From cd3f10630b5280e5ab9cf2dd743be50cf39af5a6 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:01:36 -0500
Subject: [PATCH 01/14] wip

---
 esphome/components/copy/fan/copy_fan.cpp      | 14 ++-
 esphome/components/fan/fan.cpp                | 88 +++++++++++++------
 esphome/components/fan/fan.h                  | 28 ++++--
 esphome/components/fan/fan_traits.h           | 12 +++
 .../components/hbridge/fan/hbridge_fan.cpp    |  8 +-
 esphome/components/speed/fan/speed_fan.cpp    |  8 +-
 .../components/template/fan/template_fan.cpp  |  8 +-
 7 files changed, 125 insertions(+), 41 deletions(-)

diff --git a/esphome/components/copy/fan/copy_fan.cpp b/esphome/components/copy/fan/copy_fan.cpp
index 15a7f5e025..c1e873e083 100644
--- a/esphome/components/copy/fan/copy_fan.cpp
+++ b/esphome/components/copy/fan/copy_fan.cpp
@@ -12,7 +12,11 @@ void CopyFan::setup() {
     this->oscillating = source_->oscillating;
     this->speed = source_->speed;
     this->direction = source_->direction;
-    this->preset_mode = source_->preset_mode;
+    const char *preset = source_->get_preset_mode();
+    if (preset != nullptr)
+      this->set_preset_mode_(preset);
+    else
+      this->clear_preset_mode_();
     this->publish_state();
   });
 
@@ -20,7 +24,11 @@ void CopyFan::setup() {
   this->oscillating = source_->oscillating;
   this->speed = source_->speed;
   this->direction = source_->direction;
-  this->preset_mode = source_->preset_mode;
+  const char *preset = source_->get_preset_mode();
+  if (preset != nullptr)
+    this->set_preset_mode_(preset);
+  else
+    this->clear_preset_mode_();
   this->publish_state();
 }
 
@@ -49,7 +57,7 @@ void CopyFan::control(const fan::FanCall &call) {
     call2.set_speed(*call.get_speed());
   if (call.get_direction().has_value())
     call2.set_direction(*call.get_direction());
-  if (!call.get_preset_mode().empty())
+  if (call.has_preset_mode())
     call2.set_preset_mode(call.get_preset_mode());
   call2.perform();
 }
diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index 5b4f437f99..e38b7b43a4 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -17,6 +17,27 @@ const LogString *fan_direction_to_string(FanDirection direction) {
   }
 }
 
+FanCall &FanCall::set_preset_mode(const std::string &preset_mode) { return this->set_preset_mode(preset_mode.c_str()); }
+
+FanCall &FanCall::set_preset_mode(const char *preset_mode) {
+  if (preset_mode == nullptr || strlen(preset_mode) == 0) {
+    this->preset_mode_ = nullptr;
+    return *this;
+  }
+
+  // Find and validate pointer from traits immediately
+  auto traits = this->parent_.get_traits();
+  const char *validated_mode = traits.find_preset_mode(preset_mode);
+  if (validated_mode != nullptr) {
+    this->preset_mode_ = validated_mode;  // Store pointer from traits
+  } else {
+    // Preset mode not found in traits - log warning and don't set
+    ESP_LOGW(TAG, "%s: Preset mode '%s' not supported", this->parent_.get_name().c_str(), preset_mode);
+    this->preset_mode_ = nullptr;
+  }
+  return *this;
+}
+
 void FanCall::perform() {
   ESP_LOGD(TAG, "'%s' - Setting:", this->parent_.get_name().c_str());
   this->validate_();
@@ -32,8 +53,8 @@ void FanCall::perform() {
   if (this->direction_.has_value()) {
     ESP_LOGD(TAG, "  Direction: %s", LOG_STR_ARG(fan_direction_to_string(*this->direction_)));
   }
-  if (!this->preset_mode_.empty()) {
-    ESP_LOGD(TAG, "  Preset Mode: %s", this->preset_mode_.c_str());
+  if (this->has_preset_mode()) {
+    ESP_LOGD(TAG, "  Preset Mode: %s", this->preset_mode_);
   }
   this->parent_.control(*this);
 }
@@ -46,30 +67,15 @@ void FanCall::validate_() {
 
     // https://developers.home-assistant.io/docs/core/entity/fan/#preset-modes
     // "Manually setting a speed must disable any set preset mode"
-    this->preset_mode_.clear();
-  }
-
-  if (!this->preset_mode_.empty()) {
-    const auto &preset_modes = traits.supported_preset_modes();
-    bool found = false;
-    for (const auto &mode : preset_modes) {
-      if (strcmp(mode, this->preset_mode_.c_str()) == 0) {
-        found = true;
-        break;
-      }
-    }
-    if (!found) {
-      ESP_LOGW(TAG, "%s: Preset mode '%s' not supported", this->parent_.get_name().c_str(), this->preset_mode_.c_str());
-      this->preset_mode_.clear();
-    }
+    this->preset_mode_ = nullptr;
   }
 
   // when turning on...
   if (!this->parent_.state && this->binary_state_.has_value() &&
       *this->binary_state_
       // ..,and no preset mode will be active...
-      && this->preset_mode_.empty() &&
-      this->parent_.preset_mode.empty()
+      && !this->has_preset_mode() &&
+      this->parent_.get_preset_mode() == nullptr
       // ...and neither current nor new speed is available...
       && traits.supports_speed() && this->parent_.speed == 0 && !this->speed_.has_value()) {
     // ...set speed to 100%
@@ -120,7 +126,7 @@ void FanRestoreState::apply(Fan &fan) {
     // Use stored preset index to get preset name
     const auto &preset_modes = traits.supported_preset_modes();
     if (this->preset_mode < preset_modes.size()) {
-      fan.preset_mode = preset_modes[this->preset_mode];
+      fan.set_preset_mode_(preset_modes[this->preset_mode]);
     }
   }
   fan.publish_state();
@@ -131,6 +137,36 @@ FanCall Fan::turn_off() { return this->make_call().set_state(false); }
 FanCall Fan::toggle() { return this->make_call().set_state(!this->state); }
 FanCall Fan::make_call() { return FanCall(*this); }
 
+const char *Fan::find_preset_mode_(const char *preset_mode) { return this->get_traits().find_preset_mode(preset_mode); }
+
+bool Fan::set_preset_mode_(const char *preset_mode) {
+  const char *validated = this->find_preset_mode_(preset_mode);
+  if (validated == nullptr) {
+    return false;  // Preset mode not supported
+  }
+  if (this->preset_mode_ == validated) {
+    return false;  // No change
+  }
+  this->preset_mode_ = validated;
+  // Keep deprecated member in sync during deprecation period
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  this->preset_mode = validated;
+#pragma GCC diagnostic pop
+  return true;
+}
+
+bool Fan::set_preset_mode_(const std::string &preset_mode) { return this->set_preset_mode_(preset_mode.c_str()); }
+
+void Fan::clear_preset_mode_() {
+  this->preset_mode_ = nullptr;
+  // Keep deprecated member in sync during deprecation period
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  this->preset_mode.clear();
+#pragma GCC diagnostic pop
+}
+
 void Fan::add_on_state_callback(std::function<void()> &&callback) { this->state_callback_.add(std::move(callback)); }
 void Fan::publish_state() {
   auto traits = this->get_traits();
@@ -146,8 +182,9 @@ void Fan::publish_state() {
   if (traits.supports_direction()) {
     ESP_LOGD(TAG, "  Direction: %s", LOG_STR_ARG(fan_direction_to_string(this->direction)));
   }
-  if (traits.supports_preset_modes() && !this->preset_mode.empty()) {
-    ESP_LOGD(TAG, "  Preset Mode: %s", this->preset_mode.c_str());
+  const char *preset = this->get_preset_mode();
+  if (traits.supports_preset_modes() && preset != nullptr) {
+    ESP_LOGD(TAG, "  Preset Mode: %s", preset);
   }
   this->state_callback_.call();
   this->save_state_();
@@ -199,12 +236,13 @@ void Fan::save_state_() {
   state.speed = this->speed;
   state.direction = this->direction;
 
-  if (traits.supports_preset_modes() && !this->preset_mode.empty()) {
+  const char *preset = this->get_preset_mode();
+  if (traits.supports_preset_modes() && preset != nullptr) {
     const auto &preset_modes = traits.supported_preset_modes();
     // Store index of current preset mode
     size_t i = 0;
     for (const auto &mode : preset_modes) {
-      if (strcmp(mode, this->preset_mode.c_str()) == 0) {
+      if (strcmp(mode, preset) == 0) {
         state.preset_mode = i;
         break;
       }
diff --git a/esphome/components/fan/fan.h b/esphome/components/fan/fan.h
index 3739de29a2..5bbddb0005 100644
--- a/esphome/components/fan/fan.h
+++ b/esphome/components/fan/fan.h
@@ -70,11 +70,10 @@ class FanCall {
     return *this;
   }
   optional<FanDirection> get_direction() const { return this->direction_; }
-  FanCall &set_preset_mode(const std::string &preset_mode) {
-    this->preset_mode_ = preset_mode;
-    return *this;
-  }
-  std::string get_preset_mode() const { return this->preset_mode_; }
+  FanCall &set_preset_mode(const std::string &preset_mode);
+  FanCall &set_preset_mode(const char *preset_mode);
+  const char *get_preset_mode() const { return this->preset_mode_; }
+  bool has_preset_mode() const { return this->preset_mode_ != nullptr; }
 
   void perform();
 
@@ -86,7 +85,7 @@ class FanCall {
   optional<bool> oscillating_;
   optional<int> speed_;
   optional<FanDirection> direction_{};
-  std::string preset_mode_{};
+  const char *preset_mode_{nullptr};  // Pointer to string in traits (after validation)
 };
 
 struct FanRestoreState {
@@ -113,7 +112,9 @@ class Fan : public EntityBase {
   /// The current direction of the fan
   FanDirection direction{FanDirection::FORWARD};
   // The current preset mode of the fan
-  std::string preset_mode{};
+  // Deprecated: Use get_preset_mode() instead. Will be removed in 2026.5.0
+  std::string preset_mode {}
+  __attribute__((deprecated("Use get_preset_mode() instead of .preset_mode. Will be removed in 2026.5.0")));
 
   FanCall turn_on();
   FanCall turn_off();
@@ -130,6 +131,9 @@ class Fan : public EntityBase {
   /// Set the restore mode of this fan.
   void set_restore_mode(FanRestoreMode restore_mode) { this->restore_mode_ = restore_mode; }
 
+  /// Get the current preset mode (returns pointer to string stored in traits, or nullptr if not set)
+  const char *get_preset_mode() const { return this->preset_mode_; }
+
  protected:
   friend FanCall;
 
@@ -140,9 +144,19 @@ class Fan : public EntityBase {
 
   void dump_traits_(const char *tag, const char *prefix);
 
+  /// Set the preset mode (finds and stores pointer from traits). Returns true if changed.
+  bool set_preset_mode_(const char *preset_mode);
+  /// Set the preset mode (finds and stores pointer from traits). Returns true if changed.
+  bool set_preset_mode_(const std::string &preset_mode);
+  /// Clear the preset mode
+  void clear_preset_mode_();
+  /// Find and return the matching preset mode pointer from traits, or nullptr if not found.
+  const char *find_preset_mode_(const char *preset_mode);
+
   CallbackManager<void()> state_callback_{};
   ESPPreferenceObject rtc_;
   FanRestoreMode restore_mode_;
+  const char *preset_mode_{nullptr};
 };
 
 }  // namespace fan
diff --git a/esphome/components/fan/fan_traits.h b/esphome/components/fan/fan_traits.h
index bfb17a05ab..eb6f726a3c 100644
--- a/esphome/components/fan/fan_traits.h
+++ b/esphome/components/fan/fan_traits.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstring>
 #include <vector>
 #include <initializer_list>
 
@@ -39,6 +40,17 @@ class FanTraits {
   void set_supported_preset_modes(const std::vector<const char *> &preset_modes) { this->preset_modes_ = preset_modes; }
   /// Return if preset modes are supported
   bool supports_preset_modes() const { return !this->preset_modes_.empty(); }
+  /// Find and return the matching preset mode pointer from supported modes, or nullptr if not found.
+  const char *find_preset_mode(const char *preset_mode) const {
+    if (preset_mode == nullptr)
+      return nullptr;
+    for (const char *mode : this->preset_modes_) {
+      if (strcmp(mode, preset_mode) == 0) {
+        return mode;  // Return pointer from traits
+      }
+    }
+    return nullptr;
+  }
 
  protected:
   bool oscillation_{false};
diff --git a/esphome/components/hbridge/fan/hbridge_fan.cpp b/esphome/components/hbridge/fan/hbridge_fan.cpp
index 605a9d4ef3..01680ae651 100644
--- a/esphome/components/hbridge/fan/hbridge_fan.cpp
+++ b/esphome/components/hbridge/fan/hbridge_fan.cpp
@@ -51,13 +51,17 @@ void HBridgeFan::dump_config() {
 void HBridgeFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value())
+  if (call.get_speed().has_value()) {
     this->speed = *call.get_speed();
+    // Speed manually set, clear preset mode
+    this->clear_preset_mode_();
+  }
   if (call.get_oscillating().has_value())
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
     this->direction = *call.get_direction();
-  this->preset_mode = call.get_preset_mode();
+  if (call.has_preset_mode())
+    this->set_preset_mode_(call.get_preset_mode());
 
   this->write_state_();
   this->publish_state();
diff --git a/esphome/components/speed/fan/speed_fan.cpp b/esphome/components/speed/fan/speed_fan.cpp
index 57bd795416..43b149e382 100644
--- a/esphome/components/speed/fan/speed_fan.cpp
+++ b/esphome/components/speed/fan/speed_fan.cpp
@@ -23,13 +23,17 @@ void SpeedFan::dump_config() { LOG_FAN("", "Speed Fan", this); }
 void SpeedFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value())
+  if (call.get_speed().has_value()) {
     this->speed = *call.get_speed();
+    // Speed manually set, clear preset mode
+    this->clear_preset_mode_();
+  }
   if (call.get_oscillating().has_value())
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
     this->direction = *call.get_direction();
-  this->preset_mode = call.get_preset_mode();
+  if (call.has_preset_mode())
+    this->set_preset_mode_(call.get_preset_mode());
 
   this->write_state_();
   this->publish_state();
diff --git a/esphome/components/template/fan/template_fan.cpp b/esphome/components/template/fan/template_fan.cpp
index 5f4a2ae8f7..4ec7e121cf 100644
--- a/esphome/components/template/fan/template_fan.cpp
+++ b/esphome/components/template/fan/template_fan.cpp
@@ -23,13 +23,17 @@ void TemplateFan::dump_config() { LOG_FAN("", "Template Fan", this); }
 void TemplateFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value() && (this->speed_count_ > 0))
+  if (call.get_speed().has_value() && (this->speed_count_ > 0)) {
     this->speed = *call.get_speed();
+    // Speed manually set, clear preset mode
+    this->clear_preset_mode_();
+  }
   if (call.get_oscillating().has_value() && this->has_oscillating_)
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value() && this->has_direction_)
     this->direction = *call.get_direction();
-  this->preset_mode = call.get_preset_mode();
+  if (call.has_preset_mode())
+    this->set_preset_mode_(call.get_preset_mode());
 
   this->publish_state();
 }

From 58ae4a38be7b4905ce490ffe722b12de6bb9ffd7 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:04:27 -0500
Subject: [PATCH 02/14] wip

---
 esphome/components/fan/fan.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/fan/fan.h b/esphome/components/fan/fan.h
index 5bbddb0005..1ca7bfbeb3 100644
--- a/esphome/components/fan/fan.h
+++ b/esphome/components/fan/fan.h
@@ -113,8 +113,8 @@ class Fan : public EntityBase {
   FanDirection direction{FanDirection::FORWARD};
   // The current preset mode of the fan
   // Deprecated: Use get_preset_mode() instead. Will be removed in 2026.5.0
-  std::string preset_mode {}
   __attribute__((deprecated("Use get_preset_mode() instead of .preset_mode. Will be removed in 2026.5.0")));
+  std::string preset_mode{};
 
   FanCall turn_on();
   FanCall turn_off();

From cf85621d64e331d0792b47441bc5bd9a71a86873 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:05:31 -0500
Subject: [PATCH 03/14] wip

---
 esphome/components/fan/fan.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/esphome/components/fan/fan.h b/esphome/components/fan/fan.h
index 1ca7bfbeb3..6cae01999d 100644
--- a/esphome/components/fan/fan.h
+++ b/esphome/components/fan/fan.h
@@ -136,6 +136,7 @@ class Fan : public EntityBase {
 
  protected:
   friend FanCall;
+  friend struct FanRestoreState;
 
   virtual void control(const FanCall &call) = 0;
 

From 79e2340588fdf6c538b32d71360ee162017f0229 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:06:18 -0500
Subject: [PATCH 04/14] wip

---
 esphome/components/fan/fan.cpp | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index e38b7b43a4..24ce9188f4 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -121,14 +121,12 @@ void FanRestoreState::apply(Fan &fan) {
   fan.speed = this->speed;
   fan.direction = this->direction;
 
-  auto traits = fan.get_traits();
-  if (traits.supports_preset_modes()) {
-    // Use stored preset index to get preset name
-    const auto &preset_modes = traits.supported_preset_modes();
-    if (this->preset_mode < preset_modes.size()) {
-      fan.set_preset_mode_(preset_modes[this->preset_mode]);
-    }
+  // Use stored preset index to get preset name from traits
+  const auto &preset_modes = fan.get_traits().supported_preset_modes();
+  if (this->preset_mode < preset_modes.size()) {
+    fan.set_preset_mode_(preset_modes[this->preset_mode]);
   }
+
   fan.publish_state();
 }
 

From 4fabe464c8b193b29d652d1012f6f01a111985b9 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:08:24 -0500
Subject: [PATCH 05/14] wip

---
 esphome/components/fan/fan.cpp | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index 24ce9188f4..eb2e8743f3 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -139,11 +139,8 @@ const char *Fan::find_preset_mode_(const char *preset_mode) { return this->get_t
 
 bool Fan::set_preset_mode_(const char *preset_mode) {
   const char *validated = this->find_preset_mode_(preset_mode);
-  if (validated == nullptr) {
-    return false;  // Preset mode not supported
-  }
-  if (this->preset_mode_ == validated) {
-    return false;  // No change
+  if (validated == nullptr || this->preset_mode_ == validated) {
+    return false;  // Preset mode not supported or no change
   }
   this->preset_mode_ = validated;
   // Keep deprecated member in sync during deprecation period
@@ -235,16 +232,14 @@ void Fan::save_state_() {
   state.direction = this->direction;
 
   const char *preset = this->get_preset_mode();
-  if (traits.supports_preset_modes() && preset != nullptr) {
+  if (preset != nullptr) {
     const auto &preset_modes = traits.supported_preset_modes();
-    // Store index of current preset mode
-    size_t i = 0;
-    for (const auto &mode : preset_modes) {
-      if (strcmp(mode, preset) == 0) {
+    // Find index of current preset mode (pointer comparison is safe since preset is from traits)
+    for (size_t i = 0; i < preset_modes.size(); i++) {
+      if (preset_modes[i] == preset) {
         state.preset_mode = i;
         break;
       }
-      i++;
     }
   }
 

From 410afd196f05c85050c21f751e19e5598f51bd15 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:13:57 -0500
Subject: [PATCH 06/14] preen

---
 esphome/components/fan/fan_traits.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/esphome/components/fan/fan_traits.h b/esphome/components/fan/fan_traits.h
index bfb17a05ab..df345f9b04 100644
--- a/esphome/components/fan/fan_traits.h
+++ b/esphome/components/fan/fan_traits.h
@@ -37,6 +37,11 @@ class FanTraits {
   }
   /// Set the preset modes supported by the fan (from vector).
   void set_supported_preset_modes(const std::vector<const char *> &preset_modes) { this->preset_modes_ = preset_modes; }
+
+  // Deleted overloads to catch incorrect std::string usage at compile time with clear error messages
+  void set_supported_preset_modes(const std::vector<std::string> &preset_modes) = delete;
+  void set_supported_preset_modes(std::initializer_list<std::string> preset_modes) = delete;
+
   /// Return if preset modes are supported
   bool supports_preset_modes() const { return !this->preset_modes_.empty(); }
 

From 91ae8c82b0ddd655aa88197dd455cea1b26995bc Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:15:59 -0500
Subject: [PATCH 07/14] preen

---
 esphome/components/fan/fan.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/esphome/components/fan/fan.h b/esphome/components/fan/fan.h
index 6cae01999d..16fe42f9f4 100644
--- a/esphome/components/fan/fan.h
+++ b/esphome/components/fan/fan.h
@@ -112,8 +112,9 @@ class Fan : public EntityBase {
   /// The current direction of the fan
   FanDirection direction{FanDirection::FORWARD};
   // The current preset mode of the fan
-  // Deprecated: Use get_preset_mode() instead. Will be removed in 2026.5.0
-  __attribute__((deprecated("Use get_preset_mode() instead of .preset_mode. Will be removed in 2026.5.0")));
+  // Deprecated: Use get_preset_mode() for reading and set_preset_mode_() for writing. Will be removed in 2026.5.0
+  __attribute__((deprecated("Use get_preset_mode() for reading and set_preset_mode_() for writing instead of "
+                            ".preset_mode. Will be removed in 2026.5.0")));
   std::string preset_mode{};
 
   FanCall turn_on();

From 76952026b7d0d9ee9ac9be5ff66edd57f2cd1f45 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:18:14 -0500
Subject: [PATCH 08/14] preen

---
 esphome/components/copy/fan/copy_fan.cpp | 12 ++----------
 esphome/components/fan/fan.cpp           |  8 ++++++++
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/esphome/components/copy/fan/copy_fan.cpp b/esphome/components/copy/fan/copy_fan.cpp
index c1e873e083..d35ece950b 100644
--- a/esphome/components/copy/fan/copy_fan.cpp
+++ b/esphome/components/copy/fan/copy_fan.cpp
@@ -12,11 +12,7 @@ void CopyFan::setup() {
     this->oscillating = source_->oscillating;
     this->speed = source_->speed;
     this->direction = source_->direction;
-    const char *preset = source_->get_preset_mode();
-    if (preset != nullptr)
-      this->set_preset_mode_(preset);
-    else
-      this->clear_preset_mode_();
+    this->set_preset_mode_(source_->get_preset_mode());
     this->publish_state();
   });
 
@@ -24,11 +20,7 @@ void CopyFan::setup() {
   this->oscillating = source_->oscillating;
   this->speed = source_->speed;
   this->direction = source_->direction;
-  const char *preset = source_->get_preset_mode();
-  if (preset != nullptr)
-    this->set_preset_mode_(preset);
-  else
-    this->clear_preset_mode_();
+  this->set_preset_mode_(source_->get_preset_mode());
   this->publish_state();
 }
 
diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index eb2e8743f3..c4abab0b4a 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -138,6 +138,14 @@ FanCall Fan::make_call() { return FanCall(*this); }
 const char *Fan::find_preset_mode_(const char *preset_mode) { return this->get_traits().find_preset_mode(preset_mode); }
 
 bool Fan::set_preset_mode_(const char *preset_mode) {
+  if (preset_mode == nullptr) {
+    // Treat nullptr as clearing the preset mode
+    if (this->preset_mode_ == nullptr) {
+      return false;  // No change
+    }
+    this->clear_preset_mode_();
+    return true;
+  }
   const char *validated = this->find_preset_mode_(preset_mode);
   if (validated == nullptr || this->preset_mode_ == validated) {
     return false;  // Preset mode not supported or no change

From 9dcfbed8af77761f682355f96a325bb1649ca5fa Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:37:22 -0500
Subject: [PATCH 09/14] wip

---
 esphome/components/api/api_connection.cpp |  4 ++--
 esphome/components/fan/fan.cpp            | 14 +-------------
 esphome/components/fan/fan.h              |  8 +++-----
 3 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 33d5072d9c..90e37c8c59 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -410,8 +410,8 @@ uint16_t APIConnection::try_send_fan_state(EntityBase *entity, APIConnection *co
   }
   if (traits.supports_direction())
     msg.direction = static_cast<enums::FanDirection>(fan->direction);
-  if (traits.supports_preset_modes())
-    msg.set_preset_mode(StringRef(fan->preset_mode));
+  if (traits.supports_preset_modes() && fan->has_preset_mode())
+    msg.set_preset_mode(StringRef(fan->get_preset_mode()));
   return fill_and_encode_entity_state(fan, msg, FanStateResponse::MESSAGE_TYPE, conn, remaining_size, is_single);
 }
 uint16_t APIConnection::try_send_fan_info(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index c4abab0b4a..cfc09f4d53 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -151,24 +151,12 @@ bool Fan::set_preset_mode_(const char *preset_mode) {
     return false;  // Preset mode not supported or no change
   }
   this->preset_mode_ = validated;
-  // Keep deprecated member in sync during deprecation period
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-  this->preset_mode = validated;
-#pragma GCC diagnostic pop
   return true;
 }
 
 bool Fan::set_preset_mode_(const std::string &preset_mode) { return this->set_preset_mode_(preset_mode.c_str()); }
 
-void Fan::clear_preset_mode_() {
-  this->preset_mode_ = nullptr;
-  // Keep deprecated member in sync during deprecation period
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-  this->preset_mode.clear();
-#pragma GCC diagnostic pop
-}
+void Fan::clear_preset_mode_() { this->preset_mode_ = nullptr; }
 
 void Fan::add_on_state_callback(std::function<void()> &&callback) { this->state_callback_.add(std::move(callback)); }
 void Fan::publish_state() {
diff --git a/esphome/components/fan/fan.h b/esphome/components/fan/fan.h
index 16fe42f9f4..33e546b2bb 100644
--- a/esphome/components/fan/fan.h
+++ b/esphome/components/fan/fan.h
@@ -111,11 +111,6 @@ class Fan : public EntityBase {
   int speed{0};
   /// The current direction of the fan
   FanDirection direction{FanDirection::FORWARD};
-  // The current preset mode of the fan
-  // Deprecated: Use get_preset_mode() for reading and set_preset_mode_() for writing. Will be removed in 2026.5.0
-  __attribute__((deprecated("Use get_preset_mode() for reading and set_preset_mode_() for writing instead of "
-                            ".preset_mode. Will be removed in 2026.5.0")));
-  std::string preset_mode{};
 
   FanCall turn_on();
   FanCall turn_off();
@@ -135,6 +130,9 @@ class Fan : public EntityBase {
   /// Get the current preset mode (returns pointer to string stored in traits, or nullptr if not set)
   const char *get_preset_mode() const { return this->preset_mode_; }
 
+  /// Check if a preset mode is currently active
+  bool has_preset_mode() const { return this->preset_mode_ != nullptr; }
+
  protected:
   friend FanCall;
   friend struct FanRestoreState;

From e6421ac50c2960a3cdb8b633da1986f49ccece9a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:42:32 -0500
Subject: [PATCH 10/14] remove bugfix

---
 esphome/components/hbridge/fan/hbridge_fan.cpp   | 5 +----
 esphome/components/speed/fan/speed_fan.cpp       | 5 +----
 esphome/components/template/fan/template_fan.cpp | 5 +----
 3 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/esphome/components/hbridge/fan/hbridge_fan.cpp b/esphome/components/hbridge/fan/hbridge_fan.cpp
index 01680ae651..18591fb1ff 100644
--- a/esphome/components/hbridge/fan/hbridge_fan.cpp
+++ b/esphome/components/hbridge/fan/hbridge_fan.cpp
@@ -51,11 +51,8 @@ void HBridgeFan::dump_config() {
 void HBridgeFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value()) {
+  if (call.get_speed().has_value())
     this->speed = *call.get_speed();
-    // Speed manually set, clear preset mode
-    this->clear_preset_mode_();
-  }
   if (call.get_oscillating().has_value())
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
diff --git a/esphome/components/speed/fan/speed_fan.cpp b/esphome/components/speed/fan/speed_fan.cpp
index 43b149e382..c1ccb0a0bb 100644
--- a/esphome/components/speed/fan/speed_fan.cpp
+++ b/esphome/components/speed/fan/speed_fan.cpp
@@ -23,11 +23,8 @@ void SpeedFan::dump_config() { LOG_FAN("", "Speed Fan", this); }
 void SpeedFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value()) {
+  if (call.get_speed().has_value())
     this->speed = *call.get_speed();
-    // Speed manually set, clear preset mode
-    this->clear_preset_mode_();
-  }
   if (call.get_oscillating().has_value())
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
diff --git a/esphome/components/template/fan/template_fan.cpp b/esphome/components/template/fan/template_fan.cpp
index 4ec7e121cf..7793fc0b7c 100644
--- a/esphome/components/template/fan/template_fan.cpp
+++ b/esphome/components/template/fan/template_fan.cpp
@@ -23,11 +23,8 @@ void TemplateFan::dump_config() { LOG_FAN("", "Template Fan", this); }
 void TemplateFan::control(const fan::FanCall &call) {
   if (call.get_state().has_value())
     this->state = *call.get_state();
-  if (call.get_speed().has_value() && (this->speed_count_ > 0)) {
+  if (call.get_speed().has_value() && (this->speed_count_ > 0))
     this->speed = *call.get_speed();
-    // Speed manually set, clear preset mode
-    this->clear_preset_mode_();
-  }
   if (call.get_oscillating().has_value() && this->has_oscillating_)
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value() && this->has_direction_)

From d5938df53194267735ab0574a27eb5266204f346 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:45:12 -0500
Subject: [PATCH 11/14] remove bugfix

---
 esphome/components/hbridge/fan/hbridge_fan.cpp   | 3 +--
 esphome/components/speed/fan/speed_fan.cpp       | 3 +--
 esphome/components/template/fan/template_fan.cpp | 3 +--
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/esphome/components/hbridge/fan/hbridge_fan.cpp b/esphome/components/hbridge/fan/hbridge_fan.cpp
index 18591fb1ff..488208b725 100644
--- a/esphome/components/hbridge/fan/hbridge_fan.cpp
+++ b/esphome/components/hbridge/fan/hbridge_fan.cpp
@@ -57,8 +57,7 @@ void HBridgeFan::control(const fan::FanCall &call) {
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
     this->direction = *call.get_direction();
-  if (call.has_preset_mode())
-    this->set_preset_mode_(call.get_preset_mode());
+  this->set_preset_mode_(call.get_preset_mode());
 
   this->write_state_();
   this->publish_state();
diff --git a/esphome/components/speed/fan/speed_fan.cpp b/esphome/components/speed/fan/speed_fan.cpp
index c1ccb0a0bb..801593c2ac 100644
--- a/esphome/components/speed/fan/speed_fan.cpp
+++ b/esphome/components/speed/fan/speed_fan.cpp
@@ -29,8 +29,7 @@ void SpeedFan::control(const fan::FanCall &call) {
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value())
     this->direction = *call.get_direction();
-  if (call.has_preset_mode())
-    this->set_preset_mode_(call.get_preset_mode());
+  this->set_preset_mode_(call.get_preset_mode());
 
   this->write_state_();
   this->publish_state();
diff --git a/esphome/components/template/fan/template_fan.cpp b/esphome/components/template/fan/template_fan.cpp
index 7793fc0b7c..eba4c673b5 100644
--- a/esphome/components/template/fan/template_fan.cpp
+++ b/esphome/components/template/fan/template_fan.cpp
@@ -29,8 +29,7 @@ void TemplateFan::control(const fan::FanCall &call) {
     this->oscillating = *call.get_oscillating();
   if (call.get_direction().has_value() && this->has_direction_)
     this->direction = *call.get_direction();
-  if (call.has_preset_mode())
-    this->set_preset_mode_(call.get_preset_mode());
+  this->set_preset_mode_(call.get_preset_mode());
 
   this->publish_state();
 }

From cbaa15635f80f961f40c187a9e300b6696cc815e Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 11:49:35 -0500
Subject: [PATCH 12/14] remove bugfix

---
 esphome/components/fan/automation.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/esphome/components/fan/automation.h b/esphome/components/fan/automation.h
index 90661c307c..048ba04646 100644
--- a/esphome/components/fan/automation.h
+++ b/esphome/components/fan/automation.h
@@ -212,18 +212,18 @@ class FanPresetSetTrigger : public Trigger<std::string> {
  public:
   FanPresetSetTrigger(Fan *state) {
     state->add_on_state_callback([this, state]() {
-      auto preset_mode = state->preset_mode;
+      auto preset_mode = state->get_preset_mode();
       auto should_trigger = preset_mode != this->last_preset_mode_;
       this->last_preset_mode_ = preset_mode;
-      if (should_trigger) {
+      if (should_trigger && preset_mode != nullptr) {
         this->trigger(preset_mode);
       }
     });
-    this->last_preset_mode_ = state->preset_mode;
+    this->last_preset_mode_ = state->get_preset_mode();
   }
 
  protected:
-  std::string last_preset_mode_;
+  const char *last_preset_mode_{nullptr};
 };
 
 }  // namespace fan

From 5c184777c673db996a351f84492b4ba5bd00fa5e Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 31 Oct 2025 12:05:48 -0500
Subject: [PATCH 13/14] remove bugfix

---
 esphome/components/fan/automation.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/fan/automation.h b/esphome/components/fan/automation.h
index 048ba04646..48de8d66fb 100644
--- a/esphome/components/fan/automation.h
+++ b/esphome/components/fan/automation.h
@@ -212,7 +212,7 @@ class FanPresetSetTrigger : public Trigger<std::string> {
  public:
   FanPresetSetTrigger(Fan *state) {
     state->add_on_state_callback([this, state]() {
-      auto preset_mode = state->get_preset_mode();
+      const auto *preset_mode = state->get_preset_mode();
       auto should_trigger = preset_mode != this->last_preset_mode_;
       this->last_preset_mode_ = preset_mode;
       if (should_trigger && preset_mode != nullptr) {

From 6d0527ff2ad406603067a939d0b3f703db33fc0c Mon Sep 17 00:00:00 2001
From: Javier Peletier <jpeletier@users.noreply.github.com>
Date: Fri, 31 Oct 2025 20:04:55 +0100
Subject: [PATCH 14/14] [substitutions] fix jinja parsing strings that look
 like sets as sets (#11611)

---
 esphome/components/substitutions/jinja.py              | 10 ++++++++--
 .../fixtures/substitutions/00-simple_var.approved.yaml |  1 +
 .../fixtures/substitutions/00-simple_var.input.yaml    |  1 +
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/esphome/components/substitutions/jinja.py b/esphome/components/substitutions/jinja.py
index cb3c6dfac5..fb9f843da2 100644
--- a/esphome/components/substitutions/jinja.py
+++ b/esphome/components/substitutions/jinja.py
@@ -138,6 +138,7 @@ def _concat_nodes_override(values: Iterator[Any]) -> Any:
             values = chain(head, values)
         raw = "".join([str(v) for v in values])
 
+    result = None
     try:
         # Attempt to parse the concatenated string into a Python literal.
         # This allows expressions like "1 + 2" to be evaluated to the integer 3.
@@ -145,11 +146,16 @@ def _concat_nodes_override(values: Iterator[Any]) -> Any:
         # fall back to returning the raw string. This is consistent with
         #  Home Assistant's behavior when evaluating templates
         result = literal_eval(raw)
+    except (ValueError, SyntaxError, MemoryError, TypeError):
+        pass
+    else:
+        if isinstance(result, set):
+            # Sets are not supported, return raw string
+            return raw
+
         if not isinstance(result, str):
             return result
 
-    except (ValueError, SyntaxError, MemoryError, TypeError):
-        pass
     return raw
 
 
diff --git a/tests/unit_tests/fixtures/substitutions/00-simple_var.approved.yaml b/tests/unit_tests/fixtures/substitutions/00-simple_var.approved.yaml
index 795a788f62..6f3bae1ac4 100644
--- a/tests/unit_tests/fixtures/substitutions/00-simple_var.approved.yaml
+++ b/tests/unit_tests/fixtures/substitutions/00-simple_var.approved.yaml
@@ -33,3 +33,4 @@ test_list:
     {{{ "x", "79"}, { "y", "82"}}}
   - '{{{"AA"}}}'
   - '"HELLO"'
+  - '{ 79, 82 }'
diff --git a/tests/unit_tests/fixtures/substitutions/00-simple_var.input.yaml b/tests/unit_tests/fixtures/substitutions/00-simple_var.input.yaml
index 722e116d36..306119b753 100644
--- a/tests/unit_tests/fixtures/substitutions/00-simple_var.input.yaml
+++ b/tests/unit_tests/fixtures/substitutions/00-simple_var.input.yaml
@@ -34,3 +34,4 @@ test_list:
     {{{ "x", "${ position.x }"}, { "y", "${ position.y }"}}}
   - ${ '{{{"AA"}}}' }
   - ${ '"HELLO"' }
+  - '{ ${position.x}, ${position.y} }'