diff --git a/esphome/components/thermostat/thermostat_climate.cpp b/esphome/components/thermostat/thermostat_climate.cpp
index e588407c4..d5fb259da 100644
--- a/esphome/components/thermostat/thermostat_climate.cpp
+++ b/esphome/components/thermostat/thermostat_climate.cpp
@@ -3,8 +3,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace thermostat {
+namespace esphome::thermostat {
 
 static const char *const TAG = "thermostat.climate";
 
@@ -66,10 +65,12 @@ void ThermostatClimate::setup() {
 }
 
 void ThermostatClimate::loop() {
-  for (auto &timer : this->timer_) {
-    if (timer.active && (timer.started + timer.time < App.get_loop_component_start_time())) {
+  uint32_t now = App.get_loop_component_start_time();
+  for (uint8_t i = 0; i < THERMOSTAT_TIMER_COUNT; i++) {
+    auto &timer = this->timer_[i];
+    if (timer.active && (now - timer.started >= timer.time)) {
       timer.active = false;
-      timer.func();
+      this->call_timer_callback_(static_cast<ThermostatClimateTimerIndex>(i));
     }
   }
 }
@@ -916,8 +917,42 @@ uint32_t ThermostatClimate::timer_duration_(ThermostatClimateTimerIndex timer_in
   return this->timer_[timer_index].time;
 }
 
-std::function<void()> ThermostatClimate::timer_cbf_(ThermostatClimateTimerIndex timer_index) {
-  return this->timer_[timer_index].func;
+void ThermostatClimate::call_timer_callback_(ThermostatClimateTimerIndex timer_index) {
+  switch (timer_index) {
+    case THERMOSTAT_TIMER_COOLING_MAX_RUN_TIME:
+      this->cooling_max_run_time_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_COOLING_OFF:
+      this->cooling_off_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_COOLING_ON:
+      this->cooling_on_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_FAN_MODE:
+      this->fan_mode_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_FANNING_OFF:
+      this->fanning_off_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_FANNING_ON:
+      this->fanning_on_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_HEATING_MAX_RUN_TIME:
+      this->heating_max_run_time_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_HEATING_OFF:
+      this->heating_off_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_HEATING_ON:
+      this->heating_on_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_IDLE_ON:
+      this->idle_on_timer_callback_();
+      break;
+    case THERMOSTAT_TIMER_COUNT:
+    default:
+      break;
+  }
 }
 
 void ThermostatClimate::cooling_max_run_time_timer_callback_() {
@@ -1344,7 +1379,7 @@ void ThermostatClimate::set_timer_duration_in_sec_(ThermostatClimateTimerIndex t
       ESP_LOGVV(TAG, "timer %d completing immediately (elapsed %d >= new %d)", timer_index, elapsed, new_duration_ms);
       this->timer_[timer_index].active = false;
       // Trigger the timer callback immediately
-      this->timer_[timer_index].func();
+      this->call_timer_callback_(timer_index);
       return;
     } else {
       // Adjust timer to run for remaining time - keep original start time
@@ -1672,5 +1707,4 @@ ThermostatClimateTargetTempConfig::ThermostatClimateTargetTempConfig(float defau
                                                                      float default_temperature_high)
     : default_temperature_low(default_temperature_low), default_temperature_high(default_temperature_high) {}
 
-}  // namespace thermostat
-}  // namespace esphome
+}  // namespace esphome::thermostat
diff --git a/esphome/components/thermostat/thermostat_climate.h b/esphome/components/thermostat/thermostat_climate.h
index 2443af58d..564b6127b 100644
--- a/esphome/components/thermostat/thermostat_climate.h
+++ b/esphome/components/thermostat/thermostat_climate.h
@@ -10,8 +10,7 @@
 #include <array>
 #include <cinttypes>
 
-namespace esphome {
-namespace thermostat {
+namespace esphome::thermostat {
 
 enum HumidificationAction : uint8_t {
   THERMOSTAT_HUMIDITY_CONTROL_ACTION_OFF = 0,
@@ -41,13 +40,11 @@ enum OnBootRestoreFrom : uint8_t {
 
 struct ThermostatClimateTimer {
   ThermostatClimateTimer() = default;
-  ThermostatClimateTimer(bool active, uint32_t time, uint32_t started, std::function<void()> func)
-      : active(active), time(time), started(started), func(std::move(func)) {}
+  ThermostatClimateTimer(bool active, uint32_t time, uint32_t started) : active(active), time(time), started(started) {}
 
   bool active;
   uint32_t time;
   uint32_t started;
-  std::function<void()> func;
 };
 
 struct ThermostatClimateTargetTempConfig {
@@ -266,7 +263,8 @@ class ThermostatClimate : public climate::Climate, public Component {
   bool cancel_timer_(ThermostatClimateTimerIndex timer_index);
   bool timer_active_(ThermostatClimateTimerIndex timer_index);
   uint32_t timer_duration_(ThermostatClimateTimerIndex timer_index);
-  std::function<void()> timer_cbf_(ThermostatClimateTimerIndex timer_index);
+  /// Call the appropriate timer callback based on timer index
+  void call_timer_callback_(ThermostatClimateTimerIndex timer_index);
   /// Enhanced timer duration setter with running timer adjustment
   void set_timer_duration_in_sec_(ThermostatClimateTimerIndex timer_index, uint32_t time);
 
@@ -534,27 +532,16 @@ class ThermostatClimate : public climate::Climate, public Component {
   Trigger<> *prev_humidity_control_trigger_{nullptr};
 
   /// Climate action timers
-  std::array<ThermostatClimateTimer, THERMOSTAT_TIMER_COUNT> timer_{
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::cooling_max_run_time_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::cooling_off_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::cooling_on_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::fan_mode_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::fanning_off_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::fanning_on_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::heating_max_run_time_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::heating_off_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::heating_on_timer_callback_, this)),
-      ThermostatClimateTimer(false, 0, 0, std::bind(&ThermostatClimate::idle_on_timer_callback_, this)),
-  };
+  std::array<ThermostatClimateTimer, THERMOSTAT_TIMER_COUNT> timer_{};
 
   /// The set of standard preset configurations this thermostat supports (Eg. AWAY, ECO, etc)
   FixedVector<PresetEntry> preset_config_{};
   /// The set of custom preset configurations this thermostat supports (eg. "My Custom Preset")
   FixedVector<CustomPresetEntry> custom_preset_config_{};
-  /// Default custom preset to use on start up (pointer to entry in custom_preset_config_)
+
  private:
+  /// Default custom preset to use on start up (pointer to entry in custom_preset_config_)
   const char *default_custom_preset_{nullptr};
 };
 
-}  // namespace thermostat
-}  // namespace esphome
+}  // namespace esphome::thermostat