Sponge window seals are made from flexible sponge-like materials that create a tight barrier between the window frame and the window itself. This material is designed to compress and expand, filling any gaps that might allow air leaks. By creating this seal, homeowners can significantly reduce energy costs, maintain temperature, and improve overall indoor air quality. In colder months, these seals prevent cold air from seeping in, while in warmer months, they keep the cool air inside, reducing the strain on HVAC systems.