A time-of-use tariff designed for heat pumps beats a flat rate in every major market. UK heat pump tariffs price roughly 8 off-peak hours near 14–15p/kWh and save £200–350 a year against the standard variable rate. In Germany a §14a EnWG heat pump tariff costs 20–25 ct/kWh against an average of about 37 ct/kWh for standard household supply.
What kind of tariff suits a heat pump?
A heat pump is the one household load that can be moved in time without anyone noticing, because the building and the store hold heat for hours. That makes it a natural fit for time-of-use pricing and a poor fit for a flat rate, which charges the same for a kilowatt-hour at 3 a.m. as at 6 p.m.
Three tariff families exist across Europe:
- Dedicated heat pump tariffs with fixed cheap windows — typically two or three rates and around eight discounted hours a day.
- Dynamic or half-hourly tariffs that track the wholesale market, cheapest for households that automate their load and accept price volatility.
- Regulated grid-fee reductions rather than a retail product, where the network operator discounts the delivery charge in exchange for the right to curtail.
What do the leading options cost in 2026?
| Market | Mechanism | Indicative 2026 price | Typical saving |
|---|---|---|---|
| UK, heat pump tariff | 3 rates, ~8 off-peak hours | ~14.5p/kWh off-peak | £200 – 350/yr vs standard variable |
| UK, dynamic half-hourly | Wholesale-tracking | ~20 – 22p/kWh average | Beats flat rate if load is shifted |
| Germany, §14a EnWG heat pump tariff | Separate metering + reduced grid fee | 20 – 25 ct/kWh | €400 – 1,100/yr on 5,000–8,000 kWh |
| Germany, §14a grid-fee module alone | Base grid charge to €0, 60% off the energy component | Discount, not a tariff | ~€120 – 400/yr |
| France | Heures creuses / peak-day pricing | Off-peak differential | Depends on night share of load |
Treat the figures as indicative for 2026 and check current offers before switching: retail prices move quarterly and the German framework has offered an optional time-variable grid-fee module since April 2025.
How much of the load can you actually shift?
More than most people expect, and this is where the saving comes from. Three mechanisms, in order of value:
- Hot water on a timer. The whole DHW load can move into the cheap window, because a cylinder holds temperature for 8–12 hours. This alone often covers a fifth of annual heat pump consumption.
- Pre-heating the building. Running the space heating harder during off-peak hours and coasting through the expensive evening peak works well in a well-insulated house with underfloor heating, less well in a leaky one.
- Buffer charging. A buffer tank lets the compressor run in cheap hours and release later without cycling.
All three depend on the heat pump being controllable. SG Ready capability and a smart meter are the practical prerequisites, and Germany makes the grid-interface requirement explicit in its subsidy conditions.
Does shifting load hurt efficiency?
Sometimes, and the trade must be checked rather than assumed. Pre-heating pushes flow temperature up and runs the compressor at colder night-time ambient, both of which reduce COP. A rough rule: every 5 K of extra flow temperature costs about 10–12% of efficiency.
So the arithmetic is a price ratio against an efficiency ratio. If the off-peak rate is 45% below the peak rate and the efficiency penalty is 12%, shifting wins comfortably. If the differential is only 15%, it does not. Householders who measure both usually find hot water shifting is always worth it and space heating pre-charge is marginal in mild weather and clearly worth it in cold snaps.
What else changes the running cost more than the tariff?
Three things, all larger in effect than a tariff switch:
- Flow temperature. Dropping from 55 °C to 40 °C typically lifts seasonal efficiency by a quarter or more — see what flow temperature should I run my heat pump at?
- On-site generation. Solar output consumed directly is worth the retail price rather than the export price. A PVT array goes further by raising the heat pump's source temperature at the same time.
- The electricity-to-gas price ratio. Below about 3.2 a heat pump beats a gas boiler on running cost, as set out in heat pump vs gas boiler running costs. ETS2 pushes that ratio in the heat pump's favour from 2028 by adding a carbon cost to gas and oil.
Solimpeks pairs its heat pumps with Solibuffer stores precisely so that load shifting is available without compromising comfort. The tariff is the last lever, not the first: fix the flow temperature and the store first, then buy the cheapest hours available.
Frequently asked questions
Is a dynamic tariff better than a fixed heat pump tariff?
Only with automation. Dynamic tariffs average around 20–22p/kWh in the UK in 2026 and reward households that can respond to half-hourly prices. A fixed heat pump tariff with defined cheap windows gives a smaller but certain saving with no active management.
Do I need a separate meter for a heat pump tariff?
In Germany a §14a arrangement generally needs the controllable load measured separately or through a compliant smart-meter gateway. In the UK a single smart meter is sufficient because the tariff prices the whole supply by time of day.
How much can a heat pump tariff realistically save?
Around £200–350 a year in the UK against a standard variable rate, and €400–1,100 a year in Germany on annual consumption of 5,000–8,000 kWh. The saving scales with how much of the load you can move into the cheap window.
Will the grid operator switch my heat pump off?
Under Germany's §14a framework the operator may temporarily curtail controllable loads in exchange for the reduced grid fee, subject to a guaranteed minimum power level. In practice the events are short and a correctly sized buffer store makes them invisible indoors.