Do you need new radiators for air source heat pumps?

The performance of your heat pump system hinges on the compatibility and efficiency of your radiators.

Identifying whether your current radiators are single, double, or triple panel, with or without convectors, will help you decide if they meet the requirements for effective heat distribution.

Larger radiators with convectors are generally the best choice, while designer radiators, towel rails, and cast-iron models should be avoided due to their inefficiency with heat pump systems.

Careful evaluation and measurement of your existing radiators will ensure that your heating system operates at its best, providing comfort and energy efficiency.

You may be concerned about having to upgrade your radiators when considering making the jump to an air source heat pump. Sometimes, this concern puts people off the idea entirely – but it doesn’t have to!

Unless your radiators are conventional-type, 30+ year-old models, you don’t always need to upgrade your radiators for an air source heat pump system to work. It just may work less efficiently than it otherwise would.

Even with outdated panel radiators, the heat pump system will still operate but may be unfeasible to run due to increased costs. Therefore, while it is possible to use existing radiators, upgrading them can enhance efficiency and reduce running costs significantly.

If efficiency and running costs are important to you, it may be wise to look at the type of radiators you have, how many, and whether upgrading will save you more in the long run.

Upgrading radiators can lead to a more efficient system, lowering energy bills and improving overall comfort.

If the added cost of upgrading radiators isn’t something you can absorb now, it may be possible to keep your radiators and opt for a higher flow temp system. To find out more, speak to one of our experts.

The key to getting air source heat pumps working as efficiently as possible is by making the heat of the water flowing through the heating pipework (the “flow temperature”) as low as possible to comfortably heat your home.

When a gas boiler is turned on, the gas will ignite and heat the water up to potentially 80°C or more before pumping that water around the system pipework to your radiators. This high output might seem like a benefit but is often a requirement due to the lower output of the radiators.

Another problem is that properties with modern radiators tend to experience frequent cycling as a result of gas boilers working at higher flow temperatures. That is, the boiler will turn on, output a lot of heat in a short amount of time, turn off again until that heat has dissipated, and repeat the cycle. This works well with a gas boiler but not a heat pump!

Because heat pumps work by tapping into a temperature difference from the outside air, they have a more limited maximum output temperature than a gas boiler. However, this also means they can provide a consistent temperature over a longer period, avoiding the inefficient heating cycling issue.

For example, if you’re able to run your air source heat pump’s flow temperature at 45°C and the radiators are able to effectively release that heat, then your heat pump can run continuously with a much lower energy draw.

Whenever we feel it’ll benefit to upgrade, we’ll always recommend that you upgrade your radiators before installation for a few reasons.

System designers can effectively plan system output and operational efficiency by pairing particularly suitable heat pumps and radiators for your home, resulting in a much more efficient system.

While radiator replacements add to the overall time that an installer has to be present, installing them as part of the same project lets the engineer better plan that time to get the job done as quickly as possible. This avoids the need for a separate engineer in the future who might need extra time to familiarize themselves with your home’s system.

Getting the maximum efficiency possible out of your heat pump system, over the whole year, means that you could save significant amounts on your energy bills. Depending on a few factors, of course.

For example: if you’re replacing an old G-rated gas boiler and keep your energy tariff the same, you could be saving up to £240 a year on energy bills. For more information on what affects heat pump efficiency, read our dedicated efficiency page here.

If approved by our lending partner, you can split the cost of your heat pump investment into monthly repayments over a number of years. And this includes the whole system upgrade. This financing can include the cost of radiator upgrades, allowing you to manage payments more easily.

When choosing radiators for a heat pump system, bigger is generally better. Larger radiators have a greater surface area, which is crucial for the lower operating temperatures of heat pumps.

Here’s a breakdown of different types of radiators and their implications:

To ensure you have the right radiators for your heat pump, it’s crucial to identify the type you currently have. Here’s a guide to help you:

• Single panel radiators: One flat panel, usually slim and lightweight.
• Double panel radiators: Two flat panels, back-to-back, thicker than single panel radiators.
• Radiators with convectors: Panels with zig-zag metal fins (convectors) between them.
• Triple panel radiators: Three panels, very thick, and heavy.

Image source: hudevad.com

The larger the radiator, the better it will perform with a heat pump. This is because heat pumps operate at lower temperatures compared to traditional boilers, and larger radiators can dissipate heat more effectively at these lower temperatures.

Designer radiators: Often prioritise aesthetics over function, with insufficient surface area for efficient heat transfer in a heat pump system.

Towel rails: Typically designed for supplemental heating in bathrooms, not for primary heating, resulting in poor performance.

Cast iron radiators: Though effective in retaining heat, they are slow to warm up and not suitable for the lower temperature output of heat pumps.

 Have one of these radiators?

This does not necessarily mean they won’t meet the heat loss of the room, or work with an Air Source Heat Pump system. Our specialist design team will calculate the output and different flow temps of your existing radiators and advise you on weather we think it would be feasible to keep them or recommend swapping them out.