I wear my Ororo heated vest every day... inside our house! I'm a skinny old woman and used to have trouble staying warm. Nada mas! I put on the vest as soon as I get up, early in the morning. The heat control button near my left collar bone gives me three color coded options: hot, medium, and warm. The vest heats up within seconds, and the small battery pack in an inside pocket keeps it going for hours. I bought one for my adult daughter, a mother of two little ones,who used to wear bulky sweaters or coats inside their house to stay warm. Now the snug vest keeps her warm and happy every morning, much less expensive than turning up the thermostat and blasting heat through the whole house. This is a great product. Oh, I also wear it to our unheated rock climbing gym, and under a windbreaker when I hike on cold windy mornings.