Can heat pumps be used with existing radiators?

Heat pumps are becoming more popular in the UK as more households seek sustainable heating methods and take advantage of the many government grants available. 

While they offer a promising path to reduced carbon emissions, many homeowners are still uncertain about the practicalities and financial implications.

One question people have is if they can use a heat pump with existing radiators. In most cases, yes—but there are some exceptions. 

Discover everything you need to know in this post, so you can make a smooth transition towards heat pumps without having to worry. 

First things first, how do heat pumps work?

Before we explore the relationship between heat pumps and radiators, let’s briefly cover how the pumps work. Unlike conventional boilers or other heating methods, a heat pump doesn’t require fossil fuels, as it generates energy from natural sources. 

There are three types of heat pumps: 

• Air-Source Heat Pumps: ASHPs collect heat from the air and turn it into energy, which can heat and cool your property. These pumps are the most popular option, as they’re compatible with the majority of properties. 
• Ground-Source Heat Pumps: GSHPs are the most consistent solution, as they collect heat from the ground, which always has stable temperatures. A downside of ground-source heat pumps is their extensive space requirements. 
• Water-Source Heat Pumps: WSHPs are more consistent than air-source heat pumps, but they require a nearby pond, river, or lake, making them the least popular option. 

While heat pumps are more sustainable than fossil fuels, they deliver heat at lower temperatures than traditional boilers. The lower outputs can cause issues with your existing radiators. 

Are heat pumps and radiators compatible?

The main problem households experience when using a heat pump with existing radiators is the lower temperature output. 

While conventional boilers usually heat water to temperatures between 60°C and 70°C, heat pumps have a much lower output, at between 40°C and 50°C.

So, when you try to connect radiators designed for higher temperatures with a heat pump, it can cause issues. 

This doesn’t necessarily mean that your heat pumps and radiators are incompatible, as there are multiple factors to consider. 

Let’s take a look at them. 

Radiator size matters

The size of your radiators plays a role in whether they’ll work with the heat pump. For example, older properties usually have large radiators with high heat outputs, but smaller radiators might struggle to produce enough heat for the room.

There’s always the option to install larger radiators, which can perform at lower heating points. 

Contacting a specialist heat pump installation service is the best way to determine whether your radiators are sufficient.

Building insulation 

Your building’s insulation is another viral consideration, as well-insulated homes retain heat more effectively.

If your property has high insulation and low heat loss, your existing radiators are more likely to work effectively with a heat pump, so the radiators’ temperatures don’t matter as much.

Buildings with low or no insulation will struggle to retain heat even with conventional boilers, so heat pumps with lower temperature outputs will be a problem.

Before installing a heat pump, you should focus on improving your property’s insulation. It will restrict heat loss and might mean you can use your existing radiators instead of upgrading them. 

Heat pump type 

Your heat pump type will also make a difference in whether you can combine it with radiators. 

Air-source heat pumps are less consistent than other types and have low water temperatures. 

Ground-source heat pumps won’t operate at higher water temperatures but are more consistent. 

Simply put, you might need to install larger radiators with an air-source heat pump, while ground-source pumps could be consistent enough to avoid extra costs.

What if my existing radiators aren’t compatible?

Don’t worry if your radiators aren’t compatible with a heat pump because you’ve got other options. 

From upgrading your radiators to exploring other heating solutions, the following options allow you to enjoy everything heat pumps have to offer AND contribute to the environment. 

Upgrading your radiators

The most obvious solution is to invest in radiators with a larger surface area. These radiators can produce more heat, but they can also be expensive. 

Double panel and convector radiators could also suit your needs, as they optimise heat output but don’t require much space. 

Upgrading to double-panel or convector radiators can boost the heat output, but it depends on your property’s insulation. 

Underfloor heating 

Underfloor heating and heat pumps are a fantastic combination because both systems operate at lower temperatures. Research shows that UFH can be up to 40% more efficient than radiators, making it an environmentally friendly alternative.

Underfloor heating systems circulate warm water through pipes in the floor, enabling them to distribute heat evenly across each room.

While radiators and heat pumps might have some cold areas, this isn’t usually an issue with underfloor systems.

Opting for underfloor heating is also more practical if you have a smaller property and don’t want to lose any wall space. 

Insulation 

As mentioned before, insulation is integral to how your property retains heat. 

Before considering expensive upgrades, you might be able to achieve consistent temperatures by improving your building’s heat retention. 

Focus on the following areas: 

• Walls: When it comes to losing heat, the walls are a major culprit. Adding insulation to the cavities or investing in panels means each room will retain more heat.  
• Loft: Heat rises, so a poorly insulated loft causes extensive problems. Taking the time to insulate it properly means your radiators won’t need a higher temperature output.
• Floor: Older properties struggle more with more floor insulation, and using the right methods will prevent heat from escaping.
• Windows and Doors: If you live in a colder area, upgrading from double to triple-glazing can be beneficial.

What are the next steps?

As you can see, your radiators shouldn’t stop you from reaping the financial and environmental rewards of heat pumps, but it’s essential to understand any potential problems before investing in an air or ground-source heat pump. 

If you’d like to explore your options for installing a heat pump, Hometree can assess your property and make tailored recommendations.

Please contact us today for more information.