When winter temperatures drop below freezing, many people begin to doubt whether heat pumps can still operate efficiently. This concern is especially common in colder regions across Europe and North America. So, does the efficiency of heat pumps decrease at low temperatures? In this blog, we’ll break down how modern air source heat pumps are designed to handle harsh climates, clarify common misconceptions, and explore what temperatures actually affect their performance.
Many businesses still question whether heat pumps can perform reliably in colder regions.
Yes！
Air source heat pumps are increasingly engineered to maintain stable heating even in harsh, sub-zero conditions. Thanks to modern innovations like inverter compressors and intelligent defrost systems, heat pumps at low temperatures have evolved to become a reliable and energy-efficient solution across Northern Europe, Canada, and parts of the U.S.
In fact, heat pumps in cold weather can deliver consistent indoor comfort even when the outdoor temperature drops below -20°C. For example, SolarEast’s R32 BLN Series is built with high-efficiency inverter technology, allowing the unit to operate at full capacity down to -25°C. This makes it an ideal heating and cooling solution for residential buildings and light commercial facilities located in cold climate zones.
What sets these systems apart is their adaptability. Advanced air source models such as our RS Series feature automatic mode switching and smart sensors to adjust performance based on ambient temperature. Whether your customer is in northern Sweden or mountainous regions of Colorado, they can trust that SolarEast’s heat pumps will deliver both comfort and savings—even in the most demanding environments.
By choosing the right model, companies can benefit from stable operation, minimal maintenance, and long-term energy savings. In the sections below, we’ll explore common misconceptions and the real science behind heat pumps at low temperatures.
To understand how heat pumps at low temperatures perform in real-world conditions, simulation testing is essential. While many systems are rated for low-temperature performance on paper, controlled testing in sub-zero environments helps verify stability, energy efficiency, and defrost behavior under continuous cold exposure.
At SolarEast, we use in-house climate chambers to simulate outdoor conditions as low as -25°C. These tests monitor system behavior over long durations, including compressor frequency, defrost cycles, and energy consumption. Through these evaluations, we’ve optimized features like smart defrost algorithms and variable-speed operation to enhance cold-weather performance across product lines.
One such model tested under extreme conditions is the 75kW R290 Commercial Heat Pump. Designed for large-scale heating and cooling needs, this unit utilizes a low-GWP R290 refrigerant, full inverter control, and an intelligent monitoring system. These technologies ensure that even during sustained low-temperature operation, the unit delivers stable output while maintaining a high seasonal COP.
While actual field conditions vary, our simulation approach ensures that systems like the 75kW R290 unit are tuned for consistent heating—even in demanding cold-climate applications. This makes it a reliable option for schools, hotels, apartment buildings, and other commercial projects requiring efficient performance through winter.
Ultimately, the goal of simulation is not to chase lab-perfect numbers—but to ensure that our heat pumps in a cold climate maintain comfort and stability, no matter the temperature drop.
When it comes to heat pumps at low temperatures, many businesses and homeowners still have concerns. Despite the rapid advancement in heat pump technologies, outdated assumptions often prevent decision-makers from choosing this energy-efficient solution. In this section, we’ll debunk three of the most common misconceptions about heat pump performance in a cold climate: capacity, efficiency, and cost.
Let’s break them down one by one.
One widespread misconception is that heat pumps lose all their heating capacity when outdoor temperatures drop. While it's true that traditional air source units struggled in cold regions in the past, modern inverter-based systems have dramatically improved capacity retention.
For example, the SolarEast RS Series can still deliver up to 90% of its rated heating output even at -20°C. This is possible thanks to advanced compressors and R410A refrigerant optimization. These systems are not only reliable in winter but also maintain stable airflow and heating for homes and small businesses in cold weather conditions.
Likewise, the BLN Series offers enhanced capacity even at extreme lows, featuring intelligent load adjustment and low ambient heating mode. Such features allow the system to adjust compressor speed and fan output to match demand—even in heat pumps at low temperatures scenarios.
So, the idea that heat pumps can’t handle frigid weather is outdated. With the right model, your customers can enjoy powerful heating without compromise.
The Efficiency
One widespread misconception is that heat pumps lose all their heating capacity when outdoor temperatures drop. While it's true that traditional air source units struggled in cold regions in the past, modern inverter-based systems have dramatically improved capacity retention.
For example, the SolarEast RS Series can still deliver up to 90% of its rated heating output even at -20°C. This is possible thanks to advanced compressors and R410A refrigerant optimization. These systems are not only reliable in winter but also maintain stable airflow and heating for homes and small businesses in cold weather conditions.
For instance, SolarEast’s R290 heat pump water heaters are equipped with full inverter compressors and built-in temperature sensors. As a result, they can deliver a COP above 4.2 even at -15°C ambient temperatures, thanks to real-time load matching and heat recovery optimization.
By leveraging these core technologies, heat pumps in a cold climate can continue operating efficiently throughout winter—without a dramatic spike in power consumption.
There’s a common belief that heat pumps at low temperatures aren’t worth the money because they require more energy to run in winter. While it’s true that colder air contains less heat, modern heat pumps are designed to extract and transfer even minimal thermal energy efficiently. As a result, their operating cost remains significantly lower than traditional electric or gas-based systems.
Instead of running at full speed all the time, inverter-driven heat pumps—like SolarEast’s RS Series—adjust power output according to actual demand. This intelligent load modulation minimizes electricity consumption and reduces utility bills, even during prolonged cold spells. Over time, the energy savings can offset the initial investment, especially in regions where energy costs are high.
For customers in cold weather regions, the return on investment (ROI) becomes clear when comparing seasonal energy efficiency. For example, a conventional gas boiler may drop below 90% efficiency in freezing temperatures, while a high-performance heat pump can still deliver a seasonal COP above 3.5. That means it produces over three units of heat for every unit of electricity—even in sub-zero conditions.
SolarEast's product lineup, including the BLN Series, is tailored for clients who want to achieve long-term savings while reducing carbon emissions. When combined with IoT control and smart scheduling, the cost-effectiveness of heat pumps at low temperatures only increases.
A common question in colder regions is what temperature is a heat pump not effective? The short answer is—it depends on the system design, refrigerant used, and control logic. But with current technology, most high-quality air source heat pumps remain effective well below freezing.
Traditionally, standard heat pumps struggle to operate efficiently below -5°C to -10°C. In these cases, their Coefficient of Performance (COP) drops sharply, and backup heating sources may be required. However, modern systems designed specifically for heat pumps at low temperatures are engineered to perform even at -20°C or lower.
Take SolarEast’s RS Series, which uses smart frequency control, cold climate tuning, and adaptive defrost to operate effectively down to -25°C. At this threshold, it still achieves stable indoor temperatures and high SCOP performance. The secret lies in a combination of:
Inverter compressor technology, which adjusts output in real-time
Optimized refrigerants (like R410A and R32) for sub-zero thermal exchange
Dual temperature sensors and proactive defrosting algorithms
Microchannel heat exchangers for enhanced low-temperature heat absorption
What many people don't realize is that heat pumps in a cold climate only become ineffective when improperly matched to the region’s climate or installed without proper sizing. In most of Europe and North America, where winter lows are commonly between -5°C and -20°C, systems like the BLN R32 Series or R290 eco heaters provide highly efficient, uninterrupted heating.
So, what temperature is a heat pump not effective? Realistically, below -30°C most air-source units will require backup heat. But in 99% of residential and commercial use cases, especially across Europe, the right heat pump will perform well all winter.