Cutting commutes up into hours per year doesn't seem all that useful. Lots of stuff takes up what sounds like ridiculous amounts of time if you look at it like that. I'd rather look at it in terms of your day.

If you plan to spend 8-9ish hours actually working, and another 10 per day on sleeping, eating, shower, and other such necessities, that leaves about 5 hours of real free time. A hour and a half a day of commute time is a pretty solid cut into that. 20 minutes of commute time is hardly noticable. Personally, I'd sooner take the 10 minute commute and have that mental seperation between work time and off time than have an extra 20 minutes a day and work at home.