Some ways to insulate existing walls include loose fiberglass insulation, cellulose or spray foam. Curtains and wall coverings are also a handy way to insulate existing rooms.
Although fiberglass batting can be difficult to apply to an existing wall, loose fiberglass is much easier to install. However, it lacks the density that some other forms of insulation offer and it can be difficult to apply evenly. To add loose fiberglass to a wall, drill a small hole in the wall and pump the fiberglass into the space.
Cellulose insulation is made out of materials, such as recycled newspapers, which are treated with chemicals to offer insulation. It is dense and less susceptible to mold and insects. Like loose fiberglass, homeowners can pump cellulose insulation into an existing wall through a small hole. There are also a few similar insulation products on the market made from rock or wool.
Spray foam insulation includes products made out of polyurethane, phenolic and cementitious. Homeowners can apply it to small or large areas of the wall, and it is very easy to apply around obstructions. Like other fill-in insulation products, homeowners can spray it through a hole in the wall. However, it expands after it is sprayed, which helps it get into crevices and corners. This helps prevent empty spaces and air leaks. Therefore, it is a very effective form of insulation.
Homeowners on a budget can insulate existing walls using curtains and wall hangings. Many walls loose heat through windows and doors, so thick curtains can help prevent heat loss. Wall hangings, large pictures and other decorative coverings provide additional insulation to walls.