It depends on where you come from really. My country that used to teach british english (laser, colour, apologise) is currently overrun by youngsters who spend too much time online with US english and their way of speech (lazer, color, etc..) now many can't even make up their mind whether they want to apologise to the lazer or the laser to apologize to them.
I was taught to read H(Haitch) and Z (zed) not edge and zee.
So for those whose schools teach US English will read H as eitch will an HDB (because they thought the H was an E), myself who was taught UK English read H (haitch) will give it a HDB (because H is not a vowel).