High Temperature Heat Pumps: Costs & Benefits

Last Updated on June 30, 2025

Looking for a more efficient way to heat your home without changing your existing radiators? High temperature heat pumps could be the solution. Designed to deliver hot water at higher temperatures than standard air source heat pumps, they’re ideal for retrofitting older properties or replacing boilers with minimal disruption. 

Whether you’re a homeowner, landlord, or a commercial property owner in the UK, this guide will help you understand if this renewable technology is right for you.

What Are High Temperature Heat Pumps? 

High temperature heat pumps are a type of air source heat pump (ASHP) that can deliver water temperatures up to 75°C, making them ideal for older heating systems with standard or oversized radiators. 

Unlike traditional ASHPs that typically output water at 35–55°C, high temperature models offer a more like-for-like boiler replacement.

How Do High Temperature Heat Pumps Work?

High temperature heat pumps work by:

• Extracting heat from the outside air, even at temperatures as low as -20°C.
  
• Using a refrigeration cycle to compress and transfer the heat indoors.
  
• Heating water to a higher temperature using an enhanced compressor or integrated booster system.

These systems are suitable for use in off-gas grid homes, period properties, and buildings with higher heat demands.

What Are the Pros and Cons of High Temperature Heat Pumps?

Below I’ll explain discuss the benefits and drawbacks of high temperature heat pumps:

How Much Do High Temperature Heat Pumps Cost to Install?

Installation costs vary depending on the size of the system and the complexity of the property layout. In the table below are average installation and running costs::

Note: You may be eligible for heat pump grants under the Boiler Upgrade Scheme (BUS), which offers £7,500 towards installation.

How Much Can a High Temperature Heat Pump Save You on Energy Costs?

Savings vary depending on your previous heating system, property type, and insulation, but here’s a typical breakdown:

Homes switching from electric heating (e.g., direct electric, storage heaters) can save £600–£1,000 per year. 

According to the UK Government’s Department for Energy Security & Net Zero, high temperature heat pumps like other heat pumps are “three times more efficient than gas boilers”, and using one with a smart electricity tariff can reduce energy bills by around £100 per year.

Meanwhile, London Council data estimated that replacing electric heating in an 18,000 kWh-demand building can save £1,080/year.

Homes replacing oil or LPG heating systems can expect significant annual savings due to the high efficiency of heat pumps:

According to Energy Saving Trust, air source heat pumps are “more than three times more efficient than a gas or oil boiler”, which substantially reduces energy consumption relative to fossil fuel systems

The UK Government’s “Heat-Pump” campaign site highlights that heat pumps can deliver carbon savings of up to 70% compared to gas boilers, implying similar reductions in running costs if replacing oil or LPG systems

Gas boiler users may see modest savings or break-even, depending on installation efficiency and tariffs. The Energy Saving Trust reports typical heat pump running costs can be £14/year more or equivalent to a new A-rated gas boiler; however, older G-rated boilers can be £340/year more expensive to run.

Do You Need Planning Permission to Install a High Temperature Heat Pump?

In most cases, planning permission is not required to install a high temperature heat pump in England and Wales, as heat pumps fall under Permitted Development Rights. However:

• The unit must be installed at least 1 metre from the property boundary.
  
• It must comply with MCS (Microgeneration Certification Scheme) standards.
  
• In listed buildings or conservation areas, special permissions may apply.

Always consult your local authority if you’re unsure.

Which Properties Are Suitable for High Temperature Heat Pumps?

These systems are particularly suitable for:

• Older properties with existing radiators
  
• Homes without underfloor heating
  
• Rural or off-grid homes using oil or LPG
  
• Large buildings with higher heat demands
  
• Properties with poor insulation, though some upgrades may be needed

Will High Temperature Heat Pumps Work in Old Houses?

Yes, high temperature heat pumps will work in old houses. Because they supply higher temperature water, they’re more compatible with:

• Traditional radiators
  
• Less insulated buildings
  
• Homes without modern retrofit upgrades

They’re especially useful in Victorian homes, stone cottages, and heritage properties, where replacing the entire heating system is impractical.

Will a High Temperature Heat Pump Work With My Existing Heating System?

In many cases, yes, high temperature heat pumps will work with an existing heating system. These systems are designed to integrate with:

• Existing hot water cylinders
  
• Standard or oversized radiators
  
• Some legacy boiler systems (as hybrids)

They reduce the need to rip out or replace current infrastructure, making retrofitting cost-effective and less invasive.

Can High Temperature Heat Pumps Work Alongside a Boiler?

Yes. High temperature heat pumps will work alongside a boiler. This is known as a hybrid heat pump system, where:

• The boiler provides backup during extreme cold spells.
  
• The heat pump handles day-to-day heating and hot water needs.

This setup can reduce gas consumption and gradually transition your home to renewables.

Do High Temperature Heat Pumps Work With Existing Radiators?

Yes, high temperature heat pumps will work with existing radiators, especially with larger radiators. Standard ASHPs require low flow temperatures, which might not be compatible, but high temperature models don’t need radiator upgrades in most homes.

That said, heat loss calculations are essential to confirm compatibility and efficiency.

What Are the Space Requirements for a High Temperature Heat Pump?

You’ll need:

• Outdoor space (usually at the rear or side of the property) for the external unit
  
• Indoor space for a hot water cylinder
  
• Good ventilation and clearances for airflow

Minimum space required: Around 1m² outdoors + space for an indoor unit similar to a tall fridge.

What Maintenance and Servicing Do High Temperature Heat Pumps Need?

High temperature heat pumps require regular maintenance to ensure peak performance and longevity. You’ll need:

• Annual servicing by a qualified engineer
  
• Occasional cleaning of the outdoor unit
  
• System checks and pressure top-ups

Average service cost: £150–£250 per year
Warranty: Typically 5–7 years, extendable up to 10 years with servicing.

How Long Do High Temperature Heat Pumps Last? 

The lifespan of a high temperature heat pump is typically 15–20 years, with proper maintenance.

What Is the Environmental Impact of High Temperature Heat Pumps?

The environmental impact of using a high temperature heat pump include:

• Reduce carbon emissions
  
• Use renewable heat from the air
  
• Help the UK move toward net zero targets

By switching to a high temperature heat pump, you’re investing in a greener future while retaining comfort and performance.

Ready to Slash Your Energy Bills? Request a Free Air Source Heat Pump Quote from Eco Happy

Don’t wait to future-proof your home or investment property. At Eco Happy, we specialise in MCS-accredited high temperature air source heat pump installations across the UK. Our team handles everything, from design and paperwork to installation and aftercare.

Free no-obligation quote
Guidance on claiming £7,500 government grants
Expert advice on compatibility with your property