On cold nights, you use a blanket to keep you warm. The walls around your house use a blanket, too! Inside the walls is a blanket of material called insulation (IN-SU-LA-SHUN). Just like you stay warm under a blanket, your house stays warm inside its blanket of insulation.
Insulation also helps if you live where it's warm outside. Instead of helping to keep the heat in, the insulation helps keep the heat out. Does that sound strange? Well, here's something you can do to see how it works.
There are many kinds of insulation that are used in the walls and ceilings of houses. If your home gets too hot in the summer or too cold in the winter, your parents might need to add more insulation to your house. My house uses a new kind of insulation called cellulose (SEL-YOU-LOS) insulation. It's made from recycled cardboard, so it's good for the Earth.