if you really want to, you could shrink the home edition partition after uninstalling everything. then dual boot with your edu edition and just use that os as the default one. this would leave your home edition alone in case you want to use it again.
with that said. i don't think you would lose the home edition since the key is stored on MS server and is based on the hardware installed. so in theory you should be able to install the edu version fresh and go back and forth at will so long as your edu version is valid. this is theory of course as i have not tried any such thing myself. no use for edu version so never tested it with any scenarios.