As with other air source heat pumps, a high-temperature heat pump is a renewable heating and cooling system that extracts heat from the outside air and transfers it to a building to provide warmth, or cooling.
The 'high-temperature' aspect of this type of heat pump refers to its ability to generate hot water at temperatures up to 80°C, which is higher than the typical maximum output of a standard air source heat pump. Regular heat pumps draw warmth from the outside – from the air, the ground, or water – and release it inside at 35°C to 55°C. This is a lower level than gas boilers, which typically run at 60°C to 80°C. This makes it suitable for use in applications where high-temperature hot water is required, such as for space heating or domestic hot water production. It achieves this by using a different refrigerant to other types of air source heat pump.
A standard air-water source heat pump takes longer than a boiler to heat home spaces, so that requires larger radiators (or underfloor heating) to ensure the time taken to heat the rooms is less of an impact, also good insulation of a property is necessary to stop heat from escaping during the process. High temperature air source heating operates at the same heating level as traditional gas boilers, which means that you can switch to a high temperature renewable heat pump without needing new radiators or extensive insulation (although you will be using more energy to heat a poorly insulated building.
High Temperature Heat Pump Benefits
High-temperature air source heat pumps are generally more energy-efficient than traditional heating systems, and can also provide cooling during the summer months. High temperature heat pumps are a popular choice for both residential and commercial buildings, especially in areas where natural gas is not available, or where electricity is cheaper than other fuel sources.
However as high temperature air source heat pumps are more capable than standard models, the pay-off is that they’re usually more expensive too. You can expect to pay around 25% more for a high temperature heat pump. Performance wise standard temperature heat pumps typically produce three units of heat for every unit of electricity it receives, a high temperature unit will usually provide 2.5 units of heat.
High Temperature ASHP Considerations
While performance equates to a higher energy spend with a high temperature heat pump, it is worth weighing this additional cost against the benefits of being able to heat your home quickly and not having to get new radiators or insulation installed.
Integrating this with solar panels too could see you offsetting even more carbon and even making money through selling your microgenerated electricity back to the National Grid, qualifying for any energy Smart Export Guarantee (SEG) tarrifs plus any current UK Government incentives too.
High temperature air source heat pumps are not suitable for all homes and British housing stock. As with standard air source heat pumps, they are mainly too large and high-powered for flats or small houses. Also many high temperature models are also slightly heavier than the average heat pump, by about 10 kg.
Overall high temperature heat pumps are suited to more homes than standard air source heat pumps. Plus, as well as being disruptive and prohibitively expensive for some, any building related work is impossible to carry out in many listed properties - so whilst replacing a gas boiler with a high temperature heat pump isn’t as straightforward as getting a new boiler, it is logistically far simpler and more logical than installing a standard heat pump to help achieve a lower carbon footprint.
When we discuss air source heat pump options, whether you have a low temperature or high temperature heat pump does take some consideration. Do firstly consider the reasons why you want to change your heating system. Our aim is for you to feel happy with your investment and end up with a heat pump capable of heating your home properly and one that saves you money on your heating bills, while reducing your carbon footprint. However considerations for low vs the high temperature ASHP heating can be weighted by variables.
Which temperature air source heat pump is best for me ?
In considering which is the best option for you, between a standard or high temperature air source heat pump, it will help to think carefully about :
What suits your lifestyle and living circumstances best
What type of central heating system do you currently have
What size is your property and how much space does it have
What EPC rating is your property
The type of central heating heating system you have in your property, what appliances you have to distribute the heat and whether it is zoned, will be big factors in whether a low or high temperature heat pump would be best for you. The most common types of low temperature radiant heating components are low temperature radiators or underfloor heating. Both use hot water to heat a property and only require a maximum water temperature of 55°C. Installing new underfloor heating is a lot more disruptive and expensive than replacing your existing radiators with low temperature ones. However, by installing underfloor heating in certain rooms, you can free up space around your home among other benefits. Read more about underfloor heating here : underfloor heating solutions
If you have a traditional boiler central heating system, the most straightforward option would be to have a high temperature air source heat pump installed. An alternative option, which would save you more money on your energy bills, would be to replace your existing radiators with larger low temperature ones. However, you will need to consider where your existing radiators are placed and whether it would be easy to replace them. If there is enough space and you're happy to spend a little more in the short term, a low temperature heat pump could still be a good option.
While the internal components of an air source heat pump installation does not occupy much indoor space, the installation of larger low temperature radiators could make your property feel a little cramped. While underfloor heating is a much more costly option - it is undoubtedly the most energy efficient and space reclaiming solution. Overall you should be mindful that any air source heat pump installation will take up some indoor space, but the main space requirement will always be outdoors. High temperature heat pumps have larger outdoor units as they require more power to produce more heat, than their low temperature alternatives. This can mean they are not viable if you have a very small garden or no garden at all.
If your home is poorly insulated and suffers heat loss through single glazed windows, thin walls or flooring with no insulation - radiators with water at temperatures of 45°C and less will leave your home feeling rather chilly. While most low temperature air source heat pumps are capable of heating water to a maximum temperature of 65°C they are actually most efficient when providing water temperatures of around 35 – 45°C. If there is no way to improve your home's energy efficiency and it is still losing heat, you will most likely benefit from investing in a high temperature air source heat pump. However, if your home has loft insulation, double glazing and a number of other energy efficient measures in place, a low temperature air source heat pump should be more than capable of keeping your home nice and warm.
It is always worth considering the option that you can combine solar PV with other renewable technologies such as heat pumps, solar hot water systems and solar battery storage and increase your savings overall, with a good return on your investment. All these technologies interoperate well with each other. Solar PV for example could help power a heat pump, or several of these systems could feed into a thermal store instead of sending surplus electricity to the grid. Alternatively also, a solar PV diverter switch can power the immersion heater in your hot water tank, storing hot water for you to use later.
Gasway Services is an Appointed Representative of Koze Group Ltd (reference no. 830489). Gasway Services acts on behalf of Koze Group Ltd as a credit broker (not as a lender) and offers credit products through a panel of lenders.