diff --git a/src/devices/boiler.cpp b/src/devices/boiler.cpp
index af8037124..3cb34e0c1 100644
--- a/src/devices/boiler.cpp
+++ b/src/devices/boiler.cpp
@@ -1202,7 +1202,7 @@ bool Boiler::set_pump_delay(const char * value, const int8_t id) {
 // on a RC35 it's by EMSESP::send_write_request(0x37, 0x10, 2, &set, 1, 0); (set is 1,2,3) 1=hot, 2=eco, 3=intelligent
 bool Boiler::set_warmwater_mode(const char * value, const int8_t id) {
     uint8_t set;
-    if (!Helpers::value2enum(value, set, {"hot", "eco", "intelligent"})) {
+    if (!Helpers::value2enum(value, set, {F("hot"), F("eco"), F("intelligent")})) {
         LOG_WARNING(F("Set boiler warm water mode: Invalid value"));
         return false;
     }
diff --git a/src/devices/thermostat.cpp b/src/devices/thermostat.cpp
index 804a82090..184da790c 100644
--- a/src/devices/thermostat.cpp
+++ b/src/devices/thermostat.cpp
@@ -419,7 +419,7 @@ bool Thermostat::export_values_main(JsonObject & rootThermostat) {
     // Floordry
     if (Helpers::hasValue(floordrystatus_) && Helpers::hasValue(floordrytemp_) && (floordrytemp_ > 0)) {
         char s[10];
-        rootThermostat["floordry"]     = Helpers::render_enum(s, {"off", "start", "heat", "hold", "cool", "end"}, floordrystatus_);
+        rootThermostat["floordry"]     = Helpers::render_enum(s, {F("off"), F("start"), F("heat"), F("hold"), F("cool"), F("end")}, floordrystatus_);
         rootThermostat["floordrytemp"] = floordrytemp_;
     }
 
@@ -447,9 +447,9 @@ bool Thermostat::export_values_main(JsonObject & rootThermostat) {
     if (Helpers::hasValue(ibaBuildingType_)) {
         char s[10];
         if (model == EMS_DEVICE_FLAG_RC300 || model == EMS_DEVICE_FLAG_RC100) {
-            rootThermostat["building"] = Helpers::render_enum(s, {"light", "medium", "heavy"}, ibaBuildingType_ - 1);
+            rootThermostat["building"] = Helpers::render_enum(s, {F("light"), F("medium"), F("heavy")}, ibaBuildingType_ - 1);
         } else {
-            rootThermostat["building"] = Helpers::render_enum(s, {"light", "medium", "heavy"}, ibaBuildingType_);
+            rootThermostat["building"] = Helpers::render_enum(s, {F("light"), F("medium"), F("heavy")}, ibaBuildingType_);
         }
     }
 
@@ -457,9 +457,9 @@ bool Thermostat::export_values_main(JsonObject & rootThermostat) {
     if (Helpers::hasValue(wwMode_)) {
         char s[10];
         if (model == EMS_DEVICE_FLAG_RC300 || model == EMS_DEVICE_FLAG_RC100) {
-            rootThermostat["wwmode"] = Helpers::render_enum(s, {"off", "low", "high", "auto", "own_prog"}, wwMode_);
+            rootThermostat["wwmode"] = Helpers::render_enum(s, {F("off"), F("low"), F("high"), F("auto"), F("own_prog")}, wwMode_);
         } else {
-            rootThermostat["wwmode"] = Helpers::render_enum(s, {"off", "on", "auto"}, wwMode_);
+            rootThermostat["wwmode"] = Helpers::render_enum(s, {F("off"), F("on"), F("auto")}, wwMode_);
         }
     }
 
@@ -476,7 +476,7 @@ bool Thermostat::export_values_main(JsonObject & rootThermostat) {
     // Warm Water circulation mode
     if (Helpers::hasValue(wwCircMode_)) {
         char s[7];
-        rootThermostat["wwcircmode"] = Helpers::render_enum(s, {"off", "on", "auto"}, wwCircMode_);
+        rootThermostat["wwcircmode"] = Helpers::render_enum(s, {F("off"), F("on"), F("auto")}, wwCircMode_);
     }
 
     return (rootThermostat.size());
@@ -608,7 +608,7 @@ bool Thermostat::export_values_hc(uint8_t mqtt_format, JsonObject & rootThermost
             // Summer mode
             if (Helpers::hasValue(hc->summer_setmode)) {
                 char s[7];
-                dataThermostat["summermode"] = Helpers::render_enum(s, {"summer", "auto", "winter"}, hc->summer_setmode);
+                dataThermostat["summermode"] = Helpers::render_enum(s, {F("summer"), F("auto"), F("winter")}, hc->summer_setmode);
             }
 
             // mode - always force showing this when in HA so not to break HA's climate component
@@ -1514,7 +1514,7 @@ bool Thermostat::set_remotetemp(const char * value, const int8_t id) {
 // 0xA5 - Set the building settings
 bool Thermostat::set_building(const char * value, const int8_t id) {
     uint8_t bd = 0;
-    if (!Helpers::value2enum(value, bd, {"light", "medium", "heavy"})) {
+    if (!Helpers::value2enum(value, bd, {F("light"), F("medium"), F("heavy")})) {
         LOG_WARNING(F("Set building: Invalid value"));
         return false;
     }
@@ -1533,7 +1533,7 @@ bool Thermostat::set_building(const char * value, const int8_t id) {
 // 0xA5 Set the language settings
 bool Thermostat::set_language(const char * value, const int8_t id) {
     uint8_t lg = 0;
-    if (!Helpers::value2enum(value, lg, {"german", "dutch", "french", "italian"})) {
+    if (!Helpers::value2enum(value, lg, {F("german"), F("dutch"), F("french"), F("italian")})) {
         LOG_WARNING(F("Set language: Invalid value"));
         return false;
     }
@@ -1586,14 +1586,14 @@ bool Thermostat::set_roominfluence(const char * value, const int8_t id) {
 bool Thermostat::set_wwmode(const char * value, const int8_t id) {
     uint8_t set = 0xFF;
     if ((this->model() == EMS_DEVICE_FLAG_RC300) || (this->model() == EMS_DEVICE_FLAG_RC100)) {
-        if (!Helpers::value2enum(value, set, {"off", "low", "high", "auto", "own"})) {
+        if (!Helpers::value2enum(value, set, {F("off"), F("low"), F("high"), F("auto"), F("own")})) {
             LOG_WARNING(F("Set warm water mode: Invalid mode"));
             return false;
         }
         LOG_INFO(F("Setting warm water mode to %s"), value);
         write_command(0x02F5, 2, set, 0x02F5);
     } else {
-        if (!Helpers::value2enum(value, set, {"off", "on", "auto"})) {
+        if (!Helpers::value2enum(value, set, {F("off"), F("on"), F("auto")})) {
             LOG_WARNING(F("Set warm water mode: Invalid mode"));
             return false;
         }
@@ -1631,7 +1631,7 @@ bool Thermostat::set_wwtemplow(const char * value, const int8_t id) {
 // sets the thermostat ww circulation working mode, where mode is a string
 bool Thermostat::set_wwcircmode(const char * value, const int8_t id) {
     uint8_t set = 0xFF;
-    if (!Helpers::value2enum(value, set, {"off", "on", "auto"})) {
+    if (!Helpers::value2enum(value, set, {F("off"), F("on"), F("auto")})) {
         LOG_WARNING(F("Set warm water circulation mode: Invalid mode"));
         return false;
     }
@@ -1909,7 +1909,7 @@ bool Thermostat::set_summermode(const char * value, const int8_t id) {
         return false;
     }
     uint8_t set = 0xFF;
-    if (!Helpers::value2enum(value, set, {"summer", "auto", "winter"})) {
+    if (!Helpers::value2enum(value, set, {F("summer"), F("auto"), F("winter")})) {
         LOG_WARNING(F("Setting summer mode: Invalid mode"));
         return false;
     }
diff --git a/src/devices/thermostat.h b/src/devices/thermostat.h
index 486e49daa..8e949ca69 100644
--- a/src/devices/thermostat.h
+++ b/src/devices/thermostat.h
@@ -133,7 +133,7 @@ class Thermostat : public EMSdevice {
     std::vector<uint16_t> summer_typeids;
 
     std::string datetime_;  // date and time stamp
-    std::string errorCode_; // code as string i.e. "A22(816)"
+    std::string errorCode_; // code from 0xA2 as string i.e. "A22(816)"
 
     bool changed_       = false;
     bool ha_registered_ = false;
diff --git a/src/helpers.cpp b/src/helpers.cpp
index 2dfe27324..328b69d71 100644
--- a/src/helpers.cpp
+++ b/src/helpers.cpp
@@ -136,19 +136,20 @@ char * Helpers::render_boolean(char * result, bool value) {
 }
 
 // depending on format render a number or a string
-char * Helpers::render_enum(char * result, const std::vector<std::string> & value, const uint8_t no) {
+char * Helpers::render_enum(char * result, const std::vector<const __FlashStringHelper *> value, const uint8_t no) {
     if (no >= value.size()) {
         return nullptr; // out of bounds
     }
+    std::string str = uuid::read_flash_string(value[no]);
     if (bool_format() == BOOL_FORMAT_ONOFF) {
-        strcpy(result, value[no].c_str());
+        strcpy(result, str.c_str());
     } else if (bool_format() == BOOL_FORMAT_TRUEFALSE) {
-        if (no == 0 && value[0] == "off") {
+        if (no == 0 && uuid::read_flash_string(value[0]) == "off") {
             strlcpy(result, "false", 7);
-        } else if (no == 1 && value[1] == "on") {
+        } else if (no == 1 && uuid::read_flash_string(value[1]) == "on") {
             strlcpy(result, "true", 6);
         } else {
-            strcpy(result, value[no].c_str());
+            strcpy(result, str.c_str());
         }
     } else {
         itoa(result, no);
@@ -462,13 +463,14 @@ bool Helpers::value2bool(const char * v, bool & value) {
 }
 
 // checks to see if a string is member of a vector and return the index, also allow true/false for on/off
-bool Helpers::value2enum(const char * v, uint8_t & value, const std::vector<std::string> & strs) {
+bool Helpers::value2enum(const char * v, uint8_t & value, const std::vector<const __FlashStringHelper *> strs) {
     if ((v == nullptr) || (strlen(v) == 0)) {
         return false;
     }
     std::string str = toLower(v);
     for (value = 0; value < strs.size(); value++) {
-        if ((strs[value] == "off" && str == "false") || (strs[value] == "on" && str == "true") || (str == strs[value]) || (v[0] == '0' + value)) {
+        std::string str1 = uuid::read_flash_string(strs[value]);
+        if ((str1 == "off" && str == "false") || (str1 == "on" && str == "true") || (str == str1) || (v[0] == '0' + value)) {
             return true;
         }
     }
diff --git a/src/helpers.h b/src/helpers.h
index 80e4ec171..ce4cdd584 100644
--- a/src/helpers.h
+++ b/src/helpers.h
@@ -39,7 +39,7 @@ class Helpers {
     static char * render_value(char * result, const int16_t value, const uint8_t format);
     static char * render_value(char * result, const char * value, uint8_t format);
     static char * render_boolean(char * result, bool value);
-    static char * render_enum(char * result, const std::vector<std::string> & value, const uint8_t no);
+    static char * render_enum(char * result, const std::vector<const __FlashStringHelper *> value, const uint8_t no);
 
     static char *      hextoa(char * result, const uint8_t value);
     static std::string data_to_hex(const uint8_t * data, const uint8_t length);
@@ -62,7 +62,7 @@ class Helpers {
     static bool value2float(const char * v, float & value);
     static bool value2bool(const char * v, bool & value);
     static bool value2string(const char * v, std::string & value);
-    static bool value2enum(const char * v, uint8_t & value, const std::vector<std::string> & strs);
+    static bool value2enum(const char * v, uint8_t & value, const std::vector<const __FlashStringHelper *> strs);
 
     static void bool_format(uint8_t bool_format) {
         bool_format_ = bool_format;