Heat-pump electricity tariffs across Europe

Why HP tariffs exist — load shifting and grid economics

Heat-pump tariffs exist because a heat pump is not an ordinary household load. It is large enough to matter to the grid, but flexible enough to be shifted by a few hours without reducing comfort. That combination is valuable.

From the supplier and network perspective, the logic is simple. If a heat pump can be encouraged to run harder during lower-demand hours, the system uses generation and network capacity more efficiently. That is the economic basis behind country-specific products such as Germany’s Wärmepumpentarif, France’s heures creuses variants, and UK time-of-use offers such as Octopus Cosy and Agile.

For buyers, the key point is that these tariffs are not merely generic night rates with a different label. They are designed around the operating pattern of space heating and domestic hot water:

• pre-heating the building fabric overnight,
• charging a buffer or cylinder before the morning peak,
• using mild daytime windows when wholesale prices or network stress are lower,
• reducing compressor operation in expensive periods.

This only works if the heat pump can be metered separately, controlled explicitly, or both. A nominal tariff discount without control integration often leaves much of the value unrealised.

Germany — Wärmepumpentarif and the smart-meter requirement

Germany’s Wärmepumpentarif is the clearest example of a dedicated heat-pump electricity product. In the usual structure, the heat pump is metered separately from the general household load, and the supplier applies a lower unit rate to that metered consumption.

The practical attraction is material: Wärmepumpentarif typically discounts heat-pump-attributed metering by about €0.10–0.15/kWh versus the household default. That is large enough to change annual running costs substantially for systems consuming several thousand kilowatt-hours per year.

The condition is complexity. These offers usually require:

• a dedicated metering arrangement for the heat pump,
• utility approval of the controllable load setup,
• and increasingly, smart-meter or smart-meter-gateway capable infrastructure as Germany moves toward more dynamic and controllable consumption under current network rules (BNetzA — Stromnetzentgelt overview, Germany).

For retrofit buyers, that means the tariff should not be evaluated on unit price alone. Also check:

For installers, Germany remains a market where electrical design decisions upstream of commissioning can determine whether the homeowner ever accesses the cheaper tariff at all.

France — heures creuses and tempo

France has a more familiar time-of-use structure, but it still matters for heat pumps. The standard reference point is heures creuses, where the customer receives roughly 8 hours of cheaper electricity, usually at night (EDF — Tarif Bleu Heures Creuses tariff sheet).

For heat pumps, that night window is useful because it overlaps well with early-morning ramp-up. The overlap is good, but not perfect. A typical heating profile wants strong output before occupants wake and before morning outdoor temperatures rise only marginally. If the cheap period ends too early, part of that ramp spills into higher-priced hours.

Still, heures creuses works reasonably well for:

• overnight space-heating pre-charge in well-insulated homes,
• domestic hot-water heating,
• buffer tank charging,
• and low-temperature emitters with enough thermal inertia.

The more complex French option is Tempo, along with older EJP-style concepts. These tariffs do not merely differentiate day and night. They also introduce a small number of “red days” with very high electricity prices. That changes the control problem completely. On ordinary days, the tariff can look attractive; on red days, careless operation becomes expensive very quickly.

That is why Tempo-type structures make smart heat-pump control essential. A heat pump on a red day should generally:

• raise room and cylinder temperature before the expensive period if comfort and emitter design allow,
• reduce target temperatures during the peak price window,
• use stored heat where available,
• and avoid unnecessary domestic hot-water cycles.

Without that logic, the tariff becomes a behavioural burden rather than a cost advantage.

United Kingdom — Octopus Cosy, Agile and heat-pump tariffs

The UK market has moved fastest on supplier-specific heat-pump tariffs. Octopus Cosy is the most obviously heat-pump-oriented example. Its cheaper windows are 04:00–07:00 and 13:00–16:00, which are unusually well aligned with heat-up cycles rather than generic household demand patterns (Octopus Energy — Cosy tariff documentation).

That shape matters. The early-morning window supports pre-heating before occupancy and before the usual breakfast peak. The afternoon window supports a second charge into the building or buffer before the more expensive evening period. For many homes, that is more usable than a single uninterrupted overnight cheap block.

Agile is different. It exposes the customer to frequently changing prices tied more closely to wholesale conditions (Octopus Energy — Agile tariff documentation). For technically engaged buyers, Agile can produce low running costs, but it asks more from the control system and from the homeowner’s tolerance for variability.

The decision between a structured tariff such as Cosy and a dynamic tariff such as Agile usually comes down to three questions:

• Does the system have enough thermal storage in the building, cylinder or buffer?
• Can the controller schedule intelligently without manual intervention?
• Does the owner prefer predictable economics or maximum optimisation potential?

Agile rewards sophistication. Cosy rewards competent scheduling.

Italy — bioraria + dedicated HP retrofits

Italy’s bioraria framework is less heat-pump-specific in branding, but still relevant in practice. The important pattern is that the cheap period commonly runs from 19:00 to 08:00 on weekdays, making overnight heat-pump buffering financially attractive.

That long cheap window is well suited to:

• charging domestic hot water overnight,
• pre-heating slab or screed systems,
• running low-temperature emitters steadily at night,
• and reducing morning-daytime compressor demand.

For retrofit projects, Italy also has a practical distinction between simply using bioraria on a standard domestic supply and creating a more dedicated electrical arrangement for the heat pump. Where a retrofit includes cylinder replacement, buffer addition, or major controls work, the economics of a dedicated heat-pump-oriented setup improve because the system can actually exploit the tariff window rather than just passively receiving it.

The weakness is familiar: without storage or control logic, a cheap overnight tariff is just a partially cheaper bill. With storage and control, it becomes an operating strategy.

Smart-control integration to actually capture the discount

Tariffs only lower bills if the heat pump changes its behaviour. That is increasingly a controls problem, not a hardware problem.

Three integration routes matter most:

• EEBUS for structured interoperability where both the heat pump and energy-management system support it.
• ModBus TCP for direct supervisory control in more technical or custom installations.
• Manufacturer-specific APIs where the vendor exposes scheduling, setpoint and domestic-hot-water controls through cloud or local interfaces.

These integrations are what turn a tariff sheet into measurable savings. In practice, the control layer should be able to:

• shift compressor-heavy run windows into cheap-tariff hours,
• pre-heat emitters, buffer tanks or domestic hot-water cylinders,
• avoid expensive “red day” or peak-price periods,
• and preserve comfort limits while optimising cost.

This matters across all the country examples above. In Germany, it helps justify the metering complexity of Wärmepumpentarif. In France, it is almost mandatory for Tempo-style tariffs with very high-price days. In the UK, it determines whether Cosy’s two windows are used well and whether Agile remains tolerable. In Italy, it makes overnight buffering profitable rather than incidental.

For buyers, the procurement question is therefore not only “Which tariff is available?” but also “Can this heat pump, controller and installer make use of it?”

Sources

• BNetzA — Stromnetzentgelt overview, Germany
• EDF — Tarif Bleu Heures Creuses tariff sheet
• Octopus Energy — Cosy and Agile tariff documentation