Your house should give you a homelike feeling since you spend a lot of time in it. Mildew can be a nuisance when it finds its way to your home. It's a gray, white, or yellow powdery substance that grows on clothes, walls, carpets, furniture, windows, and roofs. If left unattended for a long time, it can cause damage to the surfaces it grows on or causes several health risks to you and your family members, such as respiratory problems, sore throat, headaches, and coughs.