I'd say 1-2hours of productive work a day is quite common (it fits with my current experience). The difference is when you're working at home you don't have to

I'd say 1-2hours of productive work a day is quite common (it fits with my current experience). The difference is when you're working at home you don't have to pretend to be working. So when you've got no work to do you don't have to pretend to read a document. You can go for walk, do the dishes, play with your kids, work on side-project/ learn a new language. Same productivity, happier worker.