Sizing of hot and cold exterior hose bib
I'm planning to install an exterior hose bib for my house that carries both hot and cold water. The model I'm looking at is the Moen HC4005 series.
These hose bibs are "frost-free" and come in different lengths. For example, it comes in 6", 8", 10", and 12" lengths. However, the specification sheet shows that this length corresponds to only a sub-portion of the overall length of the faucet within the house. So the 6" model, for example, has another 4" of length inside the house prior to opening to the copper supply lines.
Here is a link to a diagram.
Sorry for being long winded. My question is how do I determine which size to buy? (I'm planning on running this through a 2"x6" framed wall with 1/2" sheathing and hardiplank siding.)