A Guide to High Temperature Heat Pumps

✔ A high temperature heat pump can heat your home as quickly as a gas boiler

✔ They’re three times more efficient than gas boilers

✔ They don’t require new insulation or radiators, unlike regular heat pumps

High temperature heat pumps are an excellent solution for many properties. And with heat pump costs coming down rapidly, you can affordably replace your gas boiler while helping the climate.

These machines can be installed without extra hassle, and they heat your home at the same speed as a gas boiler, making them an attractive prospect.

In this guide, we'll explain how they work, and why you should – or shouldn’t – look into purchasing one for your home.

If you want to see if a heat pump would be right for you, pop your details in this quote tool to receive free quotes from our expert installers.

What is a high temperature heat pump?

A high temperature heat pump is a renewable energy system that can heat your home to the same level of warmth – and at the same speed – as a gas boiler.

It can reach between 60°C to 80°C, which allows you to heat your home quicker than regular heat pumps, without needing to buy new radiators or insulation.

One of the ways it achieves this feat is by using superior refrigerants to low-temperature heat pumps.

Most high-temperature heat pumps use R290 or R32, which are both better for your home and the climate, and also come with industry-leading weather compensation controls.

These technological advances mean that on average, high-temperature heat pumps have to raise their flow temperature above 65°C less than 1% of the time, according to a recent government report.

That's right: the heights gas boilers can hit are now almost completely pointless.

Check out how a high temperature heat pump works later in this article for more information.

How is a high temperature heat pump different to a regular heat pump?

High temperature heat pumps can provide domestic hot water at the same temperature as boilers – around 60°C to 80°C – while regular heat pumps supply water at 45°C to 55°C.

However, regular heat pumps are catching up, with an increasing number of models reaching 60°C to 65°C, and high temperature heat pumps rarely have to actually reach these higher temperatures.

Because of this fact and their usually superior refrigerants, high temperature heat pumps are now usually just as efficient as low-temperature heat pumps.

A spokesperson for high temperature heat pump manufacturer Vattenfall told The Eco Experts: “The system is almost three times as efficient as a central heating boiler,” and this sentiment was backed up by a recent government report.

This also relates to the other main difference between the two types of heat pump: high-temperature heat pumps are more cutting-edge.

Unfortunately, our most recent National Home Energy Survey found that only 51% of people are aware of heat pumps, let alone high-temperature ones. Fortunately, that doesn't include you.

Pros and cons of high temperature heat pumps

High temperature heat pumps are usually around £1,000 more expensive than regular heat pumps.

But they're just as efficient as their low-temperature counterparts, which means you’ll likely spend roughly the same on your energy bills – but you won't have to install new radiators or insulation.

Depending on your home, it therefore may be cheaper to get a high temperature heat pump.

High temperature heat pump costs

High temperature heat pumps cost £11,000 for the average three-bedroom household, including purchase and installation.

This is 10% more than an air source heat pump costs on average, and more than double the price you'll pay for a gas boiler.

On the other hand, you'll future-proof your house against a potential gas boiler ban, and you won't have to get new insulation or radiators to do it.

Can you buy high temperature heat pumps in the UK?

You can buy the following domestic high temperature heat pumps in the UK:

• Daikin Altherma 3 H HT
• Trianco Activair High Temperature Heat Pump

Daikin's high temperature air source heat pump is available in 6-12 kW models, can supply water up to 70°C, and works when it’s as cold as -28°C outside.

You can either get a wall-mounted unit and hot water cylinder, or a single, floor-standing unit with an integrated hot water cylinder.

You can buy Trianco's model in 9 kW, 15 kW, or 22 kW varieties.

Vattenfall is also set to bring its high temperature heat pumps to the UK. The company, which is owned by the Swedish state, has already rolled out its 60°C to 80°C machines in the Netherlands.

Vattenfall’s commercial director, Mark Anderson, said: “The high temperature heat pump solution is innovative, simple to install and could be the solution to help decarbonise homes in the UK that are heated using traditional gas boilers.”

Are all homes suitable for a high temperature heat pump?

Most homes are suitable for a high temperature heat pump.

If your property currently has a gas boiler and you're unable or unwilling to change your radiators or add insulation, a high temperature heat pump could be the perfect solution.

They're also a good option for listed buildings, properties which aren't connected to the gas grid, and homes that are extremely difficult to insulate.

Replacing a gas boiler with a high temperature heat pump is also relatively straightforward, and places you at the cutting edge technologically.

But whatever your decision, we'd still recommend insulating your home as much as you can, as it's the quickest, most cost-effective way to improve your property's energy efficiency and cut your heating bills.

Is it worth getting a high temperature heat pump?

It's worth getting a high temperature heat pump in many situations.

They typically cost 10% more to buy and install than regular low-temperature heat pumps, but most UK homes need to also buy new radiators and insulation if they're getting a regular heat pump.

If the cost of these extra measures adds up to the same or more than the difference in price between the two types of heat pump, you should consider opting for a high temperature model.

They typically come with a better refrigerant and superior weather compensation controls, and can reach higher temperatures if necessary – even though it rarely is.

How do high temperature heat pumps work?

There are four main ways in which high temperature heat pumps work, either through their design or components, and they are as follows.

A design optimised for specific refrigerants

The most modern refrigerants can produce higher output temperatures in machines that use altered pressures and temperatures, though this reduces the overall amount of heat produced by a heat pump.

That means the efficiency rate of a high temperature heat pump that works in this way will be lower than a standard heat pump.

Christopher Wood, an Associate Professor at Nottingham University, told The Eco Experts: “A refrigerant is a liquid that conveniently evaporates at a certain temperature.

“With conventional refrigerants, as the temperature goes higher, the efficiency drops dramatically. That is a function of the process.

“The pursuit of a high temperature heat pump is the pursuit of a refrigerant that can do this at a higher temperature.”

Cascade systems with two separate refrigeration cycles

Cascade heat pumps use two cycles – one low temperature and one high temperature – with a different refrigerant in each.

The refrigerant in the low temperature cycle will evaporate at an extremely low temperature and condense in the heat exchanger at a relatively low pressure and temperature.

This allows heat to move to the evaporator, which makes the second refrigerant evaporate as well, then condense at a still relatively low pressure – keeping the output high.

Enhanced Vapour Injection (EVI)

EVI involves adding another loop to the heat pump cycle, which allows a small fraction of condensed refrigerant to leave through an expansion valve, into a counter flow heat exchanger.

This results in a superheated vapour that can then be injected into the compressor, increasing the heating capacity. You'll use more electricity this way, but it'll also increase the machine's efficiency.

Natural refrigerants and sorption products

These are gas-fuelled high temperature heat pumps that use a sorbent to absorb refrigerant vapour and create a new solution.

This solution is then pumped up the same pressure as the condenser, and the refrigerant is extracted from the sorbent into the generator, through heating.

This type of high temperature heat pump is not available to domestic properties in the UK.

Next steps

High temperature heat pumps are the best option for many homes, but it all depends on your property.

They cost about the same to run – and Nottingham University’s Dr Wood told us “there’s no reason why technological advances can’t be made in this field.”

If you want to see how much a heat pump would cost you, try our custom-built tool. Pop in a few details, and our professional suppliers will then get in touch with their best prices.

High temperature heat pumps: FAQs