I have/had the same problem. My stove is in my basement. I can easily heat the basement but the other floors, not very well.
Granted, I have a 2,800 square foot house built over 100 years ago
My point is that heat distribution I feel is my problem. I'm simply not "pushing" the heat where I need it to go.
It took me a little while to get the feel of my stove. I'd wake up at 3 a.m. and my nose would be cold. Right there and then I knew the stove went out! Now, it only goes out when I'm away for days.
Stick with it!