Historically, Christians have blessed things as well as people — the most common probably being their houses. House blessings can be readily found online; here is one from the Anglican tradition (PDF).
Today, however, this practice is viewed with considerable suspicion by many in the Protestant tradition, and especially in what Josh Robinson has identified as the emerging fourth branch of Christendom: evangelicalism.
For instance, I know of a pastor, a good man, who was called upon to bless a house in order to rid it of a demonic presence. While he was happy to come to the house and preach to the demon itself, commanding it to leave, he did not see any sense in “preaching to the house.”
But to bless an object is not to preach to it. It is, rather, to call upon God with regard to it.
The aim of blessing is to establish some kind of covenantal relation between the thing, its owner, and God. It is teleological, establishing a telos for the thing: a meaning and end.
God himself sets the pattern for this, by blessing the seventh day and hallowing it (Genesis 2:3). He is not preaching to the day; he is establishing a special relationship between it and him, prescribing a telos for the sabbath that the other six do not have. This is done by way of covenant; that is what covenants do; they are the promissory mechanism for creating personal, teleological bonds. In a similar way, Jacob talks about a field being blessed by Yahweh (Gen 27:27), and we read that God blessed Potiphar’s house — not meaning only the people in it, but everything he owned:
Yahweh blessed the Egyptian’s house for Joseph’s sake; and the blessing of Yahweh was upon all that he had, in the house and in the field. (Gen 39:5)
So also, God promised that if the Israelites served him, he would bless their bread and water; and contextually, by implication, their bodies and animals:
And ye shall serve Yahweh your God, and he will bless thy bread, and thy water; and I will turn aside sickness from thy inwards; there shall not be a miscarrying and barren one in thy land; the number of thy days I shall fulfill. (Ex 23:25–26; cf. Dt 28:5)
That a unique teleological relationship can be established between things and God, as well as between people and God, should be wholly uncontroversial, given that the Old Testament system of worship was entirely established on this very basis. The temple had a holy and a holy-holy place; sections specially dedicated to God, and therefore unsuitable to habitation or entry by people who had not been similarly hallowed. It had utensils which were similarly dedicated. These specific examples are fulfilled in Christ in the new covenant, of course; but the principle that places and things in general can be dedicated has not been overturned — because it is a creational, covenantal one.
Indeed, this principle is, at base, the same pattern by which we are able to own mundane property.
We are thus free to avail ourselves of blessings on places and objects, and enjoy the benefits of doing so, involving God in the ownership and teloi of our things. I do not know how these blessings, these covenant regularities, “resonate” in the spiritual realm; but church history certainly indicates that places and things can be hallowed in response to demonic activity, in order to take them back from the forces of darkness. After all, if people can be claimed back from demons, why also not the things they possess?