Heat Pump Running Costs in the UK (2026): Why Tariffs Matter, How SCOP Shapes Bills, and How to Cut the Cost per kWh of Heat

If you are comparing a heat pump to a gas boiler, “running costs” can look confusing because you are not really comparing electricity to gas. You are comparing the cost of useful heat delivered to your home. This guide shows you how to calculate that properly using your own tariff, how to interpret real-world efficiency (SCOP), and which decisions most affect bills in practice. Where helpful, examples use current Ofgem price cap figures as a reference point and explain why your results may differ.

1) Running costs: what you are really paying for

kWh of electricity is not the same as kWh of heat

A boiler burns fuel to make heat. A heat pump moves heat from outside to inside, using electricity to drive the process. The key consequence is this: the unit price of electricity is only part of the story. What matters is how many kilowatt-hours (kWh) of heat you get for each kWh of electricity you buy.

That “multiplier” is expressed as a coefficient of performance (COP). Over a whole heating season, performance varies with weather and how the system is run, so the figure that most affects annual bills is the seasonal coefficient of performance (SCOP). In plain terms, a higher SCOP means fewer purchased kWh for the same comfort.

The three inputs that dominate your bill

For most homes, running costs are dominated by three inputs:

• Your heat demand (how many kWh of heat your property needs across the season).
• Your electricity price (unit rate and, to a lesser extent, standing charge and tariff structure).
• Your system efficiency (real-world SCOP, influenced by design, controls, and how the home loses heat).

Everything else is a second-order effect. The practical goal is to reduce “£ per delivered kWh of heat” by (a) reducing heat demand, (b) buying electricity more intelligently, and (c) improving effective SCOP.

2) Tariffs in 2026: price cap basics, unit rates, and what the cap does not do

What the price cap actually caps

Ofgem’s energy price cap is often misunderstood. It does not cap your total bill. It sets a maximum for the unit rate you pay per kWh and the daily standing charge if you are on a standard variable tariff. Your total spend still depends on how much energy you use.

If you want a reliable baseline for “typical” rates, use Ofgem’s own explanation of the cap and the published unit rates for the period. For context, see Ofgem’s energy price cap explained page.

The headline numbers you should treat as inputs, not promises

Between 1 January and 31 March 2026, Ofgem’s published average (Direct Debit) price-cap figures are 27.69p/kWh for electricity and 5.93p/kWh for gas, plus standing charges. These are useful as a reference point when building a simple running-cost model, but your own tariff may be lower or higher.

The point is not to anchor on one quarter’s rates. The point is to understand how the relationship between electricity unit price, gas unit price, and SCOP affects the outcome.

Which tariff features matter most for heat pumps

• Unit rate (p/kWh): the biggest driver of running costs.
• Time-of-use periods: can reduce effective p/kWh if you can shift some heating or hot water to cheaper windows.
• Standing charge: affects total annual bill, but usually does not change the “cost per delivered kWh” calculation for incremental heating decisions.
• Export/solar interaction: if you have solar PV, the value of self-consumed electricity can materially change effective costs (but it is highly site-specific).

3) The simplest running-cost model (with worked examples)

The core formula you should use

The cleanest comparison is cost per kWh of delivered heat:

• Heat pump cost per kWh = ( ≈ Electricity unit rate ÷ SCOP
• Gas boiler cost per kWh heat ≈ Gas unit rate ÷ Boiler efficiency

This strips away marketing claims and forces the comparison onto the same basis. It is also the easiest way to test “what if” changes: a different tariff, a better SCOP through lower flow temperature, or a reduction in heat demand via insulation.

Worked example using Ofgem cap rates (illustrative)

Using Ofgem’s Jan–Mar 2026 average price-cap unit rates as an example input:

• Electricity: 27.69p/kWh
• Gas: 5.93p/kWh

Now set two realistic assumptions for illustration:

• Heat pump SCOP: 3.0 (your result could be higher or lower)
• Gas boiler efficiency: 0.90 for a modern condensing boiler running well (older systems can be lower in practice)

That gives:

• Heat pump: 27.69 ÷ 3.0 = 9.23p per kWh of heat
• Gas boiler: 5.93 ÷ 0.90 = 6.59p per kWh of heat

On this specific set of assumptions, gas is cheaper per delivered kWh. But the gap narrows quickly if either: (a) SCOP improves, or (b) the boiler is older/less efficient, or (c) you access a tariff structure that lowers your effective electricity p/kWh for a meaningful portion of heating/hot water.

Sensitivity table: how SCOP changes the answer

Keeping electricity at 27.69p/kWh (illustrative) gives the following delivered heat costs:

This is why blanket statements are unhelpful. A heat pump is not “cheap to run” or “expensive to run” in isolation. It depends on the delivered heat cost, and the delivered heat cost depends heavily on achievable SCOP and electricity price.

4) What drives SCOP up or down in real homes

Flow temperature: the lever most homeowners never see

SCOP is strongly influenced by the temperature difference that the heat pump must overcome. The larger the lift, the harder the system works and the more electricity it uses for the same heat output. Practically, this comes down to flow temperature: the temperature of the water (or air, for air-to-air systems) delivered into the building’s heating distribution.

Lower flow temperatures generally mean higher efficiency. Achieving them typically requires either: (a) larger heat emitters (underfloor heating, oversized radiators, or high-surface-area radiators), or (b) reduced heat demand (better insulation, draught control, and sensible zoning).

Controls and weather compensation

Good heat pump control is not boiler control. With a boiler, short bursts of high-temperature heat can work well. With a heat pump, efficiency typically improves when the system runs more steadily at lower temperatures, with weather compensation adjusting output based on outdoor conditions.

The Centre for Sustainable Energy notes that heat pumps can be more efficient when left on across the heating season and only set back overnight or during extended absence, rather than being driven by aggressive on/off cycles. This is not a universal rule (some homes and schedules differ), but it is a strong starting point for cost control.

Short cycling, defrost, and why “oversize/undersize” costs money either way

Two common cost drivers:

• Short cycling: frequent starts and stops reduce efficiency and can indicate poor sizing, poor control, or a mismatch between emitters and flow temperature strategy.
• Cold weather behaviour: air-source systems can spend energy on defrost cycles and may need to run harder during cold snaps. Well-designed controls and correct sizing reduce the penalty, but do not remove it entirely.

The running-cost impact is usually not a single dramatic “fault”. It is repeated small inefficiencies, every day, across a season.

5) Tariffs + controls: where most households win or lose money

Time-of-use tariffs can help, but only if your home can hold heat

Time-of-use (ToU) tariffs can reduce running costs if you can shift some heating or hot water to cheaper windows. The Centre for Sustainable Energy notes that some suppliers offer heat-pump-specific ToU structures and that you need to ensure the heat pump is set up to run during off-peak periods to benefit.

The catch is comfort. ToU savings work best when your home can “store” heat without discomfort:

• Good fabric: insulation and reasonable airtightness reduce heat loss during the day.
• Low-temp emitters: can deliver steady comfort without needing high flow temperatures at peak prices.
• Thoughtful setback: avoiding deep temperature drops that require expensive catch-up heating.

Hot water is often the easiest place to load shift

If you have a hot water cylinder, it can act as a practical “battery” for thermal energy. A common approach is to prioritise hot water production during lower-priced windows, then allow normal top-ups as required.

Do not chase tariff savings at the expense of hygiene and comfort. A well-commissioned system should include a safe hot water temperature strategy and appropriate controls. If you are unsure, ask your installer to explain how hot water scheduling is implemented and what the fallbacks are.

What to ask for: a tariff-aware control plan

If your goal is to reduce running costs, do not just ask, “Can I use a cheaper tariff?” Ask:

1. Which loads can actually be shifted? (hot water, mild-space-heating top-ups, preheating).
2. What settings change when tariff windows change? (target temps, flow temps, cylinder schedule).
3. How is comfort protected? (room thermostats, weather compensation, minimum temps).
4. How will performance be verified? (commissioning data, follow-up tweaks, monitoring approach).

6) Practical steps that cut bills before you touch the thermostat

Fabric-first “quick wins” that raise effective SCOP

You can improve outcomes even before a heat pump is installed. Anything that reduces peak heat demand helps the heat pump run at lower flow temperatures for more of the season. Practical steps typically include:

• Address obvious draught paths (while keeping necessary ventilation).
• Improve loft insulation and tackle the worst cold spots first.
• Use zoning sensibly: heat the spaces you occupy, not every room at the same level.
• Stop heat-loss surprises: open chimneys, permanently open vents, and badly sealed loft hatches.

These actions do not just reduce kWh demand. They often enable a better control strategy (lower flow temp, fewer spikes), which improves real-world efficiency again.

Design choices that affect running costs for years

If you are specifying a system, the following choices can materially change your long-term running cost profile:

• Emitter strategy: radiator upgrades or underfloor heating, where appropriate to support low flow temperatures.
• Control architecture: weather compensation, zoning, and correctly placed sensors.
• System sizing: not just “big enough”, but matched to your property’s heat loss and operating profile to avoid cycling penalties.
• Commissioning and handover: documented setup, explanation of controls, and a plan for optimisation after you have lived with it for a few weeks.

If you are in or near Bristol and want a survey that prioritises cost realism (not sales optimism), start with a structured site visit. Controlled Climate offers a free survey request process that can be used to gather the right inputs for credible estimates.

Air-to-air heat pumps (air conditioning) follow the same logic.c

Many people do not realise that common “air conditioning” systems are also heat pumps when used for heating. The cost logic is the same: the electricity unit rate divided by seasonal performance gives your delivered heat cost. If you want a related primer on cooling running costs and the factors that change the bill, Controlled Climate’s guide on the cost of running an air conditioner in the UK is a useful companion read.

7) Monitoring and maintenance: preventing performance drift

What to measure without turning your home into a lab

You do not need advanced analytics to spot the big issues. A practical monitoring approach is:

• Track electricity consumption for heating and hot water, where possible (some systems report this directly).
• Track indoor temperature stability and comfort complaints (cold rooms, uneven temperatures).
• Track whether flow temperatures are gradually creeping up over time (a common sign of settings drift or system issues).

If bills rise, you want to know whether it is driven by (a) tariff changes, (b) weather/usage changes, or (c) system performance drift.

Early warning signs that usually cost money

• Frequent cycling: repeated starts/stops, especially in mild weather.
• High flow temperatures as a default: if the system routinely runs hot to feel comfortable, efficiency will usually suffer.
• Rooms overheating then cooling: often a controls/zoning problem.
• Comfort dependence on “boost” mode: suggests the underlying control strategy needs refinement.

Maintenance: keep efficiency where it was commissioned

Heat pumps and air conditioning systems can lose performance if maintenance is neglected. Even basic issues (blocked filters, dirty coils, drainage issues, refrigerant-related faults on relevant systems) can push up energy consumption.

Servicing intervals vary by equipment and environment, but as a practical reference point, Controlled Climate lists domestic systems as typically serviced annually, with commercial systems more frequently depending on usage. If you want a clear checklist of what a proper visit should include (so you can compare providers), see Controlled Climate’s service and maintenance overview.

8) When heat pumps are cheaper to run (and when they may not be)

Strong-win scenarios (common)

Heat pumps often perform well in terms of running costs when replacing higher-cost fuels or inefficient systems, especially when paired with sensible controls and fabric improvements. Typical examples include:

• Replacing oil, LPG, or direct electric resistance heating.
• Replacing older, non-condensing boilers or systems that perform poorly in practice.
• Homes where low flow temperatures are achievable (emitter upgrades and/or improved fabric).
• Properties that can benefit from time-of-use scheduling without comfort compromise.

Borderline scenarios (be honest about these)

If you have a newer, well-performing gas boiler and your electricity unit price remains high relative to gas, a heat pump may be slightly more expensive to run on pure fuel cost terms. Energy Saving Trust explicitly notes that heat pumps can be slightly more expensive to run than a newer gas boiler because electricity is more expensive per unit.

That does not automatically make a heat pump a poor choice. It means you should approach the decision with the right levers in mind: increase SCOP (design and controls), reduce heat demand (fabric), and consider tariff structures that suit how your home is used.

Where the market is heading: electricity vs gas price balance

One reason comparisons feel unstable is that unit prices do not reflect only “energy”. Policy costs and levies also play a role. Energy Saving Trust has highlighted analysis suggesting that some levies on electricity bills contribute materially to heat pump running costs, and that rebalancing could improve competitiveness.

Do not base a purchase on guessed policy outcomes. Do base it on a realistic running-cost model for today, plus a practical plan to improve performance regardless of tariff direction.

9) Bristol and the South West: practical realities that affect costs

Common building patterns and the running-cost traps they create

Across Bristol and nearby areas, many homes have characteristics that influence heat demand and controllability: mixed insulation standards, extensions, loft conversions, and varied room-by-room occupancy. The most common running-cost traps in this kind of housing stock are:

• Trying to run high flow temperatures to compensate for high heat loss.
• Inconsistent room use without proper zoning.
• Controls that are set up like a boiler (short bursts) rather than optimised for low and steady output.

Local support and what a credible survey should include

A credible running-cost estimate should not be a single “£/month” guess. It should be a short model with inputs you can interrogate: heat demand assumptions, tariff assumptions, and an efficiency assumption that is justified by design choices (emitters, flow temperature plan, controls).

If you are in Bristol, start with the local context and coverage (so you know the provider can actually support you after install). See Controlled Climate’s Bristol coverage page. If you are ready to gather the inputs for a proper estimate, use the free survey request form to start the process.

10) Summary

Heat pump running costs are best understood as pence per delivered kWh of heat, not as “electricity is expensive”. Use a simple model (electricity unit rate ÷ SCOP) and compare it to your current heating cost (gas unit rate ÷ boiler efficiency). If the result is close, the outcome will often be decided by controllable levers: lowering flow temperatures through emitter and fabric choices, using weather compensation and steady control strategies, and selecting a tariff structure that matches how your home uses heat.

Next steps for most households:

• Write down your current unit rates (and whether they are time-of-use).
• Estimate whether your home can support lower flow temperatures (radiators, insulation, zoning).
• Ask for a survey that produces an assumptions-led estimate, not a sales-led promise.
• Plan for monitoring and maintenance so performance does not drift after commissioning.

For more practical guidance and related topics, browse the Controlled Climate guides hub or contact the team with your property specifics.

Frequently Asked Questions

Are heat pumps always cheaper to run than gas?

Not always. Outcomes depend on your electricity vs gas unit prices and your real-world SCOP. In many cases, well-installed systems can be comparable to a new gas boiler, but there are scenarios where gas remains cheaper per delivered kWh.

What SCOP should I assume when comparing quotes?

Avoid assuming a single number. Ask how the proposed design supports efficiency (flow temperature plan, emitters, controls) and what efficiency figure the installer expects for your property. Treat optimistic assumptions cautiously unless they are backed by design detail.

Will a time-of-use tariff automatically reduce my heat pump bill?

Only if your controls and your home’s thermal behaviour allow meaningful load shifting. Hot water is often the easiest place to shift demand. Space heating load shifting works best in homes that hold heat well.

Should I turn my heat pump off overnight?

Often, deep overnight setbacks can increase costs because the system has to “catch up” at higher output. Many homes perform better with modest setbacks or steady operation, but the right approach depends on heat loss and occupancy.

Do air-to-air heat pumps (air conditioning) use the same running-cost logic?

Yes. You are still paying for delivered heat or delivered cooling. The cost is driven by your unit rate and seasonal efficiency. If you also want the cooling-side perspective, see the running cost overview for air conditioning.

What maintenance actually protects running costs?

Maintenance that preserves airflow and heat transfer, and catches developing faults early. At a minimum, filters and coils should be kept clean and controls checked for drift. For service expectations, see Service & Maintenance.

What should I prepare before requesting a survey?

Recent energy bills (or kWh usage), a simple outline of room usage, any insulation upgrades done, radiator sizes (if known), and any constraints (noise sensitivity, siting limits). Then use the free survey request form to capture the essentials.