What is COP and why does it matter?

COP stands for Coefficient of Performance. It measures how much heat a heat pump produces for each unit of electricity. A COP of 3.2 means you get 3.2 kWh of heat for every 1 kWh of electricity. The higher the COP, the cheaper your heating. SCOP (Seasonal COP) is the average over a full year, accounting for colder months.

How often do you update your data?

Energy prices are updated quarterly, aligned with Ofgem price cap announcements. Installation costs are reviewed monthly using MCS data and installer survey responses. Content is reviewed at least quarterly for accuracy.

Can I verify your figures independently?

Yes. All our primary sources are publicly available. Ofgem publishes price cap data on their website. The Energy Saving Trust publishes home energy guides. MCS publishes installer data. We encourage you to check our working.

What happens if energy prices change?

We update our calculations when Ofgem announces each quarterly price cap. Between updates, the figures shown are based on the most recent cap. We always state which quarter's rates we're using.

Our Methodology

How we calculate our figures, and where our data comes from.

Researcher analysing heat pump data and methodology at a UK home office

We believe you should be able to verify every figure on our site. This page explains our data sources, calculation methods, and the assumptions we make. If you spot an error or disagree with an assumption, please let us know.

Data Sources

Energy Prices

Electricity: Ofgem price cap, currently 24.5p/kWh (Q1 2026). Standing charge: 61.37p/day.
Gas: Ofgem price cap, currently 6.5p/kWh (Q1 2026). Standing charge: 31.61p/day.
Oil: UK average heating oil price, currently approximately 7.5p/kWh equivalent. Based on 36,000 litre deliveries at current market rates, converted to kWh using a calorific value of 10.35 kWh per litre.
LPG: UK average LPG price, approximately 8.5p/kWh equivalent.

Installation Costs

Air source heat pumps: £8,000–£15,000 installed. Based on MCS installation data and installer survey responses.
Ground source heat pumps: £15,000–£35,000 installed. Based on MCS data and Ground Source Heat Pump Association guidance.
BUS grant: £7,500 (fixed amount, Ofgem).

Efficiency Data

Heat pump COP: 3.2 (seasonal average). Based on the BEIS Electrification of Heat Demonstration Project, Energy Systems Catapult field trials, and MCS monitoring data.
Gas boiler efficiency: 90% (A-rated condensing boiler). Based on Building Regulations Part L minimum standards.
Oil boiler efficiency: 85% (modern condensing model). Based on OFTEC published data.

Heat Demand Data

Annual heat demand estimates by property type and insulation level are based on Energy Saving Trust data, Building Research Establishment (BRE) housing stock models, and English Housing Survey data. Our figures represent typical UK homes and may not match your specific property.

Key Assumptions

Every calculation requires assumptions. Here are ours, stated explicitly so you can judge their reasonableness:

Heat Demand by Property Type (kWh/year)

Property Type	Good Insulation	Average Insulation	Poor Insulation
Detached	12,000 kWh	16,000 kWh	22,000 kWh
Semi-detached	9,000 kWh	12,000 kWh	16,000 kWh
Terraced	7,500 kWh	10,000 kWh	13,500 kWh
Bungalow	8,500 kWh	11,500 kWh	15,000 kWh
Flat	5,000 kWh	7,000 kWh	9,500 kWh

Radiator Upgrade Likelihood

Insulation Level	Upgrade Likelihood	Estimated Cost
Good	Unlikely	£0 (not expected)
Average	Possible	£1,500–£3,500
Poor	Likely	£3,000–£6,000

Other Assumptions

All costs are in 2026 pounds sterling and are not adjusted for future inflation
Running cost comparisons assume the same level of comfort (20–21°C room temperature)
Heat pump COP figures are seasonal averages (SCOP), not peak or laboratory values
Gas boiler efficiency accounts for flue losses, standby losses, and cycling losses
Payback calculations do not account for energy price changes (we use current rates throughout)
Lifespan figures are based on well-maintained systems with annual servicing

Calculation Methods

For a detailed, step-by-step explanation of every formula we use, see our calculation guide. Here's a summary of the key methods:

Running cost calculation

Annual running cost = (Annual heat demand ÷ System efficiency) × Fuel price per kWh

For a heat pump with COP 3.2 in a home needing 12,000 kWh: (12,000 ÷ 3.2) × £0.245 = £919 per year

Payback calculation

Payback period = Net installation cost (after grant) ÷ Annual saving vs current system

Lifetime cost calculation

Lifetime cost = Net installation cost + (Annual running cost × Lifespan) + (Annual maintenance × Lifespan)

For gas boilers, we include the cost of one replacement at year 13 (mid-life of a 25-year comparison period).

Limitations and Caveats

Our estimates are just that — estimates. They are based on typical values and may not reflect your specific situation. Key limitations:

Every home is different. Our calculations use typical values that may not match your property.
Energy prices change. Our figures are based on current Ofgem rates and will need updating as prices change.
COP varies. Real-world COP depends on installation quality, weather, flow temperature, and system sizing. Our default of 3.2 is a reasonable seasonal average but your system may differ.
Installation costs vary by region, installer, and system specification. Our ranges are broad but some installations will fall outside them.
We do not account for future energy price changes in payback calculations. If gas prices rise (as many analysts expect), heat pumps become even more attractive. If electricity prices fall (due to grid rebalancing), the same applies.

The only way to get accurate figures for your specific home is to have an MCS-certified installer perform a detailed survey.

Data last updated: 2026-03-18. Source: Ofgem, Energy Saving Trust, MCS, BEIS — compiled Q1 2026.