Smart Heat Pumps Can Cut Your Running Costs
- 58% lower running costs than predicted
Real-world monitored performance came in at around £600 per year, compared with an estimated £1,431. - Nearly 4 units of heat from every 1 unit of electricity
The system achieved a space heating SCOP of 3.85. - 45°C low-temperature design for higher efficiency
The whole system was designed to run efficiently at just 45°C flow temperature.
This project shows how a well-designed heat pump system can deliver reliable heating and lower running costs for homeowners while meeting all modern renewable energy standards.
By carefully designing the system around the property’s heating needs, Synergi SW installed a heat pump that now costs significantly less to run than predicted by standard modelling.
Property Overview
Location: Rawridge, Honiton, Devon
Previous Heating System: Wood boiler (approx. 85% efficiency)
Annual Heat Requirement: 13,795 kWh
10,216 kWh space heating
3,579 kWh hot water
The homeowner wanted a modern heating system that would be reliable, efficient and future-proof, while keeping running costs predictable.
Designing the System Properly
A key part of any successful heat pump installation is understanding exactly how much heat the home needs.
Our engineers carried out a room-by-room heat loss assessment, following MCS standards. This allowed us to design the system specifically for this property.
- Peak Heat Loss: 4.5 kW
- Outside Design Temperature: -2.07°C
- Installed Heat Pump: 5 kW Ariston Nimbus Pocket
By matching the heat pump closely to the home’s heating demand, we avoided oversizing the system. Oversized systems often cycle on and off too frequently, which reduces efficiency and increases wear.
Low-Temperature Heating for Higher Efficiency
Heat pumps work most efficiently when heating water at lower temperatures than traditional boilers.
To achieve this, the system was designed to run at a 45°C flow temperature, which significantly improves efficiency.
To ensure every room still received enough heat, radiators were carefully sized for these lower temperatures.
For example:
- Living room heat requirement: 1,409 W
- Radiators installed provide 1,564 W at 45°C
This means the room stays warm without needing hotter water, which keeps the heat pump running efficiently.
Quiet and Fully Compliant Installation
Noise is often a concern for homeowners and planners. The system was assessed using MCS acoustic guidelines.
- Manufacturer sound power: 53 dB(A)
- Calculated sound level at assessment position: 40 dB(A)
This comfortably meets permitted development requirements and ensures minimal impact on neighbouring properties.
The installation is also protected by:
- 7-year manufacturer warranty
- 2-year workmanship warranty
- Consumer Protection Association Insurance Backed Guarantee
- Full RECC and NAPIT compliance
Installation and System Protection
To ensure long-term reliability, the system included:
- 170L Joule unvented hot water cylinder
- Magnetic system filter to protect internal components
- Weather compensation controls to adjust heating automatically
- Upgraded electrical protection
- Full commissioning and optimisation before handover
These elements help protect the heat pump and maintain consistent performance over time.
Predicted vs Actual Running Costs
Before installation, a standard MCS performance estimate predicted:
- Annual electricity consumption: 4,802 kWh
- Estimated running cost: £1,431 per year (at 30p/kWh)
Using remote monitoring, we tracked the real performance of the system for over a year.
Actual results showed:
- Approx. 2,000 kWh electricity consumption per year
- Approx. £600 annual running cost
This means the system used around 58% less electricity than predicted.
This improvement comes from careful system design, correct sizing and stable operation within the home.
Understanding the Efficiency
The system achieved:
- Space Heating Efficiency (SCOP): 3.85
- Combined System Efficiency: 3.09
In simple terms:
For every 1 unit of electricity used, the system produces nearly 4 units of heat for the home.
Monitoring and Performance Verification
The system includes remote monitoring, allowing our engineers to check performance and optimise settings when needed.
Monitoring confirmed:
- Stable 45°C operating temperatures
- Consistent indoor temperature of around 21°C
- Correct system circulation and operation
- Legionella protection cycles functioning correctly
This level of monitoring ensures the system continues to perform as designed.
Conclusion
Standard modelling suggested the system would cost more than £1,400 per year to run.
In reality, monitored data shows running costs closer to £600 per year.
This project highlights how careful system design, detailed heat loss calculations and correct radiator sizing can deliver heat pump systems that provide reliable comfort while significantly reducing energy use.
For homeowners and organisations looking to invest in renewable heating, this example demonstrates how a properly engineered system can deliver both environmental and financial benefits.
