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Air Source Heat Pump Electricity Consumption: How Much Do They Use?

One of the most practical questions anyone considering a heat pump asks is: how much electricity will it actually use? It is a fair question — you are replacing gas with electricity, and electricity costs roughly four times more per kWh. So the maths needs to work.

The good news is that heat pumps do not use electricity in a one-to-one ratio with the heat they produce. Thanks to their efficiency (measured as the Coefficient of Performance, or COP), they typically produce 2.5 to 4 units of heat for every 1 unit of electricity consumed. This is why they can be cheaper to run than gas despite the higher electricity price.

This guide breaks down the actual electricity consumption you can expect — by property type, by season, and by the factors that make the biggest difference to your bill.

The Key Formula

Understanding heat pump electricity consumption comes down to one simple formula:

Electricity consumed = Heat demand ÷ COP

So if your house needs 12,000 kWh of heat per year (a typical UK three-bedroom semi), and your heat pump achieves a seasonal COP (also called SCOP or SPF) of 3.0, the electricity consumption is:

12,000 ÷ 3.0 = 4,000 kWh per year

At an electricity price of 24.5p per kWh (the 2026 Ofgem cap rate), that is roughly £980 per year in electricity for heating and hot water.

The two variables that determine your electricity consumption are therefore: (1) how much heat your house needs, and (2) how efficiently your heat pump delivers it.

Electricity Consumption by Property Type

Here are realistic annual electricity consumption figures for common UK property types, assuming a well-installed air source heat pump with seasonal efficiency (SPF) of 2.8-3.2:

Small Flat or Terraced House (1-2 Bedrooms)

  • Annual heat demand: 6,000-8,000 kWh
  • Annual electricity for heat pump: 2,000-2,800 kWh
  • Annual electricity cost: £490-£690
  • Average daily consumption (winter): 12-16 kWh
  • Average daily consumption (summer, hot water only): 2-4 kWh

Mid-Terrace or Small Semi (3 Bedrooms)

  • Annual heat demand: 10,000-14,000 kWh
  • Annual electricity for heat pump: 3,300-4,700 kWh
  • Annual electricity cost: £810-£1,150
  • Average daily consumption (winter): 18-26 kWh
  • Average daily consumption (summer, hot water only): 3-5 kWh

Semi-Detached or End-Terrace (3-4 Bedrooms)

  • Annual heat demand: 14,000-18,000 kWh
  • Annual electricity for heat pump: 4,700-6,000 kWh
  • Annual electricity cost: £1,150-£1,470
  • Average daily consumption (winter): 26-34 kWh
  • Average daily consumption (summer, hot water only): 3-5 kWh

Detached House (4-5 Bedrooms)

  • Annual heat demand: 18,000-25,000 kWh
  • Annual electricity for heat pump: 6,000-8,300 kWh
  • Annual electricity cost: £1,470-£2,030
  • Average daily consumption (winter): 34-46 kWh
  • Average daily consumption (summer, hot water only): 4-6 kWh

Older/Poorly Insulated Property

  • Annual heat demand: 20,000-30,000 kWh
  • Annual electricity for heat pump: 7,000-10,000 kWh
  • Annual electricity cost: £1,715-£2,450
  • Average daily consumption (winter): 40-56 kWh
  • Average daily consumption (summer, hot water only): 4-6 kWh

Use our heat pump calculator to get a more specific estimate based on your property details.

Monthly Breakdown

Heat pump electricity consumption varies hugely across the year. In the UK, roughly 80% of annual heating energy is consumed between October and March, with January and February being the peak months.

For a typical three-bedroom semi using 4,000 kWh of electricity per year for the heat pump:

  • January: 650-750 kWh (peak heating month)
  • February: 580-680 kWh
  • March: 450-550 kWh
  • April: 250-350 kWh
  • May: 100-150 kWh (mostly hot water)
  • June-August: 80-120 kWh per month (hot water only)
  • September: 120-180 kWh
  • October: 300-400 kWh
  • November: 480-580 kWh
  • December: 600-700 kWh

This seasonal variation means your electricity bills will be noticeably higher in winter and lower in summer — the opposite pattern to a household that uses gas for heating and electricity for everything else.

How COP Affects Electricity Consumption

The COP (Coefficient of Performance) is the ratio of heat output to electricity input. It is the single most important factor in determining how much electricity your heat pump uses.

What Is a Realistic COP?

COP is not a fixed number — it changes with conditions. It is highest when the outdoor temperature is mild and the flow temperature is low, and lowest when it is very cold outside and the flow temperature is high.

  • Mild day (10°C outside), low flow temp (35°C): COP 4.0-5.0
  • Average winter day (5°C outside), moderate flow temp (40°C): COP 3.0-3.5
  • Cold day (0°C outside), moderate flow temp (45°C): COP 2.5-3.0
  • Very cold day (-5°C outside), high flow temp (55°C): COP 1.8-2.3

The Seasonal Performance Factor (SPF) is the average COP over an entire heating season. For a well-installed system in the UK, an SPF of 2.8-3.5 is typical. The Energy Saving Trust reports an average SPF of around 2.8 for UK installations, though well-designed systems regularly achieve 3.0-3.5.

The Impact of COP on Your Bill

For a house needing 12,000 kWh of heat per year, the difference in electricity consumption (and cost) between a poorly performing and a well-performing system is significant:

  • SPF 2.5 (poor): 4,800 kWh electricity = £1,176/year
  • SPF 3.0 (average): 4,000 kWh electricity = £980/year
  • SPF 3.5 (good): 3,430 kWh electricity = £840/year
  • SPF 4.0 (excellent): 3,000 kWh electricity = £735/year

The difference between a poor and an excellent SPF is over £400 per year — every year, for the life of the system. This is why correct system design, low flow temperatures, and weather compensation matter so much.

What Affects Your Electricity Consumption

1. Building Insulation

Better insulation means lower heat demand, which directly reduces electricity consumption. A well-insulated three-bedroom semi might need 10,000 kWh of heat per year, while a poorly insulated one needs 18,000 kWh — nearly double the electricity consumption for the heat pump.

2. Flow Temperature

Running the heat pump at lower flow temperatures dramatically improves COP. Reducing the flow temperature from 55°C to 40°C can improve seasonal efficiency by 30-40%. This is the single most impactful setting on your system. It requires adequately sized radiators or underfloor heating to maintain comfort at lower temperatures.

3. Weather Compensation

A weather compensation curve automatically adjusts the flow temperature based on outdoor conditions — low flow temperature on mild days, higher on cold days. This maximises efficiency across the season. Every heat pump should have weather compensation enabled, yet some installers fail to set it up properly.

4. Hot Water Demand

Hot water typically accounts for 15-25% of a heat pump's total electricity consumption. Households that use a lot of hot water (large families, frequent baths) will see higher consumption. Hot water is heated to a higher temperature than space heating, so the COP during hot water production is lower (typically 2.0-2.5).

5. Supplementary Heating

If the immersion heater or backup electric heater runs frequently, it adds electricity consumption at a COP of 1.0 — massively increasing costs. This should only activate in exceptional circumstances (very cold weather, heavy hot water demand). If it is running regularly, something is wrong with the system design or settings.

6. Your Electricity Tariff

The amount of electricity consumed does not change with your tariff, but the cost does. Time-of-use tariffs (like Octopus Agile or Intelligent Octopus Go) can reduce your electricity cost by running the heat pump during cheap rate periods. Some homeowners combine heat pumps with solar panels, offsetting daytime consumption with free electricity.

For detailed cost analysis, see our heat pump running costs guide.

Comparing to Gas Boiler Energy Consumption

To put heat pump electricity consumption in context, compare it to the gas a boiler would use for the same house:

A three-bedroom semi needing 12,000 kWh of heat per year:

  • Gas boiler (90% efficient): Uses 13,300 kWh of gas = approximately £930/year at 7p/kWh
  • Heat pump (SPF 3.0): Uses 4,000 kWh of electricity = approximately £980/year at 24.5p/kWh
  • Heat pump (SPF 3.5): Uses 3,430 kWh of electricity = approximately £840/year at 24.5p/kWh

At current energy prices, a heat pump with average efficiency roughly matches gas costs, while a well-performing system beats gas on cost. As the electricity-to-gas price ratio continues to improve (the government has committed to rebalancing energy levies), the heat pump advantage will grow.

How to Reduce Your Heat Pump Electricity Consumption

  • Lower the flow temperature: The most impactful single change. Work with your installer to find the lowest comfortable flow temperature
  • Enable and optimise weather compensation: Ensure the curve is set correctly for your property
  • Improve insulation: Even modest improvements (loft insulation, draught-proofing) reduce heat demand
  • Reduce hot water temperature: Storing hot water at 48-50°C instead of 55°C reduces the energy needed (with a weekly legionella cycle to 60°C for safety)
  • Use a time-of-use tariff: Shift consumption to cheap rate periods where possible
  • Add solar panels: A 4kW solar array can offset 1,500-2,500 kWh of annual electricity consumption, significantly reducing your heat pump running costs
  • Ensure the backup heater is not running unnecessarily: Check your system's monitoring data

Frequently Asked Questions

How much electricity does a heat pump use per day?

It varies enormously by season. In a typical three-bedroom semi, expect 20-30 kWh per day in the coldest winter months and 3-5 kWh per day in summer (hot water only). The annual average works out at roughly 11 kWh per day.

Will my electricity bill double with a heat pump?

Your electricity bill will increase because the heat pump uses electricity, but your gas bill disappears entirely. The total energy cost (electricity minus gas savings) is typically similar to or lower than gas for a well-performing system. Your electricity consumption will increase by roughly 3,000-6,000 kWh per year depending on property size.

Can solar panels cover my heat pump electricity?

Partially. A typical 4kW solar panel system generates around 3,500-4,000 kWh per year, but most of this is in spring and summer when heating demand is lowest. Realistically, solar panels can offset 30-50% of annual heat pump electricity consumption, with the biggest impact on hot water costs in summer. Adding a battery increases the offset further.

Is a heat pump cheaper to run than a gas boiler?

At current prices, a well-performing heat pump (SPF 3.0 or above) is broadly comparable to gas in running costs — slightly cheaper in a well-insulated house, slightly more expensive in a poorly insulated one. As the electricity-to-gas price ratio improves, heat pumps will become increasingly cheaper than gas. Visit our running costs guide for detailed figures.

What happens during a power cut?

The heat pump stops, just as a gas boiler stops (modern gas boilers need electricity too). When power returns, the heat pump restarts automatically. In areas with frequent power cuts, a battery backup system can keep the heat pump running for short outages.

Does an air source heat pump use more electricity in very cold weather?

Yes. The colder it is outside, the harder the heat pump has to work and the lower its COP. On the coldest days (below -5°C), electricity consumption can be 30-50% higher than on a mild winter day. However, these extremely cold days are relatively rare in most of the UK, so the impact on annual consumption is modest.