Thank you for the question. Yes, employers are keenly interested in your volunteer work especially if the work is related to the position(s) you are interested in. For example, let's say you are interested in a marketing career. It's difficult to find a paid position in this field as a teenager without a college degree; however, many volunteer opportunities for marketing exists. You can find many opportunities on VolunteerMatch.org.
As a side-note, your volunteer work doesn't just have to be related on the career that you are interested in. For many employers it's just as important that you are an active citizen in your community and that you are willing to make a difference. A couple of years ago I hired an employee who had limited work experience, but had done a lot of volunteer work. It was clear that her volunteer work helped her to grow both personally and professionally.
Regardless of the volunteer opportunities you may pursue, it will never be a "bad" thing and should always reflect favorably.