Heat Pumps for Home Heating: How They Work, What They Cost and Whether They Pay Off in Ukraine
Volodymyr SydorenkoJuly 23, 2026
A guide to heat pumps for private houses: how they work and the coefficient of performance, types (air-to-water, ground-source, air-to-air), house requirements, sizing, electrical capacity, pairing with solar, cost, payback and running during outages.
Heat Pumps for Home Heating: How They Work, What They Cost and Whether They Pay Off in Ukraine
A heat pump is a heating technology that has become standard for new homes in Europe. It doesn't burn fuel — it moves heat from the environment (air, ground or water) into the house. For every kilowatt-hour of electricity, a modern heat pump can deliver several kilowatt-hours of heat. In Ukraine, interest in heat pumps is growing because of rising gas prices, the desire for energy independence and the availability of solar generation. Here's how they work and who they suit.
How a Heat Pump Works
The principle is the same as a fridge, but in reverse. A refrigerant circulates in a closed loop:
- In the outdoor heat exchanger (evaporator), the refrigerant absorbs heat from the air, ground or water and evaporates — even at sub-zero outdoor temperatures.
- A compressor compresses the vapor, raising its temperature.
- In the indoor heat exchanger (condenser), the refrigerant releases heat to the heating or hot water system and condenses.
- Through an expansion valve, the refrigerant returns to the evaporator and the cycle repeats.
Coefficient of Performance
A heat pump's efficiency is described by its COP — the ratio of heat produced to electricity consumed under specific conditions. SCOP is the seasonal coefficient that accounts for changing temperatures over the heating season. A SCOP of 3.5 means that, on average over the season, the pump delivers 3.5 kWh of heat for every 1 kWh of electricity.
Efficiency falls as outdoor temperature drops and as the heating water temperature rises. So heat pumps work best with low-temperature heating — underfloor heating or oversized radiators. In its overview of heat pumps, the International Energy Agency notes that modern heat pumps are several times more efficient than conventional fossil-fuel boilers.
Types of Heat Pumps
Air-to-Water
Takes heat from outdoor air and transfers it to the heating system (underfloor heating, radiators) and a hot water cylinder. The most popular type for private houses: relatively simple installation, no drilling required. Modern cold-climate models work in severe frost, though efficiency drops on those days.
Ground-Source (Geothermal)
Takes heat from the ground through a horizontal collector on the plot or vertical probes in boreholes. Ground temperature at depth is stable year-round, so efficiency is high and barely depends on frost. The downside is expensive excavation or drilling.
Water-to-Water
Uses heat from groundwater or a water body. High efficiency, but requires suitable hydrogeological conditions and compliance with water-use rules.
Air-to-Air
Essentially an inverter air conditioner running in heating mode. The cheapest option for apartments and supplementary heating of individual rooms. It doesn't heat water for radiators or domestic hot water.
Is Your House Suitable?
A heat pump works efficiently if:
- the house is well insulated — lower heat loss means a smaller pump and lower bills. Start with insulation — see apartment insulation, the principles for houses are the same, and window replacement;
- there's a low-temperature heating system — underfloor heating or radiators designed for 35–50 °C water;
- electrical capacity is sufficient — often a three-phase connection is needed;
- there's space for the outdoor unit considering noise and airflow.
In an old uninsulated house with cast-iron radiators designed for 70–80 °C, a heat pump will run inefficiently. In that case: insulation first, then new heat emitters, then the pump.
Sizing
Capacity is chosen based on a heat-loss calculation for the house at the design winter temperature, not "by eye". An oversized pump costs more and cycles on and off frequently, wearing out. An undersized one won't cope in frost and will often switch on its electric backup heater. Order a thermal calculation from a designer or installer.
Hot Water and Cooling
Most air-to-water systems also heat domestic water through an indirect cylinder. There are also standalone heat pump water heaters — the ENERGY STAR program notes they are much more efficient than conventional electric water heaters. Many heat pumps can also cool in summer — via fan coils or floor cooling.
Heat Pumps and Solar Panels
Combining a heat pump with a solar power system reduces heating costs, especially in spring and autumn, while in summer the panels cover air conditioning and hot water. In winter generation is lower, so solar can't fully cover heating, but it can cut bills substantially. More on solar systems in solar panels for home.
What Happens During Power Outages
A heat pump doesn't run without electricity — skeptics' main argument. Solutions:
- a hybrid system — a heat pump plus a gas or solid-fuel boiler as backup;
- a battery system with an inverter — keeps circulation pumps and controls running and, with enough capacity, the heat pump itself for a few hours;
- a generator with automatic transfer;
- a thermal store (buffer tank) — stores heat when electricity is available.
A well-insulated house with underfloor heating cools slowly, so outages of a few hours aren't critical. How to plan backup power is covered in apartment electrical wiring.
Cost and Payback
The system cost consists of:
- equipment (outdoor and indoor units, cylinder, buffer tank);
- installation and commissioning;
- for ground-source systems — drilling or excavation;
- upgrading the heating system if needed;
- possibly increasing electrical capacity.
Payback depends on the alternative: replacing an electric boiler pays off fastest; replacing a gas boiler takes longer and depends on gas and electricity tariffs. Current tariffs are regulated by NEURC. To estimate, take the annual heat demand (kWh), divide by SCOP and multiply by the tariff — that gives the approximate electricity cost.
Example
A 150 m² house with an annual heat demand of 15,000 kWh. A heat pump with a SCOP of 3.5 will consume about 4,300 kWh of electricity a year. An electric boiler with roughly 100% efficiency would consume 15,000 kWh. That's a saving of over 10,000 kWh a year. The comparison with gas depends on the gas price and boiler efficiency.
Comparison With Other Heating Types
- Gas boiler — lower installation cost, familiar to most owners, but depends on gas prices, needs a flue, annual gas safety checks and a gas connection.
- Solid-fuel boiler — independent and cheap to fuel, but needs daily attention, fuel storage and regular cleaning.
- Electric boiler — simplest to install but most expensive to run at standard tariffs, since 1 kWh of electricity gives only 1 kWh of heat.
- Heat pump — highest upfront cost, but the lowest cost per unit of heat among electric systems, plus summer cooling.
In practice a hybrid approach often wins: the heat pump runs most of the season, and a gas or solid-fuel boiler kicks in during the hardest frosts and long outages.
Common Mistakes
- installing a pump in an uninsulated house with high-temperature radiators;
- sizing without a heat-loss calculation;
- placing the outdoor unit in a corner without airflow or under a bedroom window;
- no buffer tank where one is needed for stable operation;
- forgetting electrical capacity — the pump trips the main breaker;
- no backup heat source for outages.
Maintenance
- an annual check of refrigerant and pressure;
- cleaning the outdoor unit of dust, leaves and snow;
- cleaning heating system filters;
- updating the controller software.
A heat pump doesn't need a flue or gas inspections.
How to Choose an Installer
- experience specifically with heat pumps, not just air conditioners;
- a thermal calculation before the quote;
- real installations you can visit;
- equipment and installation warranties, service in your region;
- a contract with a clear list of equipment and works — see how to choose a renovation contractor.
Heat Pumps in Apartments
In apartments with central heating, the realistic option is air-to-air systems (inverter air conditioners) for supplementary heating in spring and autumn and during heating outages. Outdoor units on the facade affect common property, so follow the OSBB's rules.
Frequently Asked Questions
Does a heat pump work at −20 °C? Modern cold-climate models do, but efficiency drops. Backup heating is provided for such days.
Is the outdoor unit noisy? Modern units are fairly quiet, but place them away from bedrooms and boundaries with neighbors.
How long does a heat pump last? Usually 15–20 years with proper maintenance.
Can a heat pump be added to an existing radiator system? Yes, if the radiators are large enough to heat the house at a lower water temperature. Sometimes replacing a few radiators with larger ones or adding underfloor heating in the coldest rooms is enough.
Do I need a permit? Usually not for air-source pumps. Ground-source vertical systems and groundwater use may require approvals.
Which refrigerant should I look for? Manufacturers are moving to refrigerants with a lower global warming potential, such as R32 and R290 (propane). Natural refrigerants like R290 allow higher water temperatures, which helps in older houses, but installation must follow the manufacturer's safety rules.
Is a heat pump worth it if I already have gas? If your gas boiler is new and the house isn't well insulated, the payback may be long. A common middle path is to add an air-to-water pump as the main source for most of the season and keep the gas boiler as a backup for frosts and outages.
Conclusion
A heat pump is an efficient, clean solution for a well-insulated house with low-temperature heating. Start with insulation, calculate heat loss, check electrical capacity and plan backup for outages. Combined with solar panels, a heat pump gives maximum energy independence. If you're building or buying a house, see also our guide to buying a country house.
Sources
- IEA: heat pumps and the report The Future of Heat Pumps.
- ENERGY STAR: water heaters.
- Law of Ukraine on Energy Efficiency of Buildings.
- NEURC — electricity tariffs and market rules.
- EU Energy Performance of Buildings Directive.