You can use 'CP1252' instead of 'Windows-1252':
<?php
// These two lines are equivalent
$result = iconv('Windows-1252', 'UTF-8', $string);
$result = iconv('CP1252', 'UTF-8', $string);
?>
Note: The following code points are not valid in CP1252 and will cause errors.
129 (0x81)
141 (0x8D)
143 (0x8F)
144 (0x90)
157 (0x9D)
Use the following instead:
<?php
// Remove invalid code points, convert everything else
$result = iconv('CP1252', 'UTF-8//IGNORE', $string);
?>