'To bless' refers to our praise of God and our requests for His loving care for us. As we praise God over people and objects, they are blessed for His service. Therefore, for a house blessing, it is not meant to 'clean the house', but instead we we adopt a disposition of thankfulness, for his providence and goodness, and pray that He continues to remain the center of this household.
The Bible tells of how God blessed the houses of His servants for His purposes and glory (Genesis 39:5; Ezekiel 44:30). During the house blessing, the priest sprinkles holy water in each room while praying for the inhabitants of the house. The occasion provides a great opportunity for a gathering of the members of the community to mark the joyful event and to thank God, from whom all blessings come, for the gift of a new home.