyPatch):
     """
     The wizard should be able to create an empty configuration
     """
@@ -146,7 +157,7 @@ def test_wizard_empty_config(tmp_path, monkeypatch):
     assert generated_config == ""
 
 
-def test_wizard_upload_config(tmp_path, monkeypatch):
+def test_wizard_upload_config(tmp_path: Path, monkeypatch: MonkeyPatch):
     """
     The wizard should be able to import an base64 encoded configuration
     """
@@ -168,7 +179,7 @@ def test_wizard_upload_config(tmp_path, monkeypatch):
 
 
 def test_wizard_write_defaults_platform_from_board_esp8266(
-    default_config, tmp_path, monkeypatch
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
 ):
     """
     If the platform is not explicitly set, use "ESP8266" if the board is one of the ESP8266 boards
@@ -189,7 +200,7 @@ def test_wizard_write_defaults_platform_from_board_esp8266(
 
 
 def test_wizard_write_defaults_platform_from_board_esp32(
-    default_config, tmp_path, monkeypatch
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
 ):
     """
     If the platform is not explicitly set, use "ESP32" if the board is one of the ESP32 boards
@@ -210,7 +221,7 @@ def test_wizard_write_defaults_platform_from_board_esp32(
 
 
 def test_wizard_write_defaults_platform_from_board_bk72xx(
-    default_config, tmp_path, monkeypatch
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
 ):
     """
     If the platform is not explicitly set, use "BK72XX" if the board is one of BK72XX boards
@@ -231,7 +242,7 @@ def test_wizard_write_defaults_platform_from_board_bk72xx(
 
 
 def test_wizard_write_defaults_platform_from_board_ln882x(
-    default_config, tmp_path, monkeypatch
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
 ):
     """
     If the platform is not explicitly set, use "LN882X" if the board is one of LN882X boards
@@ -252,7 +263,7 @@ def test_wizard_write_defaults_platform_from_board_ln882x(
 
 
 def test_wizard_write_defaults_platform_from_board_rtl87xx(
-    default_config, tmp_path, monkeypatch
+    default_config: dict[str, Any], tmp_path: Path, monkeypatch: MonkeyPatch
 ):
     """
     If the platform is not explicitly set, use "RTL87XX" if the board is one of RTL87XX boards
@@ -272,7 +283,7 @@ def test_wizard_write_defaults_platform_from_board_rtl87xx(
     assert "rtl87xx:" in generated_config
 
 
-def test_safe_print_step_prints_step_number_and_description(monkeypatch):
+def test_safe_print_step_prints_step_number_and_description(monkeypatch: MonkeyPatch):
     """
     The safe_print_step function prints the step number and the passed description
     """
@@ -296,7 +307,7 @@ def test_safe_print_step_prints_step_number_and_description(monkeypatch):
     assert any(f"STEP {step_num}" in arg for arg in all_args)
 
 
-def test_default_input_uses_default_if_no_input_supplied(monkeypatch):
+def test_default_input_uses_default_if_no_input_supplied(monkeypatch: MonkeyPatch):
     """
     The default_input() function should return the supplied default value if the user doesn't enter anything
     """
@@ -312,7 +323,7 @@ def test_default_input_uses_default_if_no_input_supplied(monkeypatch):
     assert retval == default_string
 
 
-def test_default_input_uses_user_supplied_value(monkeypatch):
+def test_default_input_uses_user_supplied_value(monkeypatch: MonkeyPatch):
     """
     The default_input() function should return the value that the user enters
     """
@@ -376,7 +387,9 @@ def test_wizard_rejects_existing_files(tmpdir):
     assert retval == 2
 
 
-def test_wizard_accepts_default_answers_esp8266(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_accepts_default_answers_esp8266(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     The wizard should accept the given default answers for esp8266
     """
@@ -396,7 +409,9 @@ def test_wizard_accepts_default_answers_esp8266(tmpdir, monkeypatch, wizard_answ
     assert retval == 0
 
 
-def test_wizard_accepts_default_answers_esp32(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_accepts_default_answers_esp32(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     The wizard should accept the given default answers for esp32
     """
@@ -418,7 +433,9 @@ def test_wizard_accepts_default_answers_esp32(tmpdir, monkeypatch, wizard_answer
     assert retval == 0
 
 
-def test_wizard_offers_better_node_name(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_offers_better_node_name(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     When the node name does not conform, a better alternative is offered
     * Removes special chars
@@ -449,7 +466,9 @@ def test_wizard_offers_better_node_name(tmpdir, monkeypatch, wizard_answers):
     assert wz.default_input.call_args.args[1] == expected_name
 
 
-def test_wizard_requires_correct_platform(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_requires_correct_platform(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     When the platform is not either esp32 or esp8266, the wizard should reject it
     """
@@ -471,7 +490,9 @@ def test_wizard_requires_correct_platform(tmpdir, monkeypatch, wizard_answers):
     assert retval == 0
 
 
-def test_wizard_requires_correct_board(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_requires_correct_board(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     When the board is not a valid esp8266 board, the wizard should reject it
     """
@@ -493,7 +514,9 @@ def test_wizard_requires_correct_board(tmpdir, monkeypatch, wizard_answers):
     assert retval == 0
 
 
-def test_wizard_requires_valid_ssid(tmpdir, monkeypatch, wizard_answers):
+def test_wizard_requires_valid_ssid(
+    tmpdir, monkeypatch: MonkeyPatch, wizard_answers: list[str]
+):
     """
     When the board is not a valid esp8266 board, the wizard should reject it
     """
@@ -515,7 +538,9 @@ def test_wizard_requires_valid_ssid(tmpdir, monkeypatch, wizard_answers):
     assert retval == 0
 
 
-def test_wizard_write_protects_existing_config(tmpdir, default_config, monkeypatch):
+def test_wizard_write_protects_existing_config(
+    tmpdir, default_config: dict[str, Any], monkeypatch: MonkeyPatch
+):
     """
     The wizard_write function should not overwrite existing config files and return False
     """
diff --git a/tests/unit_tests/test_writer.py b/tests/unit_tests/test_writer.py
index f1f86a322e6..970e0fada66 100644
--- a/tests/unit_tests/test_writer.py
+++ b/tests/unit_tests/test_writer.py
@@ -349,6 +349,14 @@ def test_clean_build(
     dependencies_lock = tmp_path / "dependencies.lock"
     dependencies_lock.write_text("lock file")
 
+    # Create PlatformIO cache directory
+    platformio_cache_dir = tmp_path / ".platformio" / ".cache"
+    platformio_cache_dir.mkdir(parents=True)
+    (platformio_cache_dir / "downloads").mkdir()
+    (platformio_cache_dir / "http").mkdir()
+    (platformio_cache_dir / "tmp").mkdir()
+    (platformio_cache_dir / "downloads" / "package.tar.gz").write_text("package")
+
     # Setup mocks
     mock_core.relative_pioenvs_path.return_value = str(pioenvs_dir)
     mock_core.relative_piolibdeps_path.return_value = str(piolibdeps_dir)
@@ -358,21 +366,30 @@ def test_clean_build(
     assert pioenvs_dir.exists()
     assert piolibdeps_dir.exists()
     assert dependencies_lock.exists()
+    assert platformio_cache_dir.exists()
 
-    # Call the function
-    with caplog.at_level("INFO"):
-        clean_build()
+    # Mock PlatformIO's get_project_cache_dir
+    with patch(
+        "platformio.project.helpers.get_project_cache_dir"
+    ) as mock_get_cache_dir:
+        mock_get_cache_dir.return_value = str(platformio_cache_dir)
+
+        # Call the function
+        with caplog.at_level("INFO"):
+            clean_build()
 
     # Verify all were removed
     assert not pioenvs_dir.exists()
     assert not piolibdeps_dir.exists()
     assert not dependencies_lock.exists()
+    assert not platformio_cache_dir.exists()
 
     # Verify logging
     assert "Deleting" in caplog.text
     assert ".pioenvs" in caplog.text
     assert ".piolibdeps" in caplog.text
     assert "dependencies.lock" in caplog.text
+    assert "PlatformIO cache" in caplog.text
 
 
 @patch("esphome.writer.CORE")
@@ -446,6 +463,86 @@ def test_clean_build_nothing_exists(
     assert not dependencies_lock.exists()
 
 
+@patch("esphome.writer.CORE")
+def test_clean_build_platformio_not_available(
+    mock_core: MagicMock,
+    tmp_path: Path,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test clean_build when PlatformIO is not available."""
+    # Create directory structure and files
+    pioenvs_dir = tmp_path / ".pioenvs"
+    pioenvs_dir.mkdir()
+
+    piolibdeps_dir = tmp_path / ".piolibdeps"
+    piolibdeps_dir.mkdir()
+
+    dependencies_lock = tmp_path / "dependencies.lock"
+    dependencies_lock.write_text("lock file")
+
+    # Setup mocks
+    mock_core.relative_pioenvs_path.return_value = str(pioenvs_dir)
+    mock_core.relative_piolibdeps_path.return_value = str(piolibdeps_dir)
+    mock_core.relative_build_path.return_value = str(dependencies_lock)
+
+    # Verify all exist before
+    assert pioenvs_dir.exists()
+    assert piolibdeps_dir.exists()
+    assert dependencies_lock.exists()
+
+    # Mock import error for platformio
+    with (
+        patch.dict("sys.modules", {"platformio.project.helpers": None}),
+        caplog.at_level("INFO"),
+    ):
+        # Call the function
+        clean_build()
+
+    # Verify standard paths were removed but no cache cleaning attempted
+    assert not pioenvs_dir.exists()
+    assert not piolibdeps_dir.exists()
+    assert not dependencies_lock.exists()
+
+    # Verify no cache logging
+    assert "PlatformIO cache" not in caplog.text
+
+
+@patch("esphome.writer.CORE")
+def test_clean_build_empty_cache_dir(
+    mock_core: MagicMock,
+    tmp_path: Path,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test clean_build when get_project_cache_dir returns empty/whitespace."""
+    # Create directory structure and files
+    pioenvs_dir = tmp_path / ".pioenvs"
+    pioenvs_dir.mkdir()
+
+    # Setup mocks
+    mock_core.relative_pioenvs_path.return_value = str(pioenvs_dir)
+    mock_core.relative_piolibdeps_path.return_value = str(tmp_path / ".piolibdeps")
+    mock_core.relative_build_path.return_value = str(tmp_path / "dependencies.lock")
+
+    # Verify pioenvs exists before
+    assert pioenvs_dir.exists()
+
+    # Mock PlatformIO's get_project_cache_dir to return whitespace
+    with patch(
+        "platformio.project.helpers.get_project_cache_dir"
+    ) as mock_get_cache_dir:
+        mock_get_cache_dir.return_value = "   "  # Whitespace only
+
+        # Call the function
+        with caplog.at_level("INFO"):
+            clean_build()
+
+    # Verify pioenvs was removed
+    assert not pioenvs_dir.exists()
+
+    # Verify no cache cleaning was attempted due to empty string
+    assert "PlatformIO cache" not in caplog.text
+
+
 @patch("esphome.writer.CORE")
 def test_write_gitignore_creates_new_file(
     mock_core: MagicMock,