Heat Pump: What It Is, How It Works & When It’s Worth It ⚡
The heat pump has become a leading technology in modern HVAC systems. More and more homeowners, designers, and businesses choose this solution for its energy efficiency, environmental sustainability, and year-round indoor comfort.
Unlike traditional boilers that generate heat by burning fuel, a heat pump transfers energy from an external source (air, water, or ground) into the building. This makes it a highly efficient option, especially when combined with renewable energy sources such as photovoltaics.
1. What Is a Heat Pump?
It is a thermal device that extracts heat from a low-temperature source (air, water, or ground) and transfers it to a higher-temperature environment. It works using the reverse refrigeration cycle—a technology already used in refrigerators and air conditioners.
The key difference is that a heat pump is designed to heat (and often cool) indoor spaces, providing thermal energy to a heating system or directly into the air.
2. How Does a Heat Pump Work?
The system consists of four main components:
- Evaporator: the refrigerant absorbs heat from the external source (air, water, or ground).
- Compressor: compresses the refrigerant, increasing its temperature.
- Condenser: releases heat to the home’s heating system.
- Expansion valve: lowers the pressure and temperature of the fluid, ready to begin the cycle again.
3. What Is COP and Why It Matters
COP stands for Coefficient of Performance, and it represents the ratio between the thermal energy delivered and the electrical energy consumed. For example, a COP of 4 means that for every 1 kWh of electricity used, the heat pump provides 4 kWh of heat.
A high COP indicates an efficient system, but the value depends on various factors: outdoor temperature, type of emission system (radiant floor, fan coils, or radiators), and home insulation.
Real COP values are provided by manufacturers according to EN 14511 standards and are often certified by third parties. COP is also closely related to the climate curve.
4. Climate Curve and Smart Control
The climate curve is a feature that automatically adjusts the water temperature supplied to the system based on outdoor temperatures.
A practical example:
- If it’s 0°C outside → the heat pump supplies water at 35°C
- If it’s 10°C outside → the pump supplies water at 28°C
This helps to:
- Save energy by avoiding overheating when not needed.
- Increase COP, improving overall system efficiency.
- Reduce on/off cycles, extending the machine’s lifespan.
5. High-Efficiency Heat Pump Types
- Air-to-air: heats and cools indoor air, ideal for small spaces or mild climates.
- Air-to-water: the most common in homes, provides hot water for radiators, underfloor heating, and domestic use.
- Geothermal 🌍: uses the stable underground temperature. Very efficient, but requires space and drilling.
- Water-to-water 🏞️: draws energy from a well or lake. High performance, but requires specific permits and conditions.
- Hybrid 🔁: combines a gas boiler with a heat pump to reach higher temperatures quickly. Ideal for partially insulated homes or colder regions.
For a technical comparison, see our article about underfloor heating—an ideal match for heat pumps.
6. Advantages of Heat Pumps
- High seasonal efficiency (SCOP up to 5): reduced energy use and strong performance.
- No local emissions: ideal for reducing your environmental impact.
- Compatible with photovoltaics: energy bills near zero.
- High comfort: stable indoor temperature and quiet operation.
- 3-in-1 system: heating, cooling, and hot water with one unit.
- Access to incentives: financial savings through national energy programs.
7. Low-Temperature Radiators: Operation and Benefits
Low-temperature radiators are designed to work effectively with water between 35°C and 50°C. This makes them ideal for use with heat pumps or condensing boilers, which are most efficient at these lower temperatures.
A heat pump transfers heat rather than generating it. The lower the required output temperature, the less work the compressor does, and the higher the efficiency (COP). Traditional radiators that need water at 70–80°C aren’t compatible with heat pumps, but systems optimized for 40–45°C perform very efficiently.
Low-temperature radiators often feature:
- Greater surface area to offset the lower water temperature
- High thermal conductivity materials such as aluminum or steel
- Designs that maximize heat exchange
Main benefits:
- ✅ Energy efficiency: lower consumption and better heat pump performance
- ✅ Compatibility with renewables: ideal for photovoltaic or solar thermal systems
- ✅ Even comfort: stable and consistent room temperatures
- ✅ Retrofitting ready: great for upgrades without switching to underfloor heating
Using low-temperature radiators lets your heat pump run optimally, cutting energy use and improving system longevity. Choosing the wrong emission system can greatly reduce your heat pump’s efficiency.
8. Drawbacks and Limitations ❗
- High initial investment
- Requires expert design and installation
- Outdoor unit required
- Performance varies in colder climates
- Relies on electricity
9. Heat Pump vs Condensing Boiler
| Feature | Heat Pump | Condensing Boiler |
|---|---|---|
| Energy Source | Electricity / Renewables | Natural Gas / LPG |
| Local Emissions | None | Low |
| Efficiency | COP 3–5 | 95–107% Efficiency |
| Cooling Function | Yes | No |
| PV Integration | Excellent | Poor |
10. FAQ – Frequently Asked Questions
- Is a flue required? No, heat pumps don’t produce combustion gases.
- Is it noisy? Typically 35–50 dB. When properly installed, it’s as quiet as an air conditioner.
- Compatible with radiators? Yes, heat pumps can work with radiators if optimized for low-temperature operation. As explained earlier, using low-temperature or oversized radiators is essential to maintain high COP and system performance.
- How long does it last? 15–20 years. Premium models can last even longer with proper maintenance.
11. Conclusion
Installing a heat pump is one of the smartest choices for anyone seeking an efficient, sustainable, and future-ready home.
Thanks to their high efficiency, low energy consumption, renewable energy compatibility, and available incentives, heat pumps are a solid solution for both new buildings and major renovations.
