Can Radiators Be Used With A Heat Pump?

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How does a heat pump work

When considering whether to make the move to a heat pump system, you may be wondering how heat pumps work and whether radiators are a suitable option to distribute that heat around your home, or indeed if you can make use of your existing radiators.

The simple answer is, yes, radiators can be paired with a heat pump system, and in some cases, you can possibly use your existing radiators with a heat pump, though they would need to be adequately sized so they can operate at a lower flow temperature than they usually would with a gas boiler.

If your radiators are too small, they can be easily replaced with larger radiators that operate at the correct flow temperature to use with a heat pump. An alternative might be to consider underfloor heating when installing an air source or ground source heat pump system, though we appreciate this may not always be practicable. 

If you’re looking for a way to reduce your energy bills then you may be considering heat pumps and how they can save you money and provide an efficient and cost-effective way to heat your home when compared to gas boilers. This article aims to outline all you need to know about making the switch from a gas boiler to a heat pump and combining them with radiators, whether newly fitted or existing radiators. 

Can you use existing radiators with heat pump?

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What Is An Air Source Heat Pump? 

An air source heat pump requires electricity to power it and absorb heat from the air around a building and then convert that cold air into warm air that can be used to warm a home or other space. It is intended to be a more environmentally friendly way to heat your home when compared to a traditional gas burning boiler. The pump looks like an air conditioning unit and is usually placed next to an external wall and fitting into the ground with attached pipes that carry hot water through them. 

How Does An Air Source Heat Pump Work?

The pump’s air intake is drawn in and passed over refrigerant filled tubes which raises the temperature of the fluid and turns it into a gas. The gas is then pushed through a compressor, increasing the pressure and adding more heat. This hot gas is sent through a heat exchanger with cool air or water around it. The surrounding air or water is then warmed by the refrigerant before being circulated throughout the home to provide heating via radiators, underfloor heating and hot water. 

Air source heat pumps are installed on the outer wall of your home – it’s best to pick a spot that receives direct sunlight so that the pump doesn’t have to work unnecessarily hard to heat the air around it but this recommendation isn’t essential however as the pumps are designed to heat air, even when the temperature drops below the freezing level. You can therefore be assured a heat pump will work regardless of positioning or external temperature. 

Heat Pumps With Radiators

Standard home radiator

Heat pumps tend to work better at lower temperatures, compared to gas boiler fed radiators which tend to work at higher flow temperatures. Due to the low flow temperatures (typically around 40-50°C compared to 65-70°C with a gas boiler), the heat emitting surface for a heat pump system need to be larger than for a boiler heating distribution system, and this makes underfloor heating worth considering when a heat pump system is being installed.

However, underfloor heating is not always practical, particularly with upper floors or suspended flooring, and this is where radiators become a suitable alternative. Air source and ground source heat pumps are fully able to spread warmth throughout your home using radiators, and in some cases your existing radiators may be suitable, though they will need to be of a suitable size to work effectively.

Can Heat Pumps Use My Existing Radiators?

So as long as your radiators are of a large enough size that can be set to a lower overall heating point, they will be fine to use with a heat pump. This approach works because, although radiators operate at higher temperatures, they tend to be turned off and on regularly via central heating thermostats. A heat pump that operates at a lower temperature can work continuously to provide the equivalent heat output that a gas-powered radiator would, so you don’t notice a difference in the heat generated inside your home. 

In some cases, the radiators in your home will already be of a size that can achieve the same heat setting that a heat pump can. They can operate well with a range of different types of radiator including cast iron. radiators and steel panel radiators.

To confirm if your existing radiators are suitable for use with a new heat pump system, a plumber or heating engineer can check the amount of heat currently given from your radiators to determine the right setting for the new heat pump to work at a similar rate.

When using existing radiators, a heating engineer will have to make sure that the system has been cleaned well before heat pump installation to ensure that any particles suspended within the system do not end up blocking the pump’s filter. 

What If My Radiators Can’t Be Used With A Heat Pump?

If the correct temperature flow setting cannot be achieved with your existing radiators then specific low-temperature radiators can be installed such as the Jaga Strade or Dimplex SmartRad. These are often referred to as ‘oversized’ radiators, but only in the sense that they are usually bigger than radiators used with traditional gas boilers.

One positive, if you have more recently had a new central heating system or gas boiler installed, is that there has been a tendency for heating installers to ‘oversize’ radiators so that they are capable of heating a much larger space than they actually needed to. If you are one of those households that has previously had ‘oversized’ radiators installed, it is possible you won’t have to change them.

As every home is different, the best thing to do if you are unsure whether your existing radiators can be used with a heat pump is to contact Heat Pumps UK and we can put you in touch with a qualified engineer to carry out a survey and advise on the options available to you. 

Related Questions 

When To Use A Heat Pump 

Fossil fuel heating installations are being banned in all new homes by 2025 which means low-carbon heating alternatives like heat pumps will become the norm in the UK within the next decade. 

If your current boiler is very old, has broken and needs replacing, or if you are looking for a cost-effective solution to heating your home that requires minimal maintenance, then it may be a good time to install a heat pump at your property. 

With an efficiency level of between 300-500%, heat pumps can reduce fuel bills at a time when energy costs are spiralling. 

Is My Home Suitable For A Heat Pump?

Standard home boiler

We’ve covered the requirements that existing radiators need to meet to install a heat pump, but there are a few other conditions that your home needs to meet to be a good candidate for a heat pump and also qualify for a government grant. 

As air source heat pumps to heat water to a lower temperature than gas boilers, they are best suited for heating well-insulated homes with underfloor heating or where large radiators that can function at lower temperatures are in place.  

Is Planning Permission For Heat Pump Installation Required?

In England and Scotland, air source heat pumps don’t normally require planning permission unless the building is listed or is in a Conservation area, area of Outstanding Natural Beauty, or a National park. Those in Wales do need planning permission to install a heat pump. If unsure, you should check with the local planning department.


In the vast majority of cases, radiators can be combined with a heat pump system to heat your home. In some instances, you may be able to connect your existing radiators with a new heat pump system.

While underfloor heating, where practicable, would be considered a better option due to having a larger heat emitting surface, radiators (of the right size for the system) will nonetheless perform suitably well. If you do need to replace your existing radiators as part of an overhaul of your heating system, then this can be easily done.

To get a quote for heat pump installation at your property, contact the friendly team at Heat Pumps UK.

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Ollie Creevy
Ollie has been writing content online about home improvements for over 3 years. With a real interest and in-depth knowledge of heat pumps and ECO home improvement measures you can use to save on your energy bills. Ollie also keeps up to date with all the Government grants available for you to take advantage of like ECO4 and the Boiler Upgrade Scheme.