It is not a waste of time if you take a nap or devote your time to activities other than your homework. However, you need some flexibility in your approach. For example, some days, you may have more work or a difficult assignment to complete, then you may have to consider skipping your homework-free hour. Also you may reward yourself on another day by extended homework-free time if there is not much to do... Important thing is that you learn and enjoy whilst you're completing your assignments because otherwise it may not be worthwhile if you do it just for the sake of it.

I wish you well!