Heat pumps have become a popular alternative to traditional air conditioning systems and furnaces. They can cool your home during the summer, and they can warm your home during the winter. When using a heat pump during the winter, though, you should familiarize yourself with defrost mode. Heat pumps have a defrost mode, which they’ll enter to prevent ice from building up on the outdoor unit.
What Is the Defrost Mode?
Also known as the defrost cycle, the defrost mode is designed to melt ice and frost on a heat pump’s outdoor unit. Heat pumps are similar to air conditioning systems in the sense that they feature an indoor unit and an outdoor unit.
Whether it’s cooling or warming your home, the heat pump will transfer heat between these two units; it simply moves heat in different directions when set to heating or cooling. If your heat pump is set to heating – which is typically the case when using it during the winter – the outdoor unit will absorb heat from the air or ground before transferring it to the indoor unit. The defrost mode is a special mode that heat pumps enter to protect the outdoor unit from ice.
How the Defrost Mode Works
How does the defrost mode work exactly? In normal operating mode, heat pumps create warm air by absorbing it from the outdoor ground or air. It’s not uncommon, however, for outdoor temperatures to drop below freezing during the winter. Subfreezing temperatures, of course, can lead to the buildup of ice and frost on the outdoor unit.
The outdoor unit has a sensor that will detect the presence of ice and frost. When the temperatures begin to drop and ice builds up on the outdoor unit, this sensor will tell the heat pump to enter defrost mode.
Upon entering the defrost mode, the heat pump will reverse the direction in which it transports heat. Rather than moving heat from the outdoor unit to the indoor unit, it will move heat from the indoor unit to the outdoor unit – but only for a temporary period. As heat moves to the outdoor unit, it will melt the ice and frost.
The defrost mode typically only lasts for about 10 to 15 minutes. Once the ice and frost has melted off the outdoor unit, the heat pump will return to its normal operating mode.