With winter upon us, you’re probably using your heat pump to keep yourself warm on a daily basis. If you are, you may notice that ice occasionally builds up on the outside part of the heat pump while it’s on. This isn’t automatically a problem, but it can certainly become one under the right circumstances. Let’s take a look at why ice forms on the heat pump, and when you should call for repairs.
Why It Happens
When the heat pump is in heating mode, the outside unit evaporates refrigerant to siphon thermal energy from the surrounding air. This causes the temperature around the unit to drop, and condensation to form on the coil itself. If the air outside is cold enough, this process can cause it to drop below freezing temperatures. This will cause the condensate on the coil to freeze and form ice.
When It’s a Problem
If ice is allowed to build on the heat pump unabated, it will prevent the coil from having access to the air around it. That means it won’t be able to actually heat your home. The weight of the ice can permanently warp the coil over time, so letting it sit on the heat pump can be quite problematic. The reason that this isn’t normally cause for concern is that the heat pump has a defrost cycle built into it. Every once in a while, the heat pump will reverse its refrigerant flow to melt all the ice off of the outside coil. If you notice that most of your heat pump is iced over, though, it may mean that there’s something wrong with the defrost cycle. That’s when you should call for repairs.