Hey guys new to this forum. I'm getting ready to install a wood furnace in my basement. My wife wants to pay the pros but I'm a DIY guy on everything. I have my flue figured out but I'm concerned on how to force the duct from my new furnace thru the same duct work that my current gas furnace/ac unit run through. I want to use the wood heat as my primary heat while keeping my gas furnace as a backup in case the fire goes out. Do I just tie my wood furnace duct into the end of my duct run or will that cause damage to my gas furnace if the wood furnace is forcing air through the duct work??