At some point, every appliance will have a problem. The problem can range from not working right or not working at all. One of those appliances includes your heat pump. It may appear that it isn't heating up or not turning on at all for no reason.
While people can upgrade their homes' energy efficiency in many ways, there is a lot they can do to hurt it. They unknowingly waste a lot of energy by leaving energy appliances or using them at the wrong temperature and not charging air filters.