24 August 2026
High fossil fuel prices, strict WT 2021 building standards and the pursuit of full energy independence have made the air-to-water heat pump currently the most frequently chosen heating source in Polish single-family houses. Industry data resulting from hundreds of our projects shows that a properly designed system allows you to reduce annual bills for heating and domestic hot water (DHW) by up to 60-80% compared to traditional boilers.
The following guide explains step by step the principles of technology operation, the actual purchase and installation costs, the power selection criteria, as well as the rules for integrating the system with the photovoltaic installation and energy storage.
How does an air-to-water heat pump work? Thermodynamics at a glance
An air-to-water air source heat pump does not produce heat in the combustion process (like a gas or coal boiler). The device converts free renewable energy accumulated in the atmospheric air and transfers it to the water central heating system (central heating) and the hot water storage tank (DHW).
Four key stages of the refrigeration circuit:
- Evaporation: An environmentally friendly refrigerant (e.g. R32 or natural R290 - propane) circulating inside the system boils at very low temperatures. It takes heat from the outside air and changes its state of matter from liquid to gaseous.Compression: The gaseous medium goes to the compressor. As a result of the increase in pressure, its temperature rises drastically.
- Condensing: The hot gas flows through a condenser (heat exchanger), where it gives the stored energy to the water circulating in the heating system (underfloor heating system or radiators). The refrigerant cools down and condenses again.
- Expansion: The liquid medium passes through the expansion valve, where there is a pressure drop and a decrease in temperature. The cycle begins again.
Thanks to this closed circuit of 1 kWh of electricity consumed, the pump supplies from 3.5 to even 5 kWh of thermal energy to the building.
Performance and performance indicators: COP vs SCOP
The heat pump efficiency assessment is based on two main parameters:
- COP (Coefficient of Performance): An instantaneous efficiency factor that determines the ratio of heat produced to electricity consumed under specific laboratory conditions (e.g. A7/W35 means outdoor temperature 7°C and water supply 35°C).
- SCOP (Seasonal Coefficient of Performance): Seasonal coefficient of performance. It takes into account changes in outdoor temperatures during the entire heating season in the Polish climate zone. This is a key indicator showing the real cost of operating the device on an annual basis.
Effect of Plant Supply Temperature on SCOP and Electricity Bills
Low supply temperature is the key to high heat pump efficiency. The lower the water temperature in the system, the less work the compressor has to do.
| Type of heating system | Average Power Temp | Estimated SCOP | Estimated annual cost of heating (house 150 m²)* |
| Underfloor heating (radiant) | 35°C | 4,2 – 4,8 | ~ PLN 2,800 |
| Mixed (floor heating + low-temperature radiators) | 45°C | 3,5 – 3,8 | ~ PLN 3,700 |
| Traditional radiators (modernized building) | 55°C | 2,8 – 3,2 | ~ PLN 4,900 |
*Estimated calculation for a building with an EU heat demand = 50 kWh/m²/year at the standard electricity rate from 2026.
Hymon's expert tip: Lowering the supply temperature of the central heating system by just 10°C translates into a decrease in electricity consumption by about 15-20% over the entire heating season.
Construction Comparison: Split vs Monoblock Heat Pump
When choosing an air source heat pump, investors are faced with the choice of one of two designs: Split or Monoblock.
| Feature | Spli type heat pump | Monoblock heat pump |
| Installation location of the refrigeration system | Separated: part outside, part inside building | The entire refrigeration circuit is factory-closed to the outside |
| Unit Connecting Factor | Refrigerant (f-gas) | Water or glycol solution |
| Risk of freezing of the system in the event of a power outage | None (no water in connecting pipes) | Exists (requires protection with antifreeze valves or glycol) |
| Formal requirements during assembly | F-Gas certificate for installers, entry in CRO | Installation without f-gas authorization (hermetic system) |
| Indoor Noise | Very quiet (compressor outside) | Extremely quiet (all mechanics outside) |
| Space inside the house | Requires space for a hanging/standing indoor unit | Only requires a hydraulic module (space saving) |
How much does an air-to-water heat pump with installation cost in 2026?
The total cost of the investment depends on the area of the house, its standard of insulation, the selected power of the device and the standard of the engine room.
Approximate cost estimate of heat pump installation in a single-family house (120-180 m²):
- Device (premium class 8-10 kW heat pump with R290): PLN 28,000 - 38,000 net
- Hydraulic and electrical fittings (DHW storage tank 200-300L, central heating buffer, circulation pumps, valves, protections): PLN 8,000 - 14,000 net
- Professional installation, commissioning and zero audit: PLN 7,000 - 11,000 net
- Total gross cost (incl. 8% VAT for residential construction): PLN 38,000 - 62,000
Cost-effectiveness simulation: Photovoltaics + Heat pump + Energy storage
The combination of a heat pump with photovoltaics and energy storage allows you to create an almost self-sufficient house. Changes in energy balancing and dynamic tariffs make in-house power generation and storage drastically reduce the cost of powering the pump.
10 kWp photovoltaic installation: PLN 28,000 - 38,000
Air-to-water heat pump 8-10 kW: 30 000 - 45 000 PLN
Energy storage 10 kWh: PLN 20,000 - 28,000
Installation and integration of the system: PLN 8,000 - 12,000
Total value of the comprehensive system: PLN 86,000 - 123,000
The practical effect of system integration in Hymon:
- Self-consumption of energy: Energy storage accumulates the surplus produced during the day, which allows you to power the heat pump in the evening and at night without drawing electricity from the grid at high rates.
- Energy independence: Verifiable data from our installations shows that we achieve 70-90% annual energy independence of the building.
- Return on investment: The average payback time for a complete system with funding is 5-8 years, with a projected lifespan of 20-25 years.
Heat pump power selection - How to avoid overclocking and underheating?
The most common mistake when buying a heat pump is the wrong choice of heating power. Selection "by eye" based on the size of the building leads to serious operational consequences.
Step-by-step: How Hymon engineers choose the power of the device
- Calculation of OZC (Thermal Load of the Building): Determination of the exact heat loss through walls, roof, floors and windows.
- New house (WT 2021): 30-45 W/m² demand
- House after full thermal modernization: 50-70 W/m² demand
- Old house without insulation: demand >100W/m² (requires thermal modernization before installing the pump!)
- Determination of the bivalent point: This is the outside temperature (usually between -5°C and -8°C) at which the heating capacity of the pump equals the heat loss of the building. Below this temperature, the device is automatically supported by a built-in electric heater.
- Analysis of the demand for hot water: On average, 0.25-0.3 kW of pump power per inhabitant is assumed with standard water consumption.
Case Study: Thermal modernization of a 160 m² house in the Małopolska Voivodeship
The following analysis shows the actual data from the implementation carried out by Hymon engineers.
- Investor: Mr. Marek, owner of the building from 2008 (160 m²).
- Condition before modernization: Old coal boiler. Annual coal consumption: 4.5 tons (cost at a price of PLN 1,600/t = PLN 7,200/year). High-temperature panel heaters.
- Scope of work:
- Insulation of the ceiling and replacement of windows with a triple-glazed package.
- Installation of a 9 kW monoblock air source heat pump (R290 refrigerant).
- Installation of a photovoltaic system with a capacity of 7.5 kWp.
- Replacement of radiator parts with models with increased heat dissipation area (central heating power reduced from 65°C to 45°C).
Operating results after the first full year (2025/2026):
- Energy consumption by the pump: 3,420 kWh/year.
- Production from photovoltaics: 7,800 kWh/year.
- Annual operating cost (heating + water): ~PLN 1,350 (distribution fees and purchase of energy from the grid in December-January).
- Financial savings: Over PLN 5,800 per year.
Heat pump installation - The most important installation rules
Even a top-of-the-line device will not work properly if it is installed incorrectly. Here are the key technical requirements:
- Location of the outdoor unit: The device should be placed on a stable foundation away from the corners of the building (risk of noise reflection) and at least 30-40 cm above ground level (snow protection).
- Condensate drainage: In heating mode, large amounts of water flow from the evaporator (up to several dozen liters per day). Drainage below the ground freezing zone or a heating cable in a drip tray is required.
- Sound insulation: According to the standards, the noise level on the border of a plot in single-family buildings must not exceed 40 dB(A) at night. Modern pumps generate 45-55 dB(A) directly at the unit, and at a distance of 3-4 meters the noise drops below 35 dB(A).
- Buffer in the central heating system: The buffer tank ensures the minimum required water flow through the pump, extends the compressor's operating cycles (prevents overclocking) and collects the energy necessary for the evaporator defrosting process.
Frequently Asked Questions (FAQ)
Does an air-to-water heat pump work in severe frosts at -20°C?
Yes, modern heat pumps operate stably at outdoor temperatures ranging from -22°C to -25°C. On extremely cold days, when the heating capacity of the pump decreases, the system automatically activates the built-in electric heaters to replenish the missing energy.
Is a heat pump suitable for a home with regular radiators?
Yes, but it requires a careful audit. High-temperature devices (e.g. on R290) are used for radiator installations, which supply the system with a temperature of 60-65°C. However, it is worth considering thermal modernization or enlargement of selected radiators in order to lower the supply temperature and increase the efficiency of the SCOP.
How much electricity does a heat pump use per year?
In a well-insulated detached house of 150 m² (WT 2021) with underfloor heating, the annual electricity consumption for central heating and hot water is on average 2,500 - 3,500 kWh. In older buildings, this value can be 4,500 - 6,000 kWh.
How long does it take for the Hymon team to install a heat pump?
The standard assembly of a comprehensive machine room with the foundation of the outdoor unit, hydraulic, electrical connection and first commissioning usually takes from 1 to 3 working days.
Summary and recommendations of Hymon engineers
Investing in an air-to-water heat pump is one of the most cost-effective steps on the way to an energy-efficient and maintenance-free home. The key to success is to avoid schematic solutions and conduct a reliable energy audit before buying.
Do you want to know which heat pump will be ideal for your building? Take advantage of the experience of the leader of the RES market. Arrange a free consultation and audit with Hymon experts to receive a precise device selection, quote and full support in obtaining funding.