Why Is My Outdoor Air Conditioning Unit Dripping Water in Winter?

When it comes to maintaining a comfortable indoor environment, air conditioning plays a crucial role, not just during the hot summer months, but throughout the year. As the winter season sets in, you might notice an unusual occurrence – water dripping from your air conditioner’s outdoor unit. It might look a bit worrying, but don’t panic! We’re here to explain why your outdoor air conditioning unit is dripping water in the winter months.

When an air conditioner operates in heating mode, a heat pump absorbs heat from the outside air and transfers it inside your home to warm it. When the ambient temperature outside gets very cold, the moisture in the air begins to freeze on the outdoor unit’s componentry. This is when something called de-ice mode usually begins. De-ice mode is simply the system recognising that ice has formed (or started to form) and automatically fixing this. It works by temporarily reversing the refrigerant flow to melt the ice. As the ice melts, it turns into water and drips down from the coils. This is what causes an outdoor air conditioning unit to drip water.

It is important not to stop the unit before the de-ice cycle has ended, because if the unit is restarted shortly afterwards it will run very inefficiently and may cause damage to itself. Stopping the de-ice cycle will also cause ice to build up on the heat exchanger and reduce airflow moving across it, which in turn reduces the efficiency of the air conditioning unit.

Ford & Doonan recommend turning the system on and letting it run its course. If you set the air conditioner into heating mode, but cool air is flowing out of the vents, let the system run its course. It will begin heating shortly once it has cleared the ice and frost.