What to heat your home with? A ranking of heating costs from cheapest to most expensive

Just a few years ago, choosing a heat source essentially came down to asking what was connected to the house: gas or coal, and less often electricity. Today, the decision is becoming more difficult for several reasons. Energy price protections have ended, while gas and electricity prices have returned to levels determined by the European market, which can itself be unstable due to geopolitical developments: an interrupted gas supply from one direction, a political decision, or a surge in commodity prices on the exchanges can affect your heating bill faster than we can get used to it. On top of that, EU climate policy is gradually changing the rules of the game: increasingly strict emissions standards, changing subsidy criteria, and the approaching emissions tax for households mean that a choice made a decade ago may look completely different today in terms of cost-effectiveness. In this article, we describe the seven most popular heat sources in order, from the cheapest to the most expensive to operate.

One home, so the comparison makes sense

Most heating cost comparisons available online suffer from the same problem: within a single article, homes with completely different insulation standards are mixed together, which severely distorts the comparison. To avoid this, we use one fixed reference home and stick to it throughout the article. It is a 120-square-metre home built in accordance with the current WT2021 technical conditions, with a useful energy demand of around 55 kilowatt-hours per square metre per year. In practice, this means a total demand of approximately 10,000 kilowatt-hours of energy per year, covering both space heating and domestic hot water for a family of four. All the figures later in the article refer to this one home and are approximate, since exact fuel and energy prices depend on the region, supplier, and time of year.

Heat sources from cheapest to most expensive to operate

The ranking below is based solely on the estimated annual operating cost, that is, how much you will actually pay to heat your home over the course of a season. This is deliberately separate from the cost of the initial investment, which can be exactly the opposite: the sources that are cheapest to operate usually require the greatest upfront expenditure, and vice versa.

Ground-source heat pump

A ground-source heat pump draws heat stored in the ground using either a horizontal collector or vertical boreholes. The secret to its high efficiency is that the ground temperature at a depth of several meters remains stable throughout the year, within a range of several to a dozen or so degrees, regardless of how cold it is outside. For our reference house, the annual operating cost is approximately 2,200 to 2,600 zlotys, the lowest of all seven sources. However, the investment cost is equally extreme, but in the opposite direction: a complete installation, including construction of the ground source, usually costs between 55,000 and 75,000 zlotys.

Air-source heat pump

An air-to-water heat pump draws heat directly from the surrounding air, making it much simpler to install than the ground-source version. The price of this simplicity is a clear dependence on the weather: efficiency starts to drop noticeably below zero, and during more severe frosts, around minus 10 to minus 15 degrees, it drops dramatically because the unit has to overcome an ever-greater difference between the cold air and the water temperature in the system. In practice, this means that on the coldest days of the season, an additional electric heater joins the operation, which is then reflected in the bill. The annual operating cost for our house is approximately 2,900 to 3,300 zlotys, while the investment cost usually falls between 35,000 and 50,000 zlotys. The outdoor unit is only part of the story: for the heat pump to operate stably rather than cycle continuously, it needs a properly selected buffer tank and an efficient circulation pump inside the house, and these installation requirements, along with the difference between the split and monobloc versions, are explained in more detail in a separate article about heat pumps.

Pellet boiler

A pellet boiler burns wood pellets using an automatic feeder, making operation much more convenient than with traditional fuel, although it still requires periodic human intervention. Modern feeder boilers achieve an efficiency of around 90 to 92 percent. It is worth remembering that although biomass is considered a renewable fuel, burning it still emits dust and other pollutants - less than coal, but clearly more than gas or electricity - so the quality of the boiler itself and regular cleaning have a real impact on the air quality around the house. In fact, this is one of the few combustion-based heat sources that is still eligible for funding under the Clean Air programme in 2026, provided that the boiler is on the official list of appliances and does not have what is known as an emergency grate enabling other fuels to be burned. The annual operating cost for our house is approximately 3600 to 4200 zlotys, while the investment cost, including fuel storage and a flue chimney, usually ranges from 18,000 to 28,000 zlotys.

Condensing gas boiler

A condensing boiler recovers additional heat hidden in the water vapour contained in the flue gas, meaning that in a properly designed, low-temperature system it can achieve an efficiency of 108 to 109 percent when calculated against the gas's lower heating value. This apparent impossibility - efficiency above one hundred percent - results from the calculation method itself, which does not include the heat hidden in the vapour from the outset, so when the boiler recovers it, the result naturally exceeds this limit. The annual operating cost for our house is approximately 4000 to 4500 zlotys, while the investment cost, including the gas connection and flue gas exhaust system, usually ranges from 15,000 to 22,000 zlotys.

Pea coal boiler (formerly “eco-pea coal”)

What was sold as eco-pea coal until recently has officially been called pea coal since December 2024. The change was introduced by the Ministry of Climate and Environment in a regulation banning the use of the “eco” prefix in the names of solid fuels to prevent buyers from being misled about the fuel’s environmental credentials. The coal itself has not changed; only the name on the label has changed. Modern fifth-class boilers for this fuel, the only ones permitted for installation since 2025, overwhelmingly have an automatic screw feeder operating on the same principle as a pellet boiler: fuel is automatically fed from the hopper into the combustion chamber, without manually adding it with a shovel, while the automatic controls maintain the temperature. They achieve an efficiency of around 85 to 88 percent, and the annual operating cost for our home is approximately PLN 2,200 to 2,800, which is still very inexpensive. The investment cost usually falls between PLN 15,000 and 20,000. However, it should be remembered that solid-fuel boilers are particularly vulnerable to low-temperature corrosion if the water returning from the system is too cold. We have devoted a separate article to this phenomenon and ways to protect against it.

District heating

Where a building has access to a district heating network, district heating eliminates the need for an individual heat source in the home: hot water enters ready for use through the heat substation. The annual operating cost for our home is approximately PLN 5,500 to 6,500, while the investment cost, limited to installing the connection and substation, usually falls between PLN 10,000 and 15,000.

Direct electric heating

An electric boiler or heating mats convert nearly all the electricity consumed directly into heat, without intermediate losses, but at current electricity prices this is the most expensive option to operate in this comparison. The annual operating cost for our house is approximately PLN 10,500 to 11,500, several times more than in the case of a heat pump. The investment cost, however, is the lowest of all seven heat sources, usually PLN 5,000 to 8,000, and installation itself takes literally just a few days.

Cost comparison in one table

The table below brings together the seven descriptions above in one place for quick comparison. It does not identify a single “best” option, because that depends on the circumstances of the specific house, described in the next section.

Heat source	Annual operating cost*	Investment cost*
Ground-source heat pump	PLN 2,200–2,600	PLN 55,000–75,000
Air-source heat pump	PLN 2,900–3,300	PLN 35,000–50,000
Pea coal boiler	PLN 2,200–2,800	PLN 15,000–20,000
Pellet boiler	PLN 3,600–4,200	PLN 18,000–28,000
Condensing gas boiler	PLN 4,000–4,500	PLN 15,000–22,000
District heating	PLN 5,500–6,500	PLN 10,000–15,000
Direct electric heating	PLN 10,500–11,500	PLN 5,000–8,000

* Indicatively, for the reference house described above, based on prices from the turn of 2026. Actual costs depend on the region, supplier and market price fluctuations.

What to choose in your situation

A new house with underfloor heating and a reasonable investment budget will make the best use of a heat pump, either ground-source or air-source, because low-temperature radiant heating allows it to operate at the highest possible efficiency even on colder days. An older, partially renovated house with traditional radiators and no access to the gas network will more often find a sensible compromise in a pellet boiler, which can handle a higher supply temperature without a drastic increase in bills while still qualifying for subsidies. A house without access to the gas network and without space to store solid fuel, in turn, is a natural candidate for a monobloc air-source heat pump, where the entire unit is located outside the building and only a small control module is needed indoors.

Funding can change the calculation

It is worth remembering that the investment costs mentioned above can often be significantly reduced through government programs supporting the replacement of heating systems and thermal modernization, such as Clean Air, although eligibility rules change frequently and significantly, as shown above in the case of coal and gas.

Frequently asked questions

What is the cheapest way to heat a house in 2026?

In terms of operation alone, the cheapest options are heat pumps, especially ground-source models, and pea coal boilers. However, the investment cost must also be considered: a ground-source heat pump has the lowest bills but the highest installation cost, while pea coal is cheap in both respects, at the cost of greater maintenance, a risk of corrosion, and no funding.

Can eco-pea coal still be bought in 2026?

Yes, but under a different name. Since December 2024, under a regulation issued by the Ministry of Climate and Environment, the official commercial name has been pea coal rather than eco-pea coal. The fuel itself remains available and meets the same quality standards; only the label has changed.

Can a coal- or gas-fired boiler be financed through the Clean Air program?

No. Since 2025, coal-fired boilers, including those burning pea coal, have been completely excluded from funding, regardless of their emissions class. Gas boilers lost eligibility for funding even earlier, in mid-2024. The program currently supports primarily heat pumps and, under certain conditions, pellet boilers.

What is the ETS2 tax, and how will it affect heating costs?

ETS2 is an EU CO2 emissions pricing system that will cover, among other things, fuels used to heat homes, including coal and gas, from 2027. Its introduction will gradually increase the operating costs of fossil fuel-based heating systems, which is worth considering when calculating long-term cost-effectiveness.

At what temperature does an air-source heat pump lose efficiency?

Efficiency begins to drop noticeably below zero, and during more severe frosts, around minus 10 to minus 15 degrees, it falls much more sharply because the unit has to overcome an increasingly large temperature difference between the cold air and the water in the system. On the coldest days of the season, an additional electric heater usually comes on.

Will a heat pump work in an old house with radiators?

It may work, but its efficiency will be lower than with underfloor heating because radiators require a higher supply temperature. In that case, it is especially important to choose the right heat buffer and circulation pump to avoid the emergency heater switching on frequently.