If you're considering replacing your entire HVAC system, you may want to look into installing a heat pump. The name can be misleading, but it can cool your home in the summer and warm it in the winter. When it's cooling, it functions similarly to an air conditioner; in the winter, it's the most energy-efficient heating option on the market. Instead of creating heat, heat pumps pull air from outside and transfer it inside. In the summer, it removes the warm air from inside your home and moves it outside.