We just went through a cold snap last month and got our heating bill. Let's just say I was not a happy camper. Our home consists of an old structure that was built in the late 60- early 70's then we added on in the late 90's. I have noticed that the original house seems warmer. When adding on we up-dated all the windows to double pane with the gas inside. The insulation in the new part was normal stuff, what was commonly used. A while back we insulated between the floor joist but I still think there are things we could do. We have two furnace- one for each section. We do have french doors that are a huge heat loss. We tried putting the wrap over them but couldn't seal the bottom. I am looking for advice on how to make the addition become as warm as the older part of the house. You can feel the difference. I really don't know what to do.