High Temperature Air Source Heat Pump: What Is It, Costs, Pros & Cons

Choosing a high temperature air source heat pump is an excellent option for UK homeowners and landlords who want renewable heating without replacing existing radiators or undertaking major insulation upgrades. 

These advanced systems deliver hotter water flow temperatures than standard air source heat pumps, making them ideal for older properties across Southern England, Greater London, South West England, and South Wales.

What Is a High Temperature Air Source Heat Pump?

A high temperature air source heat pump is a specialised renewable heating system designed to produce water temperatures of 65°C to 80°C, compared to the 35–55°C output of standard air source heat pumps. This higher output allows it to work effectively with traditional radiators and older heating systems.

High temperature models use advanced compressors (often two-stage or scroll), enhanced refrigerants (such as R32 or R290), and larger heat exchangers to achieve these elevated temperatures while still extracting heat from outdoor air.

Homeowners and landlords in London, Brighton, Oxford, Southampton, Bristol, and Cardiff can request a free air source heat pump quote from EE Renewables to assess whether this technology suits your property.

How Does a High Temperature Air Source Heat Pump Differ from Standard Models?

High temperature air source heat pumps differ from standard models primarily in their ability to deliver significantly hotter water, making them more suitable for direct retrofits in UK homes with existing radiators.

Standard air source heat pumps are optimised for efficiency at low temperatures and pair best with underfloor heating or oversized radiators. High temperature units sacrifice some efficiency to reach boiler-like temperatures, making them a practical bridge technology during the transition away from gas boilers.

Tip: To fully understand the role of high temperature systems, it helps to first understand how air source heat pumps work, as high temperature models are an adaptation of standard heat pump technology rather than a completely different system.

What Are the Costs of a High Temperature Air Source Heat Pump?

The costs of a high temperature air source heat pump are typically higher than standard models due to advanced technology and components. For an average 3-bedroom UK home, expect to pay £10,000–£18,000 installed before grants.

Installation Cost Breakdown (2026 prices)

• Unit + installation: £10,000–£18,000
• After £7,500 Boiler Upgrade Scheme grant: £2,500–£10,500
• Additional radiator upgrades (if needed): £0–£2,000 (often minimal)
• Electrical upgrades: £500–£2,000

Lifetime costs over 10 years are usually £18,000–£28,000 including running costs, higher than standard heat pumps due to lower efficiency.

What Are the Pros of a High Temperature Air Source Heat Pump?

The pros of a high temperature air source heat pump make it particularly attractive for retrofit projects where major system changes are impractical:

• Compatible with existing radiators (no need to replace with larger ones)
• Faster heat-up times and hotter radiators for improved comfort
• Ideal for older or poorly insulated homes (EPC D–G)
• Easier and less disruptive installation for landlords
• Still qualifies for the full £7,500 Boiler Upgrade Scheme grant
• Lower carbon emissions than gas or oil boilers
• Long lifespan (15–20 years) with proper maintenance
• Suitable for properties with limited space for extensive radiator upgrades

What Are the Cons of a High Temperature Air Source Heat Pump?

The cons of a high temperature air source heat pump centre around reduced efficiency and higher operating costs compared to standard models:

• Lower Coefficient of Performance (typically 2.0–3.0 vs 3.0–4.5 for standard ASHPs)
• Higher annual running costs (often £200–£600 more per year)
• More electricity consumption, especially in cold weather
• Higher upfront purchase price
• Slightly louder outdoor unit due to larger compressor
• Still requires good insulation for best results
• May need more frequent defrost cycles in UK winters
• Less future-proof than low-temperature systems with rising electricity prices

Which Properties Are Best Suited for High Temperature Air Source Heat Pumps?

High temperature air source heat pumps are best suited for properties with existing high-temperature radiator systems, older buildings, or homes where full insulation upgrades are too expensive or disruptive.

They perform well in Victorian, Edwardian, and solid-wall properties common in London, Brighton, Oxford, and Southampton. They are also popular for listed buildings, conservation areas, and rental properties where landlords want minimal disruption.

Pro tip: Before committing, homeowners need to know whether their home is suitable for a heat pump, as insulation levels and heat loss still influence performance even with higher flow temperatures.

On top of that, correct output is especially important for retrofit systems, which is why understanding what size air source heat pump you need helps prevent excessive running costs or underheating during cold periods.

Ready to Install a High Temperature Air Source Heat Pump?

For many homeowners, high temperature systems act as a stepping stone away from fossil fuels, and comparing air source heat pumps to gas boilers can clarify whether this approach offers the right balance of comfort, disruption, and long-term sustainability.

Ready to install a high temperature air source heat pump? EE Renewables Ltd specialises in expert high temperature air source heat pump installations across Southern England, Greater London, South West England, and South Wales. 

Request your free, no-obligation quote today for a professional assessment and tailored recommendations.

FAQs

Can high temperature air source heat pumps be used with combi boilers?

No, high temperature heat pumps are not designed to replace combi boilers directly as they require a hot water cylinder; however, they can work with system boilers or as part of a hybrid setup.

Do high temperature models qualify for the same grants as standard heat pumps?

Yes, high temperature air source heat pumps fully qualify for the £7,500 Boiler Upgrade Scheme grant as long as they are MCS-certified and replace a fossil fuel system.

How do high temperature heat pumps perform during very cold UK weather?

High temperature models maintain better heating output in sub-zero temperatures than standard units, though efficiency drops noticeably below -5°C.

Are high temperature air source heat pumps noisier than standard ones?

Yes, they tend to produce slightly more noise (typically 50–65 dB) due to larger compressors working harder to achieve higher temperatures.

Can I convert a high temperature heat pump to a low temperature system later?

Conversion is possible but expensive and rarely practical; it usually requires replacing key components like the compressor and heat exchangers.

Final Thoughts

High temperature air source heat pumps offer a practical, grant-eligible solution for UK homeowners and landlords seeking renewable heating without extensive radiator or insulation upgrades. 

While they come with higher upfront and running costs than standard models, their compatibility with existing systems makes them a valuable option for many retrofit projects across Southern England and South Wales. Professional assessment ensures you select the right technology for your property’s specific needs.