What is a common problem associated with electric heat pumps in winter?

Frost building up on the outdoor coils is a common problem associated with electric heat pumps in winter because heat pumps operate by absorbing heat from the outside air, even in cold temperatures. When the outdoor temperature drops, moisture in the air can condense on the coils and freeze, leading to frost or ice accumulation. This can inhibit the heat pump's ability to absorb heat, decreasing its efficiency and potentially causing operational issues.

To combat this issue, many heat pumps are equipped with a defrost cycle, which temporarily reverses the refrigerant flow to warm the coils and melt the frost. However, if the frost buildup is excessive or if the defrost cycle is not functioning properly, the heat pump's performance will be adversely affected, resulting in reduced heating capacity and increased energy consumption. Addressing this problem is crucial for maintaining the effectiveness of electric heat pumps during winter months.