Why Do Air Source Heat Pumps Freeze Up?

by Energie Solutions | Jan 9, 2025 | Heat Pumps, Renewable Energy

Air source heat pumps (ASHPs) are an energy-efficient way to heat your home, but during these colder months, you might notice frost or even ice forming on the outdoor unit. If this happens, don’t worry – it’s a normal part of how the system operates. Let’s break it down.

Why Does Ice Form?

Heat pumps work by pulling heat from the air, even when it’s cold outside. As the outdoor unit extracts heat, moisture from the air condenses on its coils. When temperatures drop below freezing, that moisture turns to frost or ice.

Built to Handle the Frost

Modern heat pumps are designed to handle this! They periodically switch into a defrost mode, temporarily reversing the heating cycle to warm the outdoor coils. This melts any frost, allowing the system to maintain efficiency. You might see steam rising during defrost mode – this is just the ice melting, and it’s completely normal.

image of a frozen heat pump.

When Ice Becomes a Problem

While some frost is expected, a heat pump can ice up completely if:

• The defrost system isn’t functioning properly.
• There’s poor airflow around the unit (like leaves, snow, or debris blocking it).
• The outdoor unit has a refrigerant issue or malfunction.

If your heat pump is fully covered in ice for an extended time, it’s time to call us. Our engineers can check for any underlying problems and get your system back on track.

How to Prevent Ice Build-Up

• Keep the outdoor unit clear of debris, leaves, and snow.
• Schedule regular maintenance to ensure everything is working properly.
• Make sure gutters or other sources of dripping water aren’t directing excess moisture onto the unit.

At Energie Solutions, we’re here to help you get the most out of your heat pump. If you’re experiencing problems or need maintenance, reach out to us. A well-maintained heat pump is your key to reliable, energy-efficient comfort all year long!

To find out more, get in touch with our friendly team by emailing admin@energiesolutions.co.uk or calling on 01206 396901.