diff --git a/esphome/build_gen/arduino8266.py b/esphome/build_gen/arduino8266.py
index ee5bfb1871..1f2fbb651f 100644
--- a/esphome/build_gen/arduino8266.py
+++ b/esphome/build_gen/arduino8266.py
@@ -36,6 +36,7 @@ from esphome.build_helpers.ninja import (
 from esphome.build_helpers.pch import (
     PCH_CORE_HEADER,
     PCH_HEADER_NAME,
+    mark_pch_emitted,
     pch_checksum,
     pch_enabled,
     pch_header_text,
@@ -1284,6 +1285,7 @@ def write_project(paths: InstalledPaths, ccache: str | None) -> bool:
             ]
             lines.append(f"srccxxflags = {' '.join(cxx_parts)}")
             src_cxx_override = ("$srccxxflags", gch)
+            mark_pch_emitted()
     src_objs = _ninja_compile_edges(
         lines,
         _collect_sources(src_dir),
diff --git a/esphome/build_helpers/pch.py b/esphome/build_helpers/pch.py
index bf57a157e3..eb0e0a831c 100644
--- a/esphome/build_helpers/pch.py
+++ b/esphome/build_helpers/pch.py
@@ -8,6 +8,7 @@ it too; Arduino.h visibility there is intended (esphome#8693).
 from __future__ import annotations
 
 from collections.abc import Iterable
+from dataclasses import dataclass
 import hashlib
 import json
 import logging
@@ -25,6 +26,27 @@ from esphome.build_helpers.idedata import (
     split_command,
 )
 
+_DOMAIN = "pch"
+
+
+@dataclass
+class _PCHData:
+    emitted: bool = False
+
+
+def _pch_data() -> _PCHData:
+    from esphome.core import CORE
+
+    if _DOMAIN not in CORE.data:
+        CORE.data[_DOMAIN] = _PCHData()
+    return CORE.data[_DOMAIN]
+
+
+def mark_pch_emitted() -> None:
+    """Record that this build's consumers reference the pch."""
+    _pch_data().emitted = True
+
+
 _LOGGER = logging.getLogger(__name__)
 
 # The header and its .gch/.sum sidecars live in the build directory.
@@ -81,9 +103,10 @@ def pch_enabled() -> bool:
 
 def ccache_pch_env() -> dict[str, str]:
     """Settings ccache needs to cache compiles that consume the .gch;
-    empty when the pch is disabled. User-set values win. Native backends
-    export these process-wide; only time_macros affects non-pch TUs."""
-    if not pch_enabled():
+    empty unless this build actually emitted one. User-set values win.
+    Native backends export these process-wide; only time_macros affects
+    non-pch TUs."""
+    if not (pch_enabled() and _pch_data().emitted):
         return {}
     env = {k: v for k, v in _CCACHE_PCH_ENV.items() if k not in os.environ}
     user_sloppiness = os.environ.get("CCACHE_SLOPPINESS")
diff --git a/tests/unit_tests/build_gen/test_arduino8266.py b/tests/unit_tests/build_gen/test_arduino8266.py
index 4009e91f01..dd0d9f5d40 100644
--- a/tests/unit_tests/build_gen/test_arduino8266.py
+++ b/tests/unit_tests/build_gen/test_arduino8266.py
@@ -386,6 +386,10 @@ def test_write_project_pch(tmp_path: Path) -> None:
         '#include "esphome/core/defines.h"',
     ]
     assert (build_dir / "esphome_pch.h.gch.sum").read_text().strip()
+    # Emission recorded so the framework env exports the ccache settings
+    from esphome.build_helpers.pch import ccache_pch_env
+
+    assert "CCACHE_PCH_EXTSUM" in ccache_pch_env()
 
 
 def test_write_project_pch_sum_only_with_ccache(tmp_path: Path) -> None:
@@ -456,6 +460,10 @@ def test_write_project_pch_skipped_when_user_force_include_precedes(
     assert "esphome_pch" not in content
     assert "srccxxflags" not in content
     assert "prevents the precompiled header" in caplog.text
+    # No pch emitted: the ccache relaxation must stay off
+    from esphome.build_helpers.pch import ccache_pch_env
+
+    assert ccache_pch_env() == {}
 
 
 def test_write_project_pch_disabled(
diff --git a/tests/unit_tests/build_helpers/test_pch.py b/tests/unit_tests/build_helpers/test_pch.py
index e8ea0c18bb..bb6ee81a7f 100644
--- a/tests/unit_tests/build_helpers/test_pch.py
+++ b/tests/unit_tests/build_helpers/test_pch.py
@@ -33,7 +33,14 @@ def test_pch_enabled(value: str | None, expected: bool) -> None:
         assert pch.pch_enabled() is expected
 
 
+def test_ccache_pch_env_empty_until_emitted() -> None:
+    """No sloppiness relaxation for a build that skipped the pch."""
+    with patch.dict(os.environ, {}, clear=True):
+        assert pch.ccache_pch_env() == {}
+
+
 def test_ccache_pch_env_enabled() -> None:
+    pch.mark_pch_emitted()
     with patch.dict(os.environ, {}, clear=True):
         env = pch.ccache_pch_env()
     assert env["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
@@ -48,6 +55,7 @@ def test_ccache_pch_env_disabled() -> None:
 def test_ccache_pch_env_token_check_is_membership_not_substring(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
+    pch.mark_pch_emitted()
     """A token merely containing ours must not suppress the union."""
     with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "pch_defines_extra"}, clear=True):
         env = pch.ccache_pch_env()
@@ -57,6 +65,7 @@ def test_ccache_pch_env_token_check_is_membership_not_substring(
 def test_ccache_pch_env_unions_user_sloppiness(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
+    pch.mark_pch_emitted()
     """Without pch_defines/time_macros ccache declines every pch-consuming
     compile, so missing tokens are unioned onto the user's value."""
     with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "locale"}, clear=True):
diff --git a/tests/unit_tests/test_arduino8266_toolchain.py b/tests/unit_tests/test_arduino8266_toolchain.py
index 7f41687909..a17dec4397 100644
--- a/tests/unit_tests/test_arduino8266_toolchain.py
+++ b/tests/unit_tests/test_arduino8266_toolchain.py
@@ -9,6 +9,7 @@ from unittest.mock import MagicMock, patch
 import pytest
 
 from esphome.arduino8266 import framework, toolchain
+from esphome.build_helpers.pch import mark_pch_emitted
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_COMPILE_PROCESS_LIMIT,
@@ -632,6 +633,7 @@ def test_get_idedata_accepts_preresolved_ccache() -> None:
 
 
 def test_ccache_env_includes_pch_settings() -> None:
+    mark_pch_emitted()
     """The native build exports the ccache settings the pch needs."""
     with patch.dict(os.environ, {}, clear=True):
         env = framework.ccache_env("/usr/bin/ccache")
@@ -647,6 +649,7 @@ def test_ccache_env_pch_disabled() -> None:
 
 
 def test_ccache_env_respects_user_sloppiness() -> None:
+    mark_pch_emitted()
     with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "locale"}, clear=True):
         env = framework.ccache_env("/usr/bin/ccache")
     # The user's tokens survive; the ones the pch needs are unioned on