Please Help. I'm add a addition on my house. But new codes are forcing me to pour a slab. So i'm having to put my duct work under the slab. But my real concern is my main truck is under my house and i be running 4 new ducts about 35' off my trunk. The furnace is about 30 years old already, But had it checked by 3 guys and all said its in great shape and more the big enough for my house and addition. Just want to know if it will push 4 more ducts out 35' and keep the new rooms heated and cooled. And what is a good duct to put underground? It will be filled with sand and a slab on top.
Thanks
Thanks