diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index 33141c2049..95e0d13b58 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -381,11 +381,14 @@ void WebServer::handle_js_request(AsyncWebServerRequest *request) {
 #endif
 
 // Helper functions to reduce code size by avoiding macro expansion
-static void set_json_id(JsonObject &root, EntityBase *obj, const std::string &id, JsonDetail start_config) {
-  root["id"] = id;
+static void set_json_id(JsonObject &root, EntityBase *obj, const char *prefix, JsonDetail start_config) {
+  char id_buf[160];  // object_id can be up to 128 chars + prefix + dash + null
+  const auto &object_id = obj->get_object_id();
+  snprintf(id_buf, sizeof(id_buf), "%s-%s", prefix, object_id.c_str());
+  root["id"] = id_buf;
   if (start_config == DETAIL_ALL) {
     root["name"] = obj->get_name();
-    root["icon"] = obj->get_icon();
+    root["icon"] = obj->get_icon_ref();
     root["entity_category"] = obj->get_entity_category();
     bool is_disabled = obj->is_disabled_by_default();
     if (is_disabled)
@@ -393,17 +396,19 @@ static void set_json_id(JsonObject &root, EntityBase *obj, const std::string &id
   }
 }
 
+// Keep as separate function even though only used once: reduces code size by ~48 bytes
+// by allowing compiler to share code between template instantiations (bool, float, etc.)
 template<typename T>
-static void set_json_value(JsonObject &root, EntityBase *obj, const std::string &id, const T &value,
+static void set_json_value(JsonObject &root, EntityBase *obj, const char *prefix, const T &value,
                            JsonDetail start_config) {
-  set_json_id(root, obj, id, start_config);
+  set_json_id(root, obj, prefix, start_config);
   root["value"] = value;
 }
 
 template<typename T>
-static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const std::string &id,
-                                      const std::string &state, const T &value, JsonDetail start_config) {
-  set_json_value(root, obj, id, value, start_config);
+static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const char *prefix, const std::string &state,
+                                      const T &value, JsonDetail start_config) {
+  set_json_value(root, obj, prefix, value, start_config);
   root["state"] = state;
 }
 
@@ -442,20 +447,20 @@ std::string WebServer::sensor_json(sensor::Sensor *obj, float value, JsonDetail
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
+  const auto uom_ref = obj->get_unit_of_measurement_ref();
+
   // Build JSON directly inline
   std::string state;
   if (std::isnan(value)) {
     state = "NA";
   } else {
-    state = value_accuracy_to_string(value, obj->get_accuracy_decimals());
-    if (!obj->get_unit_of_measurement().empty())
-      state += " " + obj->get_unit_of_measurement();
+    state = value_accuracy_with_uom_to_string(value, obj->get_accuracy_decimals(), uom_ref);
   }
-  set_json_icon_state_value(root, obj, "sensor-" + obj->get_object_id(), state, value, start_config);
+  set_json_icon_state_value(root, obj, "sensor", state, value, start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
-    if (!obj->get_unit_of_measurement().empty())
-      root["uom"] = obj->get_unit_of_measurement();
+    if (!uom_ref.empty())
+      root["uom"] = uom_ref;
   }
 
   return builder.serialize();
@@ -494,7 +499,7 @@ std::string WebServer::text_sensor_json(text_sensor::TextSensor *obj, const std:
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "text_sensor-" + obj->get_object_id(), value, value, start_config);
+  set_json_icon_state_value(root, obj, "text_sensor", value, value, start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
   }
@@ -567,7 +572,7 @@ std::string WebServer::switch_json(switch_::Switch *obj, bool value, JsonDetail
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "switch-" + obj->get_object_id(), value ? "ON" : "OFF", value, start_config);
+  set_json_icon_state_value(root, obj, "switch", value ? "ON" : "OFF", value, start_config);
   if (start_config == DETAIL_ALL) {
     root["assumed_state"] = obj->assumed_state();
     this->add_sorting_info_(root, obj);
@@ -607,7 +612,7 @@ std::string WebServer::button_json(button::Button *obj, JsonDetail start_config)
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "button-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "button", start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
   }
@@ -647,8 +652,7 @@ std::string WebServer::binary_sensor_json(binary_sensor::BinarySensor *obj, bool
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "binary_sensor-" + obj->get_object_id(), value ? "ON" : "OFF", value,
-                            start_config);
+  set_json_icon_state_value(root, obj, "binary_sensor", value ? "ON" : "OFF", value, start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
   }
@@ -717,8 +721,7 @@ std::string WebServer::fan_json(fan::Fan *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "fan-" + obj->get_object_id(), obj->state ? "ON" : "OFF", obj->state,
-                            start_config);
+  set_json_icon_state_value(root, obj, "fan", obj->state ? "ON" : "OFF", obj->state, start_config);
   const auto traits = obj->get_traits();
   if (traits.supports_speed()) {
     root["speed_level"] = obj->speed;
@@ -793,7 +796,7 @@ std::string WebServer::light_json(light::LightState *obj, JsonDetail start_confi
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "light-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "light", start_config);
   root["state"] = obj->remote_values.is_on() ? "ON" : "OFF";
 
   light::LightJSONSchema::dump_json(*obj, root);
@@ -881,8 +884,8 @@ std::string WebServer::cover_json(cover::Cover *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "cover-" + obj->get_object_id(), obj->is_fully_closed() ? "CLOSED" : "OPEN",
-                            obj->position, start_config);
+  set_json_icon_state_value(root, obj, "cover", obj->is_fully_closed() ? "CLOSED" : "OPEN", obj->position,
+                            start_config);
   root["current_operation"] = cover::cover_operation_to_str(obj->current_operation);
 
   if (obj->get_traits().get_supports_position())
@@ -939,7 +942,9 @@ std::string WebServer::number_json(number::Number *obj, float value, JsonDetail
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "number-" + obj->get_object_id(), start_config);
+  const auto uom_ref = obj->traits.get_unit_of_measurement_ref();
+
+  set_json_id(root, obj, "number", start_config);
   if (start_config == DETAIL_ALL) {
     root["min_value"] =
         value_accuracy_to_string(obj->traits.get_min_value(), step_to_accuracy_decimals(obj->traits.get_step()));
@@ -947,8 +952,8 @@ std::string WebServer::number_json(number::Number *obj, float value, JsonDetail
         value_accuracy_to_string(obj->traits.get_max_value(), step_to_accuracy_decimals(obj->traits.get_step()));
     root["step"] = value_accuracy_to_string(obj->traits.get_step(), step_to_accuracy_decimals(obj->traits.get_step()));
     root["mode"] = (int) obj->traits.get_mode();
-    if (!obj->traits.get_unit_of_measurement().empty())
-      root["uom"] = obj->traits.get_unit_of_measurement();
+    if (!uom_ref.empty())
+      root["uom"] = uom_ref;
     this->add_sorting_info_(root, obj);
   }
   if (std::isnan(value)) {
@@ -956,10 +961,8 @@ std::string WebServer::number_json(number::Number *obj, float value, JsonDetail
     root["state"] = "NA";
   } else {
     root["value"] = value_accuracy_to_string(value, step_to_accuracy_decimals(obj->traits.get_step()));
-    std::string state = value_accuracy_to_string(value, step_to_accuracy_decimals(obj->traits.get_step()));
-    if (!obj->traits.get_unit_of_measurement().empty())
-      state += " " + obj->traits.get_unit_of_measurement();
-    root["state"] = state;
+    root["state"] =
+        value_accuracy_with_uom_to_string(value, step_to_accuracy_decimals(obj->traits.get_step()), uom_ref);
   }
 
   return builder.serialize();
@@ -1013,7 +1016,7 @@ std::string WebServer::date_json(datetime::DateEntity *obj, JsonDetail start_con
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "date-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "date", start_config);
   std::string value = str_sprintf("%d-%02d-%02d", obj->year, obj->month, obj->day);
   root["value"] = value;
   root["state"] = value;
@@ -1071,7 +1074,7 @@ std::string WebServer::time_json(datetime::TimeEntity *obj, JsonDetail start_con
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "time-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "time", start_config);
   std::string value = str_sprintf("%02d:%02d:%02d", obj->hour, obj->minute, obj->second);
   root["value"] = value;
   root["state"] = value;
@@ -1129,7 +1132,7 @@ std::string WebServer::datetime_json(datetime::DateTimeEntity *obj, JsonDetail s
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "datetime-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "datetime", start_config);
   std::string value =
       str_sprintf("%d-%02d-%02d %02d:%02d:%02d", obj->year, obj->month, obj->day, obj->hour, obj->minute, obj->second);
   root["value"] = value;
@@ -1184,7 +1187,7 @@ std::string WebServer::text_json(text::Text *obj, const std::string &value, Json
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "text-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "text", start_config);
   root["min_length"] = obj->traits.get_min_length();
   root["max_length"] = obj->traits.get_max_length();
   root["pattern"] = obj->traits.get_pattern();
@@ -1245,7 +1248,7 @@ std::string WebServer::select_json(select::Select *obj, const std::string &value
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "select-" + obj->get_object_id(), value, value, start_config);
+  set_json_icon_state_value(root, obj, "select", value, value, start_config);
   if (start_config == DETAIL_ALL) {
     JsonArray opt = root["option"].to<JsonArray>();
     for (auto &option : obj->traits.get_options()) {
@@ -1314,7 +1317,7 @@ std::string WebServer::climate_json(climate::Climate *obj, JsonDetail start_conf
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   json::JsonBuilder builder;
   JsonObject root = builder.root();
-  set_json_id(root, obj, "climate-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "climate", start_config);
   const auto traits = obj->get_traits();
   int8_t target_accuracy = traits.get_target_temperature_accuracy_decimals();
   int8_t current_accuracy = traits.get_current_temperature_accuracy_decimals();
@@ -1467,8 +1470,7 @@ std::string WebServer::lock_json(lock::Lock *obj, lock::LockState value, JsonDet
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "lock-" + obj->get_object_id(), lock::lock_state_to_string(value), value,
-                            start_config);
+  set_json_icon_state_value(root, obj, "lock", lock::lock_state_to_string(value), value, start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
   }
@@ -1546,8 +1548,8 @@ std::string WebServer::valve_json(valve::Valve *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_icon_state_value(root, obj, "valve-" + obj->get_object_id(), obj->is_fully_closed() ? "CLOSED" : "OPEN",
-                            obj->position, start_config);
+  set_json_icon_state_value(root, obj, "valve", obj->is_fully_closed() ? "CLOSED" : "OPEN", obj->position,
+                            start_config);
   root["current_operation"] = valve::valve_operation_to_str(obj->current_operation);
 
   if (obj->get_traits().get_supports_position())
@@ -1630,8 +1632,8 @@ std::string WebServer::alarm_control_panel_json(alarm_control_panel::AlarmContro
   JsonObject root = builder.root();
 
   char buf[16];
-  set_json_icon_state_value(root, obj, "alarm-control-panel-" + obj->get_object_id(),
-                            PSTR_LOCAL(alarm_control_panel_state_to_string(value)), value, start_config);
+  set_json_icon_state_value(root, obj, "alarm-control-panel", PSTR_LOCAL(alarm_control_panel_state_to_string(value)),
+                            value, start_config);
   if (start_config == DETAIL_ALL) {
     this->add_sorting_info_(root, obj);
   }
@@ -1676,7 +1678,7 @@ std::string WebServer::event_json(event::Event *obj, const std::string &event_ty
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "event-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "event", start_config);
   if (!event_type.empty()) {
     root["event_type"] = event_type;
   }
@@ -1685,7 +1687,7 @@ std::string WebServer::event_json(event::Event *obj, const std::string &event_ty
     for (auto const &event_type : obj->get_event_types()) {
       event_types.add(event_type);
     }
-    root["device_class"] = obj->get_device_class();
+    root["device_class"] = obj->get_device_class_ref();
     this->add_sorting_info_(root, obj);
   }
 
@@ -1748,7 +1750,7 @@ std::string WebServer::update_json(update::UpdateEntity *obj, JsonDetail start_c
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
-  set_json_id(root, obj, "update-" + obj->get_object_id(), start_config);
+  set_json_id(root, obj, "update", start_config);
   root["value"] = obj->update_info.latest_version;
   root["state"] = update_state_to_string(obj->state);
   if (start_config == DETAIL_ALL) {
diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 662d0d29e9..c79682fb41 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -3,6 +3,7 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/string_ref.h"
 
 #include <strings.h>
 #include <algorithm>
@@ -348,17 +349,32 @@ ParseOnOffState parse_on_off(const char *str, const char *on, const char *off) {
   return PARSE_NONE;
 }
 
-std::string value_accuracy_to_string(float value, int8_t accuracy_decimals) {
+static inline void normalize_accuracy_decimals(float &value, int8_t &accuracy_decimals) {
   if (accuracy_decimals < 0) {
     auto multiplier = powf(10.0f, accuracy_decimals);
     value = roundf(value * multiplier) / multiplier;
     accuracy_decimals = 0;
   }
+}
+
+std::string value_accuracy_to_string(float value, int8_t accuracy_decimals) {
+  normalize_accuracy_decimals(value, accuracy_decimals);
   char tmp[32];  // should be enough, but we should maybe improve this at some point.
   snprintf(tmp, sizeof(tmp), "%.*f", accuracy_decimals, value);
   return std::string(tmp);
 }
 
+std::string value_accuracy_with_uom_to_string(float value, int8_t accuracy_decimals, StringRef unit_of_measurement) {
+  normalize_accuracy_decimals(value, accuracy_decimals);
+  char tmp[64];  // Increased to accommodate unit of measurement
+  if (unit_of_measurement.empty()) {
+    snprintf(tmp, sizeof(tmp), "%.*f", accuracy_decimals, value);
+  } else {
+    snprintf(tmp, sizeof(tmp), "%.*f %s", accuracy_decimals, value, unit_of_measurement.c_str());
+  }
+  return std::string(tmp);
+}
+
 int8_t step_to_accuracy_decimals(float step) {
   // use printf %g to find number of digits based on temperature step
   char buf[32];
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 39d39c1c94..51115105ac 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -14,6 +14,10 @@
 
 #include "esphome/core/optional.h"
 
+namespace esphome {
+class StringRef;
+}
+
 #ifdef USE_ESP8266
 #include <Esp.h>
 #endif
@@ -603,6 +607,8 @@ ParseOnOffState parse_on_off(const char *str, const char *on = nullptr, const ch
 
 /// Create a string from a value and an accuracy in decimals.
 std::string value_accuracy_to_string(float value, int8_t accuracy_decimals);
+/// Create a string from a value, an accuracy in decimals, and a unit of measurement.
+std::string value_accuracy_with_uom_to_string(float value, int8_t accuracy_decimals, StringRef unit_of_measurement);
 
 /// Derive accuracy in decimals from an increment step.
 int8_t step_to_accuracy_decimals(float step);