Hose bibbs can be used inside or outside the home. Though interior and exterior hose bibbs function similarly, they are designed for distinct purposes.
Interior Hose Bibbs
Hose bibbs installed in the home are connected to hoses which in turn connect to an appliance like a washer, water heater, or dishwasher. If the hose bibb is installed on or above the first floor, a standard bibb can be used.
A standard bibb is also called a non-frost free bib because water inside the bibb is more likely to freeze in freezing temperatures than a frost free bib. For this reason, frost-free bibbs should be installed in basements below the frost line, especially if the basement is unheated.
If water inside the hose bibb freezes, then the bib is very likely to split internally. This damage is typically unrepairable and will require you to replace the hose bibb. Additionally, a split hose bibb combined with frozen water can increase the chance of backflow into your home.
Exterior Hose Bibbs
Many plumbing systems are designed to include an incoming water line that can be used for gardening and other outdoor tasks. These water lines include a spigot within the home that can shut off water in the event that a hose bibb is not installed.
An exterior hose bibb can be attached to these water lines in order to allow water flow to be turned on and off more easily. You can allow the interior spigot to remain open and turn on and off using the hose bibb if installed.
Frost free hose bibbs are most often used outside because they are designed to prevent water from freezing within the bib during freezing temperatures.