I ride 13mi (21km) each way. It's less than an hour of ride time - which in my city is competitive with driving times during rush hour - plus a bit of overhead at each end of the ride for securing the bike, changing, etc. After a couple of weeks of riding that route every day, it didn't even feel like a hardship, just a normal thing to do. I get two hours of exercise a day while others stew in traffic; I'm happier, more energetic, I have a resting heart rate my doctor is envious of - what's not to like? Go for it.