You should try living with your family in a house with a backyard, it's quite enjoyable and could be pretty cheap over time if you see any appreciation.
Secondly there are a lot more taxes on a lot more things in SF, are you factoring that in?
Also I'd bet you are worth more than 105k in SLC if you looked around longer.
I love SF and it's great to live there for many reasons, but I don't think "cheaper than utah" is one of them.