What is COP and why does it matter?

COP (Coefficient of Performance) indicates how many kW of heat a heat pump produces from 1 kW of electricity. A heat pump with COP 4 generates 4 kW of heat from 1 kW of power — effectively 400% efficiency, compared to a gas boiler at 92-98%. COP is a point-in-time measurement that depends on outdoor temperature: higher in warmer weather, lower in cold. For real-world performance, look at the SCOP (Seasonal COP), which averages efficiency over the entire heating season.

Does a heat pump work at -20 degrees Celsius?

Modern air-to-water heat pumps can operate down to -25 or even -30 degrees (e.g., Mitsubishi Zubadan, Daikin Altherma 3), but performance drops significantly. Below -15 degrees, COP typically falls to 1.5-2.0, meaning the heat pump is still 50-100% more efficient than electric heating but no longer 3-4 times more efficient. A backup heating source (bivalent system) is common for extreme cold days. Ground-source heat pumps avoid this issue entirely since ground temperature remains constant at 8-12 degrees.

How long does a heat pump take to pay for itself?

Payback depends on many factors. Without subsidies, typically 8-12 years for air-to-water and 10-15 years for ground-source systems. With subsidies (40-50%), payback drops to 4-7 years. The exact figure depends on insulation quality, previous heating system, heated floor area, energy prices, and heat pump type. Well-insulated new builds with underfloor heating see the fastest payback, while poorly insulated older homes with radiators see the slowest.

Can I use a heat pump with old radiators?

Yes, but with reduced efficiency. Traditional radiators need 55-70 degree water, which lowers COP to 2.0-2.5 instead of 3.5-4.5. Underfloor heating (35 degree supply temperature) is ideal. A practical compromise is oversized radiators that provide sufficient heat even at 45 degree water temperature, maintaining COP around 3.0. The best approach is gradual transition: install the heat pump with existing radiators first, then convert to underfloor heating room by room during renovation.

How noisy is a heat pump?

The outdoor unit typically produces 40-55 dB in normal operation, comparable to a quiet conversation. In night (quiet) mode, this drops to 35-45 dB. The indoor unit (if applicable) runs at 25-35 dB. Placement matters: avoid placing the outdoor unit beneath bedroom windows, and maintain the required distance from neighboring properties (typically at least 3 meters). Ground-source heat pumps produce minimal noise since there is no outdoor fan unit.

What types of heat pump exist and how do they differ?

Three main types: (1) Air-to-air heat pump (essentially an inverter AC in heating mode) — cheapest but not suitable for radiator or underfloor systems, only direct air heating/cooling. (2) Air-to-water heat pump — extracts heat from air and heats water for radiators or underfloor systems, the most popular choice for residential buildings. (3) Ground-source (geothermal) heat pump — extracts heat from the ground via vertical boreholes or horizontal collectors, highest and most stable COP, but most expensive to install and requires earthworks.

Heat Pump vs Gas Heating: Which Is the Better Choice?

Upgrading your heating system is one of the most impactful energy decisions affecting your home’s costs, comfort, and environmental footprint for decades. Heat pump adoption has accelerated dramatically: over 3 million units were installed across the EU in 2023, with numbers rising year over year. Yet gas heating remains the most common heating method in Central Europe. Which technology truly delivers better value? In this comprehensive comparison, MAFER-COOL KFT experts objectively analyze both solutions — from operating principles through 10-year total cost of ownership to EU regulations and available subsidies.

Operating Principles and Efficiency

How Gas Boilers Work

A gas boiler burns natural gas to heat water, which is then circulated to radiators or underfloor heating by a pump. Modern condensing boilers recover heat from exhaust gases, achieving 92-98% efficiency. The technology is simple, well-understood, and has served reliably for decades.

Gas boiler efficiency is constant: regardless of outdoor temperature, it ranges from 92-98%. One kWh of gas burned produces 0.92-0.98 kWh of heat energy.

How Heat Pumps Work

A heat pump extracts thermal energy from the environment (air, ground, or water) and uses a compressor to raise it to a usable temperature. It works like a refrigerator in reverse: a refrigerator extracts heat from its interior and releases it through the rear grille, while a heat pump extracts heat from outdoors and delivers it to your heating system.

The key advantage is that a heat pump does not “generate” heat but “moves” it — which is why its efficiency can exceed 100%. The COP (Coefficient of Performance) expresses this: COP=4 means 1 kW of electricity produces 4 kW of heat.

COP Values at Different Temperatures

Type	COP at +7°C	COP at 0°C	COP at -7°C	COP at -15°C	COP at -20°C
Air-to-water HP (average)	4.0-5.0	3.0-3.5	2.2-2.8	1.5-2.5	1.2-2.0
Air-to-water HP (premium)	4.5-5.5	3.5-4.2	2.8-3.5	2.2-3.0	1.8-2.5
Ground-source HP	4.5-5.0	4.0-4.5	4.0-4.5	3.5-4.0	3.5-4.0
Gas boiler (reference)	0.92-0.98	0.92-0.98	0.92-0.98	0.92-0.98	0.92-0.98

The SCOP (Seasonal COP) gives the average efficiency across an entire heating season, accounting for varying temperature conditions. In Central Europe, air-to-water heat pumps typically achieve an SCOP of 3.0-3.5 (medium climate zone). This means across the whole season, 1 kW of electricity produces an average of 3.0-3.5 kW of heat.

Heat Pump Types in Detail

1. Air-to-Air Heat Pump

Essentially an inverter split AC operating in heating mode. The simplest and cheapest heat pump solution.

Pros: Low investment (500-1,300 EUR), quick installation, also provides cooling Cons: Cannot connect to radiator or underfloor systems, only direct air heating, separate unit needed per room Ideal for: Supplementary heating, small apartments, holiday homes

2. Air-to-Water Heat Pump

The most popular type for residential buildings. Extracts heat from outdoor air and heats water for radiators or underfloor heating.

Pros: Connects to existing heating systems, can produce domestic hot water, wide capacity range (4-20 kW) Cons: Efficiency drops in cold weather, outdoor unit generates noise, may need backup below -15 degrees Ideal for: Family homes, especially with underfloor heating

3. Ground-Source (Geothermal) Heat Pump

Extracts heat from the ground via vertical boreholes (80-120 m deep) or horizontal collectors (1.2-1.5 m deep, large area pipe system).

Pros: Highest and most stable COP (independent of outdoor temperature), no outdoor fan unit (silent), 50+ year borehole lifespan Cons: Highest investment cost, earthworks required, vertical boreholes need permits, horizontal collectors need large garden Ideal for: Larger homes focused on long-term economics

Investment Cost Comparison

Cost Item	Condensing Gas Boiler	Air-to-Water HP	Ground-Source HP
Equipment	800-1,500 EUR	3,000-6,500 EUR	5,200-9,000 EUR
Installation	400-800 EUR	800-1,500 EUR	2,000-4,000 EUR
Earthworks/boreholes	—	—	2,600-6,500 EUR
Hot water tank (300L)	200-400 EUR	400-800 EUR	400-800 EUR
Underfloor heating (if needed)	—	1,300-4,000 EUR	1,300-4,000 EUR
Buffer tank	—	250-650 EUR	250-650 EUR
Total	1,400-2,700 EUR	5,750-13,450 EUR	11,750-24,950 EUR

10-Year Total Cost of Ownership

Example: 120 m2 well-insulated house (annual heat demand: 12,000 kWh, 2025 European energy prices):

Cost Element	Gas Boiler	Air-to-Water HP	Ground-Source HP
Investment	2,000 EUR	9,000 EUR	15,500 EUR
Subsidy (50%)	—	-4,500 EUR	-7,750 EUR
Net investment	2,000 EUR	4,500 EUR	7,750 EUR
Annual heating cost	1,010 EUR	675 EUR	540 EUR
Annual hot water	210 EUR	130 EUR	105 EUR
Annual maintenance	65 EUR	80 EUR	50 EUR
Annual operating total	1,285 EUR	885 EUR	695 EUR
10-year total cost	14,850 EUR	13,350 EUR	14,700 EUR

Energy prices heavily influence these calculations. Gas prices have been more volatile than electricity prices in recent years. If gas prices rise 10%, the gas boiler’s 10-year cost increases by approximately 1,000 EUR. A 10% electricity price increase raises the heat pump’s 10-year cost by only about 700 EUR (because it uses less energy). Long-term, the heat pump offers more predictable operating costs.

When to Switch to a Heat Pump

A heat pump is ideal if:

Your house is well insulated (at least 10 cm facade insulation, modern windows)
You have or plan underfloor heating (35-40 degree supply temperature)
It is a new-build property (nZEB or near-zero energy building)
Your existing gas boiler is nearing end of life (15+ years old)
You can access government subsidies (40-50%)
You have or plan solar panels (self-generated electricity makes the heat pump virtually free to run)
Environmental impact matters to you
You plan to stay long-term (10+ years)

Gas heating may remain better if:

The house is poorly insulated with no renovation planned
Only high-temperature (70 degree) small radiators are installed with no underfloor heating plan
You plan to stay short-term (3-5 years)
Insufficient space for the outdoor unit
Electrical supply capacity is limited (single phase, 16A breaker)
No subsidies available
Budget is tightly constrained

Bivalent Systems: Best of Both Worlds

A bivalent system combines a heat pump and gas boiler:

Heat pump: handles heating on most days (above 0 degrees), when COP is high
Gas boiler: takes over on extreme cold days (below -10 degrees), when heat pump COP drops
Result: 40-60% lower annual heating costs compared to gas-only, with lower investment than heat pump-only

A bivalent system is particularly smart when the existing gas boiler still works (5-8 years old) and you want to transition gradually. After heat pump installation, the gas boiler only runs on the coldest peak days, extending its lifespan as well.

EU Regulations and Outlook (2025-2035)

EU energy policy clearly favors heat pumps:

REPowerEU Plan: targets 60 million heat pump installations across the EU by 2030
Energy Efficiency Directive (EED): increasingly stringent building energy requirements
F-gas Regulation: phasing out high-GWP conventional refrigerants
Energy Performance of Buildings Directive (EPBD): zero-emission heating required in new buildings from 2030 in several member states
Multiple EU countries (Germany, Netherlands, Denmark, Austria) are phasing in restrictions on new gas boiler installations

Government subsidies of 40-50% are available in many EU countries for heat pump installations, significantly improving the return on investment.

MAFER-COOL KFT assists with subsidy applications: energy assessments, application documentation, and project execution compliant with subsidy requirements. Contact us for detailed information about available support programs.

Summary

Heat pumps are the more economical and environmentally friendly choice long-term, especially for well-insulated homes with underfloor heating and available subsidies. The 10-year total cost of ownership is comparable to gas, but savings grow larger each subsequent year. Gas heating remains competitive for poorly insulated buildings, short-term planning horizons, or when subsidies are unavailable.

MAFER-COOL KFT provides expert consultation and installation for both solutions. We help you determine which technology best suits your home, and we handle the entire project — from planning through installation to maintenance — with warranty.

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Heat Pump vs Gas Heating: Which Is Better in 2025?