“Wait, what do you mean my heater’s frozen? How is that possible?” We receive this question from homeowners on occasion, often after they’ve contacted us to inspect their heater after it’s seized up and stopped working in the middle of cold stretch of winter weather. While it may seem more than a little silly to imagine that something that’s supposed to generate heat and keep you warm has literally frozen over, the truth it it’s both possible and a pretty large threat during winter months.
Why Do Heaters Freeze?
To be more specific, it’s your heat pump that freezes over. Your heat pump works to both heat and cool your home by collecting heat from one location and moving it to the other. In winter, your pump collects heat from outside, and then carries it inside using refrigerant. While it’s normal for your heat pump to have a thin layer of frost on it because of this process, a more serious problem can lead to the frost continuing to build, eventually causing it to fail.
This freezing is usually caused by a lack of air flow across your heat pump coils. When not enough air flows through your system, the coils may not be able to control their temperature as well. When temperature control systems aren’t working properly, this can lead to a snowball effect of water vapor condensing, then freezing, which causes more vapor to condense and freeze, eventually leading to a frosty problem that can cause serious damage to your system as a whole.
Here are three reasons why your system can freeze due to poor air flow:
- Dirty coils: Dirt on your heat pump’s condenser coils don’t allow them to pull in as much heat as they need to properly warm your home. When this is the case, your coils can’t maintain a constant operating temperature, and as a result over time they accumulate too much frost and your system freezes over.
- Dirty air filter: The air filter in your system needs to be clean in order to get the maximum amount of airflow over your compressor coils. If they don’t, the heat can’t radiate back into your home properly, and that could mean trouble for your heat pump. Changing your air filter can ensure your blower motor can pull as much air as possible through your system, making both more efficient and less likely to freeze over.
- Dirty outdoor unit area: The area around your outdoor unit needs to be open and free from dirt, dust, leaves, and other debris that can accumulate and restrict airflow through it. It’s a good idea to regularly inspect your outdoor unit and sweep away any debris, including any accumulated snow, from a radius of at least two feet around your outdoor unit. You should also make sure the land your outdoor unit sits on hasn’t settled or shifted, which can seriously affect your system’s ability to work properly.