10 Real Homes, 12 Months of Data: What Do Heat Pumps Actually Cost to Run?
10 Real Homes, 12 Months of Data: What Do Heat Pumps Actually Cost to Run?
One of the most common questions we hear from homeowners considering a heat pump is simple:
“How much will it cost to run?”
Rather than relying on theoretical calculations or manufacturer claims, we decided to look at something far more useful — real data from real homes.
We analysed 10 heat pump systems installed by GreenGenUK that have been operating for more than 12 months, comparing their actual electricity use with the cost of producing the same heating and hot water using other common heating systems.
The results provide a realistic picture of how heat pumps perform in everyday homes across Cornwall and Devon.
The Real Data: 10 Homes with 12 Months of Monitoring
Each system we reviewed had monitoring data available showing:
- Total electricity used by the heat pump
- Total heat delivered for heating and hot water
- A full 12-month operating period
Across these ten homes the average figures were:
| Metric | Average |
|---|---|
| Heat delivered | 13,800 kWh per year |
| Electricity used | 3,237 kWh per year |
| Seasonal efficiency (COP) | 4.1 |
In simple terms, the systems produced just over four units of heat for every unit of electricity consumed.
This level of efficiency is typical of well-designed modern heat pump systems operating in UK homes.
How These Systems Were Operated
We also asked the homeowners how they were running their heating controls.
Only three of the ten homes were using scheduled heating and hot water programmes.
The remaining seven homes were simply leaving their systems running continuously, allowing the controls to manage temperatures automatically.
In these homes:
- the room thermostat activates heating when the room temperature drops below the target setting
- the hot water cylinder reheats automatically when the tank temperature falls around 10°C below the set temperature
This is actually a very common way heat pumps are operated in practice.
Rather than switching heating on and off at specific times of day, many homeowners allow the system to run steadily in the background, maintaining a consistent temperature in the home.
Heat pumps tend to perform most efficiently when operating this way, running for longer periods at lower output rather than repeatedly starting and stopping.
Importantly, this means the results shown in this analysis represent typical everyday operation, not systems that have been heavily optimised or fine-tuned.
Average Heat Pump Running Costs
Using the average electricity price in the South West over the last 12 months (around 25p/kWh), the average annual running cost for these systems was:
£859 per year
To understand how this compares with other heating technologies, we calculated the cost of producing the same amount of heat using common alternatives.
Assumptions used:
- Boiler efficiency: 90%
- Direct electric heating efficiency: 100%
- Electricity price: 25p/kWh
- Heating oil: 70p per litre
- Bulk LPG: 47p per litre
Heat Pump Running Costs vs Other Heating Systems
| Heating System | Average Annual Cost |
|---|---|
| Heat Pump | £859 |
| Mains Gas Boiler | £925 |
| Oil Boiler (70p/litre) | £1,023 |
| Bulk LPG Boiler (47p/litre) | £1,016 |
| Direct Electric Heating | £3,450 |
A Note on LPG Prices
LPG prices vary significantly depending on how it is supplied.
Many rural homes use bulk LPG tanks, where prices during the last year have typically averaged around 45–50p per litre.
However, some properties rely on bottled LPG cylinders, particularly in smaller or older installations.
Bottled LPG is usually much more expensive, often 80p per litre or more, meaning the cost of heating with bottled LPG can be roughly double that of bulk supply.
In those situations, heat pumps can deliver significant running cost savings.
What About Direct Electric Heating?
The comparison becomes even clearer when looking at homes heated with direct electric systems such as:
- electric boilers
- storage heaters
- panel heaters
Because these systems convert electricity directly into heat at 100% efficiency, the running cost simply equals the electricity price.
Across the homes we analysed, this would result in average annual heating costs of around £3,450 per year — roughly four times higher than the heat pump systems.
Why Real Homes Matter
Heat pump performance is often debated online, but the most meaningful evidence comes from real systems operating in real homes through real winters.
Across the ten properties we analysed we observed consistent patterns:
- hot water energy use remains fairly steady year-round
- heating demand rises naturally during winter
- electricity use remains relatively low compared with the heat delivered
The result is seasonal efficiencies of around 4:1, which aligns closely with the performance expected from modern heat pumps.
What This Means for Homeowners
The key takeaway from this real-world data is simple.
A well-designed heat pump system can typically deliver:
- four times more heat than the electricity it consumes
- lower running costs than oil and direct electric heating
- running costs comparable with gas and bulk LPG
Combined with the £7,500 Boiler Upgrade Scheme, heat pumps are increasingly becoming one of the most practical and efficient ways to heat homes in the UK.
Thinking About Switching to a Heat Pump?
At GreenGenUK we specialise in designing and installing heat pump systems across Cornwall and Devon.
If you’re considering replacing an oil, LPG or electric heating system, our team can provide a full survey and system design tailored to your home.
📞 01326 564513
🌐 www.greengenuk.com
Or request a quote online and find out how a heat pump could work for your property.
Notes on the Comparison
The figures shown in this article are based on monitoring data from 10 heat pump systems installed by GreenGenUK that have been operating for more than 12 months. To allow a fair comparison with other heating technologies, several assumptions were used when estimating equivalent running costs, including electricity at 25p/kWh, heating oil at 70p per litre and bulk LPG at 47p per litre. Boiler efficiencies of 90% were assumed for gas, oil and LPG systems, with direct electric heating assumed to be 100% efficient. Fuel energy content values used were 10.35 kWh per litre for heating oil and 7.08 kWh per litre for LPG. Heat pump performance figures are based on monitored electricity consumption and heat output where available across a full 12-month period. Actual running costs and efficiencies will vary depending on factors such as property insulation, heating system design, thermostat settings, energy tariffs and weather conditions.
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