I recently bought a house that was built in 1999. It was constructed by the typical in and out contractor that did everything half cocked. My master bedroom is the typical situation of the room being colder/warmer than the rest of the home. 2 vents are located on the exterior walls. I got in the attic and notice hardly any insulation was in the attic as I could see the back of the drywall ceiling. It was cellulose insulation so I bought some and rented the machine and blew it in my self and have about 15" up there now. The room is still substantially colder than the rest of the home. The contractor installed cheap insulation in the stud cavities. The walls are 2x4 and I firmly believe that the insulation in the walls is 2" and doesn't fill the stud cavity. The front of my home is brick and the remaining walls are siding. The 2 outer walls of my bedroom are siding walls and I believe cold air is seeping through the skin and into the walls creating cold drafts causing my room to be cold. Additionally, I can feel cold air coming through receptacles and switches that are located along all walls that have siding. My question is; does any one know of a way I can add insulation to my exterior walls, that currently have insulation in them but does not fill the stud cavity, without having to cut significant openings or completely tearing out the drywall?? Thank you.