diff --git a/scripts/pi-hole/php/header.php b/scripts/pi-hole/php/header.php
index ca94d496..9ab0d721 100644
--- a/scripts/pi-hole/php/header.php
+++ b/scripts/pi-hole/php/header.php
@@ -61,9 +61,9 @@
             $temperatureunit = $_POST["tempunit"];
         }
         // Get user-defined temperature limit if set
-        if(isset($setupVars['TEMPERATURELIMIT']))
+        if(isset($setupVars['TEMPERATURE_LIMIT']))
         {
-            $temperaturelimit = intval($setupVars['TEMPERATURELIMIT']);
+            $temperaturelimit = intval($setupVars['TEMPERATURE_LIMIT']);
         }
         else
         {