How many calories do i burn an hour playing piano?

I've looked it up on multiple sites, and they say i can burn anywhere from 100 to 150 calories an hour. I play like hefty piano concertos sometimes for 3 hours straight. some people say that it doesn't replace excercise, but it is exhausting, i find myself out of breath often and exhausted even in my legs. So about how many calories do i burn an hour, YA?