STEPHEN - Is Blessing or dedicating a home a priesthood ordanince and does the Melchizidek Priesthood have to be used? OR can anyone bless a home as a child would when he asks heavenly father to, "please bless our home ....?"

JOEL - It can be done either way.
In regards to our eternal life, there are certain saving ordinances that must be performed, and they must be done in the proper manner with the proper priesthood to be accepted by God.
The dedication of the home is not a saving ordinance, but in active LDS homes it is still considered a priesthood ordinance and should be performed using the priesthood by a worthy Melchizedek priesthood holder.
According to the Church Handbook, it is considered a dedicatory prayer that a family might want to offer, asking God to bless it that it might be an ediface where the spirit of God can reside and a place where the family can worship together. Unlike church buildings homes are not consecrated to the Lord. To dedicate a home, a family might gather together and offer a prayer that includes the things mentioned above and other words as the spirit dictates. (See Church Handbook of Instructions: Book 2 p. 174, 1998)

However, since it is not a saving ordinance, it is certainly appropriate for any family to say a dedicatory prayer over their home, even if they don't have the priesthood. Of course this would not be considered an ordinance, but a simple prayer that any or all members of the family could say.