I just purchased a home built in 2004 in west michigan with a power vent water heater and high efficiency furnace. The basement is not finished and there is a fresh air pipe going to the return ducting as well as a down facing fresh air pipe that is dumping cold air into the basement. Can someone explain why and if I need the fresh air pipe? I thought it was for combustion air, then I've read it's for internal pressure. House is 2x6 and very tight. If I shouldn't eliminate the pipe shouldn't I at least put a J on it so it's not constantly dumping air?

Hello, I have a 2.5 ton heat pump system in my home. I have a foyer located between my dining room and living room, this is where the front door is located. There are 2 8" supplies for the living room and 1 8" supply for the dining. The foyer in between never had a supply put in. You can definitely feel a difference in temp in both summer and winter and can feel a slight draft. I was thinking of adding a supply and a return to the foyer to help balance out the temperature. The problem is on the outside wall is where my front door is located, and directly to the right of that is a closet, Leaving no free room along that wall except for directly in front of the door. So that would leave me either putting the register right in front of the door, or further in along the closet wall, which would put it much closer to the return. Any suggestions?