I've been getting into yoga at home too and I've tried a bunch of yoga dvds. The one I like the best at the moment is P90X's dvd. It's around 90 minutes long. The first 45 minutes are quite tough and the last half is easier as it's mostly stretching. I turn the heating up to around 25c and try to do the whole thing. It was tough at first but now I'm really enjoying it.