Heat pumps have become an increasingly popular choice for energy-efficient heating and cooling in Australian homes. But many homeowners still wonder if heat pumps work in cold weather. It’s a valid question-especially in southern parts of the country or inland areas where winter temperatures can drop well below 10°C. After all, how can a system designed to “move heat” still function when it’s cold outside?
The short answer is yes-modern heat pumps do work in cold weather. However, understanding how they operate, how performance is affected by temperature, and what types of systems are best suited for cooler climates is essential if you’re considering one for your home.
In this blog, we’ll explain how heat pumps function in winter conditions, what to look for in a system, and how to get the best performance when the temperature drops.
How Heat Pumps Work
To understand how a heat pump performs in cold weather, it helps to know how it works. Unlike traditional heating systems that generate heat by burning fuel or using electrical resistance, heat pumps operate by transferring heat from one place to another.
In heating mode, a heat pump absorbs heat from the outside air-even when it’s cold-and transfers it indoors. It does this using a refrigeration cycle, which compresses and expands a refrigerant to move heat energy. In cooling mode (like an air conditioner), the process is reversed.
It may seem counterintuitive, but even air at 5°C or lower contains usable thermal energy. The heat pump’s refrigerant can extract that heat and transfer it into your home-just like a fridge extracts heat from inside and releases it at the back.
What Happens When It Gets Cold?
While heat pumps can work efficiently in cool temperatures, their performance can be affected as the outside temperature drops. That’s because the system has to work harder to extract usable heat from colder air.
Here’s what you can generally expect:
- Above 7°C: Most heat pumps operate very efficiently, often delivering three to four times the energy they consume.
- Between 0°C and 7°C: Efficiency declines slightly, but most modern systems still perform well.
- Below 0°C: Some heat pumps may struggle to maintain output, and efficiency can drop further. However, specially designed cold-climate models can still operate reliably at sub-zero temperatures.
It’s worth noting that while heat pumps may become less efficient in very cold weather, they still work. And because they’re moving heat rather than generating it, they’re often more efficient than traditional electric heaters, even when temperatures are low.
Cold-Climate Heat Pump Technology
Advancements in heat pump technology have significantly improved performance in cold weather. If you live in an area where winter temperatures regularly drop below 5°C, look for systems specifically engineered for these conditions.
Cold-climate heat pumps typically include:
- Enhanced compressors: These maintain higher efficiency at low temperatures and ensure stable operation.
- Variable-speed motors: These allow the unit to adjust its output based on demand, improving both efficiency and comfort.
- Advanced defrost cycles: In cold and damp weather, frost can accumulate on the outdoor unit. A good heat pump system includes an automatic defrost cycle to keep performance consistent.
- Improved refrigerants: New refrigerants are better suited for extracting heat from very cold air and help maintain steady indoor temperatures.
Many reputable brands offer models designed for use in cooler climates, so don’t assume a heat pump isn’t suitable just because your winters are chilly.
Real-World Performance in Australia
In many parts of Australia-such as Perth, Adelaide, Canberra, or even parts of Victoria and Tasmania-heat pumps are increasingly being used to replace traditional hot water systems and electric or gas heaters. While these areas can experience winter temperatures in the low single digits, most homes are still well within the operating range of today’s advanced heat pumps.
Water heating, in particular, is a great use case. Systems like Eurosun heat pumps are designed to deliver efficient hot water even in colder weather. These systems can absorb heat from the surrounding air and use it to heat water stored in a tank, reducing energy consumption by up to 70% compared to conventional electric water heaters.
As more Australians look to reduce energy bills and environmental impact, the reliability of cold-weather performance has made heat pumps an attractive option even in winter-prone regions.
How to Get the Best Cold-Weather Performance
If you’re considering a heat pump and want to ensure it performs reliably in cold weather, here are a few important tips:
1. Choose the Right System for Your Climate
Always select a heat pump that’s rated for your local temperature range. Look for systems with a high Coefficient of Performance (COP) and specific cold-climate certification if available. Trusted manufacturers and installers will be able to recommend models that work best in your region.
2. Proper Sizing Matters
A heat pump must be properly sized for your home’s heating needs. An undersized unit will struggle to keep up in cold weather, while an oversized system may short-cycle and become inefficient. A qualified technician will assess your insulation, room sizes, and climate to determine the right size.
3. Maintain Your Heat Pump Regularly
Like any appliance, heat pumps need periodic maintenance. Dirty filters, blocked outdoor coils, or faulty sensors can cause your system to underperform-especially during winter, when demands are higher. Have your system professionally serviced at least once a year.
4. Install in a Sheltered Location
Outdoor units should be installed in a location that’s protected from strong winds and shaded from direct exposure. Good airflow is essential, but positioning the unit under an eave or behind a screen can help reduce frost build-up and improve efficiency in cold weather.
5. Consider a Backup Heating Option
In areas that occasionally experience freezing temperatures, having a secondary heat source-such as a small electric heater-can be helpful during the coldest days. However, with the right system, most households find they rarely need to rely on backup options.
The Bottom Line: Yes, They Work-and Work Well
So, do heat pumps work in cold weather? Absolutely. Today’s systems are built to handle Australia’s varied climate conditions, and with the right setup, they can deliver reliable, energy-efficient heating-even when the mercury drops.
Whether you’re looking to upgrade your hot water system, replace an old heater, or simply want a cleaner and more sustainable way to warm your home, heat pumps offer a compelling solution. With proper installation and maintenance, they continue to perform well throughout the seasons-saving you money while keeping your home comfortable year-round.
