When it comes to upgrading your property’s heating system, air source heat pump efficiency is a top consideration for homeowners, landlords, and commercial property managers.
As the UK continues its push toward net zero emissions, many are turning to low-carbon technologies like air source heat pumps (ASHPs) as a sustainable and cost-effective alternative to gas boilers. But how efficient are they really?
This guide breaks down ASHP efficiency, how it compares to gas heating, how much you can save, and how to maintain optimal performance.
How Efficient Are Air Source Heat Pumps Compared to Traditional Systems?
Air source heat pumps are significantly more efficient than traditional gas or oil boilers. While a modern condensing gas boiler typically operates at 90–94% efficiency (meaning 1 unit of gas gives you 0.9–0.94 units of heat), ASHPs can achieve 300–400% efficiency.
This is measured by the Coefficient of Performance (CoP) and Seasonal Coefficient of Performance (SCOP).
| System | Typical Efficiency (CoP/SCOP) | Heat Output per 1kWh Input |
|---|---|---|
| Modern Gas Boiler | 0.9–0.94 (90–94%) | 0.9–0.94 kWh |
| Air Source Heat Pump | 2.5–4.0 (250–400%) | 2.5–4.0 kWh |
Air source heat pumps extract ambient heat from the air, even in temperatures as low as -15°C, making them ideal for the UK climate.
According to the Energy Saving Trust, ASHPs can deliver up to 4 units of heat for every 1 unit of electricity consumed, demonstrating their superior efficiency over traditional heating systems.
If you’re wondering about the environmental or financial benefits overall, you may want to weigh up the air source heat pump pros and cons before committing.
What Affects Air Source Heat Pump Efficiency?
Several variables influence the efficiency of your ASHP system:
1. Property insulation and airtightness
Poorly insulated homes lose heat quickly, forcing the ASHP to work harder. Upgrading loft, cavity wall, and floor insulation can significantly improve SCOP.
2. Radiator or underfloor heating system
The type of heating distribution system in your property plays a crucial role in how efficiently an air source heat pump (ASHP) operates.
Traditional radiators are designed to work with high-temperature water (usually around 70°C), which matches well with gas boilers but reduces ASHP efficiency because heat pumps work best when delivering heat at lower temperatures.
Low-flow temperature systems, such as underfloor heating or specially designed larger radiators, operate at lower water temperatures, typically between 30°C and 45°C.
If you’re considering this pairing, it’s worth understanding how air source heat pump underfloor heating works and why it’s often recommended to maximise system performance.
This lower temperature heating means the ASHP doesn’t have to work as hard to raise the water temperature, which significantly improves its Coefficient of Performance (CoP) and overall efficiency.
In practical terms, this means:
- Underfloor heating distributes heat evenly across the floor, creating a comfortable environment at a lower temperature.
- Larger or specially designed radiators allow more heat output at lower water temperatures compared to standard radiators.
If you’re unsure about compatibility, read our article on whether air source heat pumps can heat radiators to see if your existing system will work.
By using low-temperature heating systems, your ASHP can run more efficiently, resulting in lower energy consumption and reduced heating costs.
According to the Energy Saving Trust, pairing an air source heat pump with underfloor heating or oversized radiators is one of the best ways to maximize system efficiency and comfort.
3. Sizing the unit correctly
Installing an ASHP that matches your property’s heat demand is crucial. Over- or undersized systems can reduce efficiency and lifespan.
Not sure where to start? Take a look at our guide on what size air source heat pump you need to get a better understanding based on your property’s heat load and layout.
4. Property size and heat demand
The overall size and heat requirements of your property directly impact how efficiently an ASHP performs. Larger properties naturally require more heat to maintain comfortable indoor temperatures, meaning the heat pump needs to deliver higher outputs for longer periods.
A heat pump that is properly matched to your home’s heat load will operate steadily and efficiently, avoiding excessive cycling or overworking. On the other hand, a system that’s too small will struggle to meet demand, reducing efficiency and increasing wear, while an oversized system can cycle on and off too frequently, also impacting performance negatively.
A professional heat loss survey, which considers factors such as property size, insulation, and layout, is essential to ensure your ASHP is sized correctly to achieve optimal efficiency and reliability.
If you live in a non-standard property like a flat, you might be wondering whether you can install a heat pump in a flat. The answer depends on space, access, and permissions.
How does air source heat pump efficiency compare in winter vs summer?
ASHPs are more efficient in summer, when outside temperatures are higher. In colder months, SCOP values may drop slightly, but modern units with R32 or R290 refrigerants maintain high efficiency down to -10°C and below.
For UK climates, you can expect:
| Season | Average SCOP |
|---|---|
| Summer | 3.5–4.5 |
| Winter | 2.5–3.5 |
If you’re curious about performance in cold weather specifically, read our article on how heat pumps work in winter and how modern models are designed for the UK climate.
Smart thermostats and weather compensation controls can help regulate performance year-round.
What is the Typical Efficiency of Air Source Heat Pumps by Property Size?
The efficiency of an air source heat pump (ASHP) can vary depending on the size of the unit and the type of property it serves.
These figures are typically measured by the Seasonal Coefficient of Performance (SCOP), which reflects how efficiently the system delivers heat across an entire heating season under real-world conditions.
Here’s a breakdown of typical SCOP values based on property type and corresponding ASHP size:
| Property Type | Heat Pump Size (kW) | Typical SCOP | Est. Annual Heat Demand (kWh) |
|---|---|---|---|
| 1-bed flat | 3–4 kW | 3.5–4.0 | 5,000–7,000 |
| 2–3 bed semi-detached | 5–7 kW | 3.2–3.8 | 8,000–12,000 |
| 4-bed detached | 8–12 kW | 3.0–3.5 | 13,000–18,000 |
| Small commercial unit | 10–16 kW | 2.8–3.5 | 15,000–25,000 |
These performance ranges are consistent with findings from Ofgem’s ASHP performance monitoring data, which show that well-installed and properly sized heat pumps can deliver seasonal efficiencies between 2.8 and 4.0 depending on property characteristics and system design.
Tip: The higher the SCOP, the more heat you get per unit of electricity used and the more cost-effective and eco-friendly your system will be in the long run.
How Much Money Can Air Source Heat Pumps Save You?
Switching from a gas boiler to an air source heat pump (ASHP) can lead to noticeable annual savings on your energy bills, especially if your home is well insulated and you take advantage of lower-cost electricity tariffs.
According to analysis by the Energy Saving Trust, households in a typical three-bedroom semi-detached home can save between £295 and £425 per year when moving from a gas boiler to an ASHP.
These savings increase further if you’re switching from more expensive fuels like LPG, oil, or direct electric heating.
For a more complete picture of financial benefits and what affects them, it’s helpful to understand the cost to replace a gas boiler with a heat pump, including grants, installation factors, and property type.
How Does Maintenance Impact Air Source Heat Pump Efficiency?
Routine servicing and maintenance are essential for maintaining ASHP efficiency over time.
Key maintenance practices:
- Annual professional servicing to check refrigerant levels, compressor health, and electrical connections.
- Monthly checks to clear debris from outdoor unit fans and ensure airflow isn’t obstructed.
- Cleaning filters and coils ensures maximum heat transfer and airflow.
According to The Department for Energy Security and Net Zero (DESNZ), well-maintained ASHPs retain up to 95% of their original efficiency after 10 years.
Frequently Asked Questions (FAQs)
Yes, but they may require planning permission. Check with your local planning authority, especially for outdoor units on listed buildings or in conservation areas.
Absolutely. Pairing an ASHP with solar PV panels can significantly reduce electricity costs and boost ROI. You can even store excess solar energy in a home battery for use when demand peaks.
Payback typically ranges from 7 to 12 years, depending on installation cost, fuel savings, and available grants like the Boiler Upgrade Scheme (BUS) which offers £7,500 upfront.
Yes, smart thermostats and zone controls optimise efficiency by learning usage patterns and reducing energy wastage. Some ASHPs come with manufacturer-specific smart integrations.
Modern ASHPs are quiet, typically 40–50 decibels, about the same as a fridge. Installation location and soundproof enclosures can help reduce noise further for sensitive areas. If noise is a concern, read our article on how noisy air source heat pumps are to get a better understanding.
Our Verdict
Air source heat pumps offer exceptional efficiency, especially when installed correctly and maintained well. Compared to traditional boilers, they can slash your carbon footprint and heating bills, making them an ideal choice for energy-conscious UK property owners.
From accurate sizing to smart controls and proper insulation, every element plays a role in maximising performance. By choosing a trusted local installer like Future Heat, you ensure a high-quality system that’s built to last.
Ready to reduce your heating costs and go green? Get your free air source heat pump quote from Future Heat today.
Myles Robinson is a seasoned expert in the boiler and home improvement industry, with over a decade of experience. He is deeply committed to environmental sustainability, actively promoting energy-efficient heating solutions to help households reduce their carbon footprint. By combining industry expertise with a dedication to environmental responsibility, Myles continues to lead efforts in transforming home heating practices towards a more sustainable future.
