You didn't make it clear if you would be living with just the friend or the family? If it was just a friend I would be more likely to jump in versus joining a whole family dynamic. I have had friends that did that and it caused a lot of conflict.
For those of us editors who went away to college and had roommates, some of whom were friends that we had made previously, whether from home or there on campus, we can tell you that actually living with a friend can be a completely different experience from what one imagines. Very quickly, this friend can become an adversary. So, please examine carefully this potential situation before deciding.
Pohnpei brings up a very good point. While it may seem better or more fun to be at the other person's house on a short term basis, things can change very quickly once the living situation changes and becomes a little more permanent (even if only for a year). I would suggest knowing the rules of the new house. They may differ from the rules you are familiar with enough for you to change your mind.
When we don't know you, the family you are considering, or any of the circumstances, it's really difficult to address your question in any kind of concise manner.
The situation you describe could allow you to really mature and experience growth in many non-academic ways, aside from possibly giving academic benefits. The situation could also destroy your friendship with members of this family and cause problems that would end up harming your academic efforts.
Think very carefully, examine all possible angles, talk with everyone who might be involved in any way before making this decision.
As a young adult or a teen getting away from your family for a year could be a good thing. You have to make your own decisions and choices; you have to take care of yourself. It will also teach you something about relationships. We can yell at parents and sibs when we're mad, with family friends we have to rein in the anger and deal maturely with disagreements. And "absence makes the heart grow fonder."
Being a long-term guest in someone else's home can be very stressful -- it isn't your home after all. There are so many issues to work out: rent? chores? curfews? household rules? The adults aren't your parents, but you are living under their roof and would have to live up to their conditions at all times. It isn't the same kind of environment as you would have with your own parents whom you may be able to have more flexible or negotiable circumstances. Depending on the reasons for this change you really have to ask yourself if you are ready to not only live away from your parents but to live with someone else's.
It would help to know your purpose in doing this. Is this something you want to do while you're in high school? I have noticed that teens sometimes think about doing something like this when they are not getting along with their families, and if that is your motivation, it is not a good one, really. Every teenager has problems of one sort or another with the family, and it is always best to simply stick it out and work it out. If your motive might be to be in a better school district, that is a better motive, but still, there are so many things to consider. Is the value of what might be a better education worth giving up your family and having to adjust to another family's way of life? Even with a worthy motive, there are many details that would have to be considered, for example, the financial details. This is a pretty extreme thing to do, and you need to think carefully about what your motives are in considering this.
For me, the biggest thing is to figure out whether you would really like to live away from your own family for a year. You may get along well with this family friend for short periods of time, but how will it be when that person is supposed to be standing in for your parent? It seems like it could end up in a lot of tension and bad feelings.
It's really impossible for someone who does not know you and the family friend to give you good advice about this over the internet. You probably should consult your guidance counselor at school for more help.
Much of the answer depends on circumstances. For example, if you are doing this to establish in-state residence for university, it makes sense. If this is a year abroad program, it would be an academic advantage.
The main thing you should consider is whether it will be a better study environment or a distracting one. Will you have a room where you can study? Are their other children who might be a distraction? Is it close to school or would it increase commute times? Would the family friend be able to help you with homework?