I am thinking of replacing my old insert with a new one. I am totally clueless as to what to look for and how much to pay. I currenlty have an old Kodiak Stove insert. It has a fan that goes under the box but we have never had any luck getting enough heat out of thing. The only room it heats is the room it is in which is about 15x10. I am guessing the thing is over 20 years old. Will the newer models heat a larger area? What brands do you recommend? Thanks is advance.