Hello, After last years winter and working overtime to pay my heat bill, I have been looking for ways to improve my heating costs. I bought the home last October and am getting around to leak proofing my heating/cooling system. The home is a 2 story structure. The lower half is solid brick, while the top portion is aluminum siding. My heating unit is a forced air style located in the basement. My master bedroom, which is furthest from the heating source, is the coldest room in the home. No problems on the main floor. While painting my bedroom, I pulled the cold air intake grate off and something caught my eye. It had a metal hood coming up but I could see a line of "daylight" further past the CAR. With a flashlight, I then could see the back of my siding, where it all connects together. No type of foam board or insulation. The return runs between 2 studs and goes directly down the wall and into the basement. It goes into a cold air channel between the joists in the basement ceiling along the basement wall. It appears to be the cold air return for 2 bedrooms on the second level. It then has an elbow and duct work that goes to the main cold air trunk. What I began doing is sealing the leaks in all the duct work in the basement which had no type of sealing at the duct joints. I found a fair amount of leakage for the heat duct that runs off the main trunk and goes to the cold bedroom. I have found numerous small leaks in the heat ducts and am working on those. Numerous leaks in the heating unit itself which I have patched already. I have noticed a difference in the amount and force of heat now coming out in the bedroom. However, I am curious if this cold air return where I can see the siding is normal and or allowing cold air to come in my bedroom. I can't find a fresh air vent to the HVAC. I have heard from several different sources that this is normal and from others that it is not. Mind you the same leaks I have found on the heat side of the system I am also finding on the cold air side in the duct work in the basement which I am also working on sealing. The unit has central air and the screen type filters that I have taken out and cleans. My question is simple, yet the description is long which I am sorry for. But is the cold air return in the master bedroom normal? Is this causing the cold room? The attic looks to have fresh blown in insulation, so new it looked like a fresh winter snow so I am thinking it's not the problem. Thanks for reading this long and boring problem but I am really wanting to know what to do because I can't afford to pay someone to pull siding off and fix things if need be.