2026 heat-pump radiator vs underfloor payback by country

Why radiator and underfloor systems change the same heat pump's payback

A heat pump does not have one universal payback period. The emitter system changes the seasonal efficiency it can actually deliver, which then changes running cost against gas. In practice, low-temperature underfloor heating usually gives the machine an easier job than high-temperature radiators, so the same unit can look financially strong in one retrofit and marginal in another. The core logic is simple: once electricity is several times more expensive than gas, every SCOP point matters.

The country-level price data in Househeating Pulse shows why this matters so much in 2026. Household electricity-to-gas ratios range from 1.3 in Sweden (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester) to 5.11 in Romania (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). A heat pump with a seasonal coefficient of performance of 4 sits near a rough energy-price break-even when electricity costs about 3.7 times as much as gas, because each delivered kWh of heat uses about one quarter of a kWh of electricity. That makes the difference between radiator and underfloor systems explicit: if underfloor heating helps a system stay closer to SCOP 4 territory, payback holds up in more countries; if radiators push it down, the margin narrows fast.

This is easiest to see when the price ratio is near that line. Germany sits at 3.16 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester), France at 1.78 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester), and Poland at 3.71 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). France gives both emitters more room. Poland is effectively on the threshold. Germany is below it, but not by much, so subsidy support and system temperature start to matter more. Readers can test their own assumptions in the heat-pump payback calculator, and compare local conditions in the 32-country dashboard.

What EPREL says about the efficiency gap by heat-pump type

The EPREL dataset in this corpus contains five heat-pump types: ground-water, air-water, water-water, hp-water-heater, and air-air (type_efficiency / EPREL Public API · type aggregation). Not all of them carry comparable space-heating SCOP values in the extract. For the two types the article is focused on, average SCOP is 4.54 for air-water across 30,452 models (type_efficiency / EPREL Public API · type aggregation) and 4.77 for ground-water across 213 models (type_efficiency / EPREL Public API · type aggregation).

That 0.23-point difference means ground-water averages about 5.1% higher SCOP than air-water in the EPREL aggregation here, using air-water as the baseline ((4.77 minus 4.54) / 4.54) (type_efficiency / EPREL Public API · type aggregation). For buyers comparing hydronic systems in the live EPREL catalog, that is the broad efficiency backdrop before emitter choice, control settings, and weather are added.

Across all heat-pump types in the corpus that do report SCOP, the best-performing type is water-water at 6.15 (type_efficiency / EPREL Public API · type aggregation) and the worst-performing is air-water at 4.54 (type_efficiency / EPREL Public API · type aggregation). The average SCOP gap is therefore 1.61 points (type_efficiency / EPREL Public API · type aggregation), or 35.5% relative to air-water ((6.15 minus 4.54) / 4.54) (type_efficiency / EPREL Public API · type aggregation). Ground-water sits between them at 4.77 (type_efficiency / EPREL Public API · type aggregation).

For homeowners, that does not mean water-water is automatically the best choice. It means the registry shows a large technical spread by type. Installation constraints, source availability, and subsidy rules still decide what is realistic. Those type splits are visible in the air-to-water SCOP leaderboard, the ground-source SCOP leaderboard, and the broader top SCOP ranking. For definitions such as SCOP and climate zone, the HVAC glossary and EU climate-zones explainer are the useful references.

Europe's electricity-to-gas price map in 2026

The price map is the article’s main payback lever. Of the countries in the corpus with both electricity and gas tariffs recorded, 23 have an electricity-to-gas ratio below 3.7, while four are above it: Belgium at 3.9, the United Kingdom at 4.63, Romania at 5.11, and Poland at 3.71, which is just above rather than below (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). Five countries in the tariff table have no gas price and therefore no ratio: Cyprus, Finland, Malta, Norway, and Iceland (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). The registry does not record a ratio where gas data is missing.

Among the 23 countries below 3.7, the median electricity-to-gas ratio is 2.79, represented by Spain (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). At that level, a SCOP 4 heat pump has a wide running-cost cushion against gas. That is why underfloor systems, which generally help preserve efficiency, look strongest in markets already sitting well under the line. The latest country snapshot and tariff positioning are also summarised in the market index.

A compact ranking of selected markets shows the spread:

For readers who want the original tariff source, Eurostat’s household energy price tables are published at Eurostat.

Which countries are closest to, or farthest from, the SCOP 4 break-even line

The countries closest to the 3.7 line are Poland at 3.71, Belgium at 3.9, Czechia at 3.35, Hungary at 3.23, Germany at 3.16, and Ireland at 3.11 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). For radiator systems, these are the more delicate cases because any drop in delivered seasonal efficiency quickly eats the cost advantage that a SCOP 4 assumption implies. Underfloor heating has the best chance of preserving that margin.

The farthest below the line are Sweden at 1.3, the Netherlands at 1.49, Portugal at 1.73, and France at 1.78 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). In such markets, even a higher-temperature hydronic system can remain economically plausible, because the tariff structure is already favourable.

The strongest payback case appears where low price ratios overlap with high heating demand. On that basis, Sweden stands out with a ratio of 1.3 and 4,242.38 annual HDD18 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register). France pairs a ratio of 1.78 with 2,759.65 HDD18 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register). The Netherlands also combines a low ratio of 1.49 with 2,901.04 HDD18 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register). By contrast, Portugal’s ratio is low at 1.73 but heating demand is only 851.63 HDD18 (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register), so annual savings are likely smaller simply because there is less heat to buy.

Country case studies: Germany, France, and Poland

In Germany, household electricity is 0.3869 EUR/kWh and gas is 0.1223 EUR/kWh, producing a ratio of 3.16 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). Annual HDD18 is 3,308.21 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). The current subsidy in the corpus is BEG EM with a maximum amount of 21,000 EUR and a cap of 70% of cost (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). That combination makes Germany workable for heat pumps, but not forgiving. Underfloor heating should shorten payback because the tariff ratio is only modestly below the SCOP 4 line; high-temperature radiator operation is harder to justify unless the project also captures subsidy support. The relevant programme details are on the Germany subsidy page.

In France, electricity is 0.2561 EUR/kWh and gas 0.1436 EUR/kWh, for a ratio of 1.78 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). HDD18 is 2,759.65 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). MaPrimeRénov' reaches 11,000 EUR maximum and up to 90% of cost in the most generous income band (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). The scheme excludes air-air heat pumps (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). France is therefore one of the clearest examples where both underfloor and radiator-based hydronic heat pumps can make sense financially, with underfloor still delivering the cleaner payback case. Programme detail sits on the France subsidy page.

In Poland, electricity is 0.2709 EUR/kWh and gas 0.073 EUR/kWh, giving a ratio of 3.71 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). HDD18 is 3,706.42 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages), which is higher than Germany and France in this comparison. Subsidy support is also the strongest of the three: Czyste Powietrze reaches 31,000 EUR maximum, up to 100% of cost, and runs until 2029-12-31 (country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). That is exactly the narrower market described in the editorial angle: underfloor heating can still create a strong payback case because heating demand is substantial, but radiator systems are much more dependent on subsidy support because the tariff ratio is already slightly above the SCOP 4 line. Readers can review the Poland subsidy page and compare other markets through the country index.

Where underfloor heating shortens payback the most, and where radiators remain harder to justify

The cleanest underfloor-heating payback story in 2026 is where three things line up: low electricity-to-gas ratios, meaningful heating demand, and, ideally, some upfront support. France is the clearest large-market example in this corpus at 1.78 ratio, 2,759.65 HDD18, and an 11,000 EUR subsidy ceiling (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages). Sweden looks even stronger on tariff and climate fundamentals at 1.3 ratio and 4,242.38 HDD18, though no active subsidy is recorded here (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register). The Netherlands is also favourable at 1.49 ratio, 2,901.04 HDD18, and a 2,750 EUR subsidy ceiling (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_compare / Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register).

Radiator systems remain hardest to justify where the ratio is near or above the SCOP 4 threshold. Poland at 3.71, Belgium at 3.9, the United Kingdom at 4.63, and Romania at 5.11 are the headline cases (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester). In those markets, an underfloor retrofit or a lower-flow-temperature redesign has a clearer payback logic than simply attaching a heat pump to a high-temperature radiator circuit and hoping the arithmetic works out. Germany, at 3.16 with a 21,000 EUR subsidy ceiling, sits in the middle: still viable, but much more sensitive to system design than France (price_ratio / Eurostat household band DC (electricity) / D2 (gas), latest semester; country_profile / Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages).

For model selection, this is where catalog work matters. The full heat-pump catalog, manufacturer directory, quietest heat pumps leaderboard, and methodology page are the practical next stops. For official product registration background, the EU database is EPREL.

Sources

• EPREL Public API · type aggregation — snapshot 2026-06-06
• Eurostat household band DC (electricity) / D2 (gas), latest semester — snapshot 2026-06-06
• Eurostat · NASA POWER · EEA · Househeating Pulse subsidy register — snapshot 2026-06-06
• Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages — Germany profile snapshot 2026-06-06
• Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages — France profile snapshot 2026-06-06
• Eurostat tariffs (band DC/D2 latest); NASA POWER 30y normal; EEA grid CO₂; subsidies captured manually from official programme pages — Poland profile snapshot 2026-06-06

Continue reading

• Heat pump payback calculator — A practical walkthrough for turning tariffs, SCOP and subsidies into a simple retrofit decision.
• How to read EPREL heat-pump data — What SCOP, sound power, output and energy class actually mean in product listings.
• Air-to-water vs ground-source heat pumps — A buyer-focused comparison of the two hydronic types that dominate retrofit discussions.
• Heat-pump subsidies by country — Where grant ceilings are high enough to change the economics of radiator retrofits.