My husband and I have a Grandpa Fisher stove,waiting to be hooked up. Our house is approx. 2000 sq. feet with cathedral ceilings. Our existing stove pipe is 6 inch double wall with 6 inch triple wall metal chimney which was used with our previous wood stove. Can we safely and efficiently use our existing set-up? We also have a propane furnace, however, nothing feels as warm as wood heat. Thanks in advance for your help in this matter.