The heat pump (PAC) is an economical and environmentally-friendly heating solution that draws calories from the outside air to heat a home. But what happens when temperatures plummet in winter? Many people wonder whether a heat pump can remain effective in extreme cold. Here’s what you need to know about how it works in extreme conditions.
The basic principle of the heat pump
An air-to-water or air-to-air heat pump captures the calories present in the outside air, even when it’s cold, and releases them in the form of heat inside the home. It operates using a refrigerant that circulates between the outdoor and indoor units, changing state to transfer heat.
What happens when temperatures drop?
When the outside temperature drops below 5°C, the heat pump has to work harder to produce the same amount of heat. From -5°C, its efficiency (coefficient of performance, or COP) drops significantly. However, some new-generation heat pumps are designed to operate down to -15°C, or even -20°C.
Physical and technical limits
The colder it is, the less thermal energy is available in the air. The heat pump therefore draws calories from air that is already very poor, which increases its electricity consumption. In extreme temperatures, a back-up system (electric or boiler) generally takes over to maintain a comfortable temperature in the home.
Defrosting the outdoor unit
In damp, cold weather, frost can form on the outdoor unit. To prevent clogging and loss of performance, the heat pump goes into “defrosting” mode, briefly reversing its operating cycle to heat the outdoor unit and melt the ice. This process is automatic, but may have a temporary impact on indoor heating.
Optimize winter operation
To ensure optimum performance, we recommend :
- insulate your home to limit heat loss
- do not oversize or undersize the unit
- regular maintenance, especially of the external circuit
- coupling the heat pump with auxiliary heating in very cold regions
Conclusion
A heat pump can operate even in the coldest weather, provided it has been properly sized and adapted to the local climate. The most efficient models provide efficient heating down to -20°C, while maintaining a high level of comfort.
To install or maintain a heat pump adapted to your region, consult our page dedicated to heat pumps.
Do you have a question or a project? Contact our team via the contact page.
