Do Heat Pumps Work With Radiators? Answers From the Experts

Posted by Ollie Lyon on Tuesday 11th October 2022, updated on Thursday 4th January 2024

The short answer is yes - heat pumps can work with radiators. More specifically, you can use them alongside panel or cast iron radiators. However, they cannot be used alongside all radiator types, so you may need to install new radiators.

Although commonly used in conjunction with underfloor heating, heat pumps can also be used alongside your household radiators. They are a great alternative to gas central heating and work by converting cold energy from outside into a compressed heat source, warming your home.

In this guide, we'll cover everything you need to know about heat pumps and whether you can use them alongside your radiators.

What is a heat pump?

There are two types of pumps: ground source and air source heat pumps.

Air source heat pumps are attached to the side of your home and draw in energy from the outside air temperature, which is compressed into a fluid that heats up. This hot energy is circulated through your home via a heating distribution system - either an underfloor heating system or your household radiators.

Ground source heat pumps work in the same way, except instead of drawing in energy from the air, they absorb heat energy from underground.

Read our guide to find out more about how heat pumps work.

Radiators or underfloor heating: Which is better for heat pumps?

Both radiators and underfloor heating systems are compatible with heat pumps. However, underfloor heating is often the preferred option. This is because underfloor heating can be more energy efficient than radiators as they cover a more expansive space. The large surface area covered by pumps means they can use less energy.

Despite the advantage of underfloor heating over radiators, some people's homes are unsuitable for installing an underfloor heating system. For example, suspended flooring on the upper floors often forces homeowners to consider radiators instead.

Luckily, a new radiator system can be installed throughout your home as an alternative. In some cases, you may even be able to use the radiators that are already installed in your home.

What kind of radiator is needed for a heat pump?

What kind of radiator is needed for a heat pump

If you've ever seen a radiator that uses energy from a pump, you probably noticed that it is built much bigger than standard household radiators. Generally, heat pump radiators need to be two and a half times bigger than standard.

Oversized radiators are preferred

Heat pump radiators are oversized to provide a flow temperature compatible with the heat pump. This is another reason why underfloor heating is preferred for pumps due to the wide surface area that they offer. But still, if you don't mind having extra big radiators in your home, you don't have to invest in underfloor heating.

Radiators must cater to low-flow temperatures

Heat pump radiators need to deliver a flow temperature of up to 55ºC. The typical flow temperature required for a heat pump is generally between 40 - 50°C.

Radiators designed for gas boilers have a high flow temperature, which often falls between 65 and 70°C. The hot water produced by gas boilers must be heated to a far higher temperature to warm your home sufficiently.

As flow temperature decreases, the surface area necessary increases, hence why heat pump radiators need to be bigger.

If your radiator is designed for a gas boiler (for a flow temperature that exceeds 55ºC, you'll probably need to buy new radiators to get the most out of a heat pump system.

Can I use the radiators that are already installed in my home for heat pump systems?

Using existing radiators with your ground or air source heat pump is possible, but sometimes this isn't the best approach

As we've already mentioned, radiators designed for compatibility with gas boilers will have a high flow temperature of between 65 and 70°C. This level of flow temperature will reduce the Coefficient of Performance (CoP) of your heat pump system, which would greatly lower the efficiency of your heat system.

To get the most out of your heat pump, we'd recommend investing in radiators with a low airflow temperature.

Can heat pump systems work with a combination of radiators and underfloor heating?

Can heat pump systems work with radiators and underfloor heating

It is possible to set up heat pumps with a combination of radiators and underfloor floor heating. For example, you could have floor heating as the main heat output downstairs and have radiators upstairs - both of which could be supplied by the same ground source heat pump.

One of the main issues of having a combined heating system is the delay in which it will take the heat to reach your upstairs radiators. Underfloor heating will absorb most of the heat produced by the air source pump. Your radiators upstairs may feel lukewarm for some time before they reach an adequate heat level.

FAQs

What type of radiators work best with heat pumps?

The best radiator type for pumps are ones made from aluminium. Aluminium radiators are highly conductive, more so than cast iron and steel radiators, ensuring your room gets warm as quickly as possible.

Can heat pumps be installed in older houses?

Pump installations can be carried out in old houses; however, you'll likely have to change your radiator system and pipes and improve your insulation at the same time.