Convert UTC to EST by taking care of daylight saving

I want to convert UTC time to EST by taking care to daylight saving in PHP. This is what i did so far:

$from='UTC';
$to='EST';
$format='Y-m-d H:i:s';
$date=date('2106-03-15 23:00:00');// UTC time
date_default_timezone_set($from);
$newDatetime = strtotime($date);
date_default_timezone_set($to);
$newDatetime = date($format, $newDatetime);
date_default_timezone_set('UTC');
echo $newDatetime ;//EST time

It's returning 6:00 AM EST,but due to daylight saving It should be 7:00AM EST

Any Idea?