Do I Need To Upgrade My Radiators?

When switching to a renewable heating system like an air source heat pump, many homeowners wonder whether their existing radiators will still do the job - and it’s a question we’re asked all the time.  

The answer is: not always, it depends on a few key factors.

Why Radiator Size Matters?  

Unlike gas boilers, heat pumps run at lower flow temperatures, typically between 40-50°C compared to 70-80°C. 

That means your radiators may need to be larger or more efficient to deliver the same comfort levels. If your existing radiators are small, they may struggle to emit enough heat - especially in larger rooms. 

Appropriately sized radiators are cheaper to run than undersized ones, as they reach target room temperatures faster and allow your heat pump to operate more efficiently. When radiators are too small, your system has to work overtime to compensate, increasing both energy consumption and running costs.

Are My Existing Radiators Suitable? 

The good news is, not every home needs a full radiator upgrade when switching to a heat pump. In many cases, your existing radiators will work perfectly well.  

There are a few indicators that your current radiators may need replacing:  

• You have old, single-panel radiators, which may not give off enough heat.  

• Poor insulation may mean you need larger radiators or improved insulation. 

• You have small bore pipework going to the radiators, which may need replacing. 

We will carry out a heat loss survey to determine how much warmth each room requires. This will tell us which radiators need upgrading to achieve optimal comfort and maximum efficiency for your heat pump.

Benefits of Upgrading Your Radiators 

Upgrading your radiators can improve comfort throughout your home, due to larger/modern radiators distributing heat more evenly, helping every room reach and maintain a comfortable temperature.  

When radiators are the appropriate size, it allows your system to operate at its most efficient flow temperature, which is especially important for renewable energy systems.  

Radiators which are properly matched to your heat pump's output will allow your system to run more efficiently, reducing energy consumption and keeping your running costs low.

Radiators That Work With Your Space 

Not all low-temperature radiators have to be oversized or intrusive. We take the time to understand how you use your space. From room layout and window positioning to furniture placement, we complement your home's design whilst ensuring maximum efficiency.  

A variety of styles are available to suit different spaces and aesthetics. For example, vertical radiators are a great option where wall space is limited, adding a modern, architectural look. Alternatively, wide low-level radiators work perfectly beneath windows or in open-plan areas, helping distribute warmth evenly across the room.

Radiators can also become a feature in your interior design. We can supply and install a range of designer or period-style radiators that combine functionality with style, delivering efficient heat whilst adding character to your home. 

Fan coil units are also an alternative to traditional radiators. These compact units use a small, quiet fan to circulate warm air efficiently, making them ideal for larger or open-plan spaces where extra heat output is needed. Designed for low-temperature systems like heat pumps, fan coils provide quick, even warmth while maintaining a sleek, modern look.

Can I Mix Old and New Radiators? 

In many cases, yes - you can absolutely keep your existing radiators when switching to a heat pump system, provided they’re in good condition and suitably sized to deliver the required heat output for each room. During our assessment, we’ll check the performance of every radiator in your property to see how well it matches your home’s heating demands. 

Sometimes, rather than replacing a radiator, we can reposition or repurpose it in another area of your home where it better meets the room’s heat requirements. This approach allows us to maximise what you already have, keeping costs down while ensuring the overall system remains balanced and efficient.

Should I Consider Underfloor Heating? 

When upgrading your property's heating system to a low-temperature solution like a heat pump, it is worth considering whether underfloor heating could be the right fit for your home. Underfloor heating works exceptionally well with heat pumps because it operates at lower flow temperatures, spreading heat evenly across a large surface area. Rather than heating the air around a single point (e.g. a radiator), it provides consistent warmth that radiates upwards – keeping your rooms comfortable throughout. 

Underfloor heating is a popular choice for new builds and renovations, where installation can be designed in from the start and for homeowners looking for a clean, modern finish with no visible radiators. 

While it may not be practical for every property, underfloor heating can be combined with radiators to create the most efficient solution for your home. At Green Flare, we'll assess your property and recommend the right balance – whether that’s a full UFH system, upgraded radiators, or a combination of both.

Why Choose Green Flare? 

At Green Flare, we don’t take a one-size-fits-all approach. Every home is different, which is why we carry out a comprehensive heat loss assessment and system design before recommending any radiator or heating upgrades. Whether you're keeping your existing radiators, upgrading and/or exploring underfloor heating, we'll design a solution that works in harmony with your lifestyle.