There are a variety of ways to go about this, depending on why you need to do so. If you just moved into a new house and want to have it blessed, your local pastor has a specific blessing for this.
However, if there is any evidence of a demonic infestation in the home, your priest will use more powerful prayers. These would be needed if you are experiencing some kind of demonic manifestation such as tapping or knocking noises on the walls or floors; unexplained footsteps, odors or sounds in the walls; disturbances in electronic equipment such as clocks going backward or lights turning on or off; objects moving on their own, etc.
This will also be necessary if you are experiencing signs of demonic oppression which usually come in the form of mental or emotional abuse such as thoughts of despair and suicide; nightmares; hearing voices either inside or outside of the head; experiencing negative feelings when around something holy.
In general, some of the best recommendations I've ever read about how to cleanse one's house (and soul) of evil is contained in the document: Spiritual Warfare: The Occult Has Demonic Influence by Bishop Donald W. Montrose.
These are his recommendations:
1. Confess all involvement in the occult - including any use of a ouija board, tarot cards, psychic, astrology, etc. to a priest in the sacrament of Reconciliation.
2. Remove anything from the home that has had something to do with witchcraft, a spiritualist, a medium, an oriental religion or cult or that has been used in a superstitious way. Destroy it or see to it that it is destroyed.
3. Do not keep jewelry that is symbolic of witchcraft or is a sign of the Zodiac.
4. Remove and burn all pornographic pictures and magazines—even those that have been put away in a drawer, closet or trunk.
5. Get rid of all religious literature that does not agree with the basic truth of our faith that Jesus Christ is divine. He is the Son of God, our only Savior who brings us to the Father. Remove and destroy literature from the Jehovah Witnesses, Mormons, Christian Science, Unity, Science of Mind, Scientology, Hare Krishna, Yoga, Transcendental Meditation, Divine Light Mission, Unification Church of Sun Myung Moon, the Children of God and the Way International. None of this or similar literature should be around our homes.
6. Do not allow the influence of evil to come into your home through television. Carefully monitor the programs that are seen. The values taught by television advertising are not the values preached by Our Lord Jesus Christ in the Gospel of St. Matthew, chapters 5, 6 and 7.
7. Keep blessed water in the home and use it frequently. If we wish to ask God's blessing on our own homes, we can say a simple prayer of blessing and then sprinkle holy water in each room. Such a prayer of blessing could be something like this:
"Heavenly Father, we ask your blessing upon our home. In the name of your Son Jesus we ask to be delivered from sin and all evil influence. Protect us from sickness, accidents, theft and all domestic tragedies. We place our home under the Lordship of Jesus and consecrate ourselves to the Immaculate Heart of Mary. May all who live here receive your blessing of peace and love."
An "Our Father" and "Hail Mary" could also be recited.
8. The consecration of the family and the home to the Sacred Heart of Jesus is another beautiful Catholic custom. We need to have a crucifix and pictures of the Sacred Heart and Our Blessed Lady in our homes.
9. Receive the Eucharist as often as possible. In this sacrament is the power and presence of Jesus Himself. Persons who have actually needed exorcism from the power of the Evil One have been cured by sitting in church in the presence of the Blessed Sacrament, an hour each day, for one or two months.
10. Pray to Our Lady, particularly the Rosary. Our Blessed Mother has been designated by God as the one who crushes the head of the serpent (Gen. 3:1s). The Rosary is a very powerful means of protection and salvation. Many sons and daughters have been saved from the power of sin and the loss of faith through the perseverance of their parents in saying the Holy Rosary.
If you follow these steps, you are bound to live a holy life which is the best kind of "home insurance" for protection of your property from evil!