As a newer VC Defiant owner, yeah it's impossible to control. It's a combination of leaky stove design and that stupid thermostatic control that doesn't work worth a crap. I'm either at "oh crap I need to turn this down but I already have cat on and temp as low as it goes" or ...wait no that's always where I am. I'm almost always running 600F-799F with no control over it. 6hr burn is normal with a stuffed firebox, 7hrs if I'm damn lucky. I got an 8hr burn once by putting in unsplit medium sized logs in mixed with regular splits, not worth the extra hr. All this on a rated 14hr+ stove :'D. Oh and the dealers/intallers don't have a clue how to operate them either.