Québec winters seriously test the energy efficiency of residential heat pumps. When temperatures drop well below zero, many homeowners wonder whether their system is still operating efficiently or simply consuming electricity unnecessarily. Understanding what truly influences winter performance helps you interpret how the equipment behaves, avoid unnecessary concerns, and adopt more cost-effective usage habits. This guide provides a structured overview of the factors that affect efficiency, practical solutions to optimize it, and maintenance best practices to extend the system’s lifespan.
1. Understanding Heat Pump Efficiency in Winter
A heat pump’s efficiency refers to the amount of heat produced relative to the electrical energy consumed. This concept is generally expressed as the coefficient of performance (COP). The higher the COP, the more efficient the unit. In winter, this efficiency is mainly influenced by the temperature difference between outdoors and indoors.
1.1 The relationship between COP and outdoor temperature
The colder the outdoor air, the harder the heat pump must work to extract the heat it contains. The compressor is therefore under greater load, which causes the COP to decline gradually. Despite this decrease, a unit designed for Québec’s climate remains more efficient than pure electric heating as long as the COP stays above 1.
Technical data indicate that it is not uncommon to observe COP values of 2 to 3 for some modern heat pumps even when outdoor temperatures are below –10 °C, provided the installation is appropriate and maintenance is carried out properly. This means that, even under these conditions, the unit still delivers two to three times more thermal energy than the electrical energy it consumes.
1.2 Example of estimated efficiency by temperature
The table below illustrates typical COP values based on outdoor temperature. These are general reference values used to help understand overall trends.
Table 1 – Example of estimated efficiency by outdoor temperature
| Outdoor Temperature (°C) | Estimated Efficiency (COP) | Optimal efficiency conditions |
| +5 | ≈ 3.5 | Outdoor unit well cleared, no frost, good airflow |
| –10 | ≈ 2.5 | Adequate airflow clearance, effective defrost |
| –20 | ≈ 1.8 | Cold-climate unit, presence of a backup heating system |
These values show that a heat pump remains a worthwhile option over a wide temperature range, but that it becomes important to consider backup heating when the mercury drops very low.
2. Key factors that influence winter efficiency
Efficiency does not depend solely on the heat pump model. The building, local climate, installation quality, and usage habits also play a major role. The same unit can deliver very different performance from one home to another.
2.1 Technical and environmental factors
To understand the impact of each factor, it helps to consider them one by one: outdoor temperature, humidity and frost, installation quality, and the home’s insulation. These elements interact and determine the system’s overall performance.
Table 2 – Factors influencing winter efficiency
| Factor | Impact on efficiency | Main practical solution |
| Outdoor temperature | The colder it gets, the more efficiency drops | Choose a variable-speed compressor model |
| Humidity & frost | Airflow blockage, more frequent cycles | Effective defrost and regular unit maintenance |
| Installation | Poor placement = losses and frost | Installation by a certified contractor |
| Home insulation | Poor insulation = higher heating load | Improve walls, windows, and attic insulation |
A real-world example from residential projects illustrates this well: in some homes, simply repositioning the outdoor unit away from prevailing winds and improving wall insulation significantly increased observed winter efficiency. This type of adjustment confirms the importance of viewing the heat pump as one component within a broader system, not as a standalone device.
2.2 Why choosing a climate-adapted model matters
Units designed specifically for the Canadian climate include more robust compressors, optimized defrost algorithms, and heat exchangers sized for deep cold. Studies note that a model adapted to northern conditions can improve average winter efficiency by up to about 20% compared to a non-specialized unit. Model selection therefore has a direct impact on achievable savings.
3. Optimizing efficiency and reducing costs in winter
Once the heat pump is installed, many actions can be taken to improve its efficiency. These steps, often simple, work together to reduce consumption and stabilize performance during cold spells.
3.1 Best usage practices
Before detailing corrective actions, it is useful to remember that a heat pump performs best when used consistently. Frequent starts and stops place more stress on the compressor and can reduce overall efficiency.
In most cases, it is preferable to let the unit run continuously rather than turning it off and on repeatedly. A stable thermostat setpoint helps reduce load fluctuations and maintain a strong COP.
3.2 Maintenance actions with a direct impact on efficiency
Some simple interventions can have a measurable effect on consumption and thermal efficiency. The table below outlines typical actions and estimated gains.
Table 3 – Corrective actions and estimated efficiency gains
| Corrective action | Potential impact on costs | Estimated efficiency gain |
| Regular cleaning of the outdoor fan area | Lower energy consumption | Up to about +10% efficiency |
| Accurate thermostat calibration | More controlled utility bills | About +5% efficiency |
| Replacing or cleaning filters | Reduced pressure losses | About +3% efficiency |
| Checking refrigerant level | More stable consumption | Up to about +8% efficiency |
These values provide an order of magnitude for the cumulative effect of maintenance. A homeowner who consistently applies these measures can see a noticeable reduction in winter consumption while improving indoor comfort.
4. Maintenance, reliability, and professional support
Winter efficiency depends heavily on the heat pump’s overall condition. A neglected unit, covered in frost, or obstructed by snow will see its performance drop, even if it is a high-end model.
4.1 Regular maintenance homeowners can do
Several steps can be handled by occupants themselves. The main goal is to ensure nothing interferes with operation and that airflow is not restricted.
Best practices include:
- keeping at least one meter of clearance around the outdoor unit;
- clearing snow, ice, or leaves after storms;
- cleaning or replacing indoor filters according to manufacturer recommendations;
- checking the unit regularly for any persistent ice buildup.
These habits help prevent efficiency losses and reduce the risk of winter breakdowns.
4.2 The role of professional maintenance
Annual servicing by a qualified technician helps verify elements that are not accessible to users, such as refrigerant pressure, defrost sensor calibration, or compressor condition. This complete inspection can identify early issues before they significantly affect consumption or reliability.
If you notice signs of poor performance, such as persistent ice on the unit or a sudden increase in your electricity bill, it is recommended to schedule a maintenance visit. A specialized company such as Réfrigération Jolicoeur can assess the situation and recommend targeted adjustments to restore optimal operation.
5. Good habits and signs of poor winter performance
In addition to maintenance, certain signs should catch a homeowner’s attention. Recognizing them early makes it easier to correct the situation without delay.
5.1 Daily best practices
During winter, a few simple habits help stabilize efficiency:
- avoid setting the thermostat too low at night to reduce morning recovery demand;
- do not block indoor supply or return air grilles;
- watch for heavy ice buildup on the outdoor unit;
- note any unusual changes in electricity consumption during cold spells.
These steps promote more consistent operation and help reduce performance fluctuations.
5.2 Frequently asked questions about winter efficiency
To clarify common questions, here are a few concise answers:
Does my heat pump still work at –25 °C?
Recent models designed for the Canadian climate can continue operating down to around –25 °C, but their efficiency gradually declines. A backup heating system (electric or otherwise) is often recommended to ensure comfort during extreme cold.
Should I let my heat pump run continuously?
In most cases, continuous operation is preferable to repeated on/off cycling. It stabilizes efficiency and reduces compressor wear.
What signs indicate poor winter efficiency?
Persistent ice on the unit, unusual noise, difficulty maintaining the set temperature, or a sudden increase in energy use can indicate a defrost, refrigerant, or airflow problem.
Conclusion
Heat pump winter efficiency results from a balance between the unit’s technology, installation quality, building condition, and usage habits. Even when temperatures drop below zero, a heat pump adapted to Québec’s climate can deliver strong performance, provided it is properly sized and well maintained. By applying the best practices outlined in this guide, homeowners can reduce costs, improve comfort, and extend equipment lifespan. For a detailed assessment of your installation and a clear winter optimization plan, you can consult specialists such as Réfrigération Jolicoeur, who support households in managing heat pump heating efficiently.