Households allow you to save on postage and printing costs by sending one piece of mail, not two or more, to households where you have multiple constituents. Maintaining separate records for each member of the household lets you communicate with them individually, especially by email -- for instance, if one is a board member and the other is a volunteer. Creating a household merges their giving history into a single report and allows you to send single acknowledgment and solicitation letters. Households do NOT count against your licensed limit of constituents -- in fact, creating a household will cause Bloomerang to count two constituents not as two records, and not as THREE records, but as ONE record for purposes of tracking the size of your database.
To learn more about households, including how to create them, click here.