Hail reign a fair maid with gold upon her chin,
Open up the East Gate and let the New Year in! - Welsh carol

The month that ushers in the New Year is a time to make a fresh start and what better place to begin than at home?
In Scottish tradition, the family came together to sain (ritually cleanse and bless) their house with holy water and incense.You can sain your home with holy water. Collect this from a local spring or pool between midnight and dawn, preferably toward the end of the first quarter of the moon. If this is impossible, use bottled spring water from a pure source.

If you live with other people, form a circle around your fireplace or a large candle.  Pass the water in a sunwise (clockwise) direction for everyone to drink, then take it around the house and sprinkle some in the four corners of each room.

A saining can be done by water alone.  But you can also use juniper incense, as was the custom in Scotland. This shouldn't be too hard to find, being a popular garden plant as well as one that grows wild in many parts of the world.  Cut a few sprigs the night before and put them on the hearth or other warm place to dry out a little.  (For a better burn, dry it by the hearth, on layers of newspaper or hang it in a dry place for a few days or weeks.) When you light them, have a small bowl or shell to catch any ash or sparks that might fall. Using either your hand or a long feather, fan the smoke around each member of the household in turn, then take it to each room and blow some into the four corners.

For an even simpler house blessing, light a white candle and slowly carry the flame sunwise (clockwise) around the threshold, the hearth and four corners of each room while reciting this blessing from the Hebrides, which invokes the goddess and saint, Bridget of the Hearthfire: 

May Bridget give blessing
To the house that is here
From crest and frame,
Both stone and beam; 

Both clay and wattle;
Both roof and foundation;
Both window and timber;
Both foot and head;  

Both man and woman;
Both wife and children;
Both young and old;
Both maiden and youth

Plenty of laughter,
Plenty of wealth,
Plenty of people,
Plenty of health,
Be always here.

(slightly adapted from the collection: Carmina Gadelica by Alexander Carmichael)