diff --git a/fhem/fhem.pl b/fhem/fhem.pl
index bb9c76a78..6c8deb168 100755
--- a/fhem/fhem.pl
+++ b/fhem/fhem.pl
@@ -3039,7 +3039,7 @@ evalStateFormat($)
     # Substitute reading names with their values, leave the rest untouched.
     $st = $sr;
     my $r = $hash->{READINGS};
-    $st =~ s/\b([A-Za-z_-]+)\b/($r->{$1} ? $r->{$1}{VAL} : $1)/ge;
+    $st =~ s/\b([A-Za-z_\.-]+)\b/($r->{$1} ? $r->{$1}{VAL} : $1)/ge;
 
   }
   $hash->{STATE} = ReplaceEventMap($name, $st, 1) if(defined($st));