A piece of iron either buried under or somehow put into the hearth brings good luck and safety to a new home.
That's one my family has always gone by. Although the fireplace is now plastered over because no one around here can buy coal anymore.

The 'first foot' ceremonies described above can also be done to dedicate a new house.
It should be a tall, dark-haired man.
In some places in Scotland it's also considered very, very, very good luck if a red-haired woman comes to your house and lights a fire in your hearth without saying anything to anyone.
(Once the fire's heartily roaring she can talk. She doesn't have to just leave after that.)
That said, it's bad luck if the first foot or first person in a new house is a red-haired man.